Dr. Khayati talks about the formation of three germ layers in today's video. The three germ layers are the endoderm, the ectoderm, and the mesoderm. Cells in each germ layer differentiate into tissues and embryonic organs. To know more about these germ layers in a fun manner, watch the video till the end!

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Age: 346-344Ma

Viséan

Middle Mississippian Epoch

Carboniferous Period - Giant arthropods and amphibians, early reptiles, most plants fern or lycophyte-like, known for tropical forests and seas

Paleozoic Era - pre-Dinosaurs

Location: Lancashire

Clitheroe

Salthill Quarry

Rock Type: Course grained and coursely crinoidal limestone, with lots of calcite from crinoid structure, park of a knoll-reef from the Clitheroe Limestone Formation.

Specimen:

A large crinoid column about 3.5cm in diameter, 4cm at its widest, with the clear pentastellate axial canal visible. This section is only about 1-1.5cm tall

Species:

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Echinodermata is a phylum of marine invertebrates that includes well-known groups like starfish, sea urchins, brittle stars, sea cucumbers, and crinoids. Echinoderms are characterised by their radial symmetry, typically arranged in fives, and their unique water vascular system, which aids in locomotion and feeding. This phylum is exclusively marine, and its members are often found on the sea floor, from shallow waters to the deep ocean. Echinoderms exhibit pentameral symmetry as adults, though their larvae are bilaterally symmetrical, reflecting their evolutionary relationship with other deuterostomes, including chordates.

Within this phylum, Class Crinoidea includes marine animals commonly referred to as sea lilies and feather stars. Crinoids are distinguished by their cup-shaped body (the calyx), a set of radiating arms, and a long stalk (in some species) that anchors them to the seabed. The arms are typically branched and covered with feathery extensions that aid in filter feeding, capturing small particles from the water. Though modern crinoids tend to be less prominent in marine ecosystems, they were once much more abundant and diverse, particularly during the Palaeozoic era.

Crinoids first appeared in the Ordovician period, about 480 million years ago, and quickly diversified. They were especially abundant during the Palaeozoic, with their greatest diversity occurring during the Carboniferous period, when extensive shallow seas created ideal conditions for large crinoid populations. Fossil crinoids are especially common in limestone deposits from this time, with entire beds of rock often composed almost entirely of disarticulated crinoid fragments, particularly their stems. These fossils are widespread in regions like the UK, where crinoid-rich limestone formations are frequently found.

Crinoids come in two main forms: stalked crinoids, or sea lilies, which attach to the sea floor via a flexible stalk, and unstalked crinoids, or feather stars, which are mobile and can swim or crawl along the substrate using their arms. In the fossil record, stalked crinoids were much more abundant, with long, segmented stalks that could grow several meters in length. The stalks are composed of individual ossicles, small calcareous plates that are commonly found as fossils, especially in Carboniferous limestone beds. The most well-known fossil remains of crinoids are these stem ossicles, which are often referred to as "Indian beads" due to their cylindrical shape.

Crinoids reached their peak during the Palaeozoic, forming extensive colonies in shallow seas, often in association with coral reefs. Their filter-feeding mechanism allowed them to occupy a specialised ecological niche, and they played an important role in marine ecosystems as suspension feeders. However, crinoids were significantly affected by the Permian-Triassic mass extinction about 252 million years ago, which wiped out many marine species. Although crinoids survived this event, their diversity and abundance were greatly reduced.

In the Mesozoic era, crinoids experienced a resurgence, though not to the same levels of diversity as in the Palaeozoic. Feather stars (unstalked crinoids) became more prominent during the Jurassic and Cretaceous periods, adapting to more mobile lifestyles compared to their sessile ancestors. Today, feather stars are found in a variety of marine environments, from shallow reefs to deep-sea habitats, while stalked crinoids are largely restricted to deep water.

Crinoids are unique among echinoderms in that they are suspension feeders, using their feathery arms to catch plankton and other small particles from the water. Their arms are lined with cilia that move captured food towards their central mouth, which is located on the upper surface of the calyx. This feeding strategy differs from other echinoderms, such as sea urchins, which graze on algae, or starfish, which are typically predatory.

Despite their decline in modern oceans, crinoids remain important in the fossil record due to their abundant and well-preserved remains, particularly in Palaeozoic and Mesozoic sedimentary rocks. The characteristic segmented stalks and calyx plates of crinoids make them highly recognisable fossils, and they provide key insights into the structure and biodiversity of ancient marine ecosystems. In particular, Carboniferous limestone deposits, such as those found in the UK, are often rich in crinoid remains, offering palaeontologists a detailed record of these once-dominant marine invertebrates.

This is another photo that the data for is largely lost. The photo was taken in tidepools not far from Half Moon Bay. Per iNaturalist, The Starburst Anemone is found in the north west Pacific Ocean. In the United States it occurs between central California and Baja California. It lives in the lower intertidal zone in rocky habitats, often in the shelter of cracks and crevices. When the tide is out it is often concealed by shell fragments and other particles that adhere to it.

Amazingly, Anthopleura sola aggressively defends its territory from other anemones (of same species) which are genetically dissimilar. When A. sola encounters a different genetic colony, the anemones extend specialized tentacles (called acrorhagi). The white tips of acrorhagi have a concentration of stinging cells (nematocytes) and are used solely to deter other colonies from encroaching on their space. The nematocysts sting the ectoderm of the invader, causing tissue necrosis and forcing the competitor to move away.

Es una red de tejidos de origen ectodérmico. Su función primordial es la de captar y procesar la señales.

rapidamente ejerciendo

The chicken at 24 hours looks more like a primitive animal than a baby chicken. Yet only a few hours after the growing process begins a few vital parts are already noticeable. From the slide, you can see the primitive streak, which eventually turns into the three levels of endoderm, mesoderm, and ectoderm. Another vital part that is beginning to form and can be visible is the forebrain, which eventually turns into the brain of the chicken. The chicken progresses quickly and starts to look more like a chicken at 56 hours. One interesting fact about the chick at 56 hours is that human embryos look almost exactly the same at this stage in development. The optic cup begins to form, which is where the eyes eventually are placed. At this point in development, the chick’s heart becomes to be more visible.

Secções transversais (dar zoom)

A sequência de secções ilustra a formação do tubo neural da região cervical p/ cefálica e caudal (↨).

A.

3- Pregas neurais (neuroectoderma)

4- Ectoderme

6- Endoderme

7- Sulco neural

8- Neuroporo cranial

9- Intestino anterior

B.

2- Notocorda

3- Tubo neural

4- Ectoderme

5- Mesênquima cefálico

6- Endoderme

C.

2- Notocorda

3- Pregas neurais

D.

1- Sulco primitivo

Age: 330–329 Ma

Serpukhovian Age

Late Mississippian Epoch

Carboniferous Period – Giant arthropods and amphibians, early reptiles, most plants fern or lycophyte-like, known for tropical forests and seas

Paleozoic Era – pre-Dinosaurs

Location: Southeast Holy Island

Lindisfarne

Northumberland

England

Rock Type: Alston Formation limestone

Species:

Siphonodendron junceum is an extinct species of colonial rugose coral that flourished during the Carboniferous period, being among the most common corals found from this period. Belonging to the family Lithostrotiidae, these corals were significant reef-builders, contributing to the development of carbonate platforms in warm, tropical seas.

Colonies of Siphonodendron junceum are distinguished by their branching, cylindrical corallites, which often formed dense, bush-like structures, and are compared to spaghetti. Each individual corallite rarely measured much more than 6 millimetres in diameter, with internal septa arranged in a radial pattern to support the coral’s skeletal framework, though septa are often hard to make out and seem absent in this species. Its preferred environment consisted of shallow, clear, and warm marine settings

Note: Anthozoa is sometimes considered a subphylum, with its major consituents making up the classes. These being Class Ceriantharia, Hexacorallia (including Scleractinia and Rugosa), Octocorallia, and Tabulata. These will all be included in this collection, but ordered by their type above the usual ordering by level of taxonomic precision and alphabetically.

Cnidaria is a phylum of simple aquatic animals, best known for their radial symmetry, nematocysts (stinging cells), and a body plan organised around a central cavity. The phylum includes organisms like jellyfish, sea anemones, hydras, and corals. Most cnidarians have two basic body forms: the free-swimming medusa (as seen in jellyfish) and the sessile polyp (typical of corals and sea anemones). Cnidarians exhibit a diploblastic structure, meaning they possess two primary cell layers, the ectoderm and endoderm, with a gelatinous layer called the mesoglea in between. While many cnidarians are carnivorous, using their stinging cells to capture prey, some, particularly corals, have developed symbiotic relationships with photosynthetic organisms like zooxanthellae, which assist in nutrient production.

Within this diverse phylum, Class Anthozoa includes organisms that exist exclusively in the polyp form and lack a medusa stage. Anthozoans are primarily sessile, attached to the substrate, and include groups like corals and sea anemones. Among anthozoans, corals are the most significant from a geological and palaeontological perspective due to their capacity to build massive reef structures over geological time. Coral polyps typically secrete calcium carbonate to form exoskeletons, which fossilise readily, making them important indicators in the fossil record. Anthozoa is further divided into orders such as Hexacorallia, which includes the modern reef-building corals, and Octocorallia, which comprises soft corals and sea fans.

The fossil record of corals is particularly rich, with three major types standing out: tabulate corals, rugose corals, and scleractinian corals, each representing different eras of coral dominance in Earth's history.

Tabulate corals were dominant during the Palaeozoic era, especially from the Ordovician to the Permian. These corals are characterised by their colonial nature and the presence of horizontal internal divisions known as tabulae. Unlike later corals, tabulate corals lacked septa (vertical internal walls) and often formed large, tightly packed colonies. They contributed significantly to reef ecosystems in shallow tropical seas during the Silurian and Devonian periods. However, they became extinct at the end of the Permian, during the Permian-Triassic mass extinction. Their decline mirrored broader ecological upheavals that affected much of marine life at that time.

Rugose corals, also known as horn corals, coexisted with tabulate corals and appeared in the Ordovician, flourishing through the Devonian and into the Carboniferous. These corals could be either solitary or colonial, and their most distinctive feature is the presence of septal divisions within the coral skeleton, radiating from a central point. The solitary forms often resembled a horn in shape, giving them their common name. Rugose corals also contributed to Palaeozoic reef systems and are frequently found as fossils in limestone formations from these periods. Like the tabulate corals, rugose corals were wiped out during the Permian-Triassic extinction, marking the end of their dominance in marine ecosystems.

Following the extinction of tabulate and rugose corals, the Scleractinian corals (modern corals) emerged in the Triassic and have been the primary reef-builders ever since. Scleractinian corals also possess calcareous skeletons but differ from their predecessors in their skeletal microstructure, which is composed of aragonite rather than calcite. These corals are notable for their ability to form both solitary and colonial structures, with colonial forms building the vast coral reefs seen in modern oceans. Reef-building scleractinians rely heavily on symbiotic zooxanthellae, which enable them to thrive in nutrient-poor, sunlit waters by performing photosynthesis. Scleractinians became the dominant corals from the Jurassic onwards, and they continue to dominate coral reef ecosystems today, making them critical components of modern marine biodiversity.

Age: 346-344Ma

Viséan

Middle Mississippian Epoch

Carboniferous Period - Giant arthropods and amphibians, early reptiles, most plants fern or lycophyte-like, known for tropical forests and seas

Paleozoic Era - pre-Dinosaurs

Location: Lancashire

Clitheroe

Salthill Quarry

Rock Type: Course grained and coursely crinoidal limestone, with lots of calcite from crinoid structure, park of a knoll-reef from the Clitheroe Limestone Formation.

Specimen:

A large crinoid column about 3.5cm in diameter, 4cm at its widest, with the clear pentastellate axial canal visible. This section is only about 1-1.5cm tall

Species:

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Echinodermata is a phylum of marine invertebrates that includes well-known groups like starfish, sea urchins, brittle stars, sea cucumbers, and crinoids. Echinoderms are characterised by their radial symmetry, typically arranged in fives, and their unique water vascular system, which aids in locomotion and feeding. This phylum is exclusively marine, and its members are often found on the sea floor, from shallow waters to the deep ocean. Echinoderms exhibit pentameral symmetry as adults, though their larvae are bilaterally symmetrical, reflecting their evolutionary relationship with other deuterostomes, including chordates.

Within this phylum, Class Crinoidea includes marine animals commonly referred to as sea lilies and feather stars. Crinoids are distinguished by their cup-shaped body (the calyx), a set of radiating arms, and a long stalk (in some species) that anchors them to the seabed. The arms are typically branched and covered with feathery extensions that aid in filter feeding, capturing small particles from the water. Though modern crinoids tend to be less prominent in marine ecosystems, they were once much more abundant and diverse, particularly during the Palaeozoic era.

Crinoids first appeared in the Ordovician period, about 480 million years ago, and quickly diversified. They were especially abundant during the Palaeozoic, with their greatest diversity occurring during the Carboniferous period, when extensive shallow seas created ideal conditions for large crinoid populations. Fossil crinoids are especially common in limestone deposits from this time, with entire beds of rock often composed almost entirely of disarticulated crinoid fragments, particularly their stems. These fossils are widespread in regions like the UK, where crinoid-rich limestone formations are frequently found.

Crinoids come in two main forms: stalked crinoids, or sea lilies, which attach to the sea floor via a flexible stalk, and unstalked crinoids, or feather stars, which are mobile and can swim or crawl along the substrate using their arms. In the fossil record, stalked crinoids were much more abundant, with long, segmented stalks that could grow several meters in length. The stalks are composed of individual ossicles, small calcareous plates that are commonly found as fossils, especially in Carboniferous limestone beds. The most well-known fossil remains of crinoids are these stem ossicles, which are often referred to as "Indian beads" due to their cylindrical shape.

Crinoids reached their peak during the Palaeozoic, forming extensive colonies in shallow seas, often in association with coral reefs. Their filter-feeding mechanism allowed them to occupy a specialised ecological niche, and they played an important role in marine ecosystems as suspension feeders. However, crinoids were significantly affected by the Permian-Triassic mass extinction about 252 million years ago, which wiped out many marine species. Although crinoids survived this event, their diversity and abundance were greatly reduced.

In the Mesozoic era, crinoids experienced a resurgence, though not to the same levels of diversity as in the Palaeozoic. Feather stars (unstalked crinoids) became more prominent during the Jurassic and Cretaceous periods, adapting to more mobile lifestyles compared to their sessile ancestors. Today, feather stars are found in a variety of marine environments, from shallow reefs to deep-sea habitats, while stalked crinoids are largely restricted to deep water.

Crinoids are unique among echinoderms in that they are suspension feeders, using their feathery arms to catch plankton and other small particles from the water. Their arms are lined with cilia that move captured food towards their central mouth, which is located on the upper surface of the calyx. This feeding strategy differs from other echinoderms, such as sea urchins, which graze on algae, or starfish, which are typically predatory.

Despite their decline in modern oceans, crinoids remain important in the fossil record due to their abundant and well-preserved remains, particularly in Palaeozoic and Mesozoic sedimentary rocks. The characteristic segmented stalks and calyx plates of crinoids make them highly recognisable fossils, and they provide key insights into the structure and biodiversity of ancient marine ecosystems. In particular, Carboniferous limestone deposits, such as those found in the UK, are often rich in crinoid remains, offering palaeontologists a detailed record of these once-dominant marine invertebrates.

Anthopleura elegantissima is agonistic toward other individuals with different genetic disposition. When one colony of genetically identical polyps encounters a different genetic colony, the two will wage territorial battles. A. elegantissima has specialized tentacles called acrorhagi that are used solely to deter other colonies from encroaching on their space. When a polyp makes physical contact with a non-clonemate, it extends the acrorhagi to attack the competing anemone with stinging cells called nematocytes. Acrorhagi of the attacking anemone leave behind a 'peel' of the ectoderm and nematocysts that causes tissue necrosis in the receiving animal.

Age: 346-344Ma

Viséan

Middle Mississippian Epoch

Carboniferous Period - Giant arthropods and amphibians, early reptiles, most plants fern or lycophyte-like, known for tropical forests and seas

Paleozoic Era - pre-Dinosaurs

Location: Lancashire

Clitheroe

Salthill Quarry

Rock Type: Course grained and coursely crinoidal limestone, with lots of calcite from crinoid structure, park of a knoll-reef from the Clitheroe Limestone Formation.

Specimen:

A large crinoid column about 3.5cm in diameter, 4cm at its widest, with the clear pentastellate axial canal visible. This section is only about 1-1.5cm tall

Species:

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Echinodermata is a phylum of marine invertebrates that includes well-known groups like starfish, sea urchins, brittle stars, sea cucumbers, and crinoids. Echinoderms are characterised by their radial symmetry, typically arranged in fives, and their unique water vascular system, which aids in locomotion and feeding. This phylum is exclusively marine, and its members are often found on the sea floor, from shallow waters to the deep ocean. Echinoderms exhibit pentameral symmetry as adults, though their larvae are bilaterally symmetrical, reflecting their evolutionary relationship with other deuterostomes, including chordates.

Within this phylum, Class Crinoidea includes marine animals commonly referred to as sea lilies and feather stars. Crinoids are distinguished by their cup-shaped body (the calyx), a set of radiating arms, and a long stalk (in some species) that anchors them to the seabed. The arms are typically branched and covered with feathery extensions that aid in filter feeding, capturing small particles from the water. Though modern crinoids tend to be less prominent in marine ecosystems, they were once much more abundant and diverse, particularly during the Palaeozoic era.

Crinoids first appeared in the Ordovician period, about 480 million years ago, and quickly diversified. They were especially abundant during the Palaeozoic, with their greatest diversity occurring during the Carboniferous period, when extensive shallow seas created ideal conditions for large crinoid populations. Fossil crinoids are especially common in limestone deposits from this time, with entire beds of rock often composed almost entirely of disarticulated crinoid fragments, particularly their stems. These fossils are widespread in regions like the UK, where crinoid-rich limestone formations are frequently found.

Crinoids come in two main forms: stalked crinoids, or sea lilies, which attach to the sea floor via a flexible stalk, and unstalked crinoids, or feather stars, which are mobile and can swim or crawl along the substrate using their arms. In the fossil record, stalked crinoids were much more abundant, with long, segmented stalks that could grow several meters in length. The stalks are composed of individual ossicles, small calcareous plates that are commonly found as fossils, especially in Carboniferous limestone beds. The most well-known fossil remains of crinoids are these stem ossicles, which are often referred to as "Indian beads" due to their cylindrical shape.

Crinoids reached their peak during the Palaeozoic, forming extensive colonies in shallow seas, often in association with coral reefs. Their filter-feeding mechanism allowed them to occupy a specialised ecological niche, and they played an important role in marine ecosystems as suspension feeders. However, crinoids were significantly affected by the Permian-Triassic mass extinction about 252 million years ago, which wiped out many marine species. Although crinoids survived this event, their diversity and abundance were greatly reduced.

In the Mesozoic era, crinoids experienced a resurgence, though not to the same levels of diversity as in the Palaeozoic. Feather stars (unstalked crinoids) became more prominent during the Jurassic and Cretaceous periods, adapting to more mobile lifestyles compared to their sessile ancestors. Today, feather stars are found in a variety of marine environments, from shallow reefs to deep-sea habitats, while stalked crinoids are largely restricted to deep water.

Crinoids are unique among echinoderms in that they are suspension feeders, using their feathery arms to catch plankton and other small particles from the water. Their arms are lined with cilia that move captured food towards their central mouth, which is located on the upper surface of the calyx. This feeding strategy differs from other echinoderms, such as sea urchins, which graze on algae, or starfish, which are typically predatory.

Despite their decline in modern oceans, crinoids remain important in the fossil record due to their abundant and well-preserved remains, particularly in Palaeozoic and Mesozoic sedimentary rocks. The characteristic segmented stalks and calyx plates of crinoids make them highly recognisable fossils, and they provide key insights into the structure and biodiversity of ancient marine ecosystems. In particular, Carboniferous limestone deposits, such as those found in the UK, are often rich in crinoid remains, offering palaeontologists a detailed record of these once-dominant marine invertebrates.

Age: 346-344Ma

Viséan

Middle Mississippian Epoch

Carboniferous Period - Giant arthropods and amphibians, early reptiles, most plants fern or lycophyte-like, known for tropical forests and seas

Paleozoic Era - pre-Dinosaurs

Location: Lancashire

Clitheroe

Salthill Quarry

Rock Type: Course grained and coursely crinoidal limestone, with lots of calcite from crinoid structure, park of a knoll-reef from the Clitheroe Limestone Formation.

Specimen:

A large crinoid column about 3.5cm in diameter, 4cm at its widest, with the clear pentastellate axial canal visible. This section is only about 1-1.5cm tall

Species:

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Echinodermata is a phylum of marine invertebrates that includes well-known groups like starfish, sea urchins, brittle stars, sea cucumbers, and crinoids. Echinoderms are characterised by their radial symmetry, typically arranged in fives, and their unique water vascular system, which aids in locomotion and feeding. This phylum is exclusively marine, and its members are often found on the sea floor, from shallow waters to the deep ocean. Echinoderms exhibit pentameral symmetry as adults, though their larvae are bilaterally symmetrical, reflecting their evolutionary relationship with other deuterostomes, including chordates.

Within this phylum, Class Crinoidea includes marine animals commonly referred to as sea lilies and feather stars. Crinoids are distinguished by their cup-shaped body (the calyx), a set of radiating arms, and a long stalk (in some species) that anchors them to the seabed. The arms are typically branched and covered with feathery extensions that aid in filter feeding, capturing small particles from the water. Though modern crinoids tend to be less prominent in marine ecosystems, they were once much more abundant and diverse, particularly during the Palaeozoic era.

Crinoids first appeared in the Ordovician period, about 480 million years ago, and quickly diversified. They were especially abundant during the Palaeozoic, with their greatest diversity occurring during the Carboniferous period, when extensive shallow seas created ideal conditions for large crinoid populations. Fossil crinoids are especially common in limestone deposits from this time, with entire beds of rock often composed almost entirely of disarticulated crinoid fragments, particularly their stems. These fossils are widespread in regions like the UK, where crinoid-rich limestone formations are frequently found.

