Click on photo to enlarge. Scale line in photo equals 1cm unless otherwise specified.
* Species which are commonly encountered on the beach.
Lucinidae
Lucinoma annulatum(Reeve, 1850)Western Ringed Lucineintertidal to 750m size to 82mmnorthern Mexico to central Alaska & JapanThis is occasionally found intertidally.The obvious growth rings are easily eroded.On this species the growth rings representgrowth intervals, not years.
(previous name - Lucina annulata)
Ungulinidae
juvenile with intact periostracum
This page last revised: 8-12-2011
Diplodonta impolita S.S. Berry, 1953
Rough Diplodon
intertidal to 100m size to 32mm
Oregon to northern Alaska
This is occasionally found intertidally. It is fairly round and inflated.
The shell is chalky white under a thick periostracum. It has heavy
irregular, commarginal growth lines.
Thyasiridae
Conchocele bisecta (Conrad, 1849)Giant Cleftclamsubtidal, 50-750m size to 100mmnorthern California to Bering Sea; Sea of Japan to Sea of OkhotskThis is found on mud bottoms. It is a chalky shell with a prominent cleft on the posterior end.(synonym - Conchocele disjuncta)
Thyasira flexuosa (Montagu, 1803)Flexuose Cleftclam
subtidal, 20-3000m size to 12mm
circumboreal and panarctic; reaches south to
southern California, Florida, north Africa and Japan
The shell form is extremely variable. It has very
fine sculpturing. It has many synonyms, and with
further study, it may be determined there is more
than one species.
Parvilucina tenuisculpta (Carpenter, 1864)Fine-Lined Lucineintertidal to 300m size to 15mmnorthern Mexico to northern AlaskaThis is infrequently found intertidally. It prefers mud with high organic content. The growth lines are very fine and closely spaced.
(previous name - Lucina tenuisculpta)
Bivalves
Family Lucinidae, Ungulinidae
& Thyasiridae