False Angelwing
(Petricolaria pholadiformis)

Description: The elongate shape and the heavy radial sculpturing of the shell help to distinguish the false angelwing from a similar native species (Petricola carditoides), which has fine radial sculpturing and a rounder shell shape. The false angel wing can reach a width of 25 to 80 mm. It ranges from the lower intertidal zone down to depths of 8 meters. False angel wing colors range from white to a creamy yellow.

Habitat: The false angel wing bores into soft sediments (e.g., heavy mud, clay and peat) of bays and estuaries. In contrast, the similar native species nestles in rock crevices and in the abandoned holes formed by piddocks along the open coast.

Origin: East Coast of North America.

Invaded Areas: San Francisco Bay, Newport Bay (Southern California), Willapa Bay (Washington); Europe.

Concerns: False angelwings compete with native suspension-feeding species for food, and with other boring organisms (e.g., native estuarine piddocks such as Zirfaea pilsbryi) for space. This species was first discovered in San Francisco Bay in 1927, introduced by shipping or oyster culturing, and may still be present there.