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Many well-preserved silicified megalodontids found from the Jiapila Formation of the Upper Triassic in western China show great variations in the amorphous teeth and the massive hinge plate,making the internal molds vary greatly in size and shape.Thus,the internal molds of megalodontids do not always provide reliable taxonomic characters.As a result,about 3/4 of the 132 species and 6 of 9 genera of Triassic Megalodontidae erected on the basis of internal molds have to be revised.The revised definitions of genera Neomegalodon,Triadomegalodon,and Conchodon are given in this paper.
Many well-preserved silicified megalodontids found from the Jiapila Formation of the Upper Triassic in western China show great variations in the amorphous teeth and the massive hinge plate, making the internal molds vary greatly in size and shape.Thus, the internal molds of megalodontids do not always provide reliable taxonomic characters. As a result, about 3/4 of the 132 species and 6 of 9 genera of Triassic Megalodontidae erected on the basis of internal molds have to be revised. revised definitions of genera Neomegalodon, Triadomegalodon, and Conchodon are given in this paper.