A phylogeny-based revision of the shrimp genera Altelatipes, Benthonectes and Benthesicymus (Crustacea: Decapoda: Benthesicymidae)

Abstract

Abstract A phylogenetic study of deep-sea dendrobranchiate genera Altelatipes, Benthesicymus and Benthonectes based on four molecular markers and 91 morphological characters is presented. All currently recognized species of these genera, representatives of all other genera and species groups of Benthesicymidae, and three outgroups were included in the analyses. The molecular and morphological methods retrieved similar results, the molecular methods provided better resolution of deeper nodes and higher clade support. Both types of analyses showed paraphyly of Benthesicymus, which encompass five robust clades, four of which are diagnosed as new genera (type species in parentheses): Benthesicymus s.s. (B. crenatus), Bathicaris gen. nov. (Benthesicymus brasiliensis), Dalicaris gen. nov. (Benthesicymus altus), Trichocaris gen. nov. (Benthesicymus bartletti) and Maorrancaris gen. nov. (Benthesicymus investigatoris). Altelatipes was found to be monophyletic. The evolution of the major clades of Benthesicymidae is shown to be linked to trophic specialization, while further divergence at the genus level is mainly related to sexual evolution seen in the elaboration of the copulatory structures. We provide amended diagnoses of the previously recognized and new genera, key to species of each of these genera and include an updated key to genera of Benthesicymidae.