Mitochondrial characteristics of Pseudohynobius flavomaculatus a protected salamander in China, and biogeographical implications for the family Hynobiidae (Amphibia, Caudata)

Pseudohynobius flavomaculatus a provincially-protected salamander species, inhabits mountainous areas of Chongqing and surrounding provinces in China. In the present study, the complete mitochondrial genome of P. flavomaculatus was sequenced and analyzed. The mitogenome is 16,401 bp in length and consisted of 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA genes, and a control region. We performed a novel phylogenetic analysis, which demonstrated a sister relationship between P. flavomaculatus and P. jinfo. The 95% confidence interval around our new divergence date estimate suggest that Hynobiidae originated at 101.62–119.84 (mean=110.87) Ma. Species within Hynobiidae diverged successively in the Cenozoic era, and hynobiid speciation coincides primarily with geologic events. Our biogeographical inference demonstrates that nearly all early hynobiids divergences correspond to geological estimates of orogeny, which may have contributed to the notably high dN/dS ratio in this clade. We conclude that orogeny is likely a primary, dynamic factor, which may have repeatedly initiated the process of speciation in the family Hynobiidae.