Giant Keyhole Limpet
NameGiant Keyhole Limpet
Scientific NameMegathura crenulata
Common NameGiant Keyhole Limpet
FamilyFissurellidae
GenusMegathura
Speciescrenulata
Geographic DistributionEastern Pacific Ocean, ranging from Central California (USA) south to Baja California (Mexico).
Habitatintertidal
Shell Shapeconical
Average Size (mm)100
Identifying FeaturesIts exceptionally large size for a limpet (up to 13 cm or 5 inches), the prominent black mantle that engulfs most of the shell, and the large, oval apical opening (keyhole) are its key identifying characteristics.
Raritycommon
Author CitationSowerby I, 1825
Description
The Giant Keyhole Limpet (*Megathura crenulata*) is a large marine gastropod, notable for its distinctive black mantle that often completely covers its shell. The shell itself is a flattened cone with a prominent, elongated apical opening, or 'keyhole'. It is a common inhabitant of rocky intertidal and subtidal zones along the Pacific coast of North America.
