Molecular phylogenetics of the mitten crab species in Eriocheir, sensu lato (Brachyura: Grapsidae)

Taxonomy of mitten crabs has been problematic and confusing. Eriocheir was considered to comprise four species (E. japonica, E. sinensis, E. recta, and E. leptognathus). However, recent taxonomic revision has recognized five species and three genera, Eriocheir being restricted to E. sinensis, E. japonica, and E. hepuensis, and the establishment of two genera for Neoeriocheir leptognathus and Platyeriocheir formosa. The present study analyzed the phylogeny of the species of Eriocheir, sensu lato, based on DNA sequence analysis of mitochondrial 16S rRNA, cytochrome c oxidase 1, and the first internal transcribed spacer of nuclear IRNA. The results show that the three Eriocheir, sensu stricto, species are genetically similar, indicating that they have recently radiated. Eriocheir formosa is the sister taxon of these three species, with E. leptognathus the most distantly related taxon within the group. These results support the affinities of the mitten crabs, but the genetic divergence among the crabs provides no support for separating Eriocheir, s. l., to three different genera. We suggest to retain the apparently monophyletic mitten crabs in a single genus until more evidence is available.