Tatisaurus in Yunnan

Tatisaurus is a genus of ornithischian dinosaur from the Early Jurassic from the Lower Lufeng Formation in Yunnan Province in China. Little is known as the remains are fragmentary.

Discovery and species

In 1948 and 1949 Father Edgar Oehler, a Catholic priest working for the Fu Jen Catholic University at Beijing, excavated fossils near the village of Da Di in Yunnan. Among them was the jaw bone of a herbivorous dinosaur. In 1965 David Jay Simmons named and described it as the type species Tatisaurus oehleri. The generic name is derived from Da Di, then more usually spelled as “Ta Ti”. The specific name honours Oehler. The holotype, FMNH CUP 2088, was found in the Zhangjiawa Beds of the Lufeng Formation, dating from the Sinemurian. It consists of a partial left mandible with teeth. The lower jaw bone fragment is, lacking the tip, six centimetres long. The teeth are eroded. It is the only specimen known of the species.

Simmons assigned Tatisaurus to the Hypsilophodontidae, though this group was seen by him as an evolutionary grade of “primitive” Ornithopoda, ancestral to several ornithischian groups. He felt that Tatisaurus’ affinities were with Scelidosaurus or the Ankylosauria. Later, in 1990, the specimen was reviewed by Dong Zhiming, who noted it had similarities with Huayangosaurus. He placed the two genera in the same subfamily, the Huayangosaurinae, within the Stegosauria.

Later still, in 1996, Spencer Lucas reclassified Tatisaurus oehleri as a species of ScelidosaurusS. oehleri, in order to use Scelidosaurus for a biochron. In 2007, David B. Norman and colleagues regarded this as unfounded. They instead found Tatisaurus to be a dubious basal thyreophoran, showing a single thyreophorean synapomorphy; a ventrally deflected mesial end of the dentary. If considered a thyreophoran, it would be one of the oldest known members of the group.

Tatisaurus is a genus of early thyreophoran dinosaur that lived during the Early Jurassic period. Its fossils were discovered in the Lufeng Formation in Yunnan Province, China.

Discovery and Naming

  • Initial Discovery: The type specimen of Tatisaurus, IVPP V.725, was discovered in the Lower Lufeng Formation in Yunnan Province. It was described by Yang Zhongjian (C.C. Young) in 1959.
  • Original Identification: The specimen was originally identified as a small ornithischian dinosaur.
  • Name Origin: The name Tatisaurus means “Tati lizard,” named after the Tati region in Yunnan where the fossils were found.

Physical Characteristics

  • Size: Tatisaurus was a small dinosaur, though its exact size is uncertain due to the fragmentary nature of the fossils.
  • Anatomy: The known fossils include partial jawbones with teeth. The teeth are characteristic of early thyreophorans, which are known for their armored bodies, though no armor was found with Tatisaurus.


  • Thyreophoran Dinosaur: Initially, the classification of Tatisaurus was uncertain, but it is now considered to be an early member of Thyreophora, a group that includes more derived forms such as Stegosaurus and Ankylosaurus.
  • Synonymy: There has been some debate about the classification of Tatisaurus, with some paleontologists suggesting it might be synonymous with Scelidosaurus, another early thyreophoran from the same region and time period. However, this synonymy is not universally accepted.


  • Habitat: Tatisaurus lived in the Lufeng Formation, which during the Early Jurassic period was a diverse ecosystem with a variety of dinosaurs, early mammals, and other reptiles.
  • Contemporary Fauna: Tatisaurus shared its environment with other dinosaurs such as the prosauropods Lufengosaurus and Yunnanosaurus, and the theropod Sinosaurus.

Fossil Sites in Yunnan

  • Lufeng Formation: This formation is one of the most important fossil sites in China, known for its rich assemblage of Early Jurassic vertebrate fossils. The well-preserved fossils from this area, including those of Tatisaurus, provide valuable insights into the early evolution of dinosaurs.

Tatisaurus, despite being known from limited remains, is an important genus for understanding the early diversification of thyreophoran dinosaurs. Its discovery in the Lufeng Formation adds to the significance of this region as a key site for Early Jurassic paleontology in Yunnan.