Pacific plate limpet

Appearance

This large, flat limpet has a bluish-white interior with a dark apical blotch and a marginal band or spots on the inside (photo). The apex is slightly anterior to the middle and is not directed anteriorly. It is oval in shape and the length is usually less than 1.3 times the width. The height is less than 1/3 the width. It has no prominent radial ribs but may have low, flat-topped ridges. The color is brownish, olive-green, or greenish, usually spotted, streaked, or checkered with white. Length to about 6.3 cm. This is the only Pacific limpet with brown tentacles. The edges of the shell are thin and easily broken.

Naming

Acmaea scutum, Acmaea patina, Acmaea testudinalis scutum, Acmaea tesselata, Notoacmea scutum

Distribution

Aleutian Islands, Alaska to Baja California, Mexico; rare (or absent) south of Point Conception, CA

Habitat

Rocky shores, protected from strong wave impact

Food

Grazes on microalgae and coralline algae

Predators

shore crabs, clingfish, the seastars Leptasterias hexactis, Pisaster ochraceous, Evasterias troschelii, and Pycnopodia helianthoides.