Crinoids come in two main forms: stalked crinoids, or sea lilies, which attach to the sea floor via a flexible stalk, and unstalked crinoids, or feather stars, which are mobile and can swim or crawl along the substrate using their arms. In the fossil record, stalked crinoids were much more abundant, with long, segmented stalks that could grow several meters in length. The stalks are composed of individual ossicles, small calcareous plates that are commonly found as fossils, especially in Carboniferous limestone beds. The most well-known fossil remains of crinoids are these stem ossicles, which are often referred to as "Indian beads" due to their cylindrical shape.

Crinoids reached their peak during the Palaeozoic, forming extensive colonies in shallow seas, often in association with coral reefs. Their filter-feeding mechanism allowed them to occupy a specialised ecological niche, and they played an important role in marine ecosystems as suspension feeders. However, crinoids were significantly affected by the Permian-Triassic mass extinction about 252 million years ago, which wiped out many marine species. Although crinoids survived this event, their diversity and abundance were greatly reduced.

In the Mesozoic era, crinoids experienced a resurgence, though not to the same levels of diversity as in the Palaeozoic. Feather stars (unstalked crinoids) became more prominent during the Jurassic and Cretaceous periods, adapting to more mobile lifestyles compared to their sessile ancestors. Today, feather stars are found in a variety of marine environments, from shallow reefs to deep-sea habitats, while stalked crinoids are largely restricted to deep water.

Crinoids are unique among echinoderms in that they are suspension feeders, using their feathery arms to catch plankton and other small particles from the water. Their arms are lined with cilia that move captured food towards their central mouth, which is located on the upper surface of the calyx. This feeding strategy differs from other echinoderms, such as sea urchins, which graze on algae, or starfish, which are typically predatory.

Despite their decline in modern oceans, crinoids remain important in the fossil record due to their abundant and well-preserved remains, particularly in Palaeozoic and Mesozoic sedimentary rocks. The characteristic segmented stalks and calyx plates of crinoids make them highly recognisable fossils, and they provide key insights into the structure and biodiversity of ancient marine ecosystems. In particular, Carboniferous limestone deposits, such as those found in the UK, are often rich in crinoid remains, offering palaeontologists a detailed record of these once-dominant marine invertebrates.

Age: 346-344Ma

Viséan

Middle Mississippian Epoch

Carboniferous Period - Giant arthropods and amphibians, early reptiles, most plants fern or lycophyte-like, known for tropical forests and seas

Paleozoic Era - pre-Dinosaurs

Location: Lancashire

Clitheroe

Salthill Quarry

Rock Type: Course grained and coursely crinoidal limestone, with lots of calcite from crinoid structure, park of a knoll-reef from the Clitheroe Limestone Formation.

Specimen:

A large crinoid column about 3.5cm in diameter, 4cm at its widest, with the clear pentastellate axial canal visible. This section is only about 1-1.5cm tall

Species:

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Echinodermata is a phylum of marine invertebrates that includes well-known groups like starfish, sea urchins, brittle stars, sea cucumbers, and crinoids. Echinoderms are characterised by their radial symmetry, typically arranged in fives, and their unique water vascular system, which aids in locomotion and feeding. This phylum is exclusively marine, and its members are often found on the sea floor, from shallow waters to the deep ocean. Echinoderms exhibit pentameral symmetry as adults, though their larvae are bilaterally symmetrical, reflecting their evolutionary relationship with other deuterostomes, including chordates.

Within this phylum, Class Crinoidea includes marine animals commonly referred to as sea lilies and feather stars. Crinoids are distinguished by their cup-shaped body (the calyx), a set of radiating arms, and a long stalk (in some species) that anchors them to the seabed. The arms are typically branched and covered with feathery extensions that aid in filter feeding, capturing small particles from the water. Though modern crinoids tend to be less prominent in marine ecosystems, they were once much more abundant and diverse, particularly during the Palaeozoic era.

Crinoids first appeared in the Ordovician period, about 480 million years ago, and quickly diversified. They were especially abundant during the Palaeozoic, with their greatest diversity occurring during the Carboniferous period, when extensive shallow seas created ideal conditions for large crinoid populations. Fossil crinoids are especially common in limestone deposits from this time, with entire beds of rock often composed almost entirely of disarticulated crinoid fragments, particularly their stems. These fossils are widespread in regions like the UK, where crinoid-rich limestone formations are frequently found.

Crinoids come in two main forms: stalked crinoids, or sea lilies, which attach to the sea floor via a flexible stalk, and unstalked crinoids, or feather stars, which are mobile and can swim or crawl along the substrate using their arms. In the fossil record, stalked crinoids were much more abundant, with long, segmented stalks that could grow several meters in length. The stalks are composed of individual ossicles, small calcareous plates that are commonly found as fossils, especially in Carboniferous limestone beds. The most well-known fossil remains of crinoids are these stem ossicles, which are often referred to as "Indian beads" due to their cylindrical shape.

Crinoids reached their peak during the Palaeozoic, forming extensive colonies in shallow seas, often in association with coral reefs. Their filter-feeding mechanism allowed them to occupy a specialised ecological niche, and they played an important role in marine ecosystems as suspension feeders. However, crinoids were significantly affected by the Permian-Triassic mass extinction about 252 million years ago, which wiped out many marine species. Although crinoids survived this event, their diversity and abundance were greatly reduced.

In the Mesozoic era, crinoids experienced a resurgence, though not to the same levels of diversity as in the Palaeozoic. Feather stars (unstalked crinoids) became more prominent during the Jurassic and Cretaceous periods, adapting to more mobile lifestyles compared to their sessile ancestors. Today, feather stars are found in a variety of marine environments, from shallow reefs to deep-sea habitats, while stalked crinoids are largely restricted to deep water.

Crinoids are unique among echinoderms in that they are suspension feeders, using their feathery arms to catch plankton and other small particles from the water. Their arms are lined with cilia that move captured food towards their central mouth, which is located on the upper surface of the calyx. This feeding strategy differs from other echinoderms, such as sea urchins, which graze on algae, or starfish, which are typically predatory.

Despite their decline in modern oceans, crinoids remain important in the fossil record due to their abundant and well-preserved remains, particularly in Palaeozoic and Mesozoic sedimentary rocks. The characteristic segmented stalks and calyx plates of crinoids make them highly recognisable fossils, and they provide key insights into the structure and biodiversity of ancient marine ecosystems. In particular, Carboniferous limestone deposits, such as those found in the UK, are often rich in crinoid remains, offering palaeontologists a detailed record of these once-dominant marine invertebrates.

Age: 346-344Ma

Viséan

Middle Mississippian Epoch

Carboniferous Period - Giant arthropods and amphibians, early reptiles, most plants fern or lycophyte-like, known for tropical forests and seas

Paleozoic Era - pre-Dinosaurs

Location: Lancashire

Clitheroe

Salthill Quarry

Rock Type: Course grained and coursely crinoidal limestone, with lots of calcite from crinoid structure, park of a knoll-reef from the Clitheroe Limestone Formation.

Specimen:

A large crinoid column about 3.5cm in diameter, 4cm at its widest, with the clear pentastellate axial canal visible. This section is only about 1-1.5cm tall

Species:

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Echinodermata is a phylum of marine invertebrates that includes well-known groups like starfish, sea urchins, brittle stars, sea cucumbers, and crinoids. Echinoderms are characterised by their radial symmetry, typically arranged in fives, and their unique water vascular system, which aids in locomotion and feeding. This phylum is exclusively marine, and its members are often found on the sea floor, from shallow waters to the deep ocean. Echinoderms exhibit pentameral symmetry as adults, though their larvae are bilaterally symmetrical, reflecting their evolutionary relationship with other deuterostomes, including chordates.

Within this phylum, Class Crinoidea includes marine animals commonly referred to as sea lilies and feather stars. Crinoids are distinguished by their cup-shaped body (the calyx), a set of radiating arms, and a long stalk (in some species) that anchors them to the seabed. The arms are typically branched and covered with feathery extensions that aid in filter feeding, capturing small particles from the water. Though modern crinoids tend to be less prominent in marine ecosystems, they were once much more abundant and diverse, particularly during the Palaeozoic era.

Crinoids first appeared in the Ordovician period, about 480 million years ago, and quickly diversified. They were especially abundant during the Palaeozoic, with their greatest diversity occurring during the Carboniferous period, when extensive shallow seas created ideal conditions for large crinoid populations. Fossil crinoids are especially common in limestone deposits from this time, with entire beds of rock often composed almost entirely of disarticulated crinoid fragments, particularly their stems. These fossils are widespread in regions like the UK, where crinoid-rich limestone formations are frequently found.

Crinoids come in two main forms: stalked crinoids, or sea lilies, which attach to the sea floor via a flexible stalk, and unstalked crinoids, or feather stars, which are mobile and can swim or crawl along the substrate using their arms. In the fossil record, stalked crinoids were much more abundant, with long, segmented stalks that could grow several meters in length. The stalks are composed of individual ossicles, small calcareous plates that are commonly found as fossils, especially in Carboniferous limestone beds. The most well-known fossil remains of crinoids are these stem ossicles, which are often referred to as "Indian beads" due to their cylindrical shape.

Crinoids reached their peak during the Palaeozoic, forming extensive colonies in shallow seas, often in association with coral reefs. Their filter-feeding mechanism allowed them to occupy a specialised ecological niche, and they played an important role in marine ecosystems as suspension feeders. However, crinoids were significantly affected by the Permian-Triassic mass extinction about 252 million years ago, which wiped out many marine species. Although crinoids survived this event, their diversity and abundance were greatly reduced.

In the Mesozoic era, crinoids experienced a resurgence, though not to the same levels of diversity as in the Palaeozoic. Feather stars (unstalked crinoids) became more prominent during the Jurassic and Cretaceous periods, adapting to more mobile lifestyles compared to their sessile ancestors. Today, feather stars are found in a variety of marine environments, from shallow reefs to deep-sea habitats, while stalked crinoids are largely restricted to deep water.

Crinoids are unique among echinoderms in that they are suspension feeders, using their feathery arms to catch plankton and other small particles from the water. Their arms are lined with cilia that move captured food towards their central mouth, which is located on the upper surface of the calyx. This feeding strategy differs from other echinoderms, such as sea urchins, which graze on algae, or starfish, which are typically predatory.

Despite their decline in modern oceans, crinoids remain important in the fossil record due to their abundant and well-preserved remains, particularly in Palaeozoic and Mesozoic sedimentary rocks. The characteristic segmented stalks and calyx plates of crinoids make them highly recognisable fossils, and they provide key insights into the structure and biodiversity of ancient marine ecosystems. In particular, Carboniferous limestone deposits, such as those found in the UK, are often rich in crinoid remains, offering palaeontologists a detailed record of these once-dominant marine invertebrates.

LIFE CHANGES THROUGH GROWTH AND DEVELOPMENT

Growth and Development: What is the Difference?

While growth in living organisms is a change in overall size and proportions, development is change in form. Some animals, like the frog and the Morpho butterfly, have one form when they are young and a very different form when they are adults. This often allows the immature form and the adult form to occupy different habitats and use different resources. This phenomenon is called metamorphosis.

The Frog’s Story

Take a look at the development of the fertilized frog egg.

1. After a sperm cell penetrates the egg cell, the egg begins to divide. First, there are two cells, then four, then eight, and so on. The egg becomes a hollow ball with a single layer of small cells. This is called a blastula.

2.Then, some of the cells are forced to move inwardly, change shape, and grow as the blastula becomes a gastrula. The gastrula is a three-layered embryo, made of ectodermal, mesodermal and endodermal layers.

3. Organs begin to develop. The ectoderm gives rise to skin and its derivatives, the sense organs and the brain and spinal cord. The mesoderm gives rise to muscle, connective tissue, the circulatory system and most of the excretory and reproductive systems. The endoderm gives rise to the lining of most of the digestive tract, most of the respiratory tract, the urinary bladder, liver, pancreas and some endocrine glands.

4.In about five days, this fertilized frog egg develops into a tadpole. Tadpoles have gills for breathing underwater but they also breathe through their skin. After a few weeks or months, the tadpole loses its tail and gills. It grows lungs and legs as it transforms into a frog.

Secções transversais (dar zoom)

A.

1- Ectoderme

2- Crista neural

3- Neuroectoderma

5- Vesícula óptica

6- Luz do Prosencéfalo

B.

1- Celoma

2- Ectoderma

3- Tubo neural

4- Somatopleura

5- Esplancnopleura

6- Endoderma

7- Intestino anterior

8- Tubo Encocárdico Único em formação

10- Mesênquima cervical

11- Notocorda

C.

1- Celoma

2- Ectoderm Epidermal

3- Tubo neural

4- Notocorda

5- Mesênquima cefálico

6- Intestino anterior

7- Somatopleura

8- Esplancnopleura

11- Arco da Aorta Ventral

D.

3- Somito

5- Endoderme

Age: 346-344Ma

Viséan

Middle Mississippian Epoch

Carboniferous Period - Giant arthropods and amphibians, early reptiles, most plants fern or lycophyte-like, known for tropical forests and seas

Paleozoic Era - pre-Dinosaurs

Location: Lancashire

Clitheroe

Salthill Quarry

Rock Type: Course grained and coursely crinoidal limestone, with lots of calcite from crinoid structure, park of a knoll-reef from the Clitheroe Limestone Formation.

Specimen:

A large crinoid column about 3.5cm in diameter, 4cm at its widest, with the clear pentastellate axial canal visible. This section is only about 1-1.5cm tall

Species:

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Echinodermata is a phylum of marine invertebrates that includes well-known groups like starfish, sea urchins, brittle stars, sea cucumbers, and crinoids. Echinoderms are characterised by their radial symmetry, typically arranged in fives, and their unique water vascular system, which aids in locomotion and feeding. This phylum is exclusively marine, and its members are often found on the sea floor, from shallow waters to the deep ocean. Echinoderms exhibit pentameral symmetry as adults, though their larvae are bilaterally symmetrical, reflecting their evolutionary relationship with other deuterostomes, including chordates.

Within this phylum, Class Crinoidea includes marine animals commonly referred to as sea lilies and feather stars. Crinoids are distinguished by their cup-shaped body (the calyx), a set of radiating arms, and a long stalk (in some species) that anchors them to the seabed. The arms are typically branched and covered with feathery extensions that aid in filter feeding, capturing small particles from the water. Though modern crinoids tend to be less prominent in marine ecosystems, they were once much more abundant and diverse, particularly during the Palaeozoic era.

Crinoids first appeared in the Ordovician period, about 480 million years ago, and quickly diversified. They were especially abundant during the Palaeozoic, with their greatest diversity occurring during the Carboniferous period, when extensive shallow seas created ideal conditions for large crinoid populations. Fossil crinoids are especially common in limestone deposits from this time, with entire beds of rock often composed almost entirely of disarticulated crinoid fragments, particularly their stems. These fossils are widespread in regions like the UK, where crinoid-rich limestone formations are frequently found.

Crinoids come in two main forms: stalked crinoids, or sea lilies, which attach to the sea floor via a flexible stalk, and unstalked crinoids, or feather stars, which are mobile and can swim or crawl along the substrate using their arms. In the fossil record, stalked crinoids were much more abundant, with long, segmented stalks that could grow several meters in length. The stalks are composed of individual ossicles, small calcareous plates that are commonly found as fossils, especially in Carboniferous limestone beds. The most well-known fossil remains of crinoids are these stem ossicles, which are often referred to as "Indian beads" due to their cylindrical shape.

Crinoids reached their peak during the Palaeozoic, forming extensive colonies in shallow seas, often in association with coral reefs. Their filter-feeding mechanism allowed them to occupy a specialised ecological niche, and they played an important role in marine ecosystems as suspension feeders. However, crinoids were significantly affected by the Permian-Triassic mass extinction about 252 million years ago, which wiped out many marine species. Although crinoids survived this event, their diversity and abundance were greatly reduced.

In the Mesozoic era, crinoids experienced a resurgence, though not to the same levels of diversity as in the Palaeozoic. Feather stars (unstalked crinoids) became more prominent during the Jurassic and Cretaceous periods, adapting to more mobile lifestyles compared to their sessile ancestors. Today, feather stars are found in a variety of marine environments, from shallow reefs to deep-sea habitats, while stalked crinoids are largely restricted to deep water.

Crinoids are unique among echinoderms in that they are suspension feeders, using their feathery arms to catch plankton and other small particles from the water. Their arms are lined with cilia that move captured food towards their central mouth, which is located on the upper surface of the calyx. This feeding strategy differs from other echinoderms, such as sea urchins, which graze on algae, or starfish, which are typically predatory.

Despite their decline in modern oceans, crinoids remain important in the fossil record due to their abundant and well-preserved remains, particularly in Palaeozoic and Mesozoic sedimentary rocks. The characteristic segmented stalks and calyx plates of crinoids make them highly recognisable fossils, and they provide key insights into the structure and biodiversity of ancient marine ecosystems. In particular, Carboniferous limestone deposits, such as those found in the UK, are often rich in crinoid remains, offering palaeontologists a detailed record of these once-dominant marine invertebrates.

Age: 346-344Ma

Viséan

Middle Mississippian Epoch

Carboniferous Period - Giant arthropods and amphibians, early reptiles, most plants fern or lycophyte-like, known for tropical forests and seas

Paleozoic Era - pre-Dinosaurs

Location: Lancashire

Clitheroe

Salthill Quarry

Rock Type: Course grained and coursely crinoidal limestone, with lots of calcite from crinoid structure, park of a knoll-reef from the Clitheroe Limestone Formation.

Specimen:

A large crinoid column about 3.5cm in diameter, 4cm at its widest, with the clear pentastellate axial canal visible. This section is only about 1-1.5cm tall

Species:

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Echinodermata is a phylum of marine invertebrates that includes well-known groups like starfish, sea urchins, brittle stars, sea cucumbers, and crinoids. Echinoderms are characterised by their radial symmetry, typically arranged in fives, and their unique water vascular system, which aids in locomotion and feeding. This phylum is exclusively marine, and its members are often found on the sea floor, from shallow waters to the deep ocean. Echinoderms exhibit pentameral symmetry as adults, though their larvae are bilaterally symmetrical, reflecting their evolutionary relationship with other deuterostomes, including chordates.

Within this phylum, Class Crinoidea includes marine animals commonly referred to as sea lilies and feather stars. Crinoids are distinguished by their cup-shaped body (the calyx), a set of radiating arms, and a long stalk (in some species) that anchors them to the seabed. The arms are typically branched and covered with feathery extensions that aid in filter feeding, capturing small particles from the water. Though modern crinoids tend to be less prominent in marine ecosystems, they were once much more abundant and diverse, particularly during the Palaeozoic era.

Crinoids first appeared in the Ordovician period, about 480 million years ago, and quickly diversified. They were especially abundant during the Palaeozoic, with their greatest diversity occurring during the Carboniferous period, when extensive shallow seas created ideal conditions for large crinoid populations. Fossil crinoids are especially common in limestone deposits from this time, with entire beds of rock often composed almost entirely of disarticulated crinoid fragments, particularly their stems. These fossils are widespread in regions like the UK, where crinoid-rich limestone formations are frequently found.

Crinoids come in two main forms: stalked crinoids, or sea lilies, which attach to the sea floor via a flexible stalk, and unstalked crinoids, or feather stars, which are mobile and can swim or crawl along the substrate using their arms. In the fossil record, stalked crinoids were much more abundant, with long, segmented stalks that could grow several meters in length. The stalks are composed of individual ossicles, small calcareous plates that are commonly found as fossils, especially in Carboniferous limestone beds. The most well-known fossil remains of crinoids are these stem ossicles, which are often referred to as "Indian beads" due to their cylindrical shape.

Crinoids reached their peak during the Palaeozoic, forming extensive colonies in shallow seas, often in association with coral reefs. Their filter-feeding mechanism allowed them to occupy a specialised ecological niche, and they played an important role in marine ecosystems as suspension feeders. However, crinoids were significantly affected by the Permian-Triassic mass extinction about 252 million years ago, which wiped out many marine species. Although crinoids survived this event, their diversity and abundance were greatly reduced.

In the Mesozoic era, crinoids experienced a resurgence, though not to the same levels of diversity as in the Palaeozoic. Feather stars (unstalked crinoids) became more prominent during the Jurassic and Cretaceous periods, adapting to more mobile lifestyles compared to their sessile ancestors. Today, feather stars are found in a variety of marine environments, from shallow reefs to deep-sea habitats, while stalked crinoids are largely restricted to deep water.

Crinoids are unique among echinoderms in that they are suspension feeders, using their feathery arms to catch plankton and other small particles from the water. Their arms are lined with cilia that move captured food towards their central mouth, which is located on the upper surface of the calyx. This feeding strategy differs from other echinoderms, such as sea urchins, which graze on algae, or starfish, which are typically predatory.

Despite their decline in modern oceans, crinoids remain important in the fossil record due to their abundant and well-preserved remains, particularly in Palaeozoic and Mesozoic sedimentary rocks. The characteristic segmented stalks and calyx plates of crinoids make them highly recognisable fossils, and they provide key insights into the structure and biodiversity of ancient marine ecosystems. In particular, Carboniferous limestone deposits, such as those found in the UK, are often rich in crinoid remains, offering palaeontologists a detailed record of these once-dominant marine invertebrates.

Age: 346-344Ma

Viséan

Middle Mississippian Epoch

Carboniferous Period - Giant arthropods and amphibians, early reptiles, most plants fern or lycophyte-like, known for tropical forests and seas

Paleozoic Era - pre-Dinosaurs

Location: Lancashire

Clitheroe

Salthill Quarry

Rock Type: Course grained and coursely crinoidal limestone, with lots of calcite from crinoid structure, park of a knoll-reef from the Clitheroe Limestone Formation.

