An attempt to clarify phylogenetic affinities of erymid lobsters (Decapoda) using morphological characters

A morphological-based phylogenetic analysis of a total of 33 species: 27 fossil species from eight families recognized prior to this work (Chimaerastacidae, Clytiopsidae, Erymidae, Glypheidae, Litogastridae, Nephropidae, Pemphicidae, Uncinidae), and 6 extant species from four families recognized prior to this work (Astacidae, Enoplometopidae, Nephropidae, Stenopodidae) is proposed. The cladistic analysis demonstrates that the erymid lobsters should be included with the other clawed lobsters within the infraorder Astacidea. Among Astacidea, we observed the structure recalling the intercalated plate of erymids in the extant Enoplometopus reported by Schram & Dixon. In order to test Schram & Dixon's hypothesis, we considered this structure as homologous to the intercalated plate. Our results suggest that the sharing of this character does not indicate close relationships between Enoplometopus and erymids. The erymid lobsters form a monophyletic group of six genera (Eryma, Enoploclytia, Palaeastacus, Pustulina, Stenodactylina, Tethysastacus) included in the superfamily: Erymoidea. The inclusion of a character recently identified, a delimited post-orbital area, in the morphological dataset led to the split of Erymoidea into two clades. This topology justifies a systematic rearrangement of erymid genera within two families: Enoploclytiidae fam.n., lacking a delimited post-orbital area (Enoploclytia, Pustulina), and Erymidae, showing a delimited post-orbital area. The Erymidae are also separated in two sub-families: the simplicity of the carapace groove pattern of Tethysastacus justifies its placement within Tethysastacinae subfam.n., while Eryma, Palaeastacus and Stenodactylina form the Eryminae.