Kelmayisaurus petrolicus was a large theropod dinosaur that lived some 140 to 100 million years ago in what is now the northern part of the Xinjiang autonomous region of China. It was described in 1973 by famous Chinese paleontologist Dong Zhiming.
Kelmayisaurus is known based on parts of the jaws (complete left dentary and a fragment of the left maxilla). Nevertheless, due to insufficient preservation of its fossil remains, Kelmayisaurus had gained only little attention during the following decades. In 2012, however, the material was re-studied by a team of researchers led by Steve Brusatte. The authors provided a detailed description of the jaw material and compared it to the jaws of other theropods.
The study showed that the jaw anatomy of Kelmayisaurus was similar to that observable in carcharodontosaurids, medium to large theropods that existed from the Late Jurassic to the Late Cretaceous and included some of the largest known predatory dinosaurs. The length of Kelmayisaurus petrolicus was estimated to reach 10 to 12 meters (32.8 to 39.4 feet).