Specimen:

A large crinoid column about 3.5cm in diameter, 4cm at its widest, with the clear pentastellate axial canal visible. This section is only about 1-1.5cm tall

Species:

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Echinodermata is a phylum of marine invertebrates that includes well-known groups like starfish, sea urchins, brittle stars, sea cucumbers, and crinoids. Echinoderms are characterised by their radial symmetry, typically arranged in fives, and their unique water vascular system, which aids in locomotion and feeding. This phylum is exclusively marine, and its members are often found on the sea floor, from shallow waters to the deep ocean. Echinoderms exhibit pentameral symmetry as adults, though their larvae are bilaterally symmetrical, reflecting their evolutionary relationship with other deuterostomes, including chordates.

Within this phylum, Class Crinoidea includes marine animals commonly referred to as sea lilies and feather stars. Crinoids are distinguished by their cup-shaped body (the calyx), a set of radiating arms, and a long stalk (in some species) that anchors them to the seabed. The arms are typically branched and covered with feathery extensions that aid in filter feeding, capturing small particles from the water. Though modern crinoids tend to be less prominent in marine ecosystems, they were once much more abundant and diverse, particularly during the Palaeozoic era.

Crinoids first appeared in the Ordovician period, about 480 million years ago, and quickly diversified. They were especially abundant during the Palaeozoic, with their greatest diversity occurring during the Carboniferous period, when extensive shallow seas created ideal conditions for large crinoid populations. Fossil crinoids are especially common in limestone deposits from this time, with entire beds of rock often composed almost entirely of disarticulated crinoid fragments, particularly their stems. These fossils are widespread in regions like the UK, where crinoid-rich limestone formations are frequently found.

Crinoids come in two main forms: stalked crinoids, or sea lilies, which attach to the sea floor via a flexible stalk, and unstalked crinoids, or feather stars, which are mobile and can swim or crawl along the substrate using their arms. In the fossil record, stalked crinoids were much more abundant, with long, segmented stalks that could grow several meters in length. The stalks are composed of individual ossicles, small calcareous plates that are commonly found as fossils, especially in Carboniferous limestone beds. The most well-known fossil remains of crinoids are these stem ossicles, which are often referred to as "Indian beads" due to their cylindrical shape.

Crinoids reached their peak during the Palaeozoic, forming extensive colonies in shallow seas, often in association with coral reefs. Their filter-feeding mechanism allowed them to occupy a specialised ecological niche, and they played an important role in marine ecosystems as suspension feeders. However, crinoids were significantly affected by the Permian-Triassic mass extinction about 252 million years ago, which wiped out many marine species. Although crinoids survived this event, their diversity and abundance were greatly reduced.

In the Mesozoic era, crinoids experienced a resurgence, though not to the same levels of diversity as in the Palaeozoic. Feather stars (unstalked crinoids) became more prominent during the Jurassic and Cretaceous periods, adapting to more mobile lifestyles compared to their sessile ancestors. Today, feather stars are found in a variety of marine environments, from shallow reefs to deep-sea habitats, while stalked crinoids are largely restricted to deep water.

Crinoids are unique among echinoderms in that they are suspension feeders, using their feathery arms to catch plankton and other small particles from the water. Their arms are lined with cilia that move captured food towards their central mouth, which is located on the upper surface of the calyx. This feeding strategy differs from other echinoderms, such as sea urchins, which graze on algae, or starfish, which are typically predatory.

Despite their decline in modern oceans, crinoids remain important in the fossil record due to their abundant and well-preserved remains, particularly in Palaeozoic and Mesozoic sedimentary rocks. The characteristic segmented stalks and calyx plates of crinoids make them highly recognisable fossils, and they provide key insights into the structure and biodiversity of ancient marine ecosystems. In particular, Carboniferous limestone deposits, such as those found in the UK, are often rich in crinoid remains, offering palaeontologists a detailed record of these once-dominant marine invertebrates.

Age: 346-344Ma

Viséan

Middle Mississippian Epoch

Carboniferous Period - Giant arthropods and amphibians, early reptiles, most plants fern or lycophyte-like, known for tropical forests and seas

Paleozoic Era - pre-Dinosaurs

Location: Lancashire

Clitheroe

Salthill Quarry

Rock Type: Course grained and coursely crinoidal limestone, with lots of calcite from crinoid structure, park of a knoll-reef from the Clitheroe Limestone Formation.

Specimen:

A large crinoid column about 3.5cm in diameter, 4cm at its widest, with the clear pentastellate axial canal visible. This section is only about 1-1.5cm tall

Species:

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Echinodermata is a phylum of marine invertebrates that includes well-known groups like starfish, sea urchins, brittle stars, sea cucumbers, and crinoids. Echinoderms are characterised by their radial symmetry, typically arranged in fives, and their unique water vascular system, which aids in locomotion and feeding. This phylum is exclusively marine, and its members are often found on the sea floor, from shallow waters to the deep ocean. Echinoderms exhibit pentameral symmetry as adults, though their larvae are bilaterally symmetrical, reflecting their evolutionary relationship with other deuterostomes, including chordates.

Within this phylum, Class Crinoidea includes marine animals commonly referred to as sea lilies and feather stars. Crinoids are distinguished by their cup-shaped body (the calyx), a set of radiating arms, and a long stalk (in some species) that anchors them to the seabed. The arms are typically branched and covered with feathery extensions that aid in filter feeding, capturing small particles from the water. Though modern crinoids tend to be less prominent in marine ecosystems, they were once much more abundant and diverse, particularly during the Palaeozoic era.

Crinoids first appeared in the Ordovician period, about 480 million years ago, and quickly diversified. They were especially abundant during the Palaeozoic, with their greatest diversity occurring during the Carboniferous period, when extensive shallow seas created ideal conditions for large crinoid populations. Fossil crinoids are especially common in limestone deposits from this time, with entire beds of rock often composed almost entirely of disarticulated crinoid fragments, particularly their stems. These fossils are widespread in regions like the UK, where crinoid-rich limestone formations are frequently found.

Crinoids come in two main forms: stalked crinoids, or sea lilies, which attach to the sea floor via a flexible stalk, and unstalked crinoids, or feather stars, which are mobile and can swim or crawl along the substrate using their arms. In the fossil record, stalked crinoids were much more abundant, with long, segmented stalks that could grow several meters in length. The stalks are composed of individual ossicles, small calcareous plates that are commonly found as fossils, especially in Carboniferous limestone beds. The most well-known fossil remains of crinoids are these stem ossicles, which are often referred to as "Indian beads" due to their cylindrical shape.

Crinoids reached their peak during the Palaeozoic, forming extensive colonies in shallow seas, often in association with coral reefs. Their filter-feeding mechanism allowed them to occupy a specialised ecological niche, and they played an important role in marine ecosystems as suspension feeders. However, crinoids were significantly affected by the Permian-Triassic mass extinction about 252 million years ago, which wiped out many marine species. Although crinoids survived this event, their diversity and abundance were greatly reduced.

In the Mesozoic era, crinoids experienced a resurgence, though not to the same levels of diversity as in the Palaeozoic. Feather stars (unstalked crinoids) became more prominent during the Jurassic and Cretaceous periods, adapting to more mobile lifestyles compared to their sessile ancestors. Today, feather stars are found in a variety of marine environments, from shallow reefs to deep-sea habitats, while stalked crinoids are largely restricted to deep water.

Crinoids are unique among echinoderms in that they are suspension feeders, using their feathery arms to catch plankton and other small particles from the water. Their arms are lined with cilia that move captured food towards their central mouth, which is located on the upper surface of the calyx. This feeding strategy differs from other echinoderms, such as sea urchins, which graze on algae, or starfish, which are typically predatory.

Despite their decline in modern oceans, crinoids remain important in the fossil record due to their abundant and well-preserved remains, particularly in Palaeozoic and Mesozoic sedimentary rocks. The characteristic segmented stalks and calyx plates of crinoids make them highly recognisable fossils, and they provide key insights into the structure and biodiversity of ancient marine ecosystems. In particular, Carboniferous limestone deposits, such as those found in the UK, are often rich in crinoid remains, offering palaeontologists a detailed record of these once-dominant marine invertebrates.

Age: 343–337 Ma

Viséan

Middle Mississippian Epoch

Carboniferous Period - Giant arthropods and amphibians, early reptiles, most plants fern or lycophyte-like, known for tropical forests and seas

Paleozoic Era - pre-Dinosaurs

Location: Hurst Green (Stonyhurst)

Hodder Place

Stonyhurst Bathing Hut remains by the riverbanks of the Hodder

Rock Type: Red Brook Mudstone Member within the Pendleside Limestone Formation

Species:

Palaeacis humilis is an intriguing coral species that has sparked debate regarding its classification. It belongs to the genus Palaeacis, which is currently placed within the order Tabulata, a group of extinct colonial corals that thrived from the Ordovician to the Permian. Some tabulate corals are known for their perforate skeletons, permeated with an extensive canal system partially lined with living coral tissue, and their closely spaced horizontal partitions (tabulae), although Palaeacis deviates from typical tabulate morphology in some respects. The species has been placed within the larger framework of perforate corals, bridging characteristics between the Tabulata and some Scleractinian corals found today.

Early paleontologists sometimes misidentified Palaeacis as a sponge because of its perforate skeletal structure, which is similar to the porous networks seen in certain sponge fossils. The lack of clear septa (vertical partitions within the corallites) and the simple, vase-like form may have contributed to the confusion, blurring the lines between these two marine organisms in the fossil record. However, detailed studies of the coral’s growth form and microstructure confirmed its placement within the coral lineage, despite its superficial resemblance to sponges.

The species Palaeacis humilis, like others in its genus, represents a distinctive evolutionary branch within coral history, displaying several unique features. Unlike many corals of its time, Palaeacis humilis was free-standing and unattached, a growth form not commonly found in tabulate, rugose, or scleractinian corals, which typically stand attached to the substrate.

Fossil specimens of Palaeacis humilis typically show small, wedge-shaped colonies, with a height and width of approximately 10–15 millimetres. The species' diminutive size contrasts with other coral forms of the period, particularly the larger colonial corals, or huge horn corals from the Rugosa group that dominated many marine ecosystems. Each colony consists of two to four corallites arranged in a lateral series, with the upper margins of the corallites sometimes projecting beyond the colony surface. The calices are shallow and conical, with elliptical or circular cross-sections.

The skeletal structure of Palaeacis humilis is of particular interest due to its perforate nature. The walls of the corallum are perforated by a network of pores or canals that connected adjacent corallites and likely allowed for water flow through the colony, a feature seen in modern perforate corals in the Scleractinia. The presence of perforations in both the walls and the bases of the corallites links Palaeacis to other tabulate corals like Favosites, yet the absence of a well-developed coenenchyma (the connective tissue between corallites) distinguishes Palaeacis as a unique genus.

The evolutionary placement of free-standing corals like Palaeacis humilis is significant in understanding coral evolution. While many ancient corals were sessile, attached forms, the free-standing nature of Palaeacis suggests an early shift towards independent, mobile life forms in marine environments. This development could have been an adaptive response to changing ecological pressures, allowing these corals to exploit different feeding strategies or escape from environments prone to sedimentation.

Note: Anthozoa is sometimes considered a subphylum, with its major consituents making up the classes. These being Class Ceriantharia, Hexacorallia (including Scleractinia and Rugosa), Octocorallia, and Tabulata. These will all be included in this collection, but ordered by their type above the usual ordering by level of taxonomic precision and alphabetically.

Cnidaria is a phylum of simple aquatic animals, best known for their radial symmetry, nematocysts (stinging cells), and a body plan organised around a central cavity. The phylum includes organisms like jellyfish, sea anemones, hydras, and corals. Most cnidarians have two basic body forms: the free-swimming medusa (as seen in jellyfish) and the sessile polyp (typical of corals and sea anemones). Cnidarians exhibit a diploblastic structure, meaning they possess two primary cell layers, the ectoderm and endoderm, with a gelatinous layer called the mesoglea in between. While many cnidarians are carnivorous, using their stinging cells to capture prey, some, particularly corals, have developed symbiotic relationships with photosynthetic organisms like zooxanthellae, which assist in nutrient production.

Within this diverse phylum, Class Anthozoa includes organisms that exist exclusively in the polyp form and lack a medusa stage. Anthozoans are primarily sessile, attached to the substrate, and include groups like corals and sea anemones. Among anthozoans, corals are the most significant from a geological and palaeontological perspective due to their capacity to build massive reef structures over geological time. Coral polyps typically secrete calcium carbonate to form exoskeletons, which fossilise readily, making them important indicators in the fossil record. Anthozoa is further divided into orders such as Hexacorallia, which includes the modern reef-building corals, and Octocorallia, which comprises soft corals and sea fans.

The fossil record of corals is particularly rich, with three major types standing out: tabulate corals, rugose corals, and scleractinian corals, each representing different eras of coral dominance in Earth's history.

Tabulate corals were dominant during the Palaeozoic era, especially from the Ordovician to the Permian. These corals are characterised by their colonial nature and the presence of horizontal internal divisions known as tabulae. Unlike later corals, tabulate corals lacked septa (vertical internal walls) and often formed large, tightly packed colonies. They contributed significantly to reef ecosystems in shallow tropical seas during the Silurian and Devonian periods. However, they became extinct at the end of the Permian, during the Permian-Triassic mass extinction. Their decline mirrored broader ecological upheavals that affected much of marine life at that time.

Rugose corals, also known as horn corals, coexisted with tabulate corals and appeared in the Ordovician, flourishing through the Devonian and into the Carboniferous. These corals could be either solitary or colonial, and their most distinctive feature is the presence of septal divisions within the coral skeleton, radiating from a central point. The solitary forms often resembled a horn in shape, giving them their common name. Rugose corals also contributed to Palaeozoic reef systems and are frequently found as fossils in limestone formations from these periods. Like the tabulate corals, rugose corals were wiped out during the Permian-Triassic extinction, marking the end of their dominance in marine ecosystems.

Following the extinction of tabulate and rugose corals, the Scleractinian corals (modern corals) emerged in the Triassic and have been the primary reef-builders ever since. Scleractinian corals also possess calcareous skeletons but differ from their predecessors in their skeletal microstructure, which is composed of aragonite rather than calcite. These corals are notable for their ability to form both solitary and colonial structures, with colonial forms building the vast coral reefs seen in modern oceans. Reef-building scleractinians rely heavily on symbiotic zooxanthellae, which enable them to thrive in nutrient-poor, sunlit waters by performing photosynthesis. Scleractinians became the dominant corals from the Jurassic onwards, and they continue to dominate coral reef ecosystems today, making them critical components of modern marine biodiversity.

Age: 346-344Ma

Viséan

Middle Mississippian Epoch

Carboniferous Period - Giant arthropods and amphibians, early reptiles, most plants fern or lycophyte-like, known for tropical forests and seas

Paleozoic Era - pre-Dinosaurs

Location: Lancashire

Clitheroe

Salthill Quarry

Rock Type: Course grained and coursely crinoidal limestone, with lots of calcite from crinoid structure, park of a knoll-reef from the Clitheroe Limestone Formation.

Specimen:

A large crinoid column about 3.5cm in diameter, 4cm at its widest, with the clear pentastellate axial canal visible. This section is only about 1-1.5cm tall

Species:

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Echinodermata is a phylum of marine invertebrates that includes well-known groups like starfish, sea urchins, brittle stars, sea cucumbers, and crinoids. Echinoderms are characterised by their radial symmetry, typically arranged in fives, and their unique water vascular system, which aids in locomotion and feeding. This phylum is exclusively marine, and its members are often found on the sea floor, from shallow waters to the deep ocean. Echinoderms exhibit pentameral symmetry as adults, though their larvae are bilaterally symmetrical, reflecting their evolutionary relationship with other deuterostomes, including chordates.

Within this phylum, Class Crinoidea includes marine animals commonly referred to as sea lilies and feather stars. Crinoids are distinguished by their cup-shaped body (the calyx), a set of radiating arms, and a long stalk (in some species) that anchors them to the seabed. The arms are typically branched and covered with feathery extensions that aid in filter feeding, capturing small particles from the water. Though modern crinoids tend to be less prominent in marine ecosystems, they were once much more abundant and diverse, particularly during the Palaeozoic era.

Crinoids first appeared in the Ordovician period, about 480 million years ago, and quickly diversified. They were especially abundant during the Palaeozoic, with their greatest diversity occurring during the Carboniferous period, when extensive shallow seas created ideal conditions for large crinoid populations. Fossil crinoids are especially common in limestone deposits from this time, with entire beds of rock often composed almost entirely of disarticulated crinoid fragments, particularly their stems. These fossils are widespread in regions like the UK, where crinoid-rich limestone formations are frequently found.

Crinoids come in two main forms: stalked crinoids, or sea lilies, which attach to the sea floor via a flexible stalk, and unstalked crinoids, or feather stars, which are mobile and can swim or crawl along the substrate using their arms. In the fossil record, stalked crinoids were much more abundant, with long, segmented stalks that could grow several meters in length. The stalks are composed of individual ossicles, small calcareous plates that are commonly found as fossils, especially in Carboniferous limestone beds. The most well-known fossil remains of crinoids are these stem ossicles, which are often referred to as "Indian beads" due to their cylindrical shape.

Crinoids reached their peak during the Palaeozoic, forming extensive colonies in shallow seas, often in association with coral reefs. Their filter-feeding mechanism allowed them to occupy a specialised ecological niche, and they played an important role in marine ecosystems as suspension feeders. However, crinoids were significantly affected by the Permian-Triassic mass extinction about 252 million years ago, which wiped out many marine species. Although crinoids survived this event, their diversity and abundance were greatly reduced.

In the Mesozoic era, crinoids experienced a resurgence, though not to the same levels of diversity as in the Palaeozoic. Feather stars (unstalked crinoids) became more prominent during the Jurassic and Cretaceous periods, adapting to more mobile lifestyles compared to their sessile ancestors. Today, feather stars are found in a variety of marine environments, from shallow reefs to deep-sea habitats, while stalked crinoids are largely restricted to deep water.

Crinoids are unique among echinoderms in that they are suspension feeders, using their feathery arms to catch plankton and other small particles from the water. Their arms are lined with cilia that move captured food towards their central mouth, which is located on the upper surface of the calyx. This feeding strategy differs from other echinoderms, such as sea urchins, which graze on algae, or starfish, which are typically predatory.

Despite their decline in modern oceans, crinoids remain important in the fossil record due to their abundant and well-preserved remains, particularly in Palaeozoic and Mesozoic sedimentary rocks. The characteristic segmented stalks and calyx plates of crinoids make them highly recognisable fossils, and they provide key insights into the structure and biodiversity of ancient marine ecosystems. In particular, Carboniferous limestone deposits, such as those found in the UK, are often rich in crinoid remains, offering palaeontologists a detailed record of these once-dominant marine invertebrates.

ectodermo y con flores fucsias

Age: 346-344Ma

Viséan

Middle Mississippian Epoch

Carboniferous Period - Giant arthropods and amphibians, early reptiles, most plants fern or lycophyte-like, known for tropical forests and seas

Paleozoic Era - pre-Dinosaurs

Location: Lancashire

Clitheroe

Salthill Quarry

Rock Type: Course grained and coursely crinoidal limestone, with lots of calcite from crinoid structure, park of a knoll-reef from the Clitheroe Limestone Formation.

Specimen:

A large crinoid column about 3.5cm in diameter, 4cm at its widest, with the clear pentastellate axial canal visible. This section is only about 1-1.5cm tall

Species:

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Echinodermata is a phylum of marine invertebrates that includes well-known groups like starfish, sea urchins, brittle stars, sea cucumbers, and crinoids. Echinoderms are characterised by their radial symmetry, typically arranged in fives, and their unique water vascular system, which aids in locomotion and feeding. This phylum is exclusively marine, and its members are often found on the sea floor, from shallow waters to the deep ocean. Echinoderms exhibit pentameral symmetry as adults, though their larvae are bilaterally symmetrical, reflecting their evolutionary relationship with other deuterostomes, including chordates.

Within this phylum, Class Crinoidea includes marine animals commonly referred to as sea lilies and feather stars. Crinoids are distinguished by their cup-shaped body (the calyx), a set of radiating arms, and a long stalk (in some species) that anchors them to the seabed. The arms are typically branched and covered with feathery extensions that aid in filter feeding, capturing small particles from the water. Though modern crinoids tend to be less prominent in marine ecosystems, they were once much more abundant and diverse, particularly during the Palaeozoic era.

Crinoids first appeared in the Ordovician period, about 480 million years ago, and quickly diversified. They were especially abundant during the Palaeozoic, with their greatest diversity occurring during the Carboniferous period, when extensive shallow seas created ideal conditions for large crinoid populations. Fossil crinoids are especially common in limestone deposits from this time, with entire beds of rock often composed almost entirely of disarticulated crinoid fragments, particularly their stems. These fossils are widespread in regions like the UK, where crinoid-rich limestone formations are frequently found.

Crinoids come in two main forms: stalked crinoids, or sea lilies, which attach to the sea floor via a flexible stalk, and unstalked crinoids, or feather stars, which are mobile and can swim or crawl along the substrate using their arms. In the fossil record, stalked crinoids were much more abundant, with long, segmented stalks that could grow several meters in length. The stalks are composed of individual ossicles, small calcareous plates that are commonly found as fossils, especially in Carboniferous limestone beds. The most well-known fossil remains of crinoids are these stem ossicles, which are often referred to as "Indian beads" due to their cylindrical shape.

Crinoids reached their peak during the Palaeozoic, forming extensive colonies in shallow seas, often in association with coral reefs. Their filter-feeding mechanism allowed them to occupy a specialised ecological niche, and they played an important role in marine ecosystems as suspension feeders. However, crinoids were significantly affected by the Permian-Triassic mass extinction about 252 million years ago, which wiped out many marine species. Although crinoids survived this event, their diversity and abundance were greatly reduced.

In the Mesozoic era, crinoids experienced a resurgence, though not to the same levels of diversity as in the Palaeozoic. Feather stars (unstalked crinoids) became more prominent during the Jurassic and Cretaceous periods, adapting to more mobile lifestyles compared to their sessile ancestors. Today, feather stars are found in a variety of marine environments, from shallow reefs to deep-sea habitats, while stalked crinoids are largely restricted to deep water.

Crinoids are unique among echinoderms in that they are suspension feeders, using their feathery arms to catch plankton and other small particles from the water. Their arms are lined with cilia that move captured food towards their central mouth, which is located on the upper surface of the calyx. This feeding strategy differs from other echinoderms, such as sea urchins, which graze on algae, or starfish, which are typically predatory.

