Frontiers in Marine Science (Nov 2015)
Comparative genetic and phenotypic analysis of grayling (Thymallus sp) from Central Asia (Kazachstan, Russia, Mongolia) and their systematic placement in the genus
Abstract
Comprehensive analysis of grayling from Lake Markakol, Kazachstan, the upper Ob (Biya) in the Tuva republic, Russia, and the Central Asian basin in Mongolia reveal relatively close relationships of three putative taxa in the region. Approximate Bayesian Computation supports a very recent divergence (5-10,000 generations) for populations in the Lake Markakol region, and approximate 1-200,000 year divergence from Mongolian grayling, T. brevirostris. Both of these lineages are approximately equally divergent (ca- 1.5%) from T. nikolskii and T. svetovidovi in the upper Ob and Enisey drainage, respectively. Microsatellite analysis of Mongolia grayling support only a single taxon, despite highly divergent (piscivorous and benthivorous) phenotypes throughout their distribution. These results are integrated into a review of our systematic knowledge of the entire genus throughout their native distribution. We recognize at least 12 good biological species, and suggest that several additional sub-specific lineages are of high evolutionary interest. We outline both the genetic divergences and phenotypic differences among these taxa, present their proposed ranges including insights into their zoogeographic origins. We highlight the similarities and differences that grayling evolution and diversity exhibit compared to other salmonid fishes, and outline a conservative philosophy on systematic revision.
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