The complete mitogenome of the hydrothermal vent crab Xenograpsus testudinatus (Decapoda, Brachyura) and comparison with brachyuran crabs.

In this study, we analyzed the complete mitochondrial (mt) genome of a hydrothermal vent crab Xenograpsus testudinatus (Decapoda: Brachyura) obtained from the hydrothermal vents off Kueishantao Island, Taiwan, which extend from the deep sea Okinawa Trench. The mitogenome of X. testudinatus was 15,796 bp in length and contained the same 37 genes (e.g. 2 rRNAs, 22 tRNAs, and 13 PCGs) found in other metazoan mitogenomes. Analysis of the structural mt gene order in X. testudinatus revealed that the 13 PCGs, excluding a translocation of ND6-Cyt b cluster, were similarly ordered when compared to the pancrustacean ground pattern; however the tRNAs were severely rearranged. Phylogenetic analysis of decapod mitogenomes showed that the molecular taxonomy of the vent crab was in accordance with its morphological systematics. Together, these findings suggest that the vent crab studied here has little mitochondrial genetic variation when compared with morphologically defined conspecifics from other marine habitats.