A new Gammarus species from Xinjiang Uygur Autonomous Region (China) with a key to Xinjiang freshwater gammarids (Crustacea, Amphipoda, Gammaridae)

A new species of the genus Gammarus Fabricius, 1775 is described and illustrated from Xinjiang Uygur Autonomous Region, China. Gammarus zhouqiongi sp. nov. is characterized by pereopods III–IV with long straight setae on posterior margins; inner ramus of uropod III more than twice as long as peduncle, reaching 0.7 times the length of outer ramus; inner ramus with plumose setae, and outer ramus with both plumose setae and long simple setae. Detailed morphological comparisons with related species are discussed. The K2P distances for each marker (CO1, 16S, 28S, and EF1α) of the new species differ from those of other Gammarus species in Xinjiang. Both phylogenetic trees based on separate (CO1, 16S, 28S, and EF1α) and combined (CO1+16S+28S+EF1α) markers show that the new species is an independent branch. A key to identify Gammarus species in Xinjiang is provided.