(Linné, 1758)

Description:
The shell is thick and irregularly oval. Inequivalve: right valve with a small byssal notch in anterior ear, cemented to the substratum in later life, becoming irregular, and more deeply convex than the left, upper valve. Small individuals, attached only by the byssus, with 35-50 regular, radiating ribs on each valve; larger, cemented shells with up to 70 coarse, spiny ribs on each valve, usually worn or partly obscured by encrusting organisms. Margin is crenulate (C. pusio-drawing).

Size:
Up to 50 mm long.

Colour:
Variable, from dull white or grey, to yellow, red or brown, sometimes in irregular patterns.

Animal:
Mantle with a double margin, the inner finely fringed and the outer edged with long tentacles. The eye-spots at the base of the tentacles are few in number.

Habitat:
Adult stage lives attached to hard substrata by its lower valve. From low on the shore, to at least 100 m.

Distribution:
Distributed from Norway and Iceland, south to west Africa, and in the Mediterranean (Distr. C. pusio).

Kingdom Animalia
Phylum Mollusca
Class Bivalvia
Subclass Pteromorphia
Order Pterioida
Family Pectinidae
Genus Crassadoma
Species Crassadoma pusio

Status in World Register of Marine Species

Synonym of Talochlamys pusio (Linnaeus, 1758)

Scientific synonyms and common names

Ostrea pusio Linné, 1758
Pecten distortus da Costa, 1778
Ostrea miniata Von Born, 1780
Ostrea sinuosa Gmelin, 1791
Pecten spinosus Brown, 1827
Pecten irregularis Deshayes, 1832
Pecten crotilus Reeve, 1853
Pecten pusillus Locard, 1886
Pecten distortus var. elongata Locard, 1888 non Pecten elongatus Lamarck, 1819 non Pecten elongatus McCoy in Griffith, 1844
Pecten distortus var. minor Locard, 1888
Pecten distortus var. lutea Locard, 1888 non Pecten luteus Bosc, 1801
Pecten distortus var. fusca Locard, 1888 non Pecten fuscus Bosc, 1801 non Pecten fuscus Sowerby G.B. II, 1842 non Pecten fuscus Linsley, 1848
Pecten distortus var. grisea Locard, 1888 non Pecten griseus Lamarck, 1819
Pecten distortus var. inflata Locard, 1888 non Pecten inflatus Bosc, 1801
Pecten isabella sensu MacGillivray, 1843 non Lamarck, 1819
Crassodoma distorta
Chlamys distorta
Hinnites distortus

Hayward, P.J., Wigham, G.D. & N. Yonow, 1990. Mollusca I: Polyplacophora, Scaphopoda, and Gastropoda. In: The Marine Fauna of the British Isles and North-West Europe. (ed. P.J. Hayward & J.S. Ryland). Clarendon Press, Oxford: 628-730.

Seaward, D.R., 1990. Distribution of the marine molluscs of north west Europe. Nature Conservancy Council.

Step, E., 1927. Shell life. 421 pp. Frederick Warne & Co., LTD, London.

Wagner, H. P., 1991. Review of the European Pectinidae. Vitra Marina, 41(1): 1-48.

You can continue searching for Crassadoma pusio on one of these Web sites:

Fauna Europaea (animals) | IOPI (plants) | NCBI (genetic)

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