Distribution of species in deep-sea biogeographic provinces and molecular phylogeny for the superfamily Neotanaoidea (Peracarida; Tanaidacea) indicate high levels of connectivity

Abstract

Here we analyze available recorded occurrences for species of Neotanaoidea, a deep-sea peracarid superfamily, in the frame of biogeographic bathyal, abyssal, and hadal provinces. In addition, we provide the first phylogeny based on molecular data for this group. Despite the existence of large knowledge gaps, the observed patterns reveal levels of connectivity across biogeographic provinces, oceans, and depths higher than initially expected for a superfamily consisting of relatively small deep-sea benthic invertebrates without a pelagic larval stage, and therefore hypothetically low mobility capabilities. We have detected neotanaid species with closely related populations across the Pacific Ocean or able to overpass a geographical barrier as significant as the Mid-Atlantic Ridge. Additionally, the molecular analyses expose the need for a taxonomic review of the four genera within Neotanaoidea. A search for better suited morphological and possibly ecological characters as diagnostic traits for genera and species should be undertaken, aiming at a better definition of the existing taxa and the description of new ones.