Heteromysis sabelliphila sp. nov. (Mysida, Mysidae, Heteromysinae) in facultative association with sabellids from the Cape Verde Islands (subtropical N.E. Atlantic)
A survey of crustaceans associated with benthic invertebrates in near-shore habitats at islands of the Cape Verde archipelago yielded a new species belonging to the genusHeteromysis, subgenusOlivemysis:H. sabelliphilasp. nov. shows a non-obligatory association with the sabellid polychaeteBranchiomma nigromaculatumonly during the night. This is the first documented mysid–polychaete association. The mysids apparently took particles collected by the polychaete, suggesting a kleptoparasitic interspecific relationship. A set of three specifically modified setae on the antennular trunk is shared by the new species with twoHeteromysisspecies from Madeira (subtropical N.E. Atlantic), suggesting a close morphological relationship within the subgenusOlivemysis: withH. wirtzi, commensal of the sea anemoneTelmatactis cricoides, and withH. dardani, commensal of the hermit crabDardanus calidus. A key to the Heteromysinae of the E. Atlantic and Mediterranean is given.