Acila castrensis   (Hinds, 1843)

divaricate nutclam

Description: An oval shell shape, which is abruptly truncated on its posterior end. Shell sculpture is strongly divaricated (chevron ribs).

Size: 15-20 mm.

Ecology: Shallow infaunal in soft sediments (mud, silt) from nearshore to upper bathyal depths (5-400 m).

Geological range: Late Miocene-Recent (12-0 million years ago).

Geographic distribution: Alaska (61°N) to Baja California Sur, Mexico (24°N), Russian Federation, and Japan. Reported from the Purisima Formation (Pliocene, California), San Pedro Sand (Pleistocene, California), Skonun Formation (Miocene, Canada), Tachilni Formation (Miocene, Alaska), Timms Point Silt (Pleistocene, California), and Towsley Formation (Pliocene, California).

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