Laqueus californianus (Koch, 1848)

Common name(s): Lampshell, Brachiopod

Synonyms:
Class Articulata
Order Terebratulida
Suborder Terebratellidina
Family Laqueidae
Laqueus californianus shell from 120 m depth off Yellow Island, San Juan Channel, WA
(Photo by: Dave Cowles, August 2007)
Description:  This brachiopod has a pedicle and the shell is at least as long (hinge to opening) as wide (side to side when facing opening), and inflated. The anterior margins of the valves (at the opening) are smooth, straight, and without teeth. The shell is white or with a light tan periostracum, thin, and almost translucent.  Shells may be smooth to prominently ribbed.  The long, slender pedicle passes through a well-formed hole near the hinge of the larger (ventral) valve but the hole does not obliterate the apex of the valve.  Up to 3 (5?) cm long.

How to Distinguish from Similar Species: Crania californica has no pedicle and one valve is cemented to the rock like a jingle shell. Terebratalia transversa is wider than long and the anterior margin (opening) of the shell is undulating. Terebratulina unguicula has small teeth along the anterior margin, the shell is not translucent, and the apex of the shell is completely obliterated by the hole for the pedicle.

Geographical Range: British Columbia to Southern California, Sea of Japan

Depth Range:  Occasionally intertidal; subtidal to 486 m

Habitat:  Attached to rock

Biology/Natural History:  Sexes are separate.

Articulate brachiopods such as this species have interlocking teeth at the hinge.  The teeth prevent the shell valves from being opened more than a few degrees from each other, and will break at the hinge if an attempt is made to open the shell farther.  Articulate brachiopods also have a blind gut with no anus, so any undigested material must be spit back up through the mouth.



 

References:

Dichotomous Keys:
  Kozloff 1987, 1996

General References:
  Harbo, 1999
  Johnson and Snook, 1955
  Rice, 1973
 

Scientific Articles:

Web sites:


General Notes and Observations:  Locations, abundances, unusual behaviors:
I have rarely seen this brachiopod near Rosario though it is said to be common in some places (most often subtidally).  It can be found in Enteroctopus dofleini middens near Rosario. Terebratalia transversa is far more commonly found in our area.

Underside

This view of the ventral side shows how the ventral (larger) valve overlaps the dorsal (smaller) valve near the hinge, and has a hole through which the pedicle projects.  The pedicle is a fleshy stalk used to anchor the animal to a rock.

Side view

As can be seen in this side view, the larger (ventral) valve overlaps the smaller valve where the pedicle exits.  The ventral valve is on top.
Articulate brachiopods generally live with the ventral valve upwards like this.
 

Brachial arms

A view inside the shell, such as this view made by shining a strong light through the dorsal shell (on bottom), shows the brachial arms which support the lophophore.
Such a scaffold is characteristic of Order Terebratulida. 

Laqueus-Terebratalia

This photo shows a small Terebratalia transversa (left) and a normal-sized Laqueus californianus (right) for comparison. L. californianus is more elongated than is
T. transversa and the opening between the valves forms a straight line rather than a sinuous one.


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