02 Jorunna tomentosa.

Length 43 mm. Menai Strait, Wales. February 2014.

Ample yellow mantle covers whole body. Large, translucent, pale, unpigmented, bipinnate and tripinnate gills surround a contrasting brown anal papilla.

Lateral rows of brown blotches; 3 on left, 5 on right of animal.

White-capped caryophyllidia around bases of rhinophores and in several white spots scattered across the mantle.

 

Full SPECIES DESCRIPTION BELOW

Key id. features at flic.kr/p/EjpcXr

PDF available at www.researchgate.net/publication/356760098_Jorunna_toment...

Sets of OTHER SPECIES: www.flickr.com/photos/56388191@N08/collections/

 

Jorunna tomentosa (Cuvier, 1804)

 

Current taxonomy: World Register of Marine Species (WoRMS)

www.marinespecies.org/aphia.php?p=taxdetails&id=140166

 

Synonyms: Doris tomentosa Cuvier, 1804; Doris johnstoni Alder & Hancock, 1845.

Meaning of name:

Jorunna = possibly named after Jórunn,a woman in the Icelandic Laxdaela Saga.

tomentosa (Latin) = like cushion stuffing. i.e. soft and yielding.

Vernacular: Schwamm-Sternschnecke (German); satijnslak (Dutch);

 

GLOSSARY below.

 

Description

Up to 60 mm long. The ample mantle covers the whole body. It is sandy-brown 1Jt flic.kr/p/EjpcXr , grey, grey-cream, yellow 2Jt flic.kr/p/K2ALfV , yellow cream 3Jt flic.kr/p/EjpceH , buff-orange or white 4Jt flic.kr/p/K2AJ14 . It often has faint freckles, and a few dark blotches in two or three longitudinal rows 5Jt flic.kr/p/EjpbfP . The periphery of the mantle has small, opaque, white glands 3Jt flic.kr/p/EjpceH , but they are obscure on some. The mantle surface has crowded, small, match-like caryophyllidia (retractile tubercles) 8Jt flic.kr/p/K2AFXB with a ring of sharp projecting spicules surrounding the rounded apex of each. The underside of the mantle often looks slightly granular 6Jt flic.kr/p/K2AGXH . The slug’s general appearance is velvety, and it is soft and yielding to touch. Its profile is convex, but it varies with degree of extension. The anterior half is often lower than the posterior when extended fully 7Jt flic.kr/p/22B7pn2 & 1Jt flic.kr/p/EjpcXr . The mantle is slightly raised into a rim bearing caryophyllidia around the rhinophore base 8Jt flic.kr/p/K2AFXB ,and into a distinct collar-like sheath around the gill pocket 9Jt flic.kr/p/22B7oGe .

The short, stout rhinophores have a translucent whitish, or slightly tinted, basal stem, and a conical, lamellated, yellow-cream to grey, distal part bearing red to brown pigment dots/marks 8Jt flic.kr/p/K2AFXB . There are about ten to fifteen close set lamellae 8Jt flic.kr/p/K2AFXB and a short nipple like apex. Left and right lamellae meet at an anterior groove.

On adults there are 14 to 17 large, translucent, pale, unpigmented, bipinnate and tripinnate gills around a contrasting brown anal papilla 2Jt flic.kr/p/K2ALfV , 4Jt flic.kr/p/K2AJ14 & 17Jt flic.kr/p/K2ADhB . The main stem of each plume is broad and flattened. The gills can be held in a variety of positions 9Jt flic.kr/p/22B7oGe ; when fully expanded they are 'elegant, beautiful and blossom-like' (Alder & Hancock, 1845) 10Jt flic.kr/p/K2AFB6 & 11Jt flic.kr/p/22B75ok . They stand in a pit surrounded by a distinctly raised collar which folds in over them when they are retracted into the pit 12Jt flic.kr/p/22B7nRM .

