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牙形石是牙形动物器官的组成部分,它们的形态演变代表动物本身的演化趋向。国外对二叠纪至三叠纪初牙形类演化研究较多,Clark et Mosher(1966),Sweet(1970,1977), Clark et Behnken(1979)和 Kozur(1978,1989)等都发表过重要文献。国内文献相对较少,蒋武(1988)据四川盆地的资料,恢复了 Neogondolella 和 Anchignathodus 两属的演化系列。本文以牙形石的多分子(器官)分类为基础,据湘西北地区五个剖面所采得大量标本的研究,论述三个牙形石属的演化趋势。
Conodont is part of a tooth-shaped animal organ, and their morphological evolution represents the evolution of the animal itself. There are many foreign studies on the evolution of Early Periwinkle from the Permian to the Triassic. Clark et Mosher (1966), Sweet (1970,1977), Clark et Behnken (1979) and Kozur (1978,1989) literature. Relatively few domestic literatures, Jiang Wu (1988), according to the data from the Sichuan Basin, restored the evolutionary series of Neogondolella and Anchignathodus. Based on the multi-molecular (organ) classification of conodont, a large number of specimens taken from five sections in the northwestern part of Hunan Province are studied in this paper. The evolutional trends of three conodonts are discussed.