The Psittacosaurus biochron, Early Cretaceous of Asia

Fossils of the primitive ceratopsian dinosaur Psittacosaurus are widely distributed in Asia in Russia (western Siberia), Mongolia, China (Liaoning, Nei Monggol, Gansu, Ningxia, Xinjiang, Shandong, and Hebei provinces), Thailand, and possibly Japan. All Psittacosaurus records are of Early Cretaceous age, and a Psittacosaurus biochron can be recognized equivalent to the Tsagantsabian and Khukhtekian land-vertebrate faunachrons (LVF). The Tsagantsabian LVF is defined as the time interval between the first appearance datum (FAD) of Psittacosaurus, and the FAD of the turtle Peishanemys. The Khukhtekian LVF is the time between the FAD of Peishanemys and the FAD of the ceratopsian dinosaur Microceratops (=beginning of the Baynshirenian LVF). Cross correlation to the standard global chronostratigraphic scale, mostly by radioisotopic dates and palynology, indicates the Tsagantsabian is Barremian-early Aptian, and the Khukhtekian is late Aptian-Albian. The duration of the Psittacosaurus biochron thus is about 20 myr of Barremian-Albian time.