The phylogeny of the stomatopod Crustacea

The stomatopods, or mantis shrimps, are malacostracan crustaceans of the su bclass Hoplocarida. Extant hoplocarids belong to the order Stomatopoda and suborder Unipeltata, comprising the extinct, stem-lineage pseudosculdids an d sculdids, and the crown group. Cladistic analysis including most or all g enera of the unipeltatan families, and rooted to the extinct Tyrannophontid ae, resulted in four most-parsimonious cladograms. The present results are more highly resolved and more robust than previous studies as the result of : more precise identification of suitable outgroups; a more complete outgro up data set, lessening the impact of missing data; and increased taxonomic sampling. The results largely support the existing five-superfamily classif ication, but as with two recent cladistic studies, Gonodactyloidea was poly phyletic. Gonodactyloidea is the basal crown-group superfamily and comprise s mostly 'smashers'. Two clades of 'spearers', Eurysquillidae and Parasquil lidae, previously considered gonodactyloids, are more closely related to th e Squilloidea and are referred to new superfamilies. The familial classific ation within Lysiosquilloidea is modified. Rather than deriving the 'smashe rs' from a long line of 'spearers', the present analysis suggests that the Unipeltata diverged in two broad directions from the outset. Hence, the gon odactyloid 'smashers' became specialised for hard substrates, and the remai nder diversified into the other modern superfamilies, evolving more efficie nt 'spearing' claws, and occupying soft substrates.