The head is pale and slightly translucent. The mouth projects as a short tube 13Jt flic.kr/p/K2AEvi which can be expanded 14Jt flic.kr/p/22B7mUr . On either side of the mouth there is a long, slender tapering oral tentacle 15Jt flic.kr/p/K2AEjX , often with a few small brownish spots.

The elongate foot has a slightly translucent white or yellowish sole which faintly reveals the viscera 16Jt flic.kr/p/22B7kkV , and the upper surface has pale yellowish brown freckling 17Jt flic.kr/p/K2ADhB . The rounded anterior is bilaminate with the upper layer extending well beyond the lower layer 15Jt flic.kr/p/K2AEjX & 18Jt flic.kr/p/22B7j8e . The upper layer has a large cleft. The bluntly tapered posterior protrudes beyond the mantle when in motion 19Jt flic.kr/p/22B7iPD . Locomotion is by monotaxic retrograde waves on the sole. The hermaphrodite genital opening is on a protrusion on the right of the body about a quarter of its length from the anterior 17Jt flic.kr/p/K2ADhB . When mating, a large penis and wide-open female accessory gland are extended 14Jt flic.kr/p/22B7mUr .

 

Key identification features

Sequencing of DNA segregated a previously unrecognised species, Jorunna artsdatabankia (Neuhaus et al, 2021) from a complex previously regarded as J. tomentosa. Other species of Jorunna occur in Iberia and the Mediterranean.

 

Jorunna tomentosa

1: Length up to 30 mm (Neuhaus et al, 2021), 55 mm (Thompson and Brown, 1984), often a similar size to Doris pseudoargus.

2: Dorsally, sandy-brown 1Jt flic.kr/p/EjpcXr , reddish brown, grey-white, grey-cream, yellow 2Jt flic.kr/p/K2ALfV , yellow cream 3Jt flic.kr/p/EjpceH , buff-orange, or white 4Jt flic.kr/p/K2AJ14. Small opaque white glands are near the periphery of the mantle 3Jt flic.kr/p/EjpceH but sometimes they are not discernible 1Jt flic.kr/p/EjpcXr . Usually, there are scattered small dark spots, and a few dark blotches in a longitudinal row on each side 5Jt flic.kr/p/EjpbfP ; sometimes the blotches are absent, or few and small 11Jt flic.kr/p/22B75ok and occasionally the small spots are absent.

3: Mantle has crowded, small, match-like caryophyllidia (retractile tubercles) 8Jt flic.kr/p/K2AFXB with a ring of sharp projecting spicules surrounding the rounded apex. The body has a velvety appearance and soft feel.

4: Large yellow-cream to grey gills surround the brown anal papilla 2Jt flic.kr/p/K2ALfV & 4Jt flic.kr/p/K2AJ14 . Gills are often paler than the mantle and sometimes have dark dots.

5: The base of extended gills is surrounded by a distinct collar-like sheath 9Jt flic.kr/p/22B7oGe which closes over the gills when they are retracted into a pit 12Jt flic.kr/p/22B7nRM.

6: Slender tapered oral tentacles 15Jt flic.kr/p/K2AEjX .

7: Convex body with raised profile 7Jt flic.kr/p/22B7pn2 .

8: Short, stout rhinophores have a translucent whitish, or slightly tinted, basal stem and a conical, lamellated, yellow-cream to grey, distal part bearing red to brown pigment dots/marks 8Jt flic.kr/p/K2AFXB .

9: Posterior of foot protrudes when in motion 19Jt flic.kr/p/22B7iPD .

 

Similar species

 

Jorunna artsdatabankia Neuhaus, Rauch, Bakken, Picton, Pola & Malaquias, 2021. [Early records from Norway, North Sea (offshore), Scotland and Ireland] 20.1Jt flic.kr/p/2mLYTR7 , 20.2Jt flic.kr/p/2mM3Y6a & 20.3Jt flic.kr/p/2mPKA3e .

