Learn About Clams & Relatives

There are dozens of large species of bivalves on this coast. Most if not all are edible and many are commercially exploited. These potentials, combined with decreasing quality of natural habitats, have led to successful culture-industries for numerous species, including Manila clams, oysters, mussels, and scallops.

NOTE the English word “bivalve” originally meant “having two leaves or parts" (as a folding door) and is derived from a Latin word meaning the same thing. The English word “clam” derives from an older word meaning “to hold fast” or “a device to clasp rigidly or hold tight” (hence, clamp); only later was the term applied to burrowing marine bivalves

ANIMATION of snail meeting a CLAM
© 2010 Thomas Carefoot

To learn about west-coast CLAMS: select a topic from the Mollusca > Clams & relatives menu at the top of the page

OR: play the ANIMATION of the snail meeting the CLAM

OR, if you want to see other animations: follow the snail on its ODYSSEY by CLICKING on any X-marked invertebrate on the map

Phylum Mollusca (lit. “soft” or “shellfish” L.)

Class Bivalvia (lit. “two folding doors” L.), referring to the two parts of a clam or scallop shell joined by a flexible hinge

SubClass Heterodonta (lit. “different tooth” G.), referring to the different patterns of hinge teeth and ligaments that characterise the different families

Order Veneroida, containing the common large clams, as well as cockles; about 25 Families are represesented

Order Myoida, containing burrowing and boring bivalves, piddocks and shipworms, as well as geoducks Panopea spp.; some 5 Families are included

NOTE recent taxonomic changes concern the butter clam, now Saxidomus gigantea (from S. giganteus), the native littleneck clam, now Leukoma staminea (from Protothaca staminea), and the Japanese littleneck clam Venerupis philippinarum (now Ruditapes philiippinarum. Since recent name changes are sometimes reversed or changed again, all older references to these species will bear the older names, but the new names will be used for any new references

NOTE two species of geoducks (geoducs) inhabit the west coast of North America: Panopea generosa from Alaska to California and P. globosa along the Baja coast of Mexico. The first species has formerly been referred to as P. abrupta, but this designation in now valid only for an extinct, fossilised taxon. Vadopalas et al. 2010 Malacologia 52: 169

The Journal of Shellfish Research has recently devoted an entire issue to the genus Panopea, focussing on the population dynamics, growth, genetics, and aquaculture of 5 world species. The issue provides an up-to-date summary of the current state of knowledge of this interesting and commercially important genus. Of the 20 papers presented, about half are of interest to the ODYSSEY. J Shellfish Res 2015 Vol. 34 (1): 3-202