Early Triassic chondrichthyans from the Zuodeng Section, Guangxi Province, South China: Palaeobiological and palaeobiogeographical implications

The Early Triassic chondrichthyans from China have been insufficiently studied. We herein present a taxonomic study of a diverse chondrichthyan fauna from the Luolou Formation at the Zuodeng section in Guangxi Province, South China. Nine elasmobranch taxa are recognized, including two hybodonts (Omanoselache halli and Hybo-dontiformes indet.), three neoselachians (Safrodus tozeri, Polyfaciodus pandus and Synechodus aff. triangulus) and four euselachians of uncertain affinities (Favusodus orientalis, Euselachii gen. et sp. indet., 'Hybodus' zuodengensis and 'Hybodus' yohi). A statistical analysis shows that the shark palaeocommunity had a high diversity and evenness, and a low dominance, indicating that the archipelagic Nanpanjiang Basin probably allowed euse-lachian sharks to thrive. Their diverse morphologies indicate that the fauna demonstrated adaptation for a wide diversity of feeding strategies, including grasping-crushing, grasping-swallowing and sharp-grasping. Palae-obiogeographically, trans-Tethyan taxa reveal a shark dispersion path between the western Neo-Tethys (Oman) and eastern Palaeo-Tethys (Zuodeng) in the Early Triassic.