Home > Northwest Shells & Marine Life > PNW Shells & Marine Life Photos > Bivalves >  Bivalves - Ostreidae, Anomiidae


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Click on photo to enlarge.  Scale line in photo equals 1cm unless otherwise specified.
* Species which are commonly encountered on the beach.










  












Anomiidae
Pododesmus macrochisma Pododesmus macrochisma
                                                                                     live individual
Pododesmus (Monia) macrochisma (Deshayes, 1839)
Green False-Jingle *
intertidal to 90m     size to 128mm
northern Mexico to northern Alaska and west to northern Japan
It is common intertidally. It attaches permanently to rocks and pilings through a
hole in its lower valve.  The lower valve is flattened and reflects the shape of
 whatever it is attached to.  The shell is light gray with a green interior and is often
camouflaged by algae and encrustations.  The shell can be very thin or quite thick.
There are possibly two subspecies.  Those from central Alaska to Japan might be
Pododesmus macrochisma macrochisma and those from central Alaska to northern
Mexico might be Pododesmus macrochisma cepio.
(previous names - Anomia macrochisma, Placunamonia cepio)  
Ostrea conchaphila
Ostrea conchaphila Carpenter, 1857
Olympia Oyster
intertidal to 50m          size to 90mm
Panama to southern Alaska
This is our only native species of oyster and it can be
hard to find.  It prefers protected waters.  The shell
shape is variable, depending on its environment.  The
area of attachment may be small to broad and the
margin may be smooth to slightly fluted.  The color
may be white, gray or purple with darker rays.  The
interior is white to greenish.
(previous name - Ostrea lurida)

Bivalves 

Family Ostreidae and Anomiidae


















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This page last revised: 5-7-2011


Ostreidae
Crassostrea gigas Crassostrea gigas Crassostrea gigas
                                                                                     live individual
Crassostrea gigas (Thunberg, 1793)
Pacific Oyster *
intertidal to 20m          size to 450mm
introduced from Japan to the U.S. and other parts of the world, naturalized
from southern California to southern Alaska and is also in commercial production
It is common intertidally.  The new growth is often purple and the growth margin
is fluted.  The shell shape is variable, depending on its environment, and the area of
attachment is small.  The exterior is often eroded and it has a white interior.  The
muscle scar is usually light-colored, but may have a purple or brownish tinge.
(previous name - Ostrea gigas)