Biodiversity and origin of freshwater fishes in the Far-Eastern Asia

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In order to elucidate the biodiversity and origin of species diversity of freshwater fishes with high endemism in Far-Eastern Asia, genetic, morphological, ecological and ethological studies were carried out in Japan, Russia, Kazafstan and Taiwan, and as the results following valuable results were obtained :1) For the phylogenetic relationships among Lethenteron species in East Asia, it was elucidated that L.japonicum, L.kessleri and L.sp. N were monophyletic and L.sp.S derived from the common ancestral stock of the genera, Lethenteron, Lampetra and Entosphenus.2) It was found that crucian carps collected from the Ob River system in Kazafstan consisted of Carassius carassius and C.auratus, the latter including two groups at least ; one is native in Kazafstan and another is introduced presumably from China.3) East Asian ninespine sticklebacks (genus Pungitius) were composed of 3 major lineages (A. B and C). A linearized molecular clock tree based on AFLP data disclosed that the lineage … More A and (B+C) were diverged about 3.0 MYA, and lineages B and C were diverged 2.2 MYA.4) MtDNA sequence data disclosed that East Asian bagrid catfishes (Pseudobagrus-group) includes two major monophyletic lineages and that one of them is distributed in the whole range, including so-called Pseudobagrus, Peltobagrus and Coreobagrus, and the other consists of Chinese Leiocassis and some Pseudobagrus species.5) MtDNA sequence data disclosed that eastern Eurasian freshwater sculpins (genera Cottus and Trachidermus) include 5 major lineages A-E, lineage A consisting of T.fasciatus and C.kazika having a catadromous life-history, and lineages B-E consisting of the remaining Cottus species having amphidromous, lacustrine and fluvial life-histories.6) A comparative analysis of the relationship between genetic and phenotypic divergence in multiple sympatric pairs of threespine sticklebacks (the Pacific Ocean and Japan Sea forms of Gasterosteus aculeatus complex) disclosed that body size of fish may play an important role at the early stage of stickleback speciation and divergence of courtship repertories play an important role at the later stage. Less