Fossil stomatopods (Crustacea: Malacostraca) and their phylogenetic impact

Abstract

The Stomatopoda form a distinctive order within the Malacostraca. It is an ancient group of benthic, obligate carnivorous crustaceans. Various studies have focused on stomatopods, mainly in regard to their taxonomy, their complex behaviour patterns, and the advanced neurophysiology of their visual systems. The α-taxonomy of this group seems well established; their phylogeny, however, still remains unclear. Palaeontological information can contribute significantly to the resolution of this group's phylogeny. Fossil evidence has already indicated that the ancestors of stomatopods probably diverged from other malacostracans in the Devonian. The first true stomatopods appear in the Carboniferous. The Mesozoic stomatopod families Sculdidae and Pseudosculdidae were studied more than a century ago. These early investigations on fossil stomatopods are of excellent quality. Unfortunately these sources were underestimated in later work on fossil stomatopods. The Cenozoic fossil stomatopod record appears to be richer than most stomatopod workers expected and all of the Cenozoic species seem to fit perfectly into the extant families. The usefulness of Cenozoic fossils for resolving phylogenetic relationships within the stomatopods seems doubtful but the Mesozoic material contains important information. The results of a preliminary cladistic analysis at family level show that the extinct Sculdidae and Pseudosculdidae are relict lineages that probably branched off at the end of the Palaeozoic or the beginning of the Mesozoic. The recent Gonodactyloidea are at the base of the clade that contains the other modern stomatopods.