Bivalves

Hiatellidae

Petersburg, AK Semiahmoo Spit, WA, intertidal Gabriola Island, BC, intertidal - in an empty pholad hole

Hiatella arctica (Linnaeus, 1767)
Arctic Hiatella *
intertidal to 1190m Chile to northern Alaska; Japan size to 78mm, but usually less than 50mm
This is commonly found intertidally. Juveniles are often found bysally attached under rocks. The shell surface can be rather rough looking. This species is under study and it is possible there is more than one species involved.

unknown locations Port Angeles, WA siphons, subtidal

Panomya ampla Dall, 1898
Ample Roughmya
intertidal to 150m Puget Sound, WA to northern Alaska size to 90mm
This is rarely found intertidally, and then usually washed up into rocks on a beach with high wave activity. The shell can be highly variable and irregular in shape. The interior has very distinctive markings. The siphon has a pink to orange ring on the inside edge of the siphon and the siphon interior may be white to orangish.

Panopea generosa Gould, 1850
Pacific Geoduck *
intertidal to 100m central California to central Alaska; Panama; Japan to Siberia size to 230mm
Commonly found intertidally in sand and mud, or at least the siphons are seen. This clam is one of the deepest burrowers and may be as far as 3 ft. below the surface of the sand. They can also be very long-lived, reaching an age of 130 years or more. The siphons are distinctive above the sand at low tide. They can be as thick as your wrist and are smooth and pale in color. They may flop to the sand if they protrude more than a few inches. The top of the siphon is smooth with no finger-like projections on the inside of the siphon holes. Horseclam siphons are often mistaken for Geoducks, but they have rough surfaced siphons with leathery plates at the top exterior of the siphon and finger-like projections lining the tops of the siphon holes.
(synonym - Panopea abrupta)

Panomya norvegica (Spengler, 1793)
Arctic Roughmya
subtidal, 20-640m size to 110mm
Circumpolar stretching south to Japan, northern Oregon, Virginea & Britain;
has occasionally been found as far south as southern California
This is a large, thick shell, without the prominent muscle scars of the P. ampla.
(synonyms - Mya norvegica, Panomya arctica)

Family Hiatellidae