Cryptomya californica (Conrad, 1837)

Common name(s): California softshell clam, California glass mya

Synonyms: Cryptomya magna Cryptomya californica
Subclass Heterodonta 
Order Myoida 
Superfamily Myoidea 
Cryptomya californica, 2 cm long, found alongside Neotrypaea californiensis burrows at Freeland Beach, Whidbey Island.
(Photo by: Dave Cowles July 2020 )

Description: Members of Order Myoida burrow and most have long siphons. The hinge has few teeth. Members of Family Myidae have an internal hinge ligament  and a large projecting chondrophore in the left valve only (Photo). Cryptomya californica has a thin shell and a shallow, inconspicuous pallial sinus that is not as deep as it is wide. Its siphons are quite short but it may live buried up to 50 cm below the sediment surface by extending its siphons into the burrow of another animal. The white shell is smooth except for fine concentric lines and has a thin yellow-brown periostracum. The anterior and posterior ends are fairly similar in shape. The umbones are very close to the middle. The valves gape slightly at the posterior end. Length to 3.7 cm (usually less than 3).

How to Distinguish from Similar Species:  Other members of Family Myidae such as Sphenia ovoidea and Mya arenaria have a pallial sinus at least as deep as wide. The umbones are anterior to the middle, and the posterior end of the shell is clearly different from the anterior.

Geographical Range:  Northern Japan to Alaska and south to Peru.

Depth Range:  Intertidal to 80 m

Habitat:  Soft mud and sand. 

Biology/Natural History:  This small clam often extends its siphons into the burrows of Neotrypaea californica,Upogebia pugettensis, or Urechis caupo raher than to the sediment surface. It also readily moves to a different site. This species broods its young.



Dichotomous Keys:
  Carlton, 2007
  Kozloff, 1987, 1996

General References:
  Harbo, 1997
  Kozloff, 1993
  Lamb and Hanby, 2005
  Morris et al., 1980

Scientific Articles:
Hiebert, T.C. 2013. Cryptomya californica. in Hiebert, T.C., B.A. Butler, and A.L. Shanks (eds.), Oregon estuarine invertebrates: Rudy's illustrated guide to common species, 3rd ed. University of Oregin Libraries and Oregon Institute of marine Biology, Charleston, OR
Lawry, E.V., 1987. Cryptomya californica (Conrad, 1837): observations on its habitat, behavior, anatomy, and physiology. Veliger 30: pp 46-54

Web sites:

General Notes and Observations: Locations, abundances, unusual behaviors:
The left valve in this species has an obvious chondrophore but the right valve does not.
Left valve Right valve
The hinge of the left valve has a prominent projecting chondrophore. The anterior end of the shell is downwards in this photo. Shell length about 2 cm. The right valve has no projecting chondrophore at the hinge. The anterior end of the shell is downward in this photo. Shell length about 2 cm.

Authors and Editors of Page:
Dave Cowles (2020):  Created original page
CSS coding for page developed by Jonathan Cowles

Salish Sea Invertebrates web site provided courtesy of Walla Walla University