Influence of historical landscapes, drainage evolution and ecological traits on patterns of genetic diversity in Southeast Asian freshwater snakehead fishes

摘要: Snakehead fishes in the family Channidae are obligate freshwater represented by two extant genera, African Parachannna and Asian Channa. These species prefer still or slow flowing water bodies, where they top predators that exercise high levels of parental care, have ability to breathe air, can tolerate poor quality, interestingly, aestivate traverse terrestrial habitat response seasonal changes availability. attributes suggest snakehead may possess dispersal potential, irrespective barriers would otherwise constrain distribution most fishes. A number biogeographical hypotheses been developed account for modern distributions across continents, including ancient vicariance during Gondwanan break-up, recent colonisation tracking formation suitable climatic conditions. Taxonomic uncertainty also surrounds some members Channa genus, as geographical taxa southern Southeast (SE) Asia very large, one case is highly disjunct. The current study adopted a molecular genetics approach gain an understanding evolution this group fishes, particular how phylogeography influenced contemporary versus historical vicariance. First, phylogeny was constructed based on multiple DNA loci calibrated with fossil evidence provide dated chronology divergence events among species, within widespread distributions. data strong trans-continental arose result out into Africa mid–Eocene. Among Channa, deep lineages indicates Oligocene-Miocene boundary time significant radiation, potentially associated climate drainage geomorphology. Mid-Miocene suggests taxonomic revision warranted taxa. Deep intra-specific (~8Mya) detected between C. striata occur sympatrically Mekong River Basin. The then examined population structure major taxa, (the chevron snakehead) micropeltes giant snakehead), SE Asia. Species specific microsatellite were used addition mitochondrial marker (Cyt b) screen neutral genetic variation wild populations. C. individuals sampled (n=988), focus being Basin, which largest basin region. divergent identified admixture analysis showed co-occur interbreeding, indicating after long periods isolation, has not resulted reproductive isolation. One lineage predominantly confined upland areas northern Lao PDR north Khorat Plateau, while other, more closely related from India, mainland Sumatra. phylogeographical pattern recovered past river networks, diversity all populations reveal low taxon, even contiguous habitats. C. (n=280) focusing lower it constitutes important fishery resource. In comparison striata, allelic extremely low, suggesting greater Populations significantly structured at least three discrete Mekong. Results implications establishing effective conservation plans managing both represent economically resources For micropeltes, likely single fisheries stock Tonle Sap Great Lake exploited operations, future management initiatives region will need this. natural require designed promote persistence localised spatial scales, level structuring uncovered unique present fine scale.