Phylogenetic analysis and systematic revision of Remipedia (Nectiopoda) from Bayesian analysis of molecular data

Abstract

We performed a phylogenetic analysis of the crustacean class Remipedia. For this purpose, we generated sequences of three different molecular markers, 16S rRNA (16S), histone 3 (H3), and cytochrome c oxidase subunit I (COI). The analyses included sequences from 20 of the 27 recent species of Remipedia, plus four still-undescribed species. The data matrix was complemented with sequences from online databases (The European Molecular Biology Laboratory and GenBank®). Campodea tillyardi (Diplura), Hutchinsoniella macracantha (Cephalocarida), Penaeus monodon (Malacostraca) and Branchinella occidentalis (Branchiopoda) served as out-groups. In addition to the classic computer-based alignment methods used for protein-coding markers (H3 and COI), an alternative approach combining structural alignment and manual optimization was used for 16S. The results of our analyses uncovered several inconsistencies with the current taxonomic classification of Remipedia. Godzilliidae and the genera Speleonectes and Lasionectes are polyphyletic, while Speleonectidae emerges as a paraphyletic group. We discuss current taxonomic diagnoses based on morphologic characters, and suggest a taxonomic revision that accords with the topologies of the phylogenetic analyses. Three new families (Kumongidae, Pleomothridae, and Cryptocorynetidae) as well as three new genera (Kumonga, Angirasu, and Xibalbanus) are erected. The family Morlockiidae and the genus Morlockia are removed from synonymy and returned to separate status.