jaw's length), shallow, and triangular, and it bears a groove that widens towards the back of the bone. A distinct fossa on the top surface of the surangular bone separates Jianianhualong from other troodontids. The angular bone projects upwards behind the dentary, like Sinovenator and various other members of the Deinonychosauria. The maxilla of Jianianhualong bore 21 teeth on each side, while the dentary bore 25 on each side. Like other troodontids, the teeth are short-crowned, strongly recurved, and unevenly distributed. The teeth at the front of the jaws are more closely packed than the rear teeth, which also have fine serrations on their rear edges. These serrations are fine, as in Sinovenator, instead of robust as in derived troodontids. Unusually, the first several teeth in the dentary appear to be angled forwards, or procumbent. This condition is present in several contemporary dromaeosaurids. Axial skeleton The vertebral column of Jianianhualong is nearly complete. However, individual vertebrae are not always possible to discern. The neck (i.e. the cervical vertebrae) is long, the torso (i.e. the dorsal vertebrae) is long, and the tail (i.e. the caudal vertebrae) is long. Overall, there may have been 31 caudal vertebrae in total. Uniquely among troodontids, the neural spine of the axis, the second cervical vertebra, has a convex top margin. Also uniquely, the front rim of the neural spine is thickened, while the rear portion is strongly expanded at the top. The length of the cervicals increases until the fifth to seventh cervicals, which have the greatest length. Further back, the remaining cervicals are significantly shorter. The front also dorsal vertebrae are relatively short, with the middle and back dorsals being longer. The dorsal ribs lack uncinate process, and the sternum is also unossified, like other troodontids. Like other theropods, the first pair of the gastralia near the front of the torso is noticeably more robust, particularly in the central portion. Similar to other paravians, the caudal vertebrae of Jianianhualong become increasingly longer towards the back of the tail; for instance, the fifteenth caudal is about twice as long as the sixth. From the twenty-third caudal backwards, the sides of the caudals become compressed such that they are sub-triangular. Towards the back of the tail, the forward and rear projections of the chevrons are roughly equal in length. Unlike Sinusonasus, where chevrons come into contact with each other, there are gaps between the chevrons of