新疆吐鲁番盆地桃树园晚二叠世非海相腹足类*

新疆吐鲁番盆地桃树园地区晚二叠世地层称作下仓房沟群, 自下而上分为泉子街组、梧桐沟组和锅底坑组, 为河–湖相碎屑沉积, 剖面连续, 层序清楚, 动、植物化石丰富。文中研究的腹足类标本产于桃东沟剖面梧桐沟组下部和中部的介壳灰岩层和灰岩透镜体中, 见有2层, 计有2科4属6种: Xinjiangospira rotundata Yu et Zhu, Xinjiangospira habita sp. nov.、Hydrobia turpanensis Wei、Hydrobia orientalis sp. nov.、Pseudamnicola taodonggouensis sp. nov.和Valvata complanusa sp. nov.; 与腹足类共生的有双壳类、叶肢介、介形类, 以及植物和脊椎动物化石等, 其中双壳类主要是Palaeanodonta, Palaeomutela和Anthraconauta 等属。该腹足动物群由Hydrobiidae 和 Valvatidae的属种组成, 标本数量多, 壳体小, 保存完好, 是迄今已知属种最丰富的古生代淡水腹足类动物群。当前梧桐沟组腹足动物群面貌与准噶尔盆地大龙口剖面小龙口组(锅底坑组), 以及非洲罗得西亚南部上二叠统卡鲁系的腹足动物群面貌一致。

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.