Psittacosaurus Sattayaraki
French paleontologist Eric Buffetaut and a Thai colleague, Varavudh Suteethorn, described a partial upper and lower jaw from the Aptian-Albian Khok Kruat Formation of Thailand in 1992, giving it the name Psittacosaurus sattayaraki. In 2000, Sereno questioned the validity of this species, citing its eroded and fragmentary nature, and noted an absence of features characteristic of the genus Psittacosaurus. However, in 2002 the original authors published new images of the fossil which seem to show teeth in the lower jaw that exhibit the bulbous vertical ridge characteristic of psittacosaurs. Other authors have also defended its validity, while some continue to regard it as dubious. Sereno (2010) proposed that the best assignment for the type material may be Ceratopsia incertae sedis.
The dentary of P. sattayaraki has a flange similar to that found in P. mongoliensis, P. sibiricus, P. major, P. lujiatunensis and P. meileyingensis, although it is less pronounced than in those species. The material appears to be roughly the same size as P. sinensis. If this species is valid, it is by far the southernmost species in the genus.
Read more about this topic: List Of Psittacosaurus Species