A new therizinosaur from the Lower Jurassic Lower Lufeng Formation of Yunnan, China

A specimen collected from the Lower Jurassic Lower Lufeng Formation of Yunn an, China. represents a new genus and species of therizinosauroid theropod. It comprises an incomplete left mandibular ramus and is here named Eshanos aurus deguchiianus. Distinctive characteristics of the new species include the presence of a round fenestra in the posterior portion of the dentary, s mall size of tooth denticles, and denticles almost perpendicular to the ant erior and posterior edges of tooth crowns. The discovery of Eshanosaurus de guchiianus extends the record of therizinosauroids from the Early Cretaceou s back to the Early Jurassic. Recent phylogenetic hypotheses placing theriz inosauroids within Coelurosauria imply this is the oldest known coelurosaur , and that diversification of the group began much earlier than was previou sly indicated by the fossil record.