Molecular phylogenetic evidence for the reorganization of the Hyperiid amphipods, a diverse group of pelagic crustaceans

► We present the first multi-locus phylogeny of the hyperiid amphipods. ► We sampled 16 of the 23 recognized hyperiidian families for 18S, 28S, H3, and COI. ► Three reciprocally monophyletic clades were supported within Physocephalata. ► Our analyses place Cystisomatidae and Paraphronimidae at the base of Physosomata. ► Results are discussed within the context of pelagic hyperiid amphipod life history.