Despite their decline in modern oceans, crinoids remain important in the fossil record due to their abundant and well-preserved remains, particularly in Palaeozoic and Mesozoic sedimentary rocks. The characteristic segmented stalks and calyx plates of crinoids make them highly recognisable fossils, and they provide key insights into the structure and biodiversity of ancient marine ecosystems. In particular, Carboniferous limestone deposits, such as those found in the UK, are often rich in crinoid remains, offering palaeontologists a detailed record of these once-dominant marine invertebrates.

Age: 346-344Ma

Viséan

Middle Mississippian Epoch

Carboniferous Period - Giant arthropods and amphibians, early reptiles, most plants fern or lycophyte-like, known for tropical forests and seas

Paleozoic Era - pre-Dinosaurs

Location: Lancashire

Clitheroe

Salthill Quarry

Rock Type: Course grained and coursely crinoidal limestone, with lots of calcite from crinoid structure, park of a knoll-reef from the Clitheroe Limestone Formation.

Specimen:

A large crinoid column about 3.5cm in diameter, 4cm at its widest, with the clear pentastellate axial canal visible. This section is only about 1-1.5cm tall

Species:

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Echinodermata is a phylum of marine invertebrates that includes well-known groups like starfish, sea urchins, brittle stars, sea cucumbers, and crinoids. Echinoderms are characterised by their radial symmetry, typically arranged in fives, and their unique water vascular system, which aids in locomotion and feeding. This phylum is exclusively marine, and its members are often found on the sea floor, from shallow waters to the deep ocean. Echinoderms exhibit pentameral symmetry as adults, though their larvae are bilaterally symmetrical, reflecting their evolutionary relationship with other deuterostomes, including chordates.

Within this phylum, Class Crinoidea includes marine animals commonly referred to as sea lilies and feather stars. Crinoids are distinguished by their cup-shaped body (the calyx), a set of radiating arms, and a long stalk (in some species) that anchors them to the seabed. The arms are typically branched and covered with feathery extensions that aid in filter feeding, capturing small particles from the water. Though modern crinoids tend to be less prominent in marine ecosystems, they were once much more abundant and diverse, particularly during the Palaeozoic era.

Crinoids first appeared in the Ordovician period, about 480 million years ago, and quickly diversified. They were especially abundant during the Palaeozoic, with their greatest diversity occurring during the Carboniferous period, when extensive shallow seas created ideal conditions for large crinoid populations. Fossil crinoids are especially common in limestone deposits from this time, with entire beds of rock often composed almost entirely of disarticulated crinoid fragments, particularly their stems. These fossils are widespread in regions like the UK, where crinoid-rich limestone formations are frequently found.

Crinoids come in two main forms: stalked crinoids, or sea lilies, which attach to the sea floor via a flexible stalk, and unstalked crinoids, or feather stars, which are mobile and can swim or crawl along the substrate using their arms. In the fossil record, stalked crinoids were much more abundant, with long, segmented stalks that could grow several meters in length. The stalks are composed of individual ossicles, small calcareous plates that are commonly found as fossils, especially in Carboniferous limestone beds. The most well-known fossil remains of crinoids are these stem ossicles, which are often referred to as "Indian beads" due to their cylindrical shape.

Crinoids reached their peak during the Palaeozoic, forming extensive colonies in shallow seas, often in association with coral reefs. Their filter-feeding mechanism allowed them to occupy a specialised ecological niche, and they played an important role in marine ecosystems as suspension feeders. However, crinoids were significantly affected by the Permian-Triassic mass extinction about 252 million years ago, which wiped out many marine species. Although crinoids survived this event, their diversity and abundance were greatly reduced.

In the Mesozoic era, crinoids experienced a resurgence, though not to the same levels of diversity as in the Palaeozoic. Feather stars (unstalked crinoids) became more prominent during the Jurassic and Cretaceous periods, adapting to more mobile lifestyles compared to their sessile ancestors. Today, feather stars are found in a variety of marine environments, from shallow reefs to deep-sea habitats, while stalked crinoids are largely restricted to deep water.

Crinoids are unique among echinoderms in that they are suspension feeders, using their feathery arms to catch plankton and other small particles from the water. Their arms are lined with cilia that move captured food towards their central mouth, which is located on the upper surface of the calyx. This feeding strategy differs from other echinoderms, such as sea urchins, which graze on algae, or starfish, which are typically predatory.

Despite their decline in modern oceans, crinoids remain important in the fossil record due to their abundant and well-preserved remains, particularly in Palaeozoic and Mesozoic sedimentary rocks. The characteristic segmented stalks and calyx plates of crinoids make them highly recognisable fossils, and they provide key insights into the structure and biodiversity of ancient marine ecosystems. In particular, Carboniferous limestone deposits, such as those found in the UK, are often rich in crinoid remains, offering palaeontologists a detailed record of these once-dominant marine invertebrates.

Age: 346-344Ma

Viséan

Middle Mississippian Epoch

Carboniferous Period - Giant arthropods and amphibians, early reptiles, most plants fern or lycophyte-like, known for tropical forests and seas

Paleozoic Era - pre-Dinosaurs

Location: Lancashire

Clitheroe

Salthill Quarry

Rock Type: Course grained and coursely crinoidal limestone, with lots of calcite from crinoid structure, park of a knoll-reef from the Clitheroe Limestone Formation.

Specimen:

A large crinoid column about 3.5cm in diameter, 4cm at its widest, with the clear pentastellate axial canal visible. This section is only about 1-1.5cm tall

Species:

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Echinodermata is a phylum of marine invertebrates that includes well-known groups like starfish, sea urchins, brittle stars, sea cucumbers, and crinoids. Echinoderms are characterised by their radial symmetry, typically arranged in fives, and their unique water vascular system, which aids in locomotion and feeding. This phylum is exclusively marine, and its members are often found on the sea floor, from shallow waters to the deep ocean. Echinoderms exhibit pentameral symmetry as adults, though their larvae are bilaterally symmetrical, reflecting their evolutionary relationship with other deuterostomes, including chordates.

Within this phylum, Class Crinoidea includes marine animals commonly referred to as sea lilies and feather stars. Crinoids are distinguished by their cup-shaped body (the calyx), a set of radiating arms, and a long stalk (in some species) that anchors them to the seabed. The arms are typically branched and covered with feathery extensions that aid in filter feeding, capturing small particles from the water. Though modern crinoids tend to be less prominent in marine ecosystems, they were once much more abundant and diverse, particularly during the Palaeozoic era.

Crinoids first appeared in the Ordovician period, about 480 million years ago, and quickly diversified. They were especially abundant during the Palaeozoic, with their greatest diversity occurring during the Carboniferous period, when extensive shallow seas created ideal conditions for large crinoid populations. Fossil crinoids are especially common in limestone deposits from this time, with entire beds of rock often composed almost entirely of disarticulated crinoid fragments, particularly their stems. These fossils are widespread in regions like the UK, where crinoid-rich limestone formations are frequently found.

Crinoids come in two main forms: stalked crinoids, or sea lilies, which attach to the sea floor via a flexible stalk, and unstalked crinoids, or feather stars, which are mobile and can swim or crawl along the substrate using their arms. In the fossil record, stalked crinoids were much more abundant, with long, segmented stalks that could grow several meters in length. The stalks are composed of individual ossicles, small calcareous plates that are commonly found as fossils, especially in Carboniferous limestone beds. The most well-known fossil remains of crinoids are these stem ossicles, which are often referred to as "Indian beads" due to their cylindrical shape.

Crinoids reached their peak during the Palaeozoic, forming extensive colonies in shallow seas, often in association with coral reefs. Their filter-feeding mechanism allowed them to occupy a specialised ecological niche, and they played an important role in marine ecosystems as suspension feeders. However, crinoids were significantly affected by the Permian-Triassic mass extinction about 252 million years ago, which wiped out many marine species. Although crinoids survived this event, their diversity and abundance were greatly reduced.

In the Mesozoic era, crinoids experienced a resurgence, though not to the same levels of diversity as in the Palaeozoic. Feather stars (unstalked crinoids) became more prominent during the Jurassic and Cretaceous periods, adapting to more mobile lifestyles compared to their sessile ancestors. Today, feather stars are found in a variety of marine environments, from shallow reefs to deep-sea habitats, while stalked crinoids are largely restricted to deep water.

Crinoids are unique among echinoderms in that they are suspension feeders, using their feathery arms to catch plankton and other small particles from the water. Their arms are lined with cilia that move captured food towards their central mouth, which is located on the upper surface of the calyx. This feeding strategy differs from other echinoderms, such as sea urchins, which graze on algae, or starfish, which are typically predatory.

Despite their decline in modern oceans, crinoids remain important in the fossil record due to their abundant and well-preserved remains, particularly in Palaeozoic and Mesozoic sedimentary rocks. The characteristic segmented stalks and calyx plates of crinoids make them highly recognisable fossils, and they provide key insights into the structure and biodiversity of ancient marine ecosystems. In particular, Carboniferous limestone deposits, such as those found in the UK, are often rich in crinoid remains, offering palaeontologists a detailed record of these once-dominant marine invertebrates.

Age: 346-344Ma

Viséan

Middle Mississippian Epoch

Carboniferous Period - Giant arthropods and amphibians, early reptiles, most plants fern or lycophyte-like, known for tropical forests and seas

Paleozoic Era - pre-Dinosaurs

Location: Lancashire

Clitheroe

Salthill Quarry

Rock Type: Course grained and coursely crinoidal limestone, with lots of calcite from crinoid structure, park of a knoll-reef from the Clitheroe Limestone Formation.

Specimen:

A large crinoid column about 3.5cm in diameter, 4cm at its widest, with the clear pentastellate axial canal visible. This section is only about 1-1.5cm tall

Species:

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Echinodermata is a phylum of marine invertebrates that includes well-known groups like starfish, sea urchins, brittle stars, sea cucumbers, and crinoids. Echinoderms are characterised by their radial symmetry, typically arranged in fives, and their unique water vascular system, which aids in locomotion and feeding. This phylum is exclusively marine, and its members are often found on the sea floor, from shallow waters to the deep ocean. Echinoderms exhibit pentameral symmetry as adults, though their larvae are bilaterally symmetrical, reflecting their evolutionary relationship with other deuterostomes, including chordates.

Within this phylum, Class Crinoidea includes marine animals commonly referred to as sea lilies and feather stars. Crinoids are distinguished by their cup-shaped body (the calyx), a set of radiating arms, and a long stalk (in some species) that anchors them to the seabed. The arms are typically branched and covered with feathery extensions that aid in filter feeding, capturing small particles from the water. Though modern crinoids tend to be less prominent in marine ecosystems, they were once much more abundant and diverse, particularly during the Palaeozoic era.

Crinoids first appeared in the Ordovician period, about 480 million years ago, and quickly diversified. They were especially abundant during the Palaeozoic, with their greatest diversity occurring during the Carboniferous period, when extensive shallow seas created ideal conditions for large crinoid populations. Fossil crinoids are especially common in limestone deposits from this time, with entire beds of rock often composed almost entirely of disarticulated crinoid fragments, particularly their stems. These fossils are widespread in regions like the UK, where crinoid-rich limestone formations are frequently found.

Crinoids come in two main forms: stalked crinoids, or sea lilies, which attach to the sea floor via a flexible stalk, and unstalked crinoids, or feather stars, which are mobile and can swim or crawl along the substrate using their arms. In the fossil record, stalked crinoids were much more abundant, with long, segmented stalks that could grow several meters in length. The stalks are composed of individual ossicles, small calcareous plates that are commonly found as fossils, especially in Carboniferous limestone beds. The most well-known fossil remains of crinoids are these stem ossicles, which are often referred to as "Indian beads" due to their cylindrical shape.

Crinoids reached their peak during the Palaeozoic, forming extensive colonies in shallow seas, often in association with coral reefs. Their filter-feeding mechanism allowed them to occupy a specialised ecological niche, and they played an important role in marine ecosystems as suspension feeders. However, crinoids were significantly affected by the Permian-Triassic mass extinction about 252 million years ago, which wiped out many marine species. Although crinoids survived this event, their diversity and abundance were greatly reduced.

In the Mesozoic era, crinoids experienced a resurgence, though not to the same levels of diversity as in the Palaeozoic. Feather stars (unstalked crinoids) became more prominent during the Jurassic and Cretaceous periods, adapting to more mobile lifestyles compared to their sessile ancestors. Today, feather stars are found in a variety of marine environments, from shallow reefs to deep-sea habitats, while stalked crinoids are largely restricted to deep water.

Crinoids are unique among echinoderms in that they are suspension feeders, using their feathery arms to catch plankton and other small particles from the water. Their arms are lined with cilia that move captured food towards their central mouth, which is located on the upper surface of the calyx. This feeding strategy differs from other echinoderms, such as sea urchins, which graze on algae, or starfish, which are typically predatory.

Despite their decline in modern oceans, crinoids remain important in the fossil record due to their abundant and well-preserved remains, particularly in Palaeozoic and Mesozoic sedimentary rocks. The characteristic segmented stalks and calyx plates of crinoids make them highly recognisable fossils, and they provide key insights into the structure and biodiversity of ancient marine ecosystems. In particular, Carboniferous limestone deposits, such as those found in the UK, are often rich in crinoid remains, offering palaeontologists a detailed record of these once-dominant marine invertebrates.

Gastrula:

Pink: Mesoderm

Yellow: Endoderm

Blue: Ectoderm

White (coming out side): Yolk plug

Age: 346-344Ma

Viséan

Middle Mississippian Epoch

Carboniferous Period - Giant arthropods and amphibians, early reptiles, most plants fern or lycophyte-like, known for tropical forests and seas

Paleozoic Era - pre-Dinosaurs

Location: Lancashire

Clitheroe

Salthill Quarry

Rock Type: Course grained and coursely crinoidal limestone, with lots of calcite from crinoid structure, park of a knoll-reef from the Clitheroe Limestone Formation.

Specimen:

A large crinoid column about 3.5cm in diameter, 4cm at its widest, with the clear pentastellate axial canal visible. This section is only about 1-1.5cm tall

Species:

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Echinodermata is a phylum of marine invertebrates that includes well-known groups like starfish, sea urchins, brittle stars, sea cucumbers, and crinoids. Echinoderms are characterised by their radial symmetry, typically arranged in fives, and their unique water vascular system, which aids in locomotion and feeding. This phylum is exclusively marine, and its members are often found on the sea floor, from shallow waters to the deep ocean. Echinoderms exhibit pentameral symmetry as adults, though their larvae are bilaterally symmetrical, reflecting their evolutionary relationship with other deuterostomes, including chordates.

Within this phylum, Class Crinoidea includes marine animals commonly referred to as sea lilies and feather stars. Crinoids are distinguished by their cup-shaped body (the calyx), a set of radiating arms, and a long stalk (in some species) that anchors them to the seabed. The arms are typically branched and covered with feathery extensions that aid in filter feeding, capturing small particles from the water. Though modern crinoids tend to be less prominent in marine ecosystems, they were once much more abundant and diverse, particularly during the Palaeozoic era.

Crinoids first appeared in the Ordovician period, about 480 million years ago, and quickly diversified. They were especially abundant during the Palaeozoic, with their greatest diversity occurring during the Carboniferous period, when extensive shallow seas created ideal conditions for large crinoid populations. Fossil crinoids are especially common in limestone deposits from this time, with entire beds of rock often composed almost entirely of disarticulated crinoid fragments, particularly their stems. These fossils are widespread in regions like the UK, where crinoid-rich limestone formations are frequently found.

Crinoids come in two main forms: stalked crinoids, or sea lilies, which attach to the sea floor via a flexible stalk, and unstalked crinoids, or feather stars, which are mobile and can swim or crawl along the substrate using their arms. In the fossil record, stalked crinoids were much more abundant, with long, segmented stalks that could grow several meters in length. The stalks are composed of individual ossicles, small calcareous plates that are commonly found as fossils, especially in Carboniferous limestone beds. The most well-known fossil remains of crinoids are these stem ossicles, which are often referred to as "Indian beads" due to their cylindrical shape.

Crinoids reached their peak during the Palaeozoic, forming extensive colonies in shallow seas, often in association with coral reefs. Their filter-feeding mechanism allowed them to occupy a specialised ecological niche, and they played an important role in marine ecosystems as suspension feeders. However, crinoids were significantly affected by the Permian-Triassic mass extinction about 252 million years ago, which wiped out many marine species. Although crinoids survived this event, their diversity and abundance were greatly reduced.

In the Mesozoic era, crinoids experienced a resurgence, though not to the same levels of diversity as in the Palaeozoic. Feather stars (unstalked crinoids) became more prominent during the Jurassic and Cretaceous periods, adapting to more mobile lifestyles compared to their sessile ancestors. Today, feather stars are found in a variety of marine environments, from shallow reefs to deep-sea habitats, while stalked crinoids are largely restricted to deep water.

Crinoids are unique among echinoderms in that they are suspension feeders, using their feathery arms to catch plankton and other small particles from the water. Their arms are lined with cilia that move captured food towards their central mouth, which is located on the upper surface of the calyx. This feeding strategy differs from other echinoderms, such as sea urchins, which graze on algae, or starfish, which are typically predatory.

Despite their decline in modern oceans, crinoids remain important in the fossil record due to their abundant and well-preserved remains, particularly in Palaeozoic and Mesozoic sedimentary rocks. The characteristic segmented stalks and calyx plates of crinoids make them highly recognisable fossils, and they provide key insights into the structure and biodiversity of ancient marine ecosystems. In particular, Carboniferous limestone deposits, such as those found in the UK, are often rich in crinoid remains, offering palaeontologists a detailed record of these once-dominant marine invertebrates.

Age: 346-344Ma

Viséan

Middle Mississippian Epoch

Carboniferous Period - Giant arthropods and amphibians, early reptiles, most plants fern or lycophyte-like, known for tropical forests and seas

Paleozoic Era - pre-Dinosaurs

Location: Lancashire

Clitheroe

Salthill Quarry

Rock Type: Course grained and coursely crinoidal limestone, with lots of calcite from crinoid structure, park of a knoll-reef from the Clitheroe Limestone Formation.

Specimen:

A large crinoid column about 3.5cm in diameter, 4cm at its widest, with the clear pentastellate axial canal visible. This section is only about 1-1.5cm tall

Species:

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Echinodermata is a phylum of marine invertebrates that includes well-known groups like starfish, sea urchins, brittle stars, sea cucumbers, and crinoids. Echinoderms are characterised by their radial symmetry, typically arranged in fives, and their unique water vascular system, which aids in locomotion and feeding. This phylum is exclusively marine, and its members are often found on the sea floor, from shallow waters to the deep ocean. Echinoderms exhibit pentameral symmetry as adults, though their larvae are bilaterally symmetrical, reflecting their evolutionary relationship with other deuterostomes, including chordates.

Within this phylum, Class Crinoidea includes marine animals commonly referred to as sea lilies and feather stars. Crinoids are distinguished by their cup-shaped body (the calyx), a set of radiating arms, and a long stalk (in some species) that anchors them to the seabed. The arms are typically branched and covered with feathery extensions that aid in filter feeding, capturing small particles from the water. Though modern crinoids tend to be less prominent in marine ecosystems, they were once much more abundant and diverse, particularly during the Palaeozoic era.

Crinoids first appeared in the Ordovician period, about 480 million years ago, and quickly diversified. They were especially abundant during the Palaeozoic, with their greatest diversity occurring during the Carboniferous period, when extensive shallow seas created ideal conditions for large crinoid populations. Fossil crinoids are especially common in limestone deposits from this time, with entire beds of rock often composed almost entirely of disarticulated crinoid fragments, particularly their stems. These fossils are widespread in regions like the UK, where crinoid-rich limestone formations are frequently found.

Crinoids come in two main forms: stalked crinoids, or sea lilies, which attach to the sea floor via a flexible stalk, and unstalked crinoids, or feather stars, which are mobile and can swim or crawl along the substrate using their arms. In the fossil record, stalked crinoids were much more abundant, with long, segmented stalks that could grow several meters in length. The stalks are composed of individual ossicles, small calcareous plates that are commonly found as fossils, especially in Carboniferous limestone beds. The most well-known fossil remains of crinoids are these stem ossicles, which are often referred to as "Indian beads" due to their cylindrical shape.

Crinoids reached their peak during the Palaeozoic, forming extensive colonies in shallow seas, often in association with coral reefs. Their filter-feeding mechanism allowed them to occupy a specialised ecological niche, and they played an important role in marine ecosystems as suspension feeders. However, crinoids were significantly affected by the Permian-Triassic mass extinction about 252 million years ago, which wiped out many marine species. Although crinoids survived this event, their diversity and abundance were greatly reduced.

In the Mesozoic era, crinoids experienced a resurgence, though not to the same levels of diversity as in the Palaeozoic. Feather stars (unstalked crinoids) became more prominent during the Jurassic and Cretaceous periods, adapting to more mobile lifestyles compared to their sessile ancestors. Today, feather stars are found in a variety of marine environments, from shallow reefs to deep-sea habitats, while stalked crinoids are largely restricted to deep water.

Crinoids are unique among echinoderms in that they are suspension feeders, using their feathery arms to catch plankton and other small particles from the water. Their arms are lined with cilia that move captured food towards their central mouth, which is located on the upper surface of the calyx. This feeding strategy differs from other echinoderms, such as sea urchins, which graze on algae, or starfish, which are typically predatory.

Despite their decline in modern oceans, crinoids remain important in the fossil record due to their abundant and well-preserved remains, particularly in Palaeozoic and Mesozoic sedimentary rocks. The characteristic segmented stalks and calyx plates of crinoids make them highly recognisable fossils, and they provide key insights into the structure and biodiversity of ancient marine ecosystems. In particular, Carboniferous limestone deposits, such as those found in the UK, are often rich in crinoid remains, offering palaeontologists a detailed record of these once-dominant marine invertebrates.

Species:

Siphonodendron junceum is an extinct species of colonial rugose coral that flourished during the Carboniferous period, being among the most common corals found from this period. Belonging to the family Lithostrotiidae, these corals were significant reef-builders, contributing to the development of carbonate platforms in warm, tropical seas.

