A psittacosaurid dinosaur from the Cretaceous of Thailand and its implications for the palaeogeographical history of Asia

Primitive ceratopian dinosaurs of the family Psittacosauridae were hitherto known only from central and northern Asia, from northern China to Mongolia and Siberia. This paper reports the discovery of psittacosaurid jaws in Early Cretaceous rocks of the Khorat Plateau in north-eastern Thailand. These fossils are clearly referrable to the genus Psittacosaurus Osborn and may represent a new species. They constitute a significant new element of the hitherto poorly known Cretaceous continental vertebrate fauna of South-East Asia, suggesting that it was basically similar to that of northern and central Asia. This in turn confirms that, contrary to some recent palaeogeographical reconstructions, by Early Cretaceous times the Indochina block, on which the Thai psittacosaurids have been found, had become part of mainland Asia.