1: Up to 40 mm long (Neuhaus et al, 2021).

2: Dorsally, plain yellow to white with sparse, irregularly scattered, small brown spots. Opaque white glands on periphery of mantle, but may not be discernible.

3: Mantle has crowded, small, match-like, retractile tubercles (caryophyllidia) with a ring of sharp projecting spicules surrounding the rounded apex. They are longer than on J. tomentosa, so may look more plush in close view.

4: Gills are concolorous with the mantle. They lack any dark dots.

5: Base of extended gills surrounded by a raised rim which closes over the gills when they are retracted into a pit.

6: Slender tapered oral tentacles.

7: Convex body with raised profile.

8: Rhinophores yellow-cream to white without any dark dots on the lamellae (Neuhaus et al., 2021).

9: Posterior of foot protrudes at the posterior slightly, or not at all, when in motion.

 

Rostanga rubra (Risso, 1818)

1: Up to 15 mm long (20 mm in Mediterranean).

2: Mantle bright scarlet 21Jt flic.kr/p/FQykVf to orange 22Jt flic.kr/p/22B7gLv , with sparse scattered black or reddish-brown spots. Characteristic white or pale yellow patch around bases of, and between, rhinophores looks like spectacles 21Jt flic.kr/p/FQykVf , sometimes indistinct 22Jt flic.kr/p/22B7gLv . Many opaque white glands on periphery of mantle.

3: Mantle covered with densely packed caryophyllidia which are thicker than those on J. tomentosa with shorter projecting spicules 23Jt flic.kr/p/FQykoo

4: Translucent unipinnate gills, tinted as mantle, usually held erect to form cylinder around brown tubular anus 24Jt flic.kr/p/22B7gmH .

5: Base of extended gills surrounded by slightly raised rim bearing caryophyllidia, not a distinct collar-like sheath 24Jt flic.kr/p/22B7gmH .

6: Slender tapered oral tentacles 25Jt flic.kr/p/FQykhm .

7: Convex body with raised profile 22Jt flic.kr/p/22B7gLv .

8: Rhinophores translucent white or yellowish with opaque white and brown spots on the lamellae which are deeply cleft and widely separated at the anterior 23Jt flic.kr/p/FQykoo .

9: Posterior of foot protrudes a little at the posterior when in motion.

 

 

Doris pseudoargus Rapp, 1827.

1: Up to 120 mm long, but often similar size to Jorunna tomentosa.

2: Usually lemon yellow to red, frequently variegated with large blotches of colours such as purple, pink, red, brown, green and white. Plain yellow specimens superficially resemble J. tomentosa but often have a distinguishing trace of purple on the gills 26Jt flic.kr/p/22B7g6H & 27Jt flic.kr/p/K2AALV .

3: Variously sized, rounded, spiculose tubercles 27Jt flic.kr/p/K2AALV give a stiff unyielding feel to the mantle.

4: Voluminous gills resembling curled kale. Often blotched with variable amount of lilac or purple 26Jt flic.kr/p/22B7g6H & 27Jt flic.kr/p/K2AALV. The anal papilla may be brownish if gills are dark 28Jt flic.kr/p/22B7ePV .

5: Base of gills not surrounded by collar-like sheath 28Jt flic.kr/p/22B7ePV .

6: Short, thick, oral tentacles 29Jt flic.kr/p/FQyipy .

7: Convex body with raised profile 26Jt flic.kr/p/22B7g6H .

8: Rhinophores have a translucent whitish, or slightly tinted, basal stem and a yellow or orange distal part with 20 or more lamellae, often with small flecks of opaque white. Conical, when retracted like on J. tomentosa, but much more slender than that species when fully extended 27.1Jt flic.kr/p/2mMoweB .

9: Posterior of foot protrudes a little when in motion.

 

Acanthodoris pilosa (Abildgaard in Müller, 1789)

1: Usual maximum length 40 mm.

