Late Permian non-marine gastropods from Taoshuyuan, Turpan Basin, Xinjiang
The Late Permian Xiacangfanggou Group in Taoshuyuan area of Turpan Basin, Xinjiang consists of the Quanzijie, Wutonggou and Guodikeng formations in ascending order. The sedimentary sequence represents continuous fluvial-lacustrine siliciclastic deposits with abundant animal and plant fossils. The gastropod specimens described in this paper are found from the bioclastic limestone layers and limestone concretions in the lower and middle parts of the Wutonggou Formation at the Taodonggou section. These gastropod fossils collected from two horizons are assigned to six species, four genera belonging to two families. These species are Xinjiangospira rotundata, Xinjiangospira habita sp. nov., Hydrobia turpanensis, Hydrobia orientalis sp. nov., Pseudamnicola taodonggouensis sp. nov. and Valvata complanusa sp. nov. Other associated fossils are bivalves, phyllopods, ostracods, vertebrates and plants. The bivalves are dominated by Palaeanodonta, Palaeomutela and Anthraconauta. The Late Permian gastropod fauna from the Wutonggou Formation is composed of freshwater Hydrobiidae and Valvatidae. Characterized by well-preserved speci mens in large quantity, this fauna represents the most abundant Paleozoic freshwater gastropod fauna known so far. This fauna shows similarity to those from the Xiaolongkou Formation (= Guodikeng Formation) from the Dalongkou section, Junggar Basin, and the Upper Permian (Karu System) in southern Rhodesia, Africa.