biostudies-literatureChen YNational Natural Science Foundation of China1393https://www.ebi.ac.uk/biostudies/studies/S-EPMC12732399biostudies-literatureUnknown16(12)<h4>Background</h4>Phylogeographic surveys of obligate freshwater fishes could serve as a pivotal lens through which the biological footprints of historic drainage rearrangements can be deciphered.<h4>Methods</h4>Focusing on the headwater-restricted cyprinid <i>Acrossocheilus kreyenbergii</i> in the Pearl, Yangtze, and Huai river basins, we examined variations in mitochondrial cytochrome <i>b</i> gene (<i>Cyt b</i>) to elucidate the phylogeographic architecture and evolutionary history of this stream fish in South-Central China through integrative analyses of phylogeny, ancestral area reconstruction, genetic structure, and population demography.<h4>Results</h4>A time-calibrated phylogeny recovered two primary lineages, K-I and K-II, which diverged ca. 2.15 Ma: K-I split into K-Ia (Huai RivGenesMountains, Lakes, and Ancient Drainage Networks Sculpt the Phylogeographic Architecture of the Stream Headwater Fish &lt;i&gt;Acrossocheilus kreyenbergii&lt;/i&gt; in China.PMC1273239931872209Fu CLe ZChen YDeng GfalseMountains, Lakes, and Ancient Drainage Networks Sculpt the Phylogeographic Architecture of the Stream Headwater Fish &lt;i&gt;Acrossocheilus kreyenbergii&lt;/i&gt; in China.<h4>Background</h4>Phylogeographic surveys of obligate freshwater fishes could serve as a pivotal lens through which the biological footprints of historic drainage rearrangements can be deciphered.<h4>Methods</h4>Focusing on the headwater-restricted cyprinid <i>Acrossocheilus kreyenbergii</i> in the Pearl, Yangtze, and Huai river basins, we examined variations in mitochondrial cytochrome <i>b</i> gene (<i>Cyt b</i>) to elucidate the phylogeographic architecture and evolutionary history of this stream fish in South-Central China through integrative analyses of phylogeny, ancestral area reconstruction, genetic structure, and population demography.<h4>Results</h4>A time-calibrated phylogeny recovered two primary lineages, K-I and K-II, which diverged ca. 2.15 Ma: K-I split into K-Ia (Huai Riv2025-01-01T00:00:00Z2025 Nov2026-05-28T03:19:39.648Z2026-05-28T03:11:23.561ZS-EPMC127323994146506610.3390/genes16121393