Species Account

Heteranomia squamula (Linnaeus, 1758)

Anomioidea : Anomiidae

Tebble name: Heteranomia squamula (Linnaeus)
Smith & Heppell name: Heteranomia squamula (L., 1758)

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

Depth Range
Continental Shelf (to 200m)
Continental Margin Zone (200 - 500m)
Bathyal (500 - 2000m)

Additional Information & Related 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.


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Record last modified: 17/05/2016