The evolutionary history and contemporary biogeography jointly shape the genetic architecture of marine species. This study investigates the phylogeny and population genetics of two closely related syngnathid fishes, Trachyrhamphus serratus and Trachyrhamphus longirostris. We report the first record of T. longirostris along the mainland coast of China, with samples collected from Yantai, Kenting, Zhanjiang, and Beihai. Population genetic analyses reveal genetic differentiation within T. longirostris, which exhibits low levels of genetic diversity across all sampled populations compared to T. serratus. The star-like haplotype network and significantly negative neutrality test values collectively indicate a recent population expansion event in T. longirostris. This study offers important insights into the evolutionary dynamics and biogeographic patterning of syngnathid fishes, with clear implications for their conservation and management.
Wang et al. (Fri,) studied this question.