Ennucula tenuis (Montagu, 1808)

Common name(s): Smooth nutclam

Synonyms: Nucula tenuis, N. bellotii, N. quirica, Nuculoma tenuis Ennucula tenuis
Subclass Protobranchia (Streptoneura, Paleotaxodonta)
Ennucula tenuis, about 2.5 cm long, from 100-120 m depth in the San Juan Channel
(Photo by: Dave Cowles, July 2015 )

Description:  Unlike most other bivalves in this area, but characteristic of  the Glycymeridids and of other members of Order Nuculoida, this species has taxodont dentition on its hinge (photo).  The hinge ligament is internal (photo).  The shell is definitely longer than it is high. The outside is fairly smooth and it has no radial ribs or other prominent radial sculpture-just small concentric growth lines.  The interior of the valves is pearly (photo), and it has no pallial sinus.

How to Distinguish from Similar Species:Acila castrensis also has taxodont dentition and an internal ligament but it has clear radial sculpturing in a chevronlike pattern (though not actual radial ribs).

Geographical Range:  Eastern Pacific and western Atlantic Ocean.

Depth Range:

Habitat:  In fine sediment offshore.

Biology/Natural History:



Dichotomous Keys:
  Carlton, 2007
  Kozloff, 1987, 1996

General References:
  Coan, E.V., P. Valentich-Scott, and F.R. Bernard, 2000.  Bivalve seashells of western North America.  Santa Barbara Museum of Natural History, Santa Barbara, CA.  764 pp.

Scientific Articles:

Web sites:

General Notes and Observations: Locations, abundances, unusual behaviors:

This shell was found ilive n the catch from a small otter trawl at 100-120 m depth in the San Juan Channel, in fine sediment and shell hash.  The flesh of the living clam is pale yellow.

This view of the inside of the shell shows the taxodont dentition, the pearly interior, and the fact that the hinge ligament is internal.

This closeup of the hinge shows the very distinct taxodont dentition

Authors and Editors of Page:
Dave Cowles (2015):  Created original page
CSS coding for page developed by Jonathan Cowles (2007)

Salish Sea Invertebrates web site provided courtesy of Walla Walla University