Abstract

A detailed taxonomic study of a diverse chondrichthyan fauna from the Ladinian-Carnian (Middle-Late Triassic) interval at Nimaigu locality in Guizhou Province, South China is presented. Six taxa are described, two of which are assigned to Elasmobranchii incertae sedis (aff. Rosaodus sp., Rosaodus xingyiensis gen. et sp. nov.), three to the Euselachii (Euselachii gen. et sp. indet., Favusodus orientalis gen. et sp. nov., Keichouodus nimaiguensis gen. et sp. nov.) and the last one representing a possible Holocephali (aff. Arctacanthus sp.). Their stratigraphic distribution is documented on a bed-by-bed basis. This fauna is unusual because it is dominated by sharks with a cladodont-like dentition, which were barely known after the end-Permian mass extinction, and almost devoid of durophagous euselachians, which make it different from all other contemporaneous shark faunas worldwide. Transitional features are documented between “cladodont” teeth and those of neoselachian sharks, which provide new insights on the replacement pattern of “ancient” sharks by “modern” ones.