Status of Eualus pusiolus in the northeastern Pacific, with a description of a new species of Eualus (Decapoda: Hippolytidae)

Abstract

The presence of Eualus pusiolus (Krøyer, 1841) in the northeastern Pacific is confirmed, and a new species that has often been confused with E. pusiolus is described and illustrated. Eualus butleri, n. sp., is found inside hexactinellid sponges and is distinguished by an elongated basal article of the antennular peduncle that exceeds the stylocerite, slender pereopods, and pronounced sexual dimorphism, with males larger than females and bearing enlarged third maxillipeds. A key to all known northeastern Pacific species of Eualus is included.