Revision of basal calanoid copepod families,with a description of a new species and genus of Pseudocyclopidae

A newly discovered plesiomorphic genus and species of calanoid copepod ( P inkertonius ambiguus gen. et sp. nov. ) taken with an epibenthic sledge from the flanks of the Chatham Rise, east of New Zealand, at a depth of about 900 m, could not be assigned to any known genus or family based on available diagnoses. A morphology‐based cladistic analysis of all genera previously placed in the Epacteriscidae, Pseudocyclopidae, Ridgewayiidae, Boholinidae, and the new taxon is presented. The Pseudocyclopidae and Epacteriscidae are confirmed as monophyletic families, and the family names Ridgewayiidae and Boholinidae become synonyms of Pseudocyclopidae. There are no grounds upon which more than a single basal superfamily, the Pseudocyclopoidea, can be recognized. The superfamily Pseudocyclopoidea, and families Pseudocyclopidae, Epacteriscidae, and the new genus are diagnosed. P inkertonius ambiguus gen. et sp. nov. is placed within the Pseudocyclopidae. Genetic data adds to the definition of the new taxon and confirms the basal position of the Pseudocyclopoidea in a revised Calanoida phylogeny. This phylogeny contributes to an improved resolution of the relationships among the Centropagoidea, Megacalanoidea, Bathypontioidea, Eucalanoidea, and Clausocalanoidea, as well as providing testable hypotheses for future work. © 2014 The Linnean Society of London