Symbiosis between the alpheid shrimp, Athanas ornithorhynchus Banner and Banner, 1973 (Crustacea : Decapoda), and the brittle star, Macrophiothrix longipeda (Lamarck, 1816) (Echinodermata: Ophiuroidea)

Symbiosis between the alpheid shrimp, Athanas ornithorhynchus Banner and Banner, 1973 (Crustacea: Decapoda), and the brittle star, Macrophiothrix longipeda (Lamarck, 1816) (Echinodermata: Ophiuroidea). Zoological Studies 44(2): 234-241. The rarely collected alpheid shrimp, Athanas ornithorhynchus Banner and Banner, characterized by a unique platypus bill-shaped dactylus of the minor cheliped, is reported for the first time from Vietnam. Most shrimps were found directly on the arms of large brittle stars, Macrophiothrix longipeda (Lamarck), which were dwelling under mud-covered boulders, at depths between 16 and 35 m. The association of the shrimps with the ophiuroids observed in the field, the close attachment of the shrimps to their hosts in aquaria, and the disruptive colour pattern, which renders shrimps cryptic against the arms of their host suggest that A. ornithorhynchus lives symbiotically with Macrophiothrix, at least locally in Nhatrang Bay, Vietnam. The possible trophic dependence of the shrimps on their hosts remains to be shown. This is the first report of a possibly stable association between an alpheid shrimp and a brittle star.