Phylogeography and population structure of (Richardson, 1845) (Tetraodontiformes, Tetraodontidae) in the South China Sea.

The climate fluctuations during the Late Pleistocene significantly influenced the phylogeographic structure and historical dynamics of marine fishes in the marginal seas of the western Pacific Ocean. The puffer fish, , holds substantial nutritional and economic value in the South China Sea. To investigate the demographic history and population structure of the , the mitochondrial DNA and Cyt gene datasets from 300 individuals across eight populations in the South China Sea were sequenced. Our findings revealed high haplotype diversity (0.874 ± 0.013) and low nucleotide diversity (0.00075 ± 0.00058). The phylogenetic tree and haplotype networks revealed no significant genetic differentiation along the northern coast of South China Sea. Neutrality tests, mismatch distribution analyses, and Bayesian skyline plots suggested that underwent population expansion during the Late Pleistocene. Both ocean currents and climate change significantly influenced the geographical distribution and genetic population structure of .