2: Dorsally white or brown 30Jt flic.kr/p/22B7e9X , occasionally, black or yellow 31Jt flic.kr/p/FQyi81 . Pale colours may be evenly freckled darker, but not with large patches of pigment.

3: Soft, tall, thin, conical tubercles on mantle 31Jt flic.kr/p/FQyi81, but sometimes contracted or poorly developed and not so distinctive 32Jt flic.kr/p/22B7dAT. Body soft and yielding.

4: Voluminous tripinnate gills can contract but not retract into pocket; usually, opaque white pigment along each side of translucent midribs forms a star when gills expanded 32Jt flic.kr/p/22B7dAT . Anal papilla not brown, except possibly on brown specimens.

5: Base of gills not surrounded by collar-like sheath.

6: Narrow oral veil extended laterally into broad, flat oral tentacles. Anterior of veil has two protrusions centrally 33Jt flic.kr/p/22B7cRM .

7 Convex body with raised profile 30Jt flic.kr/p/22B7e9X .

8: Long rhinophores bent rearwards; concolorous with body and no dark dots on pale colour forms. Up to 24 lamellae on large specimens.

9: Posterior of foot protrudes a little when in motion.

 

Cadlina laevis (Linnaeus, 1767) 33.1Jt flic.kr/p/2mMC83S

1: Usual maximum length 32 mm.

2: Shiny white with opaque yellow or white glands near the periphery and, sometimes, has an opaque yellow or white peripheral border.

3: Unobtrusive, very small, un-crowded, soft tubercles give very soft texture to mantle.

4: White gills not voluminous, hidden much of the time retracted into pocket.

5: Base of gills not surrounded by collar-like sheath.

6: Very small oral tentacles.

7: Body has a flattened low profile.

8: Rhinophores white or yellowish with about 12 lamellae and no dark dots.

9: Posterior of foot protrudes when in motion.

 

Similar species in the Mediterranean

There are several difficult-to-differentiate similar species in the Mediterranean; see opistobranquis.info/en/?s=Jorunna . The following is insufficient to differentiate them all, but workers in north-western Europe need to be aware of them in case some spread north with climate change.

 

Jorunna onubensis Cervera, García-Gómez & García, 1986,

Jorunna onubensis is very similar to J. tomentosa. The external features below are described in the original description of J. onubensis, based on four intertidal specimens from Huelva, southern Spain. The features illustrated in this Flickr account are on a specimen from Catalonia of J. onubensis identified by Miquel Pontes and confirmed by Prof. J. Lucas Cervera. Many features are common to both J. onubensis and J. tomentosa; those in bold font may be the best features for distinguishing them, but confirmation by dissection and/or D.N.A, sequencing is desirable. Specimens of J. onubensis photographed by one of the authors of its first published description, J. C. García Gómez, can be seen with other south European Jorunna species at opistobranquis.info/en/?s=Jorunna

It has been recorded from Spain, Portugal, Madeira and the Canary Islands.

 

1: 12 mm to 18 mm long (four specimens March & April 1984). 2: Light brown, often slightly pinkish, mantle 34Jt flic.kr/p/FQyhy5 [sometimes grey?]. Sometimes with scattered dark, greyish or greyish-brown, blotches of varying size. Small opaque glands near posterior border of mantle 36Jt flic.kr/p/22B7b8M .

3: Very fine, crowded, linear tubercles (caryophyllidia), similar to J. tomentosa, some with opaque, bright-white apex 37Jt flic.kr/p/22B7aUv 4: The light brown to transparent whitish gills have a fine brown punctuation, hardly distinguishable to the naked eye 38Jt flic.kr/p/22B7aQx & 39Jt flic.kr/p/22B7a9H The end of the anal papilla is brown with whitish striations that subdivide it into unequal parts 38Jt flic.kr/p/22B7aQx

5: Base of extended gills surrounded by collar-like sheath 39Jt flic.kr/p/22B7a9H which closes over the gills when they are retracted into a pit 35Jt flic.kr/p/22B7bHp .

