Alioramus

Alioramus is a genus of tyrannosaurid dinosaur. It was about 20 feet long. It lived during the Upper Cretaceous period in what is now Mongolia.
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".
Wetter climate.
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.