Reference 17298

Since the description of the first remipede crustacean, Speleonectes lucayensis Yager, 1981, the number of taxa within the order Nectiopoda has increased at irregular intervals. At present, a total of 16 species is recognized, comprising seven genera and two families. However, recent discoveries of new taxa have revealed critical diagnostic inconsistencies at and below the family level. These discoveries include, in particular, a new family of Remipedia from the Turks and Caicos Islands. The new family shares several characters with the Speleonectidae, but it also exhibits some derived features that might be shared with the Godzilliidae. Obviously, the current taxonomic structure within the Nectiopoda has become unstable and inadequate. Therefore, an investigation of phylogenetic relationships between remipede species seemed highly desirable. Here, we present a cladistic analysis of the Remipedia, including all currently known Recent species and the Carboniferous fossil Tesnusocaris (Enantiopoda). We compared different methodological approaches and coding options using a data matrix of 25-30 morphologic characters. Both monophyly of the Godziliidae and the status of the new family were supported, while the status of the Speleonectidae remained ambiguous. We also found, however, that the use of morphologic characters alone appears insufficient to resolve phylogenetic relationships within the Remipedia, and accordingly, contribute to a stable revision of the group. Consequently, we are conducting molecular sequence analyses in a continued attempt to reconstruct the phylogeny of this group of hermaphroditic stygobionts. In addition to our morphologic data, we are investigating nine genes, including five mitochondrial markers, two nuclear ribosomal and two protein-encoding genes to analyze the phylogeny of Remipedia and evaluate their phylogenetic position within the Crustacea.