Dolphin-Toothed Nut Clam

Ennucula delphinodonta

A small bivalve, reaching only four millimetres in size. Olive brown, oval shell with concentric ridges.

Authority

Mighels & C. B. Adams, 1842

Classification Details

Phylum: Mollusca (molluscs); Class: Bivalvia (bivalve molluscs).

Habitat

Found from Labrador to Maryland on Canadian and American coasts. Also known from West Greenland, Norway, and the Barents Sea. Found in soft sediments.

Diet

Sub-surface deposit feeder. Two long tentacles extend from pockets called labial palps on either side of the mouth. These search for organic particles in the sediment. Particles pass down a groove in the tentacle to the lamellae where ciliated tracts sort the particles.

Reproduction

Sexes are separate. Fertilization occurs within the mantle cavity. Females carry 20 to 70 eggs. Developing embryos are carried in the sack for two to four weeks before emerging through the mother's mantle and settling. There is no planktonic larval phase.

Fun Facts

This species was described from specimens that were found in the stomach of a haddock.

The teeth on the hinge of the shell are long, slender and pointed - presumably the source of the scientific name which means “dolphin tooth”.

References

Drew GA (1901) The Life–History of Nucula delphinodonta (Mighels). Quarterly Journal of Microscopical Science 44, 313–391.

Mateeva TA (1979) Adaptations to bearing of eggs in some marine bivalves. Proceedings of the Institute of Zoology of the USSR 80, 39–43.

Mighels JW and Adams CB (1842). Descriptions of twenty–four new species of New England shells. Boston Journal of Natural History 4, 37–54, pl. 4, available online at http://biodiversitylibrary.org/page/5362938

MolluscaBase (2020) MolluscaBase. Ennucula delphinodonta (Mighels & C. B. Adams, 1842). Accessed through: World Register of Marine Species at: http://www.marinespecies.org/aphia.php?p=taxdetails&id=506605 Accessed online 20 January 2020.

Scheltema Rudolf and Williams I (2009) Reproduction among protobranch bivalves of the family Nuculidae from sublittoral, bathyal, and abyssal depths off the New England coast of North America. Deep Sea Research Part II: Topical Studies in Oceanography 56, 1835–1846. 10.1016/j.dsr2.2009.05.024.

Van Guelpen L, Pohle G, Vanden Berghe E and Costello MJ (2005) Marine Species Registers for the North Atlantic Ocean. World Wide Web electronic publication. http://www.vliz.be/vmdcdata/narms/