Colonies of Siphonodendron junceum are distinguished by their branching, cylindrical corallites, which often formed dense, bush-like structures, and are compared to spaghetti. Each individual corallite rarely measured much more than 6 millimetres in diameter, with internal septa arranged in a radial pattern to support the coral’s skeletal framework, though septa are often hard to make out and seem absent in this species. Its preferred environment consisted of shallow, clear, and warm marine settings

Note: Anthozoa is sometimes considered a subphylum, with its major consituents making up the classes. These being Class Ceriantharia, Hexacorallia (including Scleractinia and Rugosa), Octocorallia, and Tabulata. These will all be included in this collection, but ordered by their type above the usual ordering by level of taxonomic precision and alphabetically.

Cnidaria is a phylum of simple aquatic animals, best known for their radial symmetry, nematocysts (stinging cells), and a body plan organised around a central cavity. The phylum includes organisms like jellyfish, sea anemones, hydras, and corals. Most cnidarians have two basic body forms: the free-swimming medusa (as seen in jellyfish) and the sessile polyp (typical of corals and sea anemones). Cnidarians exhibit a diploblastic structure, meaning they possess two primary cell layers, the ectoderm and endoderm, with a gelatinous layer called the mesoglea in between. While many cnidarians are carnivorous, using their stinging cells to capture prey, some, particularly corals, have developed symbiotic relationships with photosynthetic organisms like zooxanthellae, which assist in nutrient production.

Within this diverse phylum, Class Anthozoa includes organisms that exist exclusively in the polyp form and lack a medusa stage. Anthozoans are primarily sessile, attached to the substrate, and include groups like corals and sea anemones. Among anthozoans, corals are the most significant from a geological and palaeontological perspective due to their capacity to build massive reef structures over geological time. Coral polyps typically secrete calcium carbonate to form exoskeletons, which fossilise readily, making them important indicators in the fossil record. Anthozoa is further divided into orders such as Hexacorallia, which includes the modern reef-building corals, and Octocorallia, which comprises soft corals and sea fans.

The fossil record of corals is particularly rich, with three major types standing out: tabulate corals, rugose corals, and scleractinian corals, each representing different eras of coral dominance in Earth's history.

Tabulate corals were dominant during the Palaeozoic era, especially from the Ordovician to the Permian. These corals are characterised by their colonial nature and the presence of horizontal internal divisions known as tabulae. Unlike later corals, tabulate corals lacked septa (vertical internal walls) and often formed large, tightly packed colonies. They contributed significantly to reef ecosystems in shallow tropical seas during the Silurian and Devonian periods. However, they became extinct at the end of the Permian, during the Permian-Triassic mass extinction. Their decline mirrored broader ecological upheavals that affected much of marine life at that time.

Rugose corals, also known as horn corals, coexisted with tabulate corals and appeared in the Ordovician, flourishing through the Devonian and into the Carboniferous. These corals could be either solitary or colonial, and their most distinctive feature is the presence of septal divisions within the coral skeleton, radiating from a central point. The solitary forms often resembled a horn in shape, giving them their common name. Rugose corals also contributed to Palaeozoic reef systems and are frequently found as fossils in limestone formations from these periods. Like the tabulate corals, rugose corals were wiped out during the Permian-Triassic extinction, marking the end of their dominance in marine ecosystems.

Following the extinction of tabulate and rugose corals, the Scleractinian corals (modern corals) emerged in the Triassic and have been the primary reef-builders ever since. Scleractinian corals also possess calcareous skeletons but differ from their predecessors in their skeletal microstructure, which is composed of aragonite rather than calcite. These corals are notable for their ability to form both solitary and colonial structures, with colonial forms building the vast coral reefs seen in modern oceans. Reef-building scleractinians rely heavily on symbiotic zooxanthellae, which enable them to thrive in nutrient-poor, sunlit waters by performing photosynthesis. Scleractinians became the dominant corals from the Jurassic onwards, and they continue to dominate coral reef ecosystems today, making them critical components of modern marine biodiversity.

Age: 346-344Ma

Viséan

Middle Mississippian Epoch

Carboniferous Period - Giant arthropods and amphibians, early reptiles, most plants fern or lycophyte-like, known for tropical forests and seas

Paleozoic Era - pre-Dinosaurs

Location: Lancashire

Clitheroe

Salthill Quarry

Rock Type: Course grained and coursely crinoidal limestone, with lots of calcite from crinoid structure, park of a knoll-reef from the Clitheroe Limestone Formation.

Specimen:

A large crinoid column about 3.5cm in diameter, 4cm at its widest, with the clear pentastellate axial canal visible. This section is only about 1-1.5cm tall

Species:

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Echinodermata is a phylum of marine invertebrates that includes well-known groups like starfish, sea urchins, brittle stars, sea cucumbers, and crinoids. Echinoderms are characterised by their radial symmetry, typically arranged in fives, and their unique water vascular system, which aids in locomotion and feeding. This phylum is exclusively marine, and its members are often found on the sea floor, from shallow waters to the deep ocean. Echinoderms exhibit pentameral symmetry as adults, though their larvae are bilaterally symmetrical, reflecting their evolutionary relationship with other deuterostomes, including chordates.

Within this phylum, Class Crinoidea includes marine animals commonly referred to as sea lilies and feather stars. Crinoids are distinguished by their cup-shaped body (the calyx), a set of radiating arms, and a long stalk (in some species) that anchors them to the seabed. The arms are typically branched and covered with feathery extensions that aid in filter feeding, capturing small particles from the water. Though modern crinoids tend to be less prominent in marine ecosystems, they were once much more abundant and diverse, particularly during the Palaeozoic era.

Crinoids first appeared in the Ordovician period, about 480 million years ago, and quickly diversified. They were especially abundant during the Palaeozoic, with their greatest diversity occurring during the Carboniferous period, when extensive shallow seas created ideal conditions for large crinoid populations. Fossil crinoids are especially common in limestone deposits from this time, with entire beds of rock often composed almost entirely of disarticulated crinoid fragments, particularly their stems. These fossils are widespread in regions like the UK, where crinoid-rich limestone formations are frequently found.

Crinoids come in two main forms: stalked crinoids, or sea lilies, which attach to the sea floor via a flexible stalk, and unstalked crinoids, or feather stars, which are mobile and can swim or crawl along the substrate using their arms. In the fossil record, stalked crinoids were much more abundant, with long, segmented stalks that could grow several meters in length. The stalks are composed of individual ossicles, small calcareous plates that are commonly found as fossils, especially in Carboniferous limestone beds. The most well-known fossil remains of crinoids are these stem ossicles, which are often referred to as "Indian beads" due to their cylindrical shape.

Crinoids reached their peak during the Palaeozoic, forming extensive colonies in shallow seas, often in association with coral reefs. Their filter-feeding mechanism allowed them to occupy a specialised ecological niche, and they played an important role in marine ecosystems as suspension feeders. However, crinoids were significantly affected by the Permian-Triassic mass extinction about 252 million years ago, which wiped out many marine species. Although crinoids survived this event, their diversity and abundance were greatly reduced.

In the Mesozoic era, crinoids experienced a resurgence, though not to the same levels of diversity as in the Palaeozoic. Feather stars (unstalked crinoids) became more prominent during the Jurassic and Cretaceous periods, adapting to more mobile lifestyles compared to their sessile ancestors. Today, feather stars are found in a variety of marine environments, from shallow reefs to deep-sea habitats, while stalked crinoids are largely restricted to deep water.

Crinoids are unique among echinoderms in that they are suspension feeders, using their feathery arms to catch plankton and other small particles from the water. Their arms are lined with cilia that move captured food towards their central mouth, which is located on the upper surface of the calyx. This feeding strategy differs from other echinoderms, such as sea urchins, which graze on algae, or starfish, which are typically predatory.

Despite their decline in modern oceans, crinoids remain important in the fossil record due to their abundant and well-preserved remains, particularly in Palaeozoic and Mesozoic sedimentary rocks. The characteristic segmented stalks and calyx plates of crinoids make them highly recognisable fossils, and they provide key insights into the structure and biodiversity of ancient marine ecosystems. In particular, Carboniferous limestone deposits, such as those found in the UK, are often rich in crinoid remains, offering palaeontologists a detailed record of these once-dominant marine invertebrates.

Age: 346–344 Ma

Viséan

Middle Mississippian Epoch

Carboniferous Period – Giant arthropods and amphibians, early reptiles, most plants fern or lycophyte-like, known for tropical forests and seas

Paleozoic Era – pre-Dinosaurs

Location: Lancashire

Clitheroe

Salthill Quarry

Rock Type: Coarse-grained and coarsely crinoidal limestone, with abundant calcite from crinoid structures, part of a knoll-reef within the Clitheroe Limestone Formation

Species:

Cladochonus is an extinct genus of tabulate coral that lived during the Carboniferous period, approximately 346 to 344 million years ago. Tabulate corals, among the most ancient coral types to evolve, are characterised by their lateral tabulae, skeletal structures that rise in stacked plates, rather than the radial septa seen in rugose or modern scleractinian corals. This distinctive feature made tabulate corals structurally weaker, limiting their ability to compete for space in high-energy environments.

In the competitive knoll-reefs [more accurately considered to be banks] ecosystem of tropical Carboniferous seas, with towering crinoids and dense coral growths, Cladochonus sp. found a unique survival strategy. Instead of competing on the muddy seafloor, this small, spindly coral adapted to an epizoan lifestyle, growing around and along the stalks of sea lilies (crinoids). This climbing behaviour allowed its anemone-like polyps to reach higher into the nutrient-rich ocean currents, avoiding the sediment-laden seafloor and bypassing competition for resources.

Fossils of Cladochonus sp. often show pale, circular structures embedded along crinoid stems, connected by creeping skeletal lines. These are the remains of the coral’s tube-like skeletons, which wrapped around the crinoids for support. This relationship was not symbiotic, however; evidence from fossilised crinoids indicates they reacted to the encroaching coral by growing to envelop or block the coral. This suggests the crinoids expended energy defending themselves, marking the relationship as parasitic in nature, as the coral benefited from the crinoid’s height while causing some harm to its host.

Ecologically, Cladochonus sp. played a small but significant role in the tropical reef systems of the Carboniferous, adapting to challenges by using other organisms to secure a competitive advantage. Its fossils, often preserved intertwined with crinoid stems, provide a snapshot of this dynamic, ancient marine relationship. Like other tabulate corals, Cladochonus sp. eventually declined and disappeared by the end of the Permian period, leaving a fascinating record of its adaptations.

Note: Anthozoa is sometimes considered a subphylum, with its major consituents making up the classes. These being Class Ceriantharia, Hexacorallia (including Scleractinia and Rugosa), Octocorallia, and Tabulata. These will all be included in this collection, but ordered by their type above the usual ordering by level of taxonomic precision and alphabetically.

Cnidaria is a phylum of simple aquatic animals, best known for their radial symmetry, nematocysts (stinging cells), and a body plan organised around a central cavity. The phylum includes organisms like jellyfish, sea anemones, hydras, and corals. Most cnidarians have two basic body forms: the free-swimming medusa (as seen in jellyfish) and the sessile polyp (typical of corals and sea anemones). Cnidarians exhibit a diploblastic structure, meaning they possess two primary cell layers, the ectoderm and endoderm, with a gelatinous layer called the mesoglea in between. While many cnidarians are carnivorous, using their stinging cells to capture prey, some, particularly corals, have developed symbiotic relationships with photosynthetic organisms like zooxanthellae, which assist in nutrient production.

Within this diverse phylum, Class Anthozoa includes organisms that exist exclusively in the polyp form and lack a medusa stage. Anthozoans are primarily sessile, attached to the substrate, and include groups like corals and sea anemones. Among anthozoans, corals are the most significant from a geological and palaeontological perspective due to their capacity to build massive reef structures over geological time. Coral polyps typically secrete calcium carbonate to form exoskeletons, which fossilise readily, making them important indicators in the fossil record. Anthozoa is further divided into orders such as Hexacorallia, which includes the modern reef-building corals, and Octocorallia, which comprises soft corals and sea fans.

The fossil record of corals is particularly rich, with three major types standing out: tabulate corals, rugose corals, and scleractinian corals, each representing different eras of coral dominance in Earth's history.

Tabulate corals were dominant during the Palaeozoic era, especially from the Ordovician to the Permian. These corals are characterised by their colonial nature and the presence of horizontal internal divisions known as tabulae. Unlike later corals, tabulate corals lacked septa (vertical internal walls) and often formed large, tightly packed colonies. They contributed significantly to reef ecosystems in shallow tropical seas during the Silurian and Devonian periods. However, they became extinct at the end of the Permian, during the Permian-Triassic mass extinction. Their decline mirrored broader ecological upheavals that affected much of marine life at that time.

Rugose corals, also known as horn corals, coexisted with tabulate corals and appeared in the Ordovician, flourishing through the Devonian and into the Carboniferous. These corals could be either solitary or colonial, and their most distinctive feature is the presence of septal divisions within the coral skeleton, radiating from a central point. The solitary forms often resembled a horn in shape, giving them their common name. Rugose corals also contributed to Palaeozoic reef systems and are frequently found as fossils in limestone formations from these periods. Like the tabulate corals, rugose corals were wiped out during the Permian-Triassic extinction, marking the end of their dominance in marine ecosystems.

Following the extinction of tabulate and rugose corals, the Scleractinian corals (modern corals) emerged in the Triassic and have been the primary reef-builders ever since. Scleractinian corals also possess calcareous skeletons but differ from their predecessors in their skeletal microstructure, which is composed of aragonite rather than calcite. These corals are notable for their ability to form both solitary and colonial structures, with colonial forms building the vast coral reefs seen in modern oceans. Reef-building scleractinians rely heavily on symbiotic zooxanthellae, which enable them to thrive in nutrient-poor, sunlit waters by performing photosynthesis. Scleractinians became the dominant corals from the Jurassic onwards, and they continue to dominate coral reef ecosystems today, making them critical components of modern marine biodiversity.

Age: 346-344Ma

Viséan

Middle Mississippian Epoch

Carboniferous Period - Giant arthropods and amphibians, early reptiles, most plants fern or lycophyte-like, known for tropical forests and seas

Paleozoic Era - pre-Dinosaurs

Location: Lancashire

Clitheroe

Salthill Quarry

Rock Type: Course grained and coursely crinoidal limestone, with lots of calcite from crinoid structure, park of a knoll-reef from the Clitheroe Limestone Formation.

Specimen:

A large crinoid column about 3.5cm in diameter, 4cm at its widest, with the clear pentastellate axial canal visible. This section is only about 1-1.5cm tall

Species:

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Echinodermata is a phylum of marine invertebrates that includes well-known groups like starfish, sea urchins, brittle stars, sea cucumbers, and crinoids. Echinoderms are characterised by their radial symmetry, typically arranged in fives, and their unique water vascular system, which aids in locomotion and feeding. This phylum is exclusively marine, and its members are often found on the sea floor, from shallow waters to the deep ocean. Echinoderms exhibit pentameral symmetry as adults, though their larvae are bilaterally symmetrical, reflecting their evolutionary relationship with other deuterostomes, including chordates.

Within this phylum, Class Crinoidea includes marine animals commonly referred to as sea lilies and feather stars. Crinoids are distinguished by their cup-shaped body (the calyx), a set of radiating arms, and a long stalk (in some species) that anchors them to the seabed. The arms are typically branched and covered with feathery extensions that aid in filter feeding, capturing small particles from the water. Though modern crinoids tend to be less prominent in marine ecosystems, they were once much more abundant and diverse, particularly during the Palaeozoic era.

Crinoids first appeared in the Ordovician period, about 480 million years ago, and quickly diversified. They were especially abundant during the Palaeozoic, with their greatest diversity occurring during the Carboniferous period, when extensive shallow seas created ideal conditions for large crinoid populations. Fossil crinoids are especially common in limestone deposits from this time, with entire beds of rock often composed almost entirely of disarticulated crinoid fragments, particularly their stems. These fossils are widespread in regions like the UK, where crinoid-rich limestone formations are frequently found.

Crinoids come in two main forms: stalked crinoids, or sea lilies, which attach to the sea floor via a flexible stalk, and unstalked crinoids, or feather stars, which are mobile and can swim or crawl along the substrate using their arms. In the fossil record, stalked crinoids were much more abundant, with long, segmented stalks that could grow several meters in length. The stalks are composed of individual ossicles, small calcareous plates that are commonly found as fossils, especially in Carboniferous limestone beds. The most well-known fossil remains of crinoids are these stem ossicles, which are often referred to as "Indian beads" due to their cylindrical shape.

Crinoids reached their peak during the Palaeozoic, forming extensive colonies in shallow seas, often in association with coral reefs. Their filter-feeding mechanism allowed them to occupy a specialised ecological niche, and they played an important role in marine ecosystems as suspension feeders. However, crinoids were significantly affected by the Permian-Triassic mass extinction about 252 million years ago, which wiped out many marine species. Although crinoids survived this event, their diversity and abundance were greatly reduced.

In the Mesozoic era, crinoids experienced a resurgence, though not to the same levels of diversity as in the Palaeozoic. Feather stars (unstalked crinoids) became more prominent during the Jurassic and Cretaceous periods, adapting to more mobile lifestyles compared to their sessile ancestors. Today, feather stars are found in a variety of marine environments, from shallow reefs to deep-sea habitats, while stalked crinoids are largely restricted to deep water.

Crinoids are unique among echinoderms in that they are suspension feeders, using their feathery arms to catch plankton and other small particles from the water. Their arms are lined with cilia that move captured food towards their central mouth, which is located on the upper surface of the calyx. This feeding strategy differs from other echinoderms, such as sea urchins, which graze on algae, or starfish, which are typically predatory.

Despite their decline in modern oceans, crinoids remain important in the fossil record due to their abundant and well-preserved remains, particularly in Palaeozoic and Mesozoic sedimentary rocks. The characteristic segmented stalks and calyx plates of crinoids make them highly recognisable fossils, and they provide key insights into the structure and biodiversity of ancient marine ecosystems. In particular, Carboniferous limestone deposits, such as those found in the UK, are often rich in crinoid remains, offering palaeontologists a detailed record of these once-dominant marine invertebrates.

Age: 166-168Ma

Middle Jurassic Epoch

Jurassic Period

Mesozoic Era - Dinosaur times

Location: Coombs Quarry

Thornborough

Buckingham

Buckinghamshire

England

Rock Type: Forest Marble. Also known as the White Limestone.

Species:

Thamnasteria is a genus of scleractinian coral known from fossils dating from the Triassic into the Eocene (from about 247.2 to 33.9 million years ago) found throughout the northern hemisphere. M. LeSauvage, the author of the genus was a physician in Caen. He wrote numerous papers on medical subjects but his other interest was in palaeontology and especially the fossils of Calcaires de Caen the type locality of the genus Thamnasteria.

Anthozoa is sometimes considered a subphylum, with its major consituents making up the classes. These being Class Ceriantharia, Hexacorallia (including Scleractinia and Rugosa), Octocorallia, and Tabulata. These will all be included in this collection, but ordered by their type above the usual ordering by level of taxonomic precision and alphabetically.

Cnidaria is a phylum of simple aquatic animals, best known for their radial symmetry, nematocysts (stinging cells), and a body plan organised around a central cavity. The phylum includes organisms like jellyfish, sea anemones, hydras, and corals. Most cnidarians have two basic body forms: the free-swimming medusa (as seen in jellyfish) and the sessile polyp (typical of corals and sea anemones). Cnidarians exhibit a diploblastic structure, meaning they possess two primary cell layers, the ectoderm and endoderm, with a gelatinous layer called the mesoglea in between. While many cnidarians are carnivorous, using their stinging cells to capture prey, some, particularly corals, have developed symbiotic relationships with photosynthetic organisms like zooxanthellae, which assist in nutrient production.

Within this diverse phylum, Class Anthozoa includes organisms that exist exclusively in the polyp form and lack a medusa stage. Anthozoans are primarily sessile, attached to the substrate, and include groups like corals and sea anemones. Among anthozoans, corals are the most significant from a geological and palaeontological perspective due to their capacity to build massive reef structures over geological time. Coral polyps typically secrete calcium carbonate to form exoskeletons, which fossilise readily, making them important indicators in the fossil record. Anthozoa is further divided into orders such as Hexacorallia, which includes the modern reef-building corals, and Octocorallia, which comprises soft corals and sea fans.

The fossil record of corals is particularly rich, with three major types standing out: tabulate corals, rugose corals, and scleractinian corals, each representing different eras of coral dominance in Earth's history.

Tabulate corals were dominant during the Palaeozoic era, especially from the Ordovician to the Permian. These corals are characterised by their colonial nature and the presence of horizontal internal divisions known as tabulae. Unlike later corals, tabulate corals lacked septa (vertical internal walls) and often formed large, tightly packed colonies. They contributed significantly to reef ecosystems in shallow tropical seas during the Silurian and Devonian periods. However, they became extinct at the end of the Permian, during the Permian-Triassic mass extinction. Their decline mirrored broader ecological upheavals that affected much of marine life at that time.

Rugose corals, also known as horn corals, coexisted with tabulate corals and appeared in the Ordovician, flourishing through the Devonian and into the Carboniferous. These corals could be either solitary or colonial, and their most distinctive feature is the presence of septal divisions within the coral skeleton, radiating from a central point. The solitary forms often resembled a horn in shape, giving them their common name. Rugose corals also contributed to Palaeozoic reef systems and are frequently found as fossils in limestone formations from these periods. Like the tabulate corals, rugose corals were wiped out during the Permian-Triassic extinction, marking the end of their dominance in marine ecosystems.

Following the extinction of tabulate and rugose corals, the Scleractinian corals (modern corals) emerged in the Triassic and have been the primary reef-builders ever since. Scleractinian corals also possess calcareous skeletons but differ from their predecessors in their skeletal microstructure, which is composed of aragonite rather than calcite. These corals are notable for their ability to form both solitary and colonial structures, with colonial forms building the vast coral reefs seen in modern oceans. Reef-building scleractinians rely heavily on symbiotic zooxanthellae, which enable them to thrive in nutrient-poor, sunlit waters by performing photosynthesis. Scleractinians became the dominant corals from the Jurassic onwards, and they continue to dominate coral reef ecosystems today, making them critical components of modern marine biodiversity.

