03 Gibbula magus. Height 19.25 mm, breadth 25.5 mm. Cardigan Bay, Wales. 2015.
Left: about 17 spiral ribs above periphery of body whorl.
Right: littoral specimen; some of circa 25 spiral ribs below periphery have been eroded smooth.
1: current growth beyond most recent growth line mainly white and free from epiphytic growths.
2: previous year's growth behind growth line is stained yellow, green etc by epiphytic growths.
With one exception, this specimen had the strongest red marks of about 100 living littoral specimens examined on a beach in Cardigan Bay. Most had no red marks.
Full SPECIES DESCRIPTION with links to images at:
Sets of OTHER SPECIES at:
www.flickr.com/photos/56388191@N08/collections/
Key identification features
Gibbula magus
* Opaque white shell 4Gm flic.kr/p/se5Uxd , sometimes with reddish marks 8Gm flic.kr/p/rUUiZD .
* Markedly stepped shell-profile 9Gm flic.kr/p/sbWrDL .
* Large conical umbilicus with wide comma-shaped groove leading into it 6Gm flic.kr/p/sebB3F .
* Snout has transverse brown to purple-black lines 13Gm flic.kr/p/rhe9yq , and distal half has dense beard of long bright blue papillae 12Gm flic.kr/p/rWMd2R .
* Black eye-pupil in blue area on stout peduncle 12Gm flic.kr/p/rWMd2R .
* Mainly sublittoral, but locally common at ELWS in favoured sheltered sites in Scilly Isles, Cardigan Bay, Connemara and Orkney. On stable sand, muddy-sand, maerl and gravel; sometimes on rock.
Similar species
Phorcus lineatus
* Shell, ground colour shades of buff 7Pl flic.kr/p/g3hrww , yellow 8Pl flic.kr/p/g3hsKA , brown 1Pl flic.kr/p/g3hsKJ and/or green 9Pl flic.kr/p/nz3eFr . Darker, more or less zig-zag, transverse streaks of dark-brown, -green, -grey or –reddish purple run across the whorls, parallel to growth lines.
* Shell-profile not stepped.
* Umbilicus completely sealed over by time 5mm wide, often leaving a dip in columella 4Pl flic.kr/p/g3hs4L (Occasionally narrow, open crack 5Pl flic.kr/p/nz3xm7 . Iberian specimens often have open umbilicus).
* Snout black or grey, lacks dense beard of long bright blue papillae 14Pl flic.kr/p/nPuhDb
* Black eye-pupil on red or yellow peduncle 14Pl flic.kr/p/nPuhDb
* Upper rocky shores between Isle of Wight and Llandudno, and most of Ireland.
Gibbula umbilicalis
* Shell always has broad red to reddish-purple bands radiating from apex across the whorls 5Gu flic.kr/p/g3iQgZ .
* Shell always has a large round umbilicus, but no wide comma-shaped groove leading into it 4Gu flic.kr/p/g3iV21 .
* Shell-profile not stepped 2Gu flic.kr/p/g3iVPG .
* Snout short, yellowish or greenish with dense transverse dark purple lines, lacks dense beard of long bight blue papillae 10Gu flic.kr/p/g3iT4d
* Middle levels of rocky shores from Kent along south and west coasts round onto north coast Scotland, with a few records on west coast of Orkney.
Gibbula cineraria
* Shell has grey or bluish grey bands radiating from apex across the whorls 3Gc flic.kr/p/k7Gxot .
* Umbilicus progressively narrows with age. Adult shell may have very restricted 26Gc flic.kr/p/g3ibVA or completely closed umbilicus 27Gc flic.kr/p/g3icEU , but juveniles 27Gu flic.kr/p/g3iMVW may have large round umbilicus.
* Shell profile of fully grown 15mm high G. cineraria may be like traditional bee-hive 6Gc flic.kr/p/kkVBzZ , but not stepped.
* Snout short, yellowish or brownish with transverse brown lines, lacks dense beard of long bright blue papillae 10Gc flic.kr/p/kmaPxE
Gibbula albida
* Opaque white shell, sometimes with reddish marks www.conchology.be/?t=66&species=Gibbula+albida .
* Stepped shell-profile.
* Some shells have umbilicus with comma-shaped groove leading into it, www.animalbase.uni-goettingen.de/zooweb/servlet/AnimalBas... but smaller than G. magus, and often closed by callus. nature22.com/estran22/mollusques/gasteropodes/gasteropode...
* Soft parts resemble G. magus; eye-pupil in blue area on peduncle, and snout has transverse brown lines but lacks dense beard of long bright blue papillae. nature22.com/estran22/mollusques/gasteropodes/gasteropode...
* Brittany southwards; not Britain.
