Echinoecus pentagonus (A. Milne Edwards, 1879): Larval Development and Systematic Position (Crustacea: Brachyura: Xanthoidea nec Parthenopoidea)

The complete larval development of Echinoecus pentagonus (A. Milne Edwards), a brachyuran crab symbiotic with echinoderms, is described and illustrated. Development consists of three (or occasionally four) zoeal stages, each lasting from 4-8 days, and a megalopal stage lasting from 11-27 days (x̄ = 13.8 days). Morphological and developmental characters exhibited by the larvae of E. pentagonus indicate that the species is not a member of the family Parthenopidae, as previously thought, but instead shows strong morphological relationships to xanthid crabs, subfamily Pilumninae. Only further studies on larvae of species in the subfamily Eumedoninae will determine whether E. pentagonus and other eumedonine genera presently assigned to the Parthenopidae will eventually be reassigned either as a separate family (Eumedonidae), or as a subfamily (Eumedoninae) of the Xanthidae sensu lato or the Pilumnidae sensu Guinot.

Duke Scholars

Author Cindy Van Dover Marine Science and Conservation