Molecular taxonomy and phylogeny of four species of Eriocheir (Decapoda: Brachyura: Grapsidae)

The taxonomy and phylogenic relationships of four species of Eriocheir were investigated by mitochondrial DNA sequencing analysis. Parts of 16S ribosomal DNA (16S rDNA) were amplified with the polymerase chain reaction (PCR). A total of 537 bp nucleotide site was sequenced for 6 individuals from Eriocheir sinensis and E. leptognathus, which were collected from Chong-ming island and San-jia Port in Shanghai, respectively. 33 (8.78%) polymorphic nucleotide sites were detected. 28 (7.45%) sites were interspecific sequence variation and the intraspecific genetic difference was small. Four haplotypes were found in both E. sinensis and E. leptognathus. Combined with the previously reported sequences (376 bp) from Pachygrapsus transversus (Sturmbauer et al., 1996), Sesarma ayatum, Chasmagnathus granulat (Schubart et al., 1998), E. japmmonicus and E. formosa (Cheng et al., 1998), phylogenetic trees were constructed with Maximum Parsimony and Neighbor-Joining method. The results indicated that E. sinensis to be more c