Siamotyrannus isanensis Buffetaut, Suteethom and Tong, 1996

Rauhut, Oliver W. M., 2003, The interrelationships and evolution of basal theropod dinosaurs, Special papers in palaeontology 69, pp. 1-213 : 31

Siamotyrannus isanensis Buffetaut, Suteethom and Tong, 1996

Age . Neocomian.

Occurrence. Sao Khu Formation, Phu Wiang, Thailand.

Diagnosis. Two parallel vertical ridges on iliac blade above and in front of the acetabulum; ischial peduncle of pubis with ventral flange, forming the posterior and most of the ventral rim of the obturator foramen, which is open ventrally anteriorly.

Remarks. Siamotyrannus is the only large theropod known from the Lower Cretaceous of south-east Asia. In the original description it was referred to the Tyrannosauridae by Buffetaut et al. (1996), but the species shows several primitive characters and lacks any of the tyrannosaurid synapomorphies used to define the group here, so it is treated as a separate OTU.