03 Gibbula magus. Height 19.25 mm, breadth 25.5 mm. Cardigan Bay, Wales. 2015.
Left: about 17 spiral ribs above periphery of body whorl.
Right: littoral specimen; some of circa 25 spiral ribs below periphery have been eroded smooth.
1: current growth beyond most recent growth line mainly white and free from epiphytic growths.
2: previous year's growth behind growth line is stained yellow, green etc by epiphytic growths.
With one exception, this specimen had the strongest red marks of about 100 living littoral specimens examined on a beach in Cardigan Bay. Most had no red marks.
Full SPECIES DESCRIPTION with links to images at:
Sets of OTHER SPECIES at:
www.flickr.com/photos/56388191@N08/collections/
Key identification features
Gibbula magus
* Opaque white shell 4Gm flic.kr/p/se5Uxd , sometimes with reddish marks 8Gm flic.kr/p/rUUiZD .
* Markedly stepped shell-profile 9Gm flic.kr/p/sbWrDL .
* Large conical umbilicus with wide comma-shaped groove leading into it 6Gm flic.kr/p/sebB3F .
* Snout has transverse brown to purple-black lines 13Gm flic.kr/p/rhe9yq , and distal half has dense beard of long bright blue papillae 12Gm flic.kr/p/rWMd2R .
* Black eye-pupil in blue area on stout peduncle 12Gm flic.kr/p/rWMd2R .
* Mainly sublittoral, but locally common at ELWS in favoured sheltered sites in Scilly Isles, Cardigan Bay, Connemara and Orkney. On stable sand, muddy-sand, maerl and gravel; sometimes on rock.
Similar species
Phorcus lineatus
* Shell, ground colour shades of buff 7Pl flic.kr/p/g3hrww , yellow 8Pl flic.kr/p/g3hsKA , brown 1Pl flic.kr/p/g3hsKJ and/or green 9Pl flic.kr/p/nz3eFr . Darker, more or less zig-zag, transverse streaks of dark-brown, -green, -grey or –reddish purple run across the whorls, parallel to growth lines.
* Shell-profile not stepped.
* Umbilicus completely sealed over by time 5mm wide, often leaving a dip in columella 4Pl flic.kr/p/g3hs4L (Occasionally narrow, open crack 5Pl flic.kr/p/nz3xm7 . Iberian specimens often have open umbilicus).
* Snout black or grey, lacks dense beard of long bright blue papillae 14Pl flic.kr/p/nPuhDb
* Black eye-pupil on red or yellow peduncle 14Pl flic.kr/p/nPuhDb
* Upper rocky shores between Isle of Wight and Llandudno, and most of Ireland.
Gibbula umbilicalis
* Shell always has broad red to reddish-purple bands radiating from apex across the whorls 5Gu flic.kr/p/g3iQgZ .
* Shell always has a large round umbilicus, but no wide comma-shaped groove leading into it 4Gu flic.kr/p/g3iV21 .
* Shell-profile not stepped 2Gu flic.kr/p/g3iVPG .
* Snout short, yellowish or greenish with dense transverse dark purple lines, lacks dense beard of long bight blue papillae 10Gu flic.kr/p/g3iT4d
* Middle levels of rocky shores from Kent along south and west coasts round onto north coast Scotland, with a few records on west coast of Orkney.
Gibbula cineraria
* Shell has grey or bluish grey bands radiating from apex across the whorls 3Gc flic.kr/p/k7Gxot .
* Umbilicus progressively narrows with age. Adult shell may have very restricted 26Gc flic.kr/p/g3ibVA or completely closed umbilicus 27Gc flic.kr/p/g3icEU , but juveniles 27Gu flic.kr/p/g3iMVW may have large round umbilicus.
* Shell profile of fully grown 15mm high G. cineraria may be like traditional bee-hive 6Gc flic.kr/p/kkVBzZ , but not stepped.
* Snout short, yellowish or brownish with transverse brown lines, lacks dense beard of long bright blue papillae 10Gc flic.kr/p/kmaPxE
Gibbula albida
* Opaque white shell, sometimes with reddish marks www.conchology.be/?t=66&species=Gibbula+albida .
* Stepped shell-profile.
* Some shells have umbilicus with comma-shaped groove leading into it, www.animalbase.uni-goettingen.de/zooweb/servlet/AnimalBas... but smaller than G. magus, and often closed by callus. nature22.com/estran22/mollusques/gasteropodes/gasteropode...
* Soft parts resemble G. magus; eye-pupil in blue area on peduncle, and snout has transverse brown lines but lacks dense beard of long bright blue papillae. nature22.com/estran22/mollusques/gasteropodes/gasteropode...
* Brittany southwards; not Britain.