Tarbosaurus

Dong, Zhiming, 1979, Dinosaurs from the Cretaceous of South China, Mesozoic and Cenozoic Red Beds of South China: Selected Papers from the " Cretaceous-Tertiary Workshop ", Institute of Vertebrate Paleontology and Paleoanthropology & Nanjing Institute of Paleontology, Nanxiong, China: Science Press, pp. 342-350 : 1-2

Tarbosaurus sp.

(Plate I, Figures 1 and 2 )

Material: Two relatively complete teeth, a dorsal vertebra, and several fragmentary foot bones. Specimens were not collected from the same locality but they are provisionally assigned the same genus based upon morphology.

Description: The teeth are large and robust with serrated anterior and posterior margins. The largest tooth is a 72 mm in length but has lost its apex. It is relatively laterally compressed, laterally convex, and medially flat. Anterior serrations extend to the midpoint of the tooth with seven to eight serrations every five millimeters. Posterior serrations may reach the tooth base with eleven serrations every five millimeter span. Serration count, tooth morphology, and size approach Tarbosaurus .

Another tooth is relatively thickly rounded and elliptical in cross-section. The anterior and posterior serrations are asymmetrical, as on the anterior margin they occur more proximomedially and on the posterior margin occur more distomedially. The serrations reach the base of the crown on both sides. Because the serrations are asymmetrical this tooth is undoubtedly a third right premaxillary tooth.

There is only a single platycoelous dorsal vertebra which is medially constricted with shallow pleurocoels and resembles that of a large theropod.

Discussion: Coelurosaur specimens were described by Young (1962) from the Nanxiong Basin, although theropods are currently rare. The specimens described above undoubtedly represent a large carnosaur species with characters leading to the diagnosis of the family Tyrannosauridae . The Nanxiong teeth are smaller than Tyrannosaurus from the Lance Fm. of North America and cf. T. rex from the Wangshi Group, of Shandong Province. Lateral compression, size, and condition of serrations approach Tarbosaurus from the Late Cretaceous of Mongolia. Thus, the Nanxiong specimens are provisionally assigned to this genus based upon their morphology and biogeography.

Figures

Figure 2. Cervical vertebra XII of Nanshiungosaurus brevispinus (x 1 / 4).