Bivalve-associates
Guides
Pinnotheridae
pea crabs, bivalve pea crabs
Pinnotheridae is a family of minute, soft-bodied crabs commonly known as pea crabs. Members are obligate symbionts that inhabit the mantles of bivalve molluscs, with occasional associations with large gastropods (genera Strombus and Haliotis), echinoids, holothurians, and ascidians. The family exhibits extensive morphological adaptations for symbiotic life, including reduced carapace calcification and specialized feeding structures. Fossil records extend to the Danian (Early Paleocene).