Sarcopterygians from the Lochkovian (Lower Devonian) of Nanning, Guangxi, China

Here we report a left cheek plate of Psarolepis, a postparietal shield of Youngolepis, a skull of Diabolepis, and a scale of Styloichthys from the Lianhuashan and Nahkaoling formations (Lochkovian, Lower Devonian) of Nanning, Guangxi. This marks the first report of Diabolepis and Styloichthys beside Qujing, Yunnan, and the latest occurrence of Psarolepis to date. The fossil community displays significant similarities to the Xujiachong Assemblage, and provides new data for the Lower Devonian stratigraphic correlation between southwestern China and northern Vietnam. Given the latest dating constraint based on the conodont evidence, we regard that the Xujiachong Assemblage has a much longer range than previously supposed, extending from the latest Lochkovian to the end of Pragian. We propose that the transition of the Nahkaoling and Lianhuashan formations in Nanning might correspond to the Guijiatun Formation in Qujing. The relatively large size of fish individuals from Guangxi is probably attributed to the increase in the oxygen content of the ocean.