Phylogenetics And Historical Biogeography Of The Genus Gammarus From Xinjiang (Crustacea: Amphipoda: Gammaridea: Gammaridae)

A total of six species of the Genus Gammarus (Gammaridae) are from Xinjiang, including Gammarus lacustris Sars, 1863, G. montanus sp. nov., G. shortpodus sp. nov., G. decorosus sp. nov., G. takesensis sp. nov., and G. tastiensis sp. nov.. The phylogenetic systematic analysis of these Gammarus species was studied in the present paper. Based on an analysis by PAUP* 4.0 (Phylogenetic Analysis Using Parsimony *and other methods version 4.0) and MacClade 4.0, we presumed that G. lacustris is more primitive compared to the others. The probably phylogenetic relationship can be shown as (G. lacustris (((G. montanus, G. shortpodus) G. decorosus) (G. takesensis, G. tastiensis))). And there maybe exist a real species between G. decorosus and the sister species, which is grouped by G. montanus and G. shortpodus, and G. takesensis and G. tastiensis respectively. On the other hand, G. decorosus itself probably is a transitional species.The historical biogeography analysis was studied with BPA (Brooks Parsimony Analysis). It's concluded from BPA analysis that there is a general pattern, (Tarim basin and its neighboring areas (Junggar basin and its neighboring areas, Ili drainage basin and its neighboring areas)), for organisms from Xinjiang, and that the distribution patterns of endemic freshwater amphipods from Xinjiang (G. montanus, G. shortpodus, G. decorosus, G. takesensis, and G. tastiensis) may have resulted from the glaciations during the Quaternary Period.The species description of Gammarus from Xinjiang, including description of five new species, is also given in the present paper. The description of each species includes: Chinese name, Latin name, literature citations, specimens examined, morphology, biology and geography. More than 260 morphological figures in 29 plates are provided. Diagnoses of each species and a key to these species are also provided.