6: Slender tapered oral tentacles, similar to J. tomentosa.

7: Convex body with raised profile, similar to J. tomentosa.

8: Short rhinophores are whitish, sometimes with strip of dark brown subapically. Basal stem transparent. About 15 lamellae form conical distal half.

9: Posterior of foot protrudes slightly when in motion.

 

Tayuva lilacina (Gould, 1852)

Synonym: Discodoris maculosa Bergh, 1884.

Occurs in Mediterranean and most tropical seas; not recorded in NW Europe.

1: Up to 60 mm long. (Juveniles, c. 10 mm length, are superficially very similar to Jorunna tomentosa.)

2: Light brown to light olive grey with many slightly darker circular patches 40Jt flic.kr/p/23YrP1D . Often, two or three rows of the patches have black-brown marks on them 41Jt flic.kr/p/K2AtdP .

3: Crowded, low, conical tubercles (not linear caryophyllidia), often several apically capped with opaque white; body has hard texture 42Jt flic.kr/p/23YrMUF . On older specimens, many tubercles are white, and the mantle may be abundantly speckled white 43Jt flic.kr/p/FQydL5 .

4: Gills golden brown with white tips 40Jt flic.kr/p/23YrP1D , but often retracted out of sight.

5: Base of extended gills surrounded by large raised sheath which closes over the gills when they are retracted into a pit 41Jt flic.kr/p/K2AtdP .

6: Slender tapered oral tentacles 42Jt flic.kr/p/23YrMUF .

7: Body has a flattened low profile 40Jt flic.kr/p/23YrP1D, but can occasionally assume a more raised profile.

8: Rhinophores tall when extended. On adults, basal stem whitish with many fine brown freckles. About 20 lamellae with many brown spots.

9: Posterior of foot may protrude very slightly when in motion.

 

Habits and ecology

J. tomentosa lives on hard-substrates on the lower shore, and sublittorally in shallow coastal waters.

It feeds on several Haliclona spp. of sponge 44Jt flic.kr/p/EjoQPp including Haliclona oculta www.habitas.org.uk/marinelife/species.asp?item=C8600 , Haliclona cinerea www.habitas.org.uk/marinelife/species.asp?item=C8560 and, perhaps, Halichondria panicea www.habitas.org.uk/marinelife/species.asp?item=C4840 . Faeces are expelled as a stream of mucus bound pellets 16Jt flic.kr/p/22B7kkV from the anus on a raised brown papilla 17Jt flic.kr/p/K2ADhB. J. tomentosa breeds when it is 19 mm long or larger. Like other dorids, it is a simultaneous hermaphrodite. The spawn is a broad ribbon attached by its edge to the prey organism or substrate in a spiral of two or three turns, which may be tight and neat (Picton & Morrow) initially, later becoming convoluted 45Jt flic.kr/p/22B7i9F . Each spawn mass has up to 145 000 ova. Spawning has been recorded from February to August in Britain and to September in the Bay of Biscay (Thompson & Brown, 1984). Veliger larvae spend about 23 days at 10º C in the plankton before metamorphosis.

 

Distribution and status

J. tomentosa occurs from northern Norway to the eastern Mediterranean. It is also reported, but requires DNA confirmation, from the Cape of Good Hope, South Africa; GBIF map www.gbif.org/species/2292454 . It is quite common around Britain and Ireland but scarce or absent in the north-east Irish Sea and between Flamborough and Kent. NBN UK map species.nbnatlas.org/species/NHMSYS0021512462

 

Acknowledgements

The comparison images and text in this account depend greatly on the generous contributions of others who provided over a third of the images. I gratefully thank Jim Anderson www.nudibranch.org/Scottish%20Nudibranchs/ , Vanessa Charles and Paula Lightfoot for use of their images. I acknowledge and thank Prof. J. Lucas Cervera, Enric Madrenas, Jakov Prkić and Miquel Pontes opistobranquis.info/en/#gsc.tab=0 for images, information and useful discussion of Mediterranean material. Any errors or omissions are my (I.F.S.) responsibility.

