Temporal range: Upper Cretaceous, 70 mya
|Skeleton mount in Texas|
The type species, A. remotus, is known from a partial skull and three foot bones. They were got from Mongolian sediments which were deposited in a humid floodplain about 70 million years ago. A second species, A. altai, known from a much more complete skeleton, was named and described in 2009. Its relationships to other tyrannosaurid genera are unclear. Some evidence suggests that Alioramus is closely related to the contemporary species Tarbosaurus bataar.
The Maastrichtian stage in Mongolia had a wetter and more humid climate than the previous stages. Sediments show there were floodplains, large river channels and soil deposits, with periodic droughts.
This animal had many teeth, which were smaller than usual in the Tyrannosauridae, and a narrow, lower skull. It may have been a sub-adult (teenager), and must have eaten different prey than Tyrannosaurus. Since the general area was a riverine delta, the prey may have been fish.
- Carr, Thomas D.; Varricchio, David J.; Sedlmayr, Jayc C.; Roberts, Eric M.; Moore, Jason R. (2017). "A new tyrannosaur with evidence for anagenesis and crocodile-like facial sensory system". Scientific Reports. 7: 44942. doi:10.1038/srep44942.
- Kurzanov, Sergei M. A new carnosaur from the Late Cretaceous of Nogon-Tsav, Mongolia". The Joint Soviet-Mongolian Paleontological Expedition Transactions (in Russian) 3: 93–104.
- Brusatte, Stephen L. et al 2009. A long-snouted, multihorned tyrannosaurid from the late Cretaceous of Mongolia. Proceedings of the National Academy of Sciences of the United States of America. online preprint (41): 17261–6. 
- Osmólska, Halszka (1997). "Nemegt Formation". In Currie, Philip J.; Kevin Padian (eds.). The Encyclopedia of Dinosaurs. San Diego: Academic Press. pp. 471–472. ISBN 978-0-12-226810-6.