Discovery of Sinaeschnidia heishankowense (Odonata: Aeschnidiidae) from the Lower Cretaceous of Baiwan Basin, southwestern Henan, China: Biogeographic implications

Abstract

The Jehol Biota is the best-preserved Cretaceous terrestrial biota and one of the most important treasures housing exceptionally-preserved fossils in the world. The Jehol Biota sensus stricto is found distributed in northern Hebei, western Liaoning and southeastern Inner Mongolia, northeast China, while the Jehol Biota sensu lato is distributed in most of East Asia. The three-stage evolution of the Jehol Biota suggests that the biota extended south to the Qinling-Dabie mountains at its second stage, including western and southern Henan. Here the adult dragonfly Sinaeschnidia heishankowense Hong, 1965 is reported for the first time from the Baiwan Formation of the Baiwan Basin, Zhenping County, southwestern Henan, China. S. heishankowense is one of the representatives of the second stage of the Jehol Biota, previously only recorded in the Lower Cretaceous Yixian Formation in western Liaoning and southeastern Inner Mongolia, and the equivalent strata in China. This finding confirms that the Jehol Biota reached southwestern Henan at its second stage, and that the Baiwan Formation in the Baiwan Basin could be generally correlated with the Yixian Formation in western Liaoning, assigned to a middle Barremian age (Lower Cretaceous) rather than to the Upper Jurassic as previously considered.