Age: 346-344Ma

Viséan

Middle Mississippian Epoch

Carboniferous Period - Giant arthropods and amphibians, early reptiles, most plants fern or lycophyte-like, known for tropical forests and seas

Paleozoic Era - pre-Dinosaurs

Location: Lancashire

Clitheroe

Salthill Quarry

Rock Type: Course grained and coursely crinoidal limestone, with lots of calcite from crinoid structure, park of a knoll-reef from the Clitheroe Limestone Formation.

Species:

Canina cylindrica is an extinct species of coral that lived during the Carboniferous period, approximately 344 to 343 million years ago. This solitary rugose coral belongs to the subclass Rugosa, known for its calcitic skeletons and distinctive cylindrical or horn-shaped growth forms.

As its name suggests, Canina cylindrica is recognised by its cylindrical coral structure, typically measuring between 3 and 8 centimetres in length and over 2 centimetres in diameter. Its smooth external surface contrasts with the intricate internal structure, which includes well-defined septa (radial plates) arranged in a characteristic pattern, as well as tabulae (horizontal partitions) that divide the coral's internal cavity into chambers.

Ecologically, Canina cylindrica thrived in the warm, shallow marine environments of the Middle Mississippian epoch, often growing in isolation on the seafloor. It was a sessile animal, relying on its tentacle-bearing polyp to capture microscopic plankton and organic particles from the surrounding water.

The presence of Canina cylindrica in the Carboniferous marine ecosystems highlights the importance of rugose corals during this period, as they contributed to reef-building and acted as habitat for various marine organisms. However, rugose corals, including Canina cylindrica, would eventually decline and become extinct by the end of the Permian, during the largest mass extinction in Earth’s history.

Note: Anthozoa is sometimes considered a subphylum, with its major consituents making up the classes. These being Class Ceriantharia, Hexacorallia (including Scleractinia and Rugosa), Octocorallia, and Tabulata. These will all be included in this collection, but ordered by their type above the usual ordering by level of taxonomic precision and alphabetically.

Cnidaria is a phylum of simple aquatic animals, best known for their radial symmetry, nematocysts (stinging cells), and a body plan organised around a central cavity. The phylum includes organisms like jellyfish, sea anemones, hydras, and corals. Most cnidarians have two basic body forms: the free-swimming medusa (as seen in jellyfish) and the sessile polyp (typical of corals and sea anemones). Cnidarians exhibit a diploblastic structure, meaning they possess two primary cell layers, the ectoderm and endoderm, with a gelatinous layer called the mesoglea in between. While many cnidarians are carnivorous, using their stinging cells to capture prey, some, particularly corals, have developed symbiotic relationships with photosynthetic organisms like zooxanthellae, which assist in nutrient production.

Within this diverse phylum, Class Anthozoa includes organisms that exist exclusively in the polyp form and lack a medusa stage. Anthozoans are primarily sessile, attached to the substrate, and include groups like corals and sea anemones. Among anthozoans, corals are the most significant from a geological and palaeontological perspective due to their capacity to build massive reef structures over geological time. Coral polyps typically secrete calcium carbonate to form exoskeletons, which fossilise readily, making them important indicators in the fossil record. Anthozoa is further divided into orders such as Hexacorallia, which includes the modern reef-building corals, and Octocorallia, which comprises soft corals and sea fans.

The fossil record of corals is particularly rich, with three major types standing out: tabulate corals, rugose corals, and scleractinian corals, each representing different eras of coral dominance in Earth's history.

Tabulate corals were dominant during the Palaeozoic era, especially from the Ordovician to the Permian. These corals are characterised by their colonial nature and the presence of horizontal internal divisions known as tabulae. Unlike later corals, tabulate corals lacked septa (vertical internal walls) and often formed large, tightly packed colonies. They contributed significantly to reef ecosystems in shallow tropical seas during the Silurian and Devonian periods. However, they became extinct at the end of the Permian, during the Permian-Triassic mass extinction. Their decline mirrored broader ecological upheavals that affected much of marine life at that time.

Rugose corals, also known as horn corals, coexisted with tabulate corals and appeared in the Ordovician, flourishing through the Devonian and into the Carboniferous. These corals could be either solitary or colonial, and their most distinctive feature is the presence of septal divisions within the coral skeleton, radiating from a central point. The solitary forms often resembled a horn in shape, giving them their common name. Rugose corals also contributed to Palaeozoic reef systems and are frequently found as fossils in limestone formations from these periods. Like the tabulate corals, rugose corals were wiped out during the Permian-Triassic extinction, marking the end of their dominance in marine ecosystems.

Following the extinction of tabulate and rugose corals, the Scleractinian corals (modern corals) emerged in the Triassic and have been the primary reef-builders ever since. Scleractinian corals also possess calcareous skeletons but differ from their predecessors in their skeletal microstructure, which is composed of aragonite rather than calcite. These corals are notable for their ability to form both solitary and colonial structures, with colonial forms building the vast coral reefs seen in modern oceans. Reef-building scleractinians rely heavily on symbiotic zooxanthellae, which enable them to thrive in nutrient-poor, sunlit waters by performing photosynthesis. Scleractinians became the dominant corals from the Jurassic onwards, and they continue to dominate coral reef ecosystems today, making them critical components of modern marine biodiversity.

Age: 345-330 Ma

Tournaisian to Viséan Age

Early to Middle Mississippian Epoch – Around the age of Romer’s Gap, noted for its unusual lack in tetrapod fossils, stunting our understanding of their evolution

Carboniferous Period – Giant arthropods and amphibians, early reptiles, most plants fern or lycophyte-like, known for tropical forests and seas

Paleozoic Era – pre-Dinosaurs

Location: Cheddar Gorge

Cheddar

Somerset

England

Rock Type: Clifton Down Limtestone Formation, Cheddar Limestone Formation, or Cheddar Oolite Formation

Species:

Lithostrotion is an extinct genus of colonial rugose corals that thrived during the Carboniferous period, approximately 360 to 335 million years ago. These corals are part of the subclass Rugosa and the family Lithostrotiidae, known for their role in forming reef-like structures in shallow marine environments.

Specimens of Lithostrotion sp. are characterised by their colonial growth pattern, where multiple cylindrical or prismatic corallites (the skeletal structures of individual coral polyps) are tightly packed together. These corallites often measure between 5 and 15 millimetres in diameter and are internally supported by radial septa and tabulae, which form intricate skeletal structures. The colonies of Lithostrotion sp. could grow to significant sizes, forming mound-like or branching structures.

Ecologically, Lithostrotion sp. lived in warm, shallow seas, contributing to the development of carbonate platforms and reef systems.

Each polyp of Lithostrotion sp. used its tentacles to capture plankton and organic particles from the water, making it an essential component of the nutrient cycles within its ecosystem.

Note: Anthozoa is sometimes considered a subphylum, with its major consituents making up the classes. These being Class Ceriantharia, Hexacorallia (including Scleractinia and Rugosa), Octocorallia, and Tabulata. These will all be included in this collection, but ordered by their type above the usual ordering by level of taxonomic precision and alphabetically.

Cnidaria is a phylum of simple aquatic animals, best known for their radial symmetry, nematocysts (stinging cells), and a body plan organised around a central cavity. The phylum includes organisms like jellyfish, sea anemones, hydras, and corals. Most cnidarians have two basic body forms: the free-swimming medusa (as seen in jellyfish) and the sessile polyp (typical of corals and sea anemones). Cnidarians exhibit a diploblastic structure, meaning they possess two primary cell layers, the ectoderm and endoderm, with a gelatinous layer called the mesoglea in between. While many cnidarians are carnivorous, using their stinging cells to capture prey, some, particularly corals, have developed symbiotic relationships with photosynthetic organisms like zooxanthellae, which assist in nutrient production.

Within this diverse phylum, Class Anthozoa includes organisms that exist exclusively in the polyp form and lack a medusa stage. Anthozoans are primarily sessile, attached to the substrate, and include groups like corals and sea anemones. Among anthozoans, corals are the most significant from a geological and palaeontological perspective due to their capacity to build massive reef structures over geological time. Coral polyps typically secrete calcium carbonate to form exoskeletons, which fossilise readily, making them important indicators in the fossil record. Anthozoa is further divided into orders such as Hexacorallia, which includes the modern reef-building corals, and Octocorallia, which comprises soft corals and sea fans.

The fossil record of corals is particularly rich, with three major types standing out: tabulate corals, rugose corals, and scleractinian corals, each representing different eras of coral dominance in Earth's history.

Tabulate corals were dominant during the Palaeozoic era, especially from the Ordovician to the Permian. These corals are characterised by their colonial nature and the presence of horizontal internal divisions known as tabulae. Unlike later corals, tabulate corals lacked septa (vertical internal walls) and often formed large, tightly packed colonies. They contributed significantly to reef ecosystems in shallow tropical seas during the Silurian and Devonian periods. However, they became extinct at the end of the Permian, during the Permian-Triassic mass extinction. Their decline mirrored broader ecological upheavals that affected much of marine life at that time.

Rugose corals, also known as horn corals, coexisted with tabulate corals and appeared in the Ordovician, flourishing through the Devonian and into the Carboniferous. These corals could be either solitary or colonial, and their most distinctive feature is the presence of septal divisions within the coral skeleton, radiating from a central point. The solitary forms often resembled a horn in shape, giving them their common name. Rugose corals also contributed to Palaeozoic reef systems and are frequently found as fossils in limestone formations from these periods. Like the tabulate corals, rugose corals were wiped out during the Permian-Triassic extinction, marking the end of their dominance in marine ecosystems.

Following the extinction of tabulate and rugose corals, the Scleractinian corals (modern corals) emerged in the Triassic and have been the primary reef-builders ever since. Scleractinian corals also possess calcareous skeletons but differ from their predecessors in their skeletal microstructure, which is composed of aragonite rather than calcite. These corals are notable for their ability to form both solitary and colonial structures, with colonial forms building the vast coral reefs seen in modern oceans. Reef-building scleractinians rely heavily on symbiotic zooxanthellae, which enable them to thrive in nutrient-poor, sunlit waters by performing photosynthesis. Scleractinians became the dominant corals from the Jurassic onwards, and they continue to dominate coral reef ecosystems today, making them critical components of modern marine biodiversity.

Age: 345-330 Ma

Tournaisian to Viséan Age

Early to Middle Mississippian Epoch – Around the age of Romer’s Gap, noted for its unusual lack in tetrapod fossils, stunting our understanding of their evolution

Carboniferous Period – Giant arthropods and amphibians, early reptiles, most plants fern or lycophyte-like, known for tropical forests and seas

Paleozoic Era – pre-Dinosaurs

Location: Cheddar Gorge

Cheddar

Somerset

England

Rock Type: Clifton Down Limtestone Formation, Cheddar Limestone Formation, or Cheddar Oolite Formation

Species:

Lithostrotion is an extinct genus of colonial rugose corals that thrived during the Carboniferous period, approximately 360 to 335 million years ago. These corals are part of the subclass Rugosa and the family Lithostrotiidae, known for their role in forming reef-like structures in shallow marine environments.

Specimens of Lithostrotion sp. are characterised by their colonial growth pattern, where multiple cylindrical or prismatic corallites (the skeletal structures of individual coral polyps) are tightly packed together. These corallites often measure between 5 and 15 millimetres in diameter and are internally supported by radial septa and tabulae, which form intricate skeletal structures. The colonies of Lithostrotion sp. could grow to significant sizes, forming mound-like or branching structures.

Ecologically, Lithostrotion sp. lived in warm, shallow seas, contributing to the development of carbonate platforms and reef systems.

Each polyp of Lithostrotion sp. used its tentacles to capture plankton and organic particles from the water, making it an essential component of the nutrient cycles within its ecosystem.

Note: Anthozoa is sometimes considered a subphylum, with its major consituents making up the classes. These being Class Ceriantharia, Hexacorallia (including Scleractinia and Rugosa), Octocorallia, and Tabulata. These will all be included in this collection, but ordered by their type above the usual ordering by level of taxonomic precision and alphabetically.

Cnidaria is a phylum of simple aquatic animals, best known for their radial symmetry, nematocysts (stinging cells), and a body plan organised around a central cavity. The phylum includes organisms like jellyfish, sea anemones, hydras, and corals. Most cnidarians have two basic body forms: the free-swimming medusa (as seen in jellyfish) and the sessile polyp (typical of corals and sea anemones). Cnidarians exhibit a diploblastic structure, meaning they possess two primary cell layers, the ectoderm and endoderm, with a gelatinous layer called the mesoglea in between. While many cnidarians are carnivorous, using their stinging cells to capture prey, some, particularly corals, have developed symbiotic relationships with photosynthetic organisms like zooxanthellae, which assist in nutrient production.

Within this diverse phylum, Class Anthozoa includes organisms that exist exclusively in the polyp form and lack a medusa stage. Anthozoans are primarily sessile, attached to the substrate, and include groups like corals and sea anemones. Among anthozoans, corals are the most significant from a geological and palaeontological perspective due to their capacity to build massive reef structures over geological time. Coral polyps typically secrete calcium carbonate to form exoskeletons, which fossilise readily, making them important indicators in the fossil record. Anthozoa is further divided into orders such as Hexacorallia, which includes the modern reef-building corals, and Octocorallia, which comprises soft corals and sea fans.

The fossil record of corals is particularly rich, with three major types standing out: tabulate corals, rugose corals, and scleractinian corals, each representing different eras of coral dominance in Earth's history.

Tabulate corals were dominant during the Palaeozoic era, especially from the Ordovician to the Permian. These corals are characterised by their colonial nature and the presence of horizontal internal divisions known as tabulae. Unlike later corals, tabulate corals lacked septa (vertical internal walls) and often formed large, tightly packed colonies. They contributed significantly to reef ecosystems in shallow tropical seas during the Silurian and Devonian periods. However, they became extinct at the end of the Permian, during the Permian-Triassic mass extinction. Their decline mirrored broader ecological upheavals that affected much of marine life at that time.

Rugose corals, also known as horn corals, coexisted with tabulate corals and appeared in the Ordovician, flourishing through the Devonian and into the Carboniferous. These corals could be either solitary or colonial, and their most distinctive feature is the presence of septal divisions within the coral skeleton, radiating from a central point. The solitary forms often resembled a horn in shape, giving them their common name. Rugose corals also contributed to Palaeozoic reef systems and are frequently found as fossils in limestone formations from these periods. Like the tabulate corals, rugose corals were wiped out during the Permian-Triassic extinction, marking the end of their dominance in marine ecosystems.

Following the extinction of tabulate and rugose corals, the Scleractinian corals (modern corals) emerged in the Triassic and have been the primary reef-builders ever since. Scleractinian corals also possess calcareous skeletons but differ from their predecessors in their skeletal microstructure, which is composed of aragonite rather than calcite. These corals are notable for their ability to form both solitary and colonial structures, with colonial forms building the vast coral reefs seen in modern oceans. Reef-building scleractinians rely heavily on symbiotic zooxanthellae, which enable them to thrive in nutrient-poor, sunlit waters by performing photosynthesis. Scleractinians became the dominant corals from the Jurassic onwards, and they continue to dominate coral reef ecosystems today, making them critical components of modern marine biodiversity.

Age: 346-344Ma

Viséan

Middle Mississippian Epoch

Carboniferous Period - Giant arthropods and amphibians, early reptiles, most plants fern or lycophyte-like, known for tropical forests and seas

Paleozoic Era - pre-Dinosaurs

Location: Lancashire

Clitheroe

Salthill Quarry

Rock Type: Course grained and coursely crinoidal limestone, with lots of calcite from crinoid structure, park of a knoll-reef from the Clitheroe Limestone Formation.

Species:

Canina cylindrica is an extinct species of coral that lived during the Carboniferous period, approximately 344 to 343 million years ago. This solitary rugose coral belongs to the subclass Rugosa, known for its calcitic skeletons and distinctive cylindrical or horn-shaped growth forms.

As its name suggests, Canina cylindrica is recognised by its cylindrical coral structure, typically measuring between 3 and 8 centimetres in length and over 2 centimetres in diameter. Its smooth external surface contrasts with the intricate internal structure, which includes well-defined septa (radial plates) arranged in a characteristic pattern, as well as tabulae (horizontal partitions) that divide the coral's internal cavity into chambers.

Ecologically, Canina cylindrica thrived in the warm, shallow marine environments of the Middle Mississippian epoch, often growing in isolation on the seafloor. It was a sessile animal, relying on its tentacle-bearing polyp to capture microscopic plankton and organic particles from the surrounding water.

The presence of Canina cylindrica in the Carboniferous marine ecosystems highlights the importance of rugose corals during this period, as they contributed to reef-building and acted as habitat for various marine organisms. However, rugose corals, including Canina cylindrica, would eventually decline and become extinct by the end of the Permian, during the largest mass extinction in Earth’s history.

Note: Anthozoa is sometimes considered a subphylum, with its major consituents making up the classes. These being Class Ceriantharia, Hexacorallia (including Scleractinia and Rugosa), Octocorallia, and Tabulata. These will all be included in this collection, but ordered by their type above the usual ordering by level of taxonomic precision and alphabetically.

Cnidaria is a phylum of simple aquatic animals, best known for their radial symmetry, nematocysts (stinging cells), and a body plan organised around a central cavity. The phylum includes organisms like jellyfish, sea anemones, hydras, and corals. Most cnidarians have two basic body forms: the free-swimming medusa (as seen in jellyfish) and the sessile polyp (typical of corals and sea anemones). Cnidarians exhibit a diploblastic structure, meaning they possess two primary cell layers, the ectoderm and endoderm, with a gelatinous layer called the mesoglea in between. While many cnidarians are carnivorous, using their stinging cells to capture prey, some, particularly corals, have developed symbiotic relationships with photosynthetic organisms like zooxanthellae, which assist in nutrient production.

Within this diverse phylum, Class Anthozoa includes organisms that exist exclusively in the polyp form and lack a medusa stage. Anthozoans are primarily sessile, attached to the substrate, and include groups like corals and sea anemones. Among anthozoans, corals are the most significant from a geological and palaeontological perspective due to their capacity to build massive reef structures over geological time. Coral polyps typically secrete calcium carbonate to form exoskeletons, which fossilise readily, making them important indicators in the fossil record. Anthozoa is further divided into orders such as Hexacorallia, which includes the modern reef-building corals, and Octocorallia, which comprises soft corals and sea fans.

The fossil record of corals is particularly rich, with three major types standing out: tabulate corals, rugose corals, and scleractinian corals, each representing different eras of coral dominance in Earth's history.

Tabulate corals were dominant during the Palaeozoic era, especially from the Ordovician to the Permian. These corals are characterised by their colonial nature and the presence of horizontal internal divisions known as tabulae. Unlike later corals, tabulate corals lacked septa (vertical internal walls) and often formed large, tightly packed colonies. They contributed significantly to reef ecosystems in shallow tropical seas during the Silurian and Devonian periods. However, they became extinct at the end of the Permian, during the Permian-Triassic mass extinction. Their decline mirrored broader ecological upheavals that affected much of marine life at that time.

Rugose corals, also known as horn corals, coexisted with tabulate corals and appeared in the Ordovician, flourishing through the Devonian and into the Carboniferous. These corals could be either solitary or colonial, and their most distinctive feature is the presence of septal divisions within the coral skeleton, radiating from a central point. The solitary forms often resembled a horn in shape, giving them their common name. Rugose corals also contributed to Palaeozoic reef systems and are frequently found as fossils in limestone formations from these periods. Like the tabulate corals, rugose corals were wiped out during the Permian-Triassic extinction, marking the end of their dominance in marine ecosystems.

Following the extinction of tabulate and rugose corals, the Scleractinian corals (modern corals) emerged in the Triassic and have been the primary reef-builders ever since. Scleractinian corals also possess calcareous skeletons but differ from their predecessors in their skeletal microstructure, which is composed of aragonite rather than calcite. These corals are notable for their ability to form both solitary and colonial structures, with colonial forms building the vast coral reefs seen in modern oceans. Reef-building scleractinians rely heavily on symbiotic zooxanthellae, which enable them to thrive in nutrient-poor, sunlit waters by performing photosynthesis. Scleractinians became the dominant corals from the Jurassic onwards, and they continue to dominate coral reef ecosystems today, making them critical components of modern marine biodiversity.

Age: 346-344Ma

Viséan

Middle Mississippian Epoch

Carboniferous Period - Giant arthropods and amphibians, early reptiles, most plants fern or lycophyte-like, known for tropical forests and seas

Paleozoic Era - pre-Dinosaurs

Location: Lancashire

Clitheroe

Salthill Quarry

Rock Type: Course grained and coursely crinoidal limestone, with lots of calcite from crinoid structure, park of a knoll-reef from the Clitheroe Limestone Formation.

Specimen:

A large crinoid column about 3.5cm in diameter, 4cm at its widest, with the clear pentastellate axial canal visible. This section is only about 1-1.5cm tall

Species:

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.

The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.

The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.

Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.

Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.

Echinodermata is a phylum of marine invertebrates that includes well-known groups like starfish, sea urchins, brittle stars, sea cucumbers, and crinoids. Echinoderms are characterised by their radial symmetry, typically arranged in fives, and their unique water vascular system, which aids in locomotion and feeding. This phylum is exclusively marine, and its members are often found on the sea floor, from shallow waters to the deep ocean. Echinoderms exhibit pentameral symmetry as adults, though their larvae are bilaterally symmetrical, reflecting their evolutionary relationship with other deuterostomes, including chordates.

Within this phylum, Class Crinoidea includes marine animals commonly referred to as sea lilies and feather stars. Crinoids are distinguished by their cup-shaped body (the calyx), a set of radiating arms, and a long stalk (in some species) that anchors them to the seabed. The arms are typically branched and covered with feathery extensions that aid in filter feeding, capturing small particles from the water. Though modern crinoids tend to be less prominent in marine ecosystems, they were once much more abundant and diverse, particularly during the Palaeozoic era.

