Species Account

Chama congregata Conrad, 1833

Chamoidea : Chamidae

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

To size: To 25mm. Shell Structure: Thick, heavy. Equivalve: Inequivalve; bottom (left) valve much larger and deeper than top (right), which acts as a lid and is smaller and flatter. Equilateral: Inequilateral. Tumidity: Very tumid. Outline: Circular to irregularly oval.

Sculpture: Thick sculpture of worn, blunt, irregular radial ‘ribs’ arranged in concentric rows. Margin: Denticulate. Ligament: Dark brown, almost length of dorsal margin. Hinge: Large ‘cardinal’ tooth with corresponding socket in each valve and a chunky lateral tooth in the left valve. Pallial Musculature: No pallial sinus. Colour: White.

Distribution & Ecology

Native to E USA from North Carolina southwards to the Caribbean.

Records from Dorset coast and Gwithian, Cornwall.

Notoriously difficult to identify due to the intraspecific variety it is difficult to pinpoint to species without a rough idea of original locality. The one specimens from Dorset was initially assumed to be from Mediterranean and was originally identified as
Chama cf. gryphoides. However, based on ocean currents and recent records from Cornwall and of other E USA species washed ashore on Devon and Ireland coasts, we are assuming that this is a West Atlantic species.

Depth Range
Continental Shelf (to 200m)

Additional Information & Related Species

Related Species


Listed are literature citing Chama congregata Conrad, 1833. Reference containing the species Type Description is highlighted.

Conrad, T.A. 1833. On some new fossil and recent shells of the United States. American Journal of Science and Arts. 23 (17): 339-346.
Holmes A.M., Oliver P.G., Trewhella S, Hill R. & Quigley D.T.G. 2015. Trans-Atlantic rafting of inshore mollusca on macro-litter. American molluscs on British and Irish shores, new records. Journal of Conchology. 42 (1): 41-49.


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Record last modified: 03/03/2022