Phylogenetic relationships among Neotropical freshwater crabs of the Pseudothelphusidae (Decapoda, Brachyura) and the taxonomic position of Ptychophallus and related genera

Abstract

The primary freshwater crab family Pseudothelphusidae is distributed with almost 300 described species from northern Mexico to the southern tributaries of the Amazon, including most of the Greater and Lesser Antilles. Its systematic grouping is solely based on morphological characters. The most recent and commonly applied classification distinguishes two subfamilies, the Epilobocerinae on the Greater Antilles, and the Pseudothelphusinae on the mainland of Central and South America and the Lesser Antilles (Rodríguez, 1982). In addition, several tribes are recognized based on the morphology of the first pair of male pleopods, the so called gonopods: the Pseudothelphusini, the Potamocarcinini, the Hypolobocerini, the Kingsleyini, and the Strengerianini. Here, we present the first molecular phylogeny of the Pseudothelphusidae, including representatives of all the subfamilies and tribes. The generaAchlidon,Allacanthos, andPtychophallusform a strongly supported monophyletic unit, clustering independently of the tribi where they have been classified so far. We present preliminary suggestions for a possibly derived taxonomy of the family.