Crinoids first appeared in the Ordovician period, about 480 million years ago, and quickly diversified. They were especially abundant during the Palaeozoic, with their greatest diversity occurring during the Carboniferous period, when extensive shallow seas created ideal conditions for large crinoid populations. Fossil crinoids are especially common in limestone deposits from this time, with entire beds of rock often composed almost entirely of disarticulated crinoid fragments, particularly their stems. These fossils are widespread in regions like the UK, where crinoid-rich limestone formations are frequently found.

Crinoids come in two main forms: stalked crinoids, or sea lilies, which attach to the sea floor via a flexible stalk, and unstalked crinoids, or feather stars, which are mobile and can swim or crawl along the substrate using their arms. In the fossil record, stalked crinoids were much more abundant, with long, segmented stalks that could grow several meters in length. The stalks are composed of individual ossicles, small calcareous plates that are commonly found as fossils, especially in Carboniferous limestone beds. The most well-known fossil remains of crinoids are these stem ossicles, which are often referred to as "Indian beads" due to their cylindrical shape.

Crinoids reached their peak during the Palaeozoic, forming extensive colonies in shallow seas, often in association with coral reefs. Their filter-feeding mechanism allowed them to occupy a specialised ecological niche, and they played an important role in marine ecosystems as suspension feeders. However, crinoids were significantly affected by the Permian-Triassic mass extinction about 252 million years ago, which wiped out many marine species. Although crinoids survived this event, their diversity and abundance were greatly reduced.

In the Mesozoic era, crinoids experienced a resurgence, though not to the same levels of diversity as in the Palaeozoic. Feather stars (unstalked crinoids) became more prominent during the Jurassic and Cretaceous periods, adapting to more mobile lifestyles compared to their sessile ancestors. Today, feather stars are found in a variety of marine environments, from shallow reefs to deep-sea habitats, while stalked crinoids are largely restricted to deep water.

Crinoids are unique among echinoderms in that they are suspension feeders, using their feathery arms to catch plankton and other small particles from the water. Their arms are lined with cilia that move captured food towards their central mouth, which is located on the upper surface of the calyx. This feeding strategy differs from other echinoderms, such as sea urchins, which graze on algae, or starfish, which are typically predatory.

Despite their decline in modern oceans, crinoids remain important in the fossil record due to their abundant and well-preserved remains, particularly in Palaeozoic and Mesozoic sedimentary rocks. The characteristic segmented stalks and calyx plates of crinoids make them highly recognisable fossils, and they provide key insights into the structure and biodiversity of ancient marine ecosystems. In particular, Carboniferous limestone deposits, such as those found in the UK, are often rich in crinoid remains, offering palaeontologists a detailed record of these once-dominant marine invertebrates.

Age: 346–344 Ma

Viséan

Middle Mississippian Epoch

Carboniferous Period – Giant arthropods and amphibians, early reptiles, most plants fern or lycophyte-like, known for tropical forests and seas

Paleozoic Era – pre-Dinosaurs

Location: Lancashire

Clitheroe

Salthill Quarry

Rock Type: Coarse-grained and coarsely crinoidal limestone, with abundant calcite from crinoid structures, part of a knoll-reef within the Clitheroe Limestone Formation

Species:

Cladochonus is an extinct genus of tabulate coral that lived during the Carboniferous period, approximately 346 to 344 million years ago. Tabulate corals, among the most ancient coral types to evolve, are characterised by their lateral tabulae, skeletal structures that rise in stacked plates, rather than the radial septa seen in rugose or modern scleractinian corals. This distinctive feature made tabulate corals structurally weaker, limiting their ability to compete for space in high-energy environments.

In the competitive knoll-reefs [more accurately considered to be banks] ecosystem of tropical Carboniferous seas, with towering crinoids and dense coral growths, Cladochonus sp. found a unique survival strategy. Instead of competing on the muddy seafloor, this small, spindly coral adapted to an epizoan lifestyle, growing around and along the stalks of sea lilies (crinoids). This climbing behaviour allowed its anemone-like polyps to reach higher into the nutrient-rich ocean currents, avoiding the sediment-laden seafloor and bypassing competition for resources.

Fossils of Cladochonus sp. often show pale, circular structures embedded along crinoid stems, connected by creeping skeletal lines. These are the remains of the coral’s tube-like skeletons, which wrapped around the crinoids for support. This relationship was not symbiotic, however; evidence from fossilised crinoids indicates they reacted to the encroaching coral by growing to envelop or block the coral. This suggests the crinoids expended energy defending themselves, marking the relationship as parasitic in nature, as the coral benefited from the crinoid’s height while causing some harm to its host.

Ecologically, Cladochonus sp. played a small but significant role in the tropical reef systems of the Carboniferous, adapting to challenges by using other organisms to secure a competitive advantage. Its fossils, often preserved intertwined with crinoid stems, provide a snapshot of this dynamic, ancient marine relationship. Like other tabulate corals, Cladochonus sp. eventually declined and disappeared by the end of the Permian period, leaving a fascinating record of its adaptations.

Note: Anthozoa is sometimes considered a subphylum, with its major consituents making up the classes. These being Class Ceriantharia, Hexacorallia (including Scleractinia and Rugosa), Octocorallia, and Tabulata. These will all be included in this collection, but ordered by their type above the usual ordering by level of taxonomic precision and alphabetically.

Cnidaria is a phylum of simple aquatic animals, best known for their radial symmetry, nematocysts (stinging cells), and a body plan organised around a central cavity. The phylum includes organisms like jellyfish, sea anemones, hydras, and corals. Most cnidarians have two basic body forms: the free-swimming medusa (as seen in jellyfish) and the sessile polyp (typical of corals and sea anemones). Cnidarians exhibit a diploblastic structure, meaning they possess two primary cell layers, the ectoderm and endoderm, with a gelatinous layer called the mesoglea in between. While many cnidarians are carnivorous, using their stinging cells to capture prey, some, particularly corals, have developed symbiotic relationships with photosynthetic organisms like zooxanthellae, which assist in nutrient production.

Within this diverse phylum, Class Anthozoa includes organisms that exist exclusively in the polyp form and lack a medusa stage. Anthozoans are primarily sessile, attached to the substrate, and include groups like corals and sea anemones. Among anthozoans, corals are the most significant from a geological and palaeontological perspective due to their capacity to build massive reef structures over geological time. Coral polyps typically secrete calcium carbonate to form exoskeletons, which fossilise readily, making them important indicators in the fossil record. Anthozoa is further divided into orders such as Hexacorallia, which includes the modern reef-building corals, and Octocorallia, which comprises soft corals and sea fans.

The fossil record of corals is particularly rich, with three major types standing out: tabulate corals, rugose corals, and scleractinian corals, each representing different eras of coral dominance in Earth's history.

Tabulate corals were dominant during the Palaeozoic era, especially from the Ordovician to the Permian. These corals are characterised by their colonial nature and the presence of horizontal internal divisions known as tabulae. Unlike later corals, tabulate corals lacked septa (vertical internal walls) and often formed large, tightly packed colonies. They contributed significantly to reef ecosystems in shallow tropical seas during the Silurian and Devonian periods. However, they became extinct at the end of the Permian, during the Permian-Triassic mass extinction. Their decline mirrored broader ecological upheavals that affected much of marine life at that time.

Rugose corals, also known as horn corals, coexisted with tabulate corals and appeared in the Ordovician, flourishing through the Devonian and into the Carboniferous. These corals could be either solitary or colonial, and their most distinctive feature is the presence of septal divisions within the coral skeleton, radiating from a central point. The solitary forms often resembled a horn in shape, giving them their common name. Rugose corals also contributed to Palaeozoic reef systems and are frequently found as fossils in limestone formations from these periods. Like the tabulate corals, rugose corals were wiped out during the Permian-Triassic extinction, marking the end of their dominance in marine ecosystems.

Following the extinction of tabulate and rugose corals, the Scleractinian corals (modern corals) emerged in the Triassic and have been the primary reef-builders ever since. Scleractinian corals also possess calcareous skeletons but differ from their predecessors in their skeletal microstructure, which is composed of aragonite rather than calcite. These corals are notable for their ability to form both solitary and colonial structures, with colonial forms building the vast coral reefs seen in modern oceans. Reef-building scleractinians rely heavily on symbiotic zooxanthellae, which enable them to thrive in nutrient-poor, sunlit waters by performing photosynthesis. Scleractinians became the dominant corals from the Jurassic onwards, and they continue to dominate coral reef ecosystems today, making them critical components of modern marine biodiversity.

Age: 345-330 Ma

Tournaisian to Viséan Age

Early to Middle Mississippian Epoch – Around the age of Romer’s Gap, noted for its unusual lack in tetrapod fossils, stunting our understanding of their evolution

Carboniferous Period – Giant arthropods and amphibians, early reptiles, most plants fern or lycophyte-like, known for tropical forests and seas

Paleozoic Era – pre-Dinosaurs

Location: Cheddar Gorge

Cheddar

Somerset

England

Rock Type: Clifton Down Limtestone Formation, Cheddar Limestone Formation, or Cheddar Oolite Formation

Species:

Lithostrotion is an extinct genus of colonial rugose corals that thrived during the Carboniferous period, approximately 360 to 335 million years ago. These corals are part of the subclass Rugosa and the family Lithostrotiidae, known for their role in forming reef-like structures in shallow marine environments.

Specimens of Lithostrotion sp. are characterised by their colonial growth pattern, where multiple cylindrical or prismatic corallites (the skeletal structures of individual coral polyps) are tightly packed together. These corallites often measure between 5 and 15 millimetres in diameter and are internally supported by radial septa and tabulae, which form intricate skeletal structures. The colonies of Lithostrotion sp. could grow to significant sizes, forming mound-like or branching structures.

Ecologically, Lithostrotion sp. lived in warm, shallow seas, contributing to the development of carbonate platforms and reef systems.

Each polyp of Lithostrotion sp. used its tentacles to capture plankton and organic particles from the water, making it an essential component of the nutrient cycles within its ecosystem.

Note: Anthozoa is sometimes considered a subphylum, with its major consituents making up the classes. These being Class Ceriantharia, Hexacorallia (including Scleractinia and Rugosa), Octocorallia, and Tabulata. These will all be included in this collection, but ordered by their type above the usual ordering by level of taxonomic precision and alphabetically.

Cnidaria is a phylum of simple aquatic animals, best known for their radial symmetry, nematocysts (stinging cells), and a body plan organised around a central cavity. The phylum includes organisms like jellyfish, sea anemones, hydras, and corals. Most cnidarians have two basic body forms: the free-swimming medusa (as seen in jellyfish) and the sessile polyp (typical of corals and sea anemones). Cnidarians exhibit a diploblastic structure, meaning they possess two primary cell layers, the ectoderm and endoderm, with a gelatinous layer called the mesoglea in between. While many cnidarians are carnivorous, using their stinging cells to capture prey, some, particularly corals, have developed symbiotic relationships with photosynthetic organisms like zooxanthellae, which assist in nutrient production.

Within this diverse phylum, Class Anthozoa includes organisms that exist exclusively in the polyp form and lack a medusa stage. Anthozoans are primarily sessile, attached to the substrate, and include groups like corals and sea anemones. Among anthozoans, corals are the most significant from a geological and palaeontological perspective due to their capacity to build massive reef structures over geological time. Coral polyps typically secrete calcium carbonate to form exoskeletons, which fossilise readily, making them important indicators in the fossil record. Anthozoa is further divided into orders such as Hexacorallia, which includes the modern reef-building corals, and Octocorallia, which comprises soft corals and sea fans.

The fossil record of corals is particularly rich, with three major types standing out: tabulate corals, rugose corals, and scleractinian corals, each representing different eras of coral dominance in Earth's history.

Tabulate corals were dominant during the Palaeozoic era, especially from the Ordovician to the Permian. These corals are characterised by their colonial nature and the presence of horizontal internal divisions known as tabulae. Unlike later corals, tabulate corals lacked septa (vertical internal walls) and often formed large, tightly packed colonies. They contributed significantly to reef ecosystems in shallow tropical seas during the Silurian and Devonian periods. However, they became extinct at the end of the Permian, during the Permian-Triassic mass extinction. Their decline mirrored broader ecological upheavals that affected much of marine life at that time.

Rugose corals, also known as horn corals, coexisted with tabulate corals and appeared in the Ordovician, flourishing through the Devonian and into the Carboniferous. These corals could be either solitary or colonial, and their most distinctive feature is the presence of septal divisions within the coral skeleton, radiating from a central point. The solitary forms often resembled a horn in shape, giving them their common name. Rugose corals also contributed to Palaeozoic reef systems and are frequently found as fossils in limestone formations from these periods. Like the tabulate corals, rugose corals were wiped out during the Permian-Triassic extinction, marking the end of their dominance in marine ecosystems.

Following the extinction of tabulate and rugose corals, the Scleractinian corals (modern corals) emerged in the Triassic and have been the primary reef-builders ever since. Scleractinian corals also possess calcareous skeletons but differ from their predecessors in their skeletal microstructure, which is composed of aragonite rather than calcite. These corals are notable for their ability to form both solitary and colonial structures, with colonial forms building the vast coral reefs seen in modern oceans. Reef-building scleractinians rely heavily on symbiotic zooxanthellae, which enable them to thrive in nutrient-poor, sunlit waters by performing photosynthesis. Scleractinians became the dominant corals from the Jurassic onwards, and they continue to dominate coral reef ecosystems today, making them critical components of modern marine biodiversity.

Age: 346–344 Ma

Viséan

Middle Mississippian Epoch

Carboniferous Period – Giant arthropods and amphibians, early reptiles, most plants fern or lycophyte-like, known for tropical forests and seas

Paleozoic Era – pre-Dinosaurs

Location: Lancashire

Clitheroe

Salthill Quarry

Rock Type: Coarse-grained and coarsely crinoidal limestone, with abundant calcite from crinoid structures, part of a knoll-reef within the Clitheroe Limestone Formation

Species:

Cladochonus is an extinct genus of tabulate coral that lived during the Carboniferous period, approximately 346 to 344 million years ago. Tabulate corals, among the most ancient coral types to evolve, are characterised by their lateral tabulae, skeletal structures that rise in stacked plates, rather than the radial septa seen in rugose or modern scleractinian corals. This distinctive feature made tabulate corals structurally weaker, limiting their ability to compete for space in high-energy environments.

In the competitive knoll-reefs [more accurately considered to be banks] ecosystem of tropical Carboniferous seas, with towering crinoids and dense coral growths, Cladochonus sp. found a unique survival strategy. Instead of competing on the muddy seafloor, this small, spindly coral adapted to an epizoan lifestyle, growing around and along the stalks of sea lilies (crinoids). This climbing behaviour allowed its anemone-like polyps to reach higher into the nutrient-rich ocean currents, avoiding the sediment-laden seafloor and bypassing competition for resources.

Fossils of Cladochonus sp. often show pale, circular structures embedded along crinoid stems, connected by creeping skeletal lines. These are the remains of the coral’s tube-like skeletons, which wrapped around the crinoids for support. This relationship was not symbiotic, however; evidence from fossilised crinoids indicates they reacted to the encroaching coral by growing to envelop or block the coral. This suggests the crinoids expended energy defending themselves, marking the relationship as parasitic in nature, as the coral benefited from the crinoid’s height while causing some harm to its host.

Ecologically, Cladochonus sp. played a small but significant role in the tropical reef systems of the Carboniferous, adapting to challenges by using other organisms to secure a competitive advantage. Its fossils, often preserved intertwined with crinoid stems, provide a snapshot of this dynamic, ancient marine relationship. Like other tabulate corals, Cladochonus sp. eventually declined and disappeared by the end of the Permian period, leaving a fascinating record of its adaptations.

Note: Anthozoa is sometimes considered a subphylum, with its major consituents making up the classes. These being Class Ceriantharia, Hexacorallia (including Scleractinia and Rugosa), Octocorallia, and Tabulata. These will all be included in this collection, but ordered by their type above the usual ordering by level of taxonomic precision and alphabetically.

Cnidaria is a phylum of simple aquatic animals, best known for their radial symmetry, nematocysts (stinging cells), and a body plan organised around a central cavity. The phylum includes organisms like jellyfish, sea anemones, hydras, and corals. Most cnidarians have two basic body forms: the free-swimming medusa (as seen in jellyfish) and the sessile polyp (typical of corals and sea anemones). Cnidarians exhibit a diploblastic structure, meaning they possess two primary cell layers, the ectoderm and endoderm, with a gelatinous layer called the mesoglea in between. While many cnidarians are carnivorous, using their stinging cells to capture prey, some, particularly corals, have developed symbiotic relationships with photosynthetic organisms like zooxanthellae, which assist in nutrient production.

Within this diverse phylum, Class Anthozoa includes organisms that exist exclusively in the polyp form and lack a medusa stage. Anthozoans are primarily sessile, attached to the substrate, and include groups like corals and sea anemones. Among anthozoans, corals are the most significant from a geological and palaeontological perspective due to their capacity to build massive reef structures over geological time. Coral polyps typically secrete calcium carbonate to form exoskeletons, which fossilise readily, making them important indicators in the fossil record. Anthozoa is further divided into orders such as Hexacorallia, which includes the modern reef-building corals, and Octocorallia, which comprises soft corals and sea fans.

The fossil record of corals is particularly rich, with three major types standing out: tabulate corals, rugose corals, and scleractinian corals, each representing different eras of coral dominance in Earth's history.

Tabulate corals were dominant during the Palaeozoic era, especially from the Ordovician to the Permian. These corals are characterised by their colonial nature and the presence of horizontal internal divisions known as tabulae. Unlike later corals, tabulate corals lacked septa (vertical internal walls) and often formed large, tightly packed colonies. They contributed significantly to reef ecosystems in shallow tropical seas during the Silurian and Devonian periods. However, they became extinct at the end of the Permian, during the Permian-Triassic mass extinction. Their decline mirrored broader ecological upheavals that affected much of marine life at that time.

Rugose corals, also known as horn corals, coexisted with tabulate corals and appeared in the Ordovician, flourishing through the Devonian and into the Carboniferous. These corals could be either solitary or colonial, and their most distinctive feature is the presence of septal divisions within the coral skeleton, radiating from a central point. The solitary forms often resembled a horn in shape, giving them their common name. Rugose corals also contributed to Palaeozoic reef systems and are frequently found as fossils in limestone formations from these periods. Like the tabulate corals, rugose corals were wiped out during the Permian-Triassic extinction, marking the end of their dominance in marine ecosystems.

Following the extinction of tabulate and rugose corals, the Scleractinian corals (modern corals) emerged in the Triassic and have been the primary reef-builders ever since. Scleractinian corals also possess calcareous skeletons but differ from their predecessors in their skeletal microstructure, which is composed of aragonite rather than calcite. These corals are notable for their ability to form both solitary and colonial structures, with colonial forms building the vast coral reefs seen in modern oceans. Reef-building scleractinians rely heavily on symbiotic zooxanthellae, which enable them to thrive in nutrient-poor, sunlit waters by performing photosynthesis. Scleractinians became the dominant corals from the Jurassic onwards, and they continue to dominate coral reef ecosystems today, making them critical components of modern marine biodiversity.

Age: 360–335 Ma

Tournaisian to Viséan Age

Early to Middle Mississippian Epoch – Around the age of Romer’s Gap, noted for its unusual lack in tetrapod fossils, stunting our understanding of their evolution

Carboniferous Period – Giant arthropods and amphibians, early reptiles, most plants fern or lycophyte-like, known for tropical forests and seas

Paleozoic Era – pre-Dinosaurs

Location: Dumfries and Galloway

Southerness Peninsula

Somewhere east of Southerness along the coastline

Rock Type: Perhaps dolomitic limestone of the Ballagan Formation

Species:

Lithostrotion is an extinct genus of colonial rugose corals that thrived during the Carboniferous period, approximately 360 to 335 million years ago. These corals are part of the subclass Rugosa and the family Lithostrotiidae, known for their role in forming reef-like structures in shallow marine environments.

Specimens of Lithostrotion sp. are characterised by their colonial growth pattern, where multiple cylindrical or prismatic corallites (the skeletal structures of individual coral polyps) are tightly packed together. These corallites often measure between 5 and 15 millimetres in diameter and are internally supported by radial septa and tabulae, which form intricate skeletal structures. The colonies of Lithostrotion sp. could grow to significant sizes, forming mound-like or branching structures.

Ecologically, Lithostrotion sp. lived in warm, shallow seas, contributing to the development of carbonate platforms and reef systems.

Each polyp of Lithostrotion sp. used its tentacles to capture plankton and organic particles from the water, making it an essential component of the nutrient cycles within its ecosystem.

Note: Anthozoa is sometimes considered a subphylum, with its major consituents making up the classes. These being Class Ceriantharia, Hexacorallia (including Scleractinia and Rugosa), Octocorallia, and Tabulata. These will all be included in this collection, but ordered by their type above the usual ordering by level of taxonomic precision and alphabetically.

Cnidaria is a phylum of simple aquatic animals, best known for their radial symmetry, nematocysts (stinging cells), and a body plan organised around a central cavity. The phylum includes organisms like jellyfish, sea anemones, hydras, and corals. Most cnidarians have two basic body forms: the free-swimming medusa (as seen in jellyfish) and the sessile polyp (typical of corals and sea anemones). Cnidarians exhibit a diploblastic structure, meaning they possess two primary cell layers, the ectoderm and endoderm, with a gelatinous layer called the mesoglea in between. While many cnidarians are carnivorous, using their stinging cells to capture prey, some, particularly corals, have developed symbiotic relationships with photosynthetic organisms like zooxanthellae, which assist in nutrient production.

Within this diverse phylum, Class Anthozoa includes organisms that exist exclusively in the polyp form and lack a medusa stage. Anthozoans are primarily sessile, attached to the substrate, and include groups like corals and sea anemones. Among anthozoans, corals are the most significant from a geological and palaeontological perspective due to their capacity to build massive reef structures over geological time. Coral polyps typically secrete calcium carbonate to form exoskeletons, which fossilise readily, making them important indicators in the fossil record. Anthozoa is further divided into orders such as Hexacorallia, which includes the modern reef-building corals, and Octocorallia, which comprises soft corals and sea fans.

