Polychaete-symbiont
Guides
Polyonyx
Polyonyx is a genus of porcelain crabs (family Porcellanidae) comprising at least 42 described species. Most species are obligate commensals of chaetopterid polychaete worms, living inside the tubes of their hosts. The genus exhibits a transversally cylindrical body form adapted for lateral movement within worm tubes. Several species frequently cohabit host tubes with other symbionts, including larger porcellanids, pinnotherid crabs, and nudibranchs.