Heteranomia squamula (Linnaeus, 1758)Anomioidea : Anomiidae
To size: To 15 mm. Shell Structure: Upper valve thin but robust, lower valve thinner often hyaline. Equivalve: Inequivalve, upper (left) valve convex; lower (right valve) flat. Equilateral: Inequilateral, beaks close to the middle of the dorsal margin. Outline: Upper subcircular but often very irregular and taking outline of substrate; lower valve similar with an oval byssus foramen. Contour: Often deformed to fit shape of attachment area.
Sculpture: Upper valve surface variable from almost smooth with concentric lines to bearing fluted spines; lower valve with comarginal lines and growth stops. Margin: Irregular but smooth. Ligament: In a half moon shaped pit beneath the beaks. Hinge: Obscure. Pallial Musculature: Upper valve with two scars the dorsal (byssus retrator) larger and joined with the smaller single adductor scar. Scars without faint radiating furrows. Lower valve with a single faint adductor scar. Periostracum: Obscure. Colour: Both valves white often semitransparent. Additional Characters: Anatomy: Ctendium with non-reflected filaments.
Distribution & Ecology
On all coasts from low intertidal to upper slope 0-c.1000m. Depth limit needs clarification. Attached by its byssus to many substrates from Laminaria in the sublittoral to Lophelia deep water corals at bathyal depths. Often in highly exposed environments
Continental Shelf (to 200m)
Continental Margin Zone (200 - 500m)
Bathyal (500 - 2000m)
Juveniles & Similar Species
Key Features & Similar Species
Listed are literature citing Heteranomia squamula (Linnaeus, 1758). Reference containing the species Type Description is highlighted.
Linnaeus C 1758. Systema Naturae. Editio decima. 1. Regnum Animale Holmiae, Laurentii Salvii. 824pp.
Winckworth, R I922. Note on the British species of Anomia. Proceedings of the Malacological Society of London. 15: 32-34.
Yonge C M 1977. Form and Evolution in the Anomiacea (Mollusca: Bivalvia)-- Pododesmus, Anomia, Patro, Enigmonia (Anomiidae): Placunanomia, Placuna (Placunidae Fam. Nov.). Philosophical Transactions of the Royal Society of London Series B. 276: 453-523.
- Conchological Society
of Great Britain & Ireland
Provides resources for understanding, identifying, recording, and conserving molluscs
Check List of European Marine Mollusca
The Marine Life Information Network for Britain and Ireland (MarLIN) provides information for marine environmental management, protection and education. It is a centre of excellence in spatially based and time-series marine biological information and supports good stewardship in the marine environment.
- NBN Gateway
National Biodiversity Network's Gateway. Use it to explore UK biodiversity data, as contributed by participating data providers.
- Malacological Society
- Unitas Malacologica
- Census of Marine Life
MarBEF, a network of excellence funded by the European Union and consisting of 94 European marine institutes, is a platform to integrate and disseminate knowledge and expertise on marine biodiversity, with links to researchers, industry, stakeholders and the general public.