A new species of Gammarus Fabricius, 1775 (Crustacea: Amphipoda: Gammaridae) from extreme high-altitude Lake Tong Tso, Qinghai-Tibetan Plateau

A new species of the genus Gammarus Fabricius, 1775 is described from Lake Tong Tso, an extreme high-altitude lake in Qinghai-Tibetan Plateau. pontual sp. nov. considered part lacustris G.O. Sars, 1863 group, which characterized by having inner ramus uropod 3 longer than half length outer ramus, and both rami covered with plumose setae. The stands apart their congeners, mainly, following combination characters: head cephalic lateral lobe truncated; gnathopods 1-2 propodus weakly armed, 1 stout seta defining palm; palm posterior margin propodus, main medially; pereopods 5-7 basis slender, crenulate; epimeral plate produced into a short spine, facial ridge present; plates 2-3 posteroventral corner sharply pointed; setae, about 80% ramus; telson apex 2 setae on each side.