Biostratigraphic significance of spinicaudatans from the Upper Cretaceous Nanxiong Group in Guangdong, South China

The spinicaudatan genus Tenuestheria was originally described from the Upper Cretaceous Lanxi Formation in Jinhua, Zhejiang Province, China. Its frequent occurrence in contemporaneous strata elsewhere makes it an important index fossil for correlating non-marine red beds in southern China. Its discovery in the Zhutian Formation of the Nanxiong Group makes it possible to correlate the formation more accurately with the Tenuestheria-bearing beds elsewhere. Previously the whole of the Nanxiong Group was correlated with Maastrichtian formations whereas now only the Zhenshui Formation is considered to be of this age. The Zhutian Formation, which underlies it, correlates with early Santonian–Campanian formations. The age of the red beds in south-east China is also adjusted to take into account radiometric age determinations from the volcanic and sedimentary succession in eastern Zhejiang.