Steromphala umbilicalis

Steromphala umbilicalis, common name the flat top shell, is a species of sea snail, a marine gastropod mollusk in the family Trochidae, the top snails.[1]

Steromphala umbilicalis
A shell of Steromphala umbilicalis
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
Subclass:	Vetigastropoda
Order:	Trochida
Superfamily:	Trochoidea
Family:	Trochidae
Genus:	Steromphala
Species:	S. umbilicalis
Binomial name
Steromphala umbilicalis (da Costa, 1778)
Synonyms[1]
Gibbula obliquata (Gmelin, 1791) Gibbula obliquata var. gradata Pallary, 1920 Gibbula umbilicalis (da Costa, 1778) Trochus cinereus Blainville, 1826 non Linnaeus, 1758 Trochus obliquatus Gmelin, 1791 Gibbula obliquata (Gmelin, 1791) Trochus sarniensis Norman, 1888 Trochus umbilicalis da Costa, 1778 (original combination) Trochus umbilicatus Montagu, 1803 Trochus umbilicatus var. atropurpurea Jeffreys, 1865 Trochus umbilicatus var. decorata Jeffreys, 1865

Description

The size of an adult shell varies between 10 mm and 22 mm. The shell is more depressed than Gibbula cineraria, and (although the base is flatter) never inclined to a pyramidal form. The spiral ridges are sharper and fewer, especially in the young. The coloring is different; both have a similar kind of marking, but in the present species the longitudinal rays or streaks are red, besides being broader and not half so many as in the other species. They are sometimes zigzag, instead of being broken into spots or interrupted by the sculpture. This species is striped, the other lineated. Just within the outer lip are two borders, one of yellow, the other of green variegated by red spots. This edging is minutely tubercled like shagreen.[2]

Distribution

This marine species occurs in European waters and in the Mediterranean Sea off Morocco.

References

1. MolluscaBase eds. (2020). MolluscaBase. Steromphala umbilicalis (da Costa, 1778). Accessed through: World Register of Marine Species at: http://www.marinespecies.org/aphia.php?p=taxdetails&id=1039850 on 2020-12-30
2. Tryon (1889), Manual of Conchology XI, Academy of Natural Sciences, Philadelphia

• Backeljau, T. (1986). Lijst van de recente mariene mollusken van België [List of the recent marine molluscs of Belgium]. Koninklijk Belgisch Instituut voor Natuurwetenschappen: Brussels, Belgium. 106 pp.
• Gofas, S.; Le Renard, J.; Bouchet, P. (2001). Mollusca, in: Costello, M.J. et al. (Ed.) (2001). European register of marine species: a check-list of the marine species in Europe and a bibliography of guides to their identification. Collection Patrimoines Naturels, 50: pp. 180–213
• Muller, Y. (2004). Faune et flore du littoral du Nord, du Pas-de-Calais et de la Belgique: inventaire. [Coastal fauna and flora of the Nord, Pas-de-Calais and Belgium: inventory]. Commission Régionale de Biologie Région Nord Pas-de-Calais: France. 307 pp

External links

• "Gibbula (Gibbula) umbilicalis". Gastropods.com. Retrieved 3 July 2011.
• Da Costa E. M., 1778: Historia Naturalis Testaceorum Britanniae; London: Millan, White, Elmsley & Robson XII + 254 + VIII p., 17 pl
• Montagu G., 1803: Testacea Britannica, or natural history of British shells, marine, land and the fresh-water, including the most minute: systematically arranged and embellished with figures; Romsey. London pp. XXXVII + 606 + 16 pl.
• [httpsGmelin J.F. (1791). Vermes. In: Gmelin J.F. (Ed.) Caroli a Linnaei Systema Naturae per Regna Tria Naturae, Ed. 13. Tome 1(6). G.E. Beer, Lipsiae [Leipzig]. pp. 3021-3910]://www.biodiversitylibrary.org/item/83098#5]
• Norman A. M., 1888: Museum Normanianum, or a catalogue of the Invertebrata of Europe, and the Arctic North Atlantic Oceans. IV Mollusca marina. V. Brachiopoda; Durham pp. 30
• Jeffreys J. G., 1862-1869: British Conchology; London, van Voorst Vol. 1: pp. CXIV + 341 [1862. Vol. 2: pp. 479 [1864]. Vol. 3: pp. 394 [1865]. Vol. 4: pp. 487 [1867]. Vol. 5: pp. 259 [1869] ]
• Pallary P., 1920: Exploration scientifique du Maroc organisée par la Société de Géographie de Paris et continuée par la Société des Sciences Naturelles du Maroc. Deuxième fascicule. Malacologie (1912) ; Larose, Rabat et Paris pp. 108, 1 pl., 1 map
• ffenzeller S., Haar N. & Steiner G. (2017). Revision of the genus complex Gibbula: an integrative approach to delineating the Eastern Mediterranean genera Gibbula Risso, 1826, Steromphala Gray, 1847, and Phorcus Risso, 1826 using DNA-barcoding and geometric morphometrics (Vetigastropoda, Trochoidea). Organisms Diversity & Evolution. 17(4): 789-812