Small theropod teeth (Dinosauria) from the Upper Jurassic Qigu Formation of the southern Junggar Basin, NW China

Two small theropod teeth from the Qigu Formation of Liuhuanggou, Xinjiang Uygur Autonomous Region, People's Republic of China are described. They are compared to hitherto known finds of theropod teeth from both the northern and southern Junggar Basin. It is concluded that they cannot be confidently referred to any morphotype hitherto known from the Upper Jurassic of the Junggar Basin. Although the teeth agree well in principal measurements with material previously described and referred to basal tetanurans or basal tyrannosauroids (morphotype 4 of Han et al. 2011), they are both considerably smaller and show the distinctive feature of a lingually displaced mesial carina. The latter feature is shared with Dromaeosaurus albertensis and an unnamed dromaeosaur from the Lower Cretaceous of Spain and Denmark. It is therefore concluded that the material possibly represents a dromaeosaurid close to these taxa. It is the first record of putative dromaeosaurid theropods from the southern Junggar Basin. As dromaeosaurids have been previously announced from the Upper Jurassic of the northern Junggar Basin, this further underlines general similarity in the Upper Jurassic dinosaurian faunas between these areas.