Species Account

Cardiomya knudseni Allen & Morgan, 1981

Verticordioidea : Cuspidariidae

Tebble name: n/a
Smith & Heppell name: n/a

To size: To 9 mm. Shell Structure: Thin, fragile. Equivalve: Slightly inequivalve, LV overlapping RV. Equilateral: Slightly inequilateral, beaks slightly in front of the midline. Tumidity: Moderately inflated. Outline: Body of shell ovate; ventral extremity at line through the beaks; anterior dorsal margin distinct; dorsal part of anterior margin obliquely truncate, remainder of anterior and ventral margins a broad curve. Rostrum about half of body length, dorsal margin straight; ventral margin concave corresponding to weak sulcus at junction of rostrum and body.

Sculpture: Body of shell with about 20 primary radial riblets, the largest mid-ventral; secondary riblets appearing later between median and posterior ribs to give a total count of up to 30. Anterior area with 1-2 feeble striations. Concentric sculpture of fine lines and growth stops. Rostrum with 3-4 fine radial lines. Margin: Margin dentate where largest ribs intersect edges. Ligament: Internal, on a very small chondrophore lying beneath the beaks. Hinge: Cardinal teeth absent; RV with a posterior lateral flange; LV without teeth. Pallial Musculature: Obscure. Periostracum: Obscure. Colour: White, internal nacreous.

Distribution & Ecology

An abyssal species recorded from both North and South Atlantic with a bathymetric range of 1661-2886m (Allen & Morgan, 1981).
Recorded from Porcupine Sea Bight by Olabarria (2005). We have seen numbers of specimens from the entire Atlantic Margin and note considerable variation such that we are not convinced that any of this material can be attributed to
C. knudseni: much of it falls within C. costellata, curta and striata.

Depth Range
Bathyal (500 - 2000m)
Abyssal Rise (2000 - 4000m)

Additional Information & Related Species


Listed are literature citing Cardiomya knudseni Allen & Morgan, 1981. Reference containing the species Type Description is highlighted.

Allen J A & Morgan R E 1981. The functional morphology of Atlantic deep water species of the families Cuspidariidae and Poromyidae (Bivalvia): an analysis of the evolution of the septibranch condition. Philosophical Transactions of the Royal Society of London Series B. 294: 413-546.
Olabarria C. 2005. Patterns of bathymetric zonation of bivalves in the Porcupine Sea Bight and adjacent abyssal plain, NE Atlantic. Deep-Sea Research I. 52: 15-31.


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Record last modified: 22/03/2016