A juvenile specimen of a new coelurosaur (Dinosauria: Theropoda) from the Middle–Late Jurassic Shishugou Formation of Xinjiang, People's Republic of China

We describe the anatomy of a new coelurosaurian theropod <i>Aorun zhaoi</i> gen. et sp. nov., from the Middle–Late Jurassic of Xinjiang, China. Histological analysis of the holotype and only known specimen shows that the new taxon is represented by the skeleton of a juvenile individual aged no more than one year. A phylogenetic analysis of theropod relationships places <i>Aorun</i> as a basal member of the Coelurosauria. Although the sole use of a sub-adult ontogenetic exemplar is potentially problematic for phylogenetic reconstruction, we show that the phylogenetic position of <i>Aorun</i> as a member of Coelurosauria is robust to the exclusion of characters known to change during theropod ontogeny. <i>Aorun</i> is the seventh theropod taxon, and temporally oldest coelurosaur, known from the Shishugou Formation, which has one of the most taxonomically diverse Jurassic coelurosaurian theropod faunas in the world.http://zoobank.org/urn:lsid:zoobank.org:pub:5CC73577-9EB3-47AB-9983-1677B278EFFD