 

Links and references

 

Alder, J. & Hancock, A. 1845-1855. A monograph of the British nudibranchiate mollusca. London, Ray Society.

www.biodiversitylibrary.org/item/131598#page/106/mode/1up &

www.biodiversitylibrary.org/item/131598#page/107/mode/1up

 

Camacho-Garcia, Y. & Gosliner, T.M. 2008. Systematic revision of Jorunna Bergh, 1876 (Nudibranchia: Discodorididae) with morphological phyplogenetic analysis. J. Mollus. Stud. 74: 143 to 181. www.researchgate.net/publication/240589318_Systematic_rev...

 

Catteneo Vietti, R., Angelini, S., Gaggero, L. & Lucchetti, G. 1995. Mineral composition of nudibranch spicules. J. Mollus. Stud. 61 (3): 331-337. Abstract at mollus.oxfordjournals.org/content/61/3/331.abstract

 

Cervera J. L., Garcia J. C. & Garcia F. J. (1986). Il genere Jorunna Bergh, 1876 (Mollusca: Gastropoda: Nudibranchia) nel litorale Iberico. Lavori, Società Italiana di Malacologia 22: 111-134

www.societaitalianadimalacologia.it/index.php?option=com_...

[Click “fasciolo completo” for 60 MB PDF. Contains illustrated original description of J. onubensis on pages 111 to 134]

 

Neuhaus J., Rauch, C., Bakken T., Picton, B., Pola M. and Malaquias, M.A.E. 2021. The genus Jorunna (Nudibranchia: Discodorididae) in Europe: a new species and a possible case of incipient speciation. Journal of Molluscan Studies 87: 1 – 31.

www.researchgate.net/publication/355042690_The_genus_Joru...

 

Picton, B.E. & Morrow, C.C. Encyclopedia of marine life of Britain and Ireland. [For prey species]. Accessed January 2018. www.habitas.org.uk/marinelife/index.html

 

Schmekel, L. & Portmann, A. 1982. Opisthobranchia des Mittelmeeres, Nudibranchia und Saccoglossa. Berlin, Springer.

 

Thompson, T.E. & Brown, G.H. 1984. Biology of opisthobranch molluscs 2. London, Ray Society.

 

Current taxonomy: World Register of Marine Species (WoRMS)

www.marinespecies.org/aphia.php?p=taxdetails&id=140166

 

Glossary

caryophyllidia = digital tubercles with terminal knob surrounded by coronet of spikes, like a clove (spice), on some dorid sea slugs.

 

cephalic = (adj.) of or on the head.

dorid = a sea slug in the infraorder Doridoidei; with gills and rhinophores on the dorsum; often shaped like half a lemon or grape.

 

lamellae = small plates on rhinophores, or leaflets of gill.(sing. lamella)

mantle = (of nudibranchs) sheet of tissue forming part or all of notum (dorsal body surface).

monotaxic = (of locomotion waves) single series of waves across complete width of foot.

papilla = (pl. papillae) small cone-shaped protrusion of flesh.

plankton = animals and plants that drift in pelagic zone (main body of water).

retrograde = (of locomotion waves on foot) waves travel from anterior to posterior.

rhinophores = (pl.) chemo-receptor tentacles on top of head of nudibranch.

tripinnate = (of gill) threefold branching; “boughs, branches, twigs” in one plane like a feather.

 

spicule = (in dorid seaslugs) small, slender, sharp-pointed feature mainly composed of calcite (CaCO3) and brucite (Mg(OH)2) .

 

unipinnate = (of gill plume) unbranched simple leaflets along each side of main rib.

veliger = shelled larva of marine gastropod or bivalve mollusc which swims by beating cilia of a velum (bilobed flap).

 

Done