Phylogenetic relationships (based on the mtDNA ND1 gene) of forms/species of pidschian-like whitefishes of Coregonus lavaretus complex in Eurasia

The results of preliminary morphological and genetic analyses of forms/species of whitefishes of the Coregonus lavaretus complex from Eurasian water bodies based on the mtDNA ND1 gene are presented. The data include haplotypes of pidschian-like whitefishes from water bodies of Central and North Europe, Siberia, and the Russian Far East. In the present study, the haplotypes of such endemic forms/species as vendace-like whitefish C. baunti Mukhomediyarov, 1948, Yukagirian whitefish C. l. pidschian n. jucagiricus Drjagin (Berg), 1932, sharp-snouted whitefish C. anaulorum Chereshnev, 1996, and Issatchenko’s whitefish C. fluviatilis Issatschenko, 1925 are also analyzed, and we support the species level of these whitefishes based on their genetics and morphology. We have identified at least 9 haplogroups encompassing 14 forms/species of Eurasian pidschian-like whitefishes with varying degrees of relatedness. It has been shown that the classical pairs of lacustrine sympatric whitefishes possess closely similar mtDNA, whereas the majority of riverine and lacustrine-riverine whitefishes have species-specific mtDNA. Moreover, we have concluded that all genetically distant whitefish forms/species inhabit the periphery of the range of the genus Coregonus Linnaeus, 1758. The discovery of multiple mtDNA phylogenetic lineages in both riverine and lacustrine whitefish forms/species confirms multiple hybridizations between different whitefish forms/species. Based on this, we hypothesize that secondary intergradation facilitates rapid speciation in the genus Coregonus. Given the multitude of genetically confirmed species, it can be assumed that further study of other whitefish complexes from poorly studied territories may reveal several more cryptic forms/species.