The fossil record of corals is particularly rich, with three major types standing out: tabulate corals, rugose corals, and scleractinian corals, each representing different eras of coral dominance in Earth's history.

Tabulate corals were dominant during the Palaeozoic era, especially from the Ordovician to the Permian. These corals are characterised by their colonial nature and the presence of horizontal internal divisions known as tabulae. Unlike later corals, tabulate corals lacked septa (vertical internal walls) and often formed large, tightly packed colonies. They contributed significantly to reef ecosystems in shallow tropical seas during the Silurian and Devonian periods. However, they became extinct at the end of the Permian, during the Permian-Triassic mass extinction. Their decline mirrored broader ecological upheavals that affected much of marine life at that time.

Rugose corals, also known as horn corals, coexisted with tabulate corals and appeared in the Ordovician, flourishing through the Devonian and into the Carboniferous. These corals could be either solitary or colonial, and their most distinctive feature is the presence of septal divisions within the coral skeleton, radiating from a central point. The solitary forms often resembled a horn in shape, giving them their common name. Rugose corals also contributed to Palaeozoic reef systems and are frequently found as fossils in limestone formations from these periods. Like the tabulate corals, rugose corals were wiped out during the Permian-Triassic extinction, marking the end of their dominance in marine ecosystems.

Following the extinction of tabulate and rugose corals, the Scleractinian corals (modern corals) emerged in the Triassic and have been the primary reef-builders ever since. Scleractinian corals also possess calcareous skeletons but differ from their predecessors in their skeletal microstructure, which is composed of aragonite rather than calcite. These corals are notable for their ability to form both solitary and colonial structures, with colonial forms building the vast coral reefs seen in modern oceans. Reef-building scleractinians rely heavily on symbiotic zooxanthellae, which enable them to thrive in nutrient-poor, sunlit waters by performing photosynthesis. Scleractinians became the dominant corals from the Jurassic onwards, and they continue to dominate coral reef ecosystems today, making them critical components of modern marine biodiversity.

Age: 344–343 Ma

Viséan

Middle Mississippian Epoch

Carboniferous Period - Giant arthropods and amphibians, early reptiles, most plants fern or lycophyte-like, known for tropical forests and seas

Paleozoic Era - pre-Dinosaurs

Location: Arnside and Silverdale AONB

Lancashire

Rock Type: Dalton Formation – limestone

Species:

Canina cylindrica is an extinct species of coral that lived during the Carboniferous period, approximately 344 to 343 million years ago. This solitary rugose coral belongs to the subclass Rugosa, known for its calcitic skeletons and distinctive cylindrical or horn-shaped growth forms.

As its name suggests, Canina cylindrica is recognised by its cylindrical coral structure, typically measuring between 3 and 8 centimetres in length and over 2 centimetres in diameter. Its smooth external surface contrasts with the intricate internal structure, which includes well-defined septa (radial plates) arranged in a characteristic pattern, as well as tabulae (horizontal partitions) that divide the coral's internal cavity into chambers.

Ecologically, Canina cylindrica thrived in the warm, shallow marine environments of the Middle Mississippian epoch, often growing in isolation on the seafloor. It was a sessile animal, relying on its tentacle-bearing polyp to capture microscopic plankton and organic particles from the surrounding water.

The presence of Canina cylindrica in the Carboniferous marine ecosystems highlights the importance of rugose corals during this period, as they contributed to reef-building and acted as habitat for various marine organisms. However, rugose corals, including Canina cylindrica, would eventually decline and become extinct by the end of the Permian, during the largest mass extinction in Earth’s history.

Note: Anthozoa is sometimes considered a subphylum, with its major consituents making up the classes. These being Class Ceriantharia, Hexacorallia (including Scleractinia and Rugosa), Octocorallia, and Tabulata. These will all be included in this collection, but ordered by their type above the usual ordering by level of taxonomic precision and alphabetically.

Cnidaria is a phylum of simple aquatic animals, best known for their radial symmetry, nematocysts (stinging cells), and a body plan organised around a central cavity. The phylum includes organisms like jellyfish, sea anemones, hydras, and corals. Most cnidarians have two basic body forms: the free-swimming medusa (as seen in jellyfish) and the sessile polyp (typical of corals and sea anemones). Cnidarians exhibit a diploblastic structure, meaning they possess two primary cell layers, the ectoderm and endoderm, with a gelatinous layer called the mesoglea in between. While many cnidarians are carnivorous, using their stinging cells to capture prey, some, particularly corals, have developed symbiotic relationships with photosynthetic organisms like zooxanthellae, which assist in nutrient production.

Within this diverse phylum, Class Anthozoa includes organisms that exist exclusively in the polyp form and lack a medusa stage. Anthozoans are primarily sessile, attached to the substrate, and include groups like corals and sea anemones. Among anthozoans, corals are the most significant from a geological and palaeontological perspective due to their capacity to build massive reef structures over geological time. Coral polyps typically secrete calcium carbonate to form exoskeletons, which fossilise readily, making them important indicators in the fossil record. Anthozoa is further divided into orders such as Hexacorallia, which includes the modern reef-building corals, and Octocorallia, which comprises soft corals and sea fans.

The fossil record of corals is particularly rich, with three major types standing out: tabulate corals, rugose corals, and scleractinian corals, each representing different eras of coral dominance in Earth's history.

Tabulate corals were dominant during the Palaeozoic era, especially from the Ordovician to the Permian. These corals are characterised by their colonial nature and the presence of horizontal internal divisions known as tabulae. Unlike later corals, tabulate corals lacked septa (vertical internal walls) and often formed large, tightly packed colonies. They contributed significantly to reef ecosystems in shallow tropical seas during the Silurian and Devonian periods. However, they became extinct at the end of the Permian, during the Permian-Triassic mass extinction. Their decline mirrored broader ecological upheavals that affected much of marine life at that time.

Rugose corals, also known as horn corals, coexisted with tabulate corals and appeared in the Ordovician, flourishing through the Devonian and into the Carboniferous. These corals could be either solitary or colonial, and their most distinctive feature is the presence of septal divisions within the coral skeleton, radiating from a central point. The solitary forms often resembled a horn in shape, giving them their common name. Rugose corals also contributed to Palaeozoic reef systems and are frequently found as fossils in limestone formations from these periods. Like the tabulate corals, rugose corals were wiped out during the Permian-Triassic extinction, marking the end of their dominance in marine ecosystems.

Following the extinction of tabulate and rugose corals, the Scleractinian corals (modern corals) emerged in the Triassic and have been the primary reef-builders ever since. Scleractinian corals also possess calcareous skeletons but differ from their predecessors in their skeletal microstructure, which is composed of aragonite rather than calcite. These corals are notable for their ability to form both solitary and colonial structures, with colonial forms building the vast coral reefs seen in modern oceans. Reef-building scleractinians rely heavily on symbiotic zooxanthellae, which enable them to thrive in nutrient-poor, sunlit waters by performing photosynthesis. Scleractinians became the dominant corals from the Jurassic onwards, and they continue to dominate coral reef ecosystems today, making them critical components of modern marine biodiversity.

Age: 346-344Ma

Viséan

Middle Mississippian Epoch

Carboniferous Period - Giant arthropods and amphibians, early reptiles, most plants fern or lycophyte-like, known for tropical forests and seas

Paleozoic Era - pre-Dinosaurs

Location: Lancashire

Clitheroe

Salthill Quarry

Rock Type: Course grained and coursely crinoidal limestone, with lots of calcite from crinoid structure, park of a knoll-reef from the Clitheroe Limestone Formation.

Species:

Canina cylindrica is an extinct species of coral that lived during the Carboniferous period, approximately 344 to 343 million years ago. This solitary rugose coral belongs to the subclass Rugosa, known for its calcitic skeletons and distinctive cylindrical or horn-shaped growth forms.

As its name suggests, Canina cylindrica is recognised by its cylindrical coral structure, typically measuring between 3 and 8 centimetres in length and over 2 centimetres in diameter. Its smooth external surface contrasts with the intricate internal structure, which includes well-defined septa (radial plates) arranged in a characteristic pattern, as well as tabulae (horizontal partitions) that divide the coral's internal cavity into chambers.

Ecologically, Canina cylindrica thrived in the warm, shallow marine environments of the Middle Mississippian epoch, often growing in isolation on the seafloor. It was a sessile animal, relying on its tentacle-bearing polyp to capture microscopic plankton and organic particles from the surrounding water.

The presence of Canina cylindrica in the Carboniferous marine ecosystems highlights the importance of rugose corals during this period, as they contributed to reef-building and acted as habitat for various marine organisms. However, rugose corals, including Canina cylindrica, would eventually decline and become extinct by the end of the Permian, during the largest mass extinction in Earth’s history.

Note: Anthozoa is sometimes considered a subphylum, with its major consituents making up the classes. These being Class Ceriantharia, Hexacorallia (including Scleractinia and Rugosa), Octocorallia, and Tabulata. These will all be included in this collection, but ordered by their type above the usual ordering by level of taxonomic precision and alphabetically.

Cnidaria is a phylum of simple aquatic animals, best known for their radial symmetry, nematocysts (stinging cells), and a body plan organised around a central cavity. The phylum includes organisms like jellyfish, sea anemones, hydras, and corals. Most cnidarians have two basic body forms: the free-swimming medusa (as seen in jellyfish) and the sessile polyp (typical of corals and sea anemones). Cnidarians exhibit a diploblastic structure, meaning they possess two primary cell layers, the ectoderm and endoderm, with a gelatinous layer called the mesoglea in between. While many cnidarians are carnivorous, using their stinging cells to capture prey, some, particularly corals, have developed symbiotic relationships with photosynthetic organisms like zooxanthellae, which assist in nutrient production.

Within this diverse phylum, Class Anthozoa includes organisms that exist exclusively in the polyp form and lack a medusa stage. Anthozoans are primarily sessile, attached to the substrate, and include groups like corals and sea anemones. Among anthozoans, corals are the most significant from a geological and palaeontological perspective due to their capacity to build massive reef structures over geological time. Coral polyps typically secrete calcium carbonate to form exoskeletons, which fossilise readily, making them important indicators in the fossil record. Anthozoa is further divided into orders such as Hexacorallia, which includes the modern reef-building corals, and Octocorallia, which comprises soft corals and sea fans.

The fossil record of corals is particularly rich, with three major types standing out: tabulate corals, rugose corals, and scleractinian corals, each representing different eras of coral dominance in Earth's history.

Tabulate corals were dominant during the Palaeozoic era, especially from the Ordovician to the Permian. These corals are characterised by their colonial nature and the presence of horizontal internal divisions known as tabulae. Unlike later corals, tabulate corals lacked septa (vertical internal walls) and often formed large, tightly packed colonies. They contributed significantly to reef ecosystems in shallow tropical seas during the Silurian and Devonian periods. However, they became extinct at the end of the Permian, during the Permian-Triassic mass extinction. Their decline mirrored broader ecological upheavals that affected much of marine life at that time.

Rugose corals, also known as horn corals, coexisted with tabulate corals and appeared in the Ordovician, flourishing through the Devonian and into the Carboniferous. These corals could be either solitary or colonial, and their most distinctive feature is the presence of septal divisions within the coral skeleton, radiating from a central point. The solitary forms often resembled a horn in shape, giving them their common name. Rugose corals also contributed to Palaeozoic reef systems and are frequently found as fossils in limestone formations from these periods. Like the tabulate corals, rugose corals were wiped out during the Permian-Triassic extinction, marking the end of their dominance in marine ecosystems.

Following the extinction of tabulate and rugose corals, the Scleractinian corals (modern corals) emerged in the Triassic and have been the primary reef-builders ever since. Scleractinian corals also possess calcareous skeletons but differ from their predecessors in their skeletal microstructure, which is composed of aragonite rather than calcite. These corals are notable for their ability to form both solitary and colonial structures, with colonial forms building the vast coral reefs seen in modern oceans. Reef-building scleractinians rely heavily on symbiotic zooxanthellae, which enable them to thrive in nutrient-poor, sunlit waters by performing photosynthesis. Scleractinians became the dominant corals from the Jurassic onwards, and they continue to dominate coral reef ecosystems today, making them critical components of modern marine biodiversity.

Age: 360–335 Ma

Tournaisian to Viséan Age

Early to Middle Mississippian Epoch – Around the age of Romer’s Gap, noted for its unusual lack in tetrapod fossils, stunting our understanding of their evolution

Carboniferous Period – Giant arthropods and amphibians, early reptiles, most plants fern or lycophyte-like, known for tropical forests and seas

Paleozoic Era – pre-Dinosaurs

Location: Dumfries and Galloway

Southerness Peninsula

Somewhere east of Southerness along the coastline

Rock Type: Perhaps dolomitic limestone of the Ballagan Formation

Species:

Lithostrotion is an extinct genus of colonial rugose corals that thrived during the Carboniferous period, approximately 360 to 335 million years ago. These corals are part of the subclass Rugosa and the family Lithostrotiidae, known for their role in forming reef-like structures in shallow marine environments.

Specimens of Lithostrotion sp. are characterised by their colonial growth pattern, where multiple cylindrical or prismatic corallites (the skeletal structures of individual coral polyps) are tightly packed together. These corallites often measure between 5 and 15 millimetres in diameter and are internally supported by radial septa and tabulae, which form intricate skeletal structures. The colonies of Lithostrotion sp. could grow to significant sizes, forming mound-like or branching structures.

Ecologically, Lithostrotion sp. lived in warm, shallow seas, contributing to the development of carbonate platforms and reef systems.

Each polyp of Lithostrotion sp. used its tentacles to capture plankton and organic particles from the water, making it an essential component of the nutrient cycles within its ecosystem.

Note: Anthozoa is sometimes considered a subphylum, with its major consituents making up the classes. These being Class Ceriantharia, Hexacorallia (including Scleractinia and Rugosa), Octocorallia, and Tabulata. These will all be included in this collection, but ordered by their type above the usual ordering by level of taxonomic precision and alphabetically.

Cnidaria is a phylum of simple aquatic animals, best known for their radial symmetry, nematocysts (stinging cells), and a body plan organised around a central cavity. The phylum includes organisms like jellyfish, sea anemones, hydras, and corals. Most cnidarians have two basic body forms: the free-swimming medusa (as seen in jellyfish) and the sessile polyp (typical of corals and sea anemones). Cnidarians exhibit a diploblastic structure, meaning they possess two primary cell layers, the ectoderm and endoderm, with a gelatinous layer called the mesoglea in between. While many cnidarians are carnivorous, using their stinging cells to capture prey, some, particularly corals, have developed symbiotic relationships with photosynthetic organisms like zooxanthellae, which assist in nutrient production.

Within this diverse phylum, Class Anthozoa includes organisms that exist exclusively in the polyp form and lack a medusa stage. Anthozoans are primarily sessile, attached to the substrate, and include groups like corals and sea anemones. Among anthozoans, corals are the most significant from a geological and palaeontological perspective due to their capacity to build massive reef structures over geological time. Coral polyps typically secrete calcium carbonate to form exoskeletons, which fossilise readily, making them important indicators in the fossil record. Anthozoa is further divided into orders such as Hexacorallia, which includes the modern reef-building corals, and Octocorallia, which comprises soft corals and sea fans.

The fossil record of corals is particularly rich, with three major types standing out: tabulate corals, rugose corals, and scleractinian corals, each representing different eras of coral dominance in Earth's history.

Tabulate corals were dominant during the Palaeozoic era, especially from the Ordovician to the Permian. These corals are characterised by their colonial nature and the presence of horizontal internal divisions known as tabulae. Unlike later corals, tabulate corals lacked septa (vertical internal walls) and often formed large, tightly packed colonies. They contributed significantly to reef ecosystems in shallow tropical seas during the Silurian and Devonian periods. However, they became extinct at the end of the Permian, during the Permian-Triassic mass extinction. Their decline mirrored broader ecological upheavals that affected much of marine life at that time.

Rugose corals, also known as horn corals, coexisted with tabulate corals and appeared in the Ordovician, flourishing through the Devonian and into the Carboniferous. These corals could be either solitary or colonial, and their most distinctive feature is the presence of septal divisions within the coral skeleton, radiating from a central point. The solitary forms often resembled a horn in shape, giving them their common name. Rugose corals also contributed to Palaeozoic reef systems and are frequently found as fossils in limestone formations from these periods. Like the tabulate corals, rugose corals were wiped out during the Permian-Triassic extinction, marking the end of their dominance in marine ecosystems.

Following the extinction of tabulate and rugose corals, the Scleractinian corals (modern corals) emerged in the Triassic and have been the primary reef-builders ever since. Scleractinian corals also possess calcareous skeletons but differ from their predecessors in their skeletal microstructure, which is composed of aragonite rather than calcite. These corals are notable for their ability to form both solitary and colonial structures, with colonial forms building the vast coral reefs seen in modern oceans. Reef-building scleractinians rely heavily on symbiotic zooxanthellae, which enable them to thrive in nutrient-poor, sunlit waters by performing photosynthesis. Scleractinians became the dominant corals from the Jurassic onwards, and they continue to dominate coral reef ecosystems today, making them critical components of modern marine biodiversity.

Age: 345-330 Ma

Tournaisian to Viséan Age

Early to Middle Mississippian Epoch – Around the age of Romer’s Gap, noted for its unusual lack in tetrapod fossils, stunting our understanding of their evolution

Carboniferous Period – Giant arthropods and amphibians, early reptiles, most plants fern or lycophyte-like, known for tropical forests and seas

Paleozoic Era – pre-Dinosaurs

Location: Cheddar Gorge

Cheddar

Somerset

England

Rock Type: Clifton Down Limtestone Formation, Cheddar Limestone Formation, or Cheddar Oolite Formation

Species:

Lithostrotion is an extinct genus of colonial rugose corals that thrived during the Carboniferous period, approximately 360 to 335 million years ago. These corals are part of the subclass Rugosa and the family Lithostrotiidae, known for their role in forming reef-like structures in shallow marine environments.

Specimens of Lithostrotion sp. are characterised by their colonial growth pattern, where multiple cylindrical or prismatic corallites (the skeletal structures of individual coral polyps) are tightly packed together. These corallites often measure between 5 and 15 millimetres in diameter and are internally supported by radial septa and tabulae, which form intricate skeletal structures. The colonies of Lithostrotion sp. could grow to significant sizes, forming mound-like or branching structures.

Ecologically, Lithostrotion sp. lived in warm, shallow seas, contributing to the development of carbonate platforms and reef systems.

Each polyp of Lithostrotion sp. used its tentacles to capture plankton and organic particles from the water, making it an essential component of the nutrient cycles within its ecosystem.

Note: Anthozoa is sometimes considered a subphylum, with its major consituents making up the classes. These being Class Ceriantharia, Hexacorallia (including Scleractinia and Rugosa), Octocorallia, and Tabulata. These will all be included in this collection, but ordered by their type above the usual ordering by level of taxonomic precision and alphabetically.

Cnidaria is a phylum of simple aquatic animals, best known for their radial symmetry, nematocysts (stinging cells), and a body plan organised around a central cavity. The phylum includes organisms like jellyfish, sea anemones, hydras, and corals. Most cnidarians have two basic body forms: the free-swimming medusa (as seen in jellyfish) and the sessile polyp (typical of corals and sea anemones). Cnidarians exhibit a diploblastic structure, meaning they possess two primary cell layers, the ectoderm and endoderm, with a gelatinous layer called the mesoglea in between. While many cnidarians are carnivorous, using their stinging cells to capture prey, some, particularly corals, have developed symbiotic relationships with photosynthetic organisms like zooxanthellae, which assist in nutrient production.

Within this diverse phylum, Class Anthozoa includes organisms that exist exclusively in the polyp form and lack a medusa stage. Anthozoans are primarily sessile, attached to the substrate, and include groups like corals and sea anemones. Among anthozoans, corals are the most significant from a geological and palaeontological perspective due to their capacity to build massive reef structures over geological time. Coral polyps typically secrete calcium carbonate to form exoskeletons, which fossilise readily, making them important indicators in the fossil record. Anthozoa is further divided into orders such as Hexacorallia, which includes the modern reef-building corals, and Octocorallia, which comprises soft corals and sea fans.

The fossil record of corals is particularly rich, with three major types standing out: tabulate corals, rugose corals, and scleractinian corals, each representing different eras of coral dominance in Earth's history.

Tabulate corals were dominant during the Palaeozoic era, especially from the Ordovician to the Permian. These corals are characterised by their colonial nature and the presence of horizontal internal divisions known as tabulae. Unlike later corals, tabulate corals lacked septa (vertical internal walls) and often formed large, tightly packed colonies. They contributed significantly to reef ecosystems in shallow tropical seas during the Silurian and Devonian periods. However, they became extinct at the end of the Permian, during the Permian-Triassic mass extinction. Their decline mirrored broader ecological upheavals that affected much of marine life at that time.

Rugose corals, also known as horn corals, coexisted with tabulate corals and appeared in the Ordovician, flourishing through the Devonian and into the Carboniferous. These corals could be either solitary or colonial, and their most distinctive feature is the presence of septal divisions within the coral skeleton, radiating from a central point. The solitary forms often resembled a horn in shape, giving them their common name. Rugose corals also contributed to Palaeozoic reef systems and are frequently found as fossils in limestone formations from these periods. Like the tabulate corals, rugose corals were wiped out during the Permian-Triassic extinction, marking the end of their dominance in marine ecosystems.

Following the extinction of tabulate and rugose corals, the Scleractinian corals (modern corals) emerged in the Triassic and have been the primary reef-builders ever since. Scleractinian corals also possess calcareous skeletons but differ from their predecessors in their skeletal microstructure, which is composed of aragonite rather than calcite. These corals are notable for their ability to form both solitary and colonial structures, with colonial forms building the vast coral reefs seen in modern oceans. Reef-building scleractinians rely heavily on symbiotic zooxanthellae, which enable them to thrive in nutrient-poor, sunlit waters by performing photosynthesis. Scleractinians became the dominant corals from the Jurassic onwards, and they continue to dominate coral reef ecosystems today, making them critical components of modern marine biodiversity.