Phylogenetic analysis of the family Ampithoidae Stebbing, 1899 (Crustacea: Amphipoda), with a synopsis of the genera

Abstract

The Ampithoidae is a speciose family of mostly herbivorous amphipods. Although these amphipods feature heavily in shallow-water community and other ecological studies, their phylogenetic relationships have been little studied. We examined the phylogenetic relationships within Ampithoidae to test the subfamilial and generic classification. Cladistic analysis of 77 morphological characters across 53 terminal taxa representing all recognised genera resulted in five most parsimonious trees, differing only in internal relationships of species of Perampithoe Conlan and Bousfield, 1982. The subfamilies Amphitholininae Conlan, 1982, and Exampithoinae Myers and Lowry, 2003, are not recognised. Most genera are recovered as monophyletic, but Cymadusa Savigny, 1816, and Ampithoe Leach, 1814, are paraphyletic. Pleonexes Spence Bate, 1857 is recognised as a valid genus and removed from the synomymy of Ampithoe. Melanesius Ledoyer, 1984, is synonymised with Exampithoe K. H. Barnard, 1925, and Peramphithoe is synonymised with Sunamphitoe Spence Bate, 1857. A revised generic classification of Ampithoidae is presented, including a key to the 15 valid genera and revised diagnoses for each genus.