Genetic Diversity and Population Structure of the Endangered Salamander Hynobius yiwuensis Inferred from Mitochondrial DNA Sequences

Understanding the genetic diversity patterns of endangered species is crucial for biodiversity conservation. The endangered salamander Hynobius yiwuensis, endemic to the mainland and Zhoushan Island in Zhejiang, China, has suffered from sharp population declines due to habitat loss. However, the levels and patterns of genetic diversity, differentiation, and population structure of H. yiwuensis remain poorly understood. Here, we explored the genetic diversity and phylogeography of H. yiwuensis based on partial mtDNA sequences (Cytb and CO1) through 111 individuals collected from seven localities. Relatively high overall haplotype diversity (h = 0.965) and low nucleotide diversity (π = 0.013) were detected. Our results, through phylogenetic trees and haplotype network analyses, revealed two divergent haplogroups, mainland and island, and the estimated divergence time indicated they diverged ~2.44 million years ago, which coincided with the period when Zhoushan Island became separated from the mainland.