Alioramus

Alioramus (meaning "Different Branch") is a genus of tyrannosaurid theropod dinosaurs from the Late Cretaceous period of Asia. It currently contains two species. The type species, A. remotus is known from a partial skull and three foot bones recovered from the Mongolian Nemegt Formation, which was deposited in a humid floodplain about 70 million years ago. These remains were named and described in 1976. A second species, A. altai, known from a much more complete skeleton also from the Nemegt Formation, was named and described in 2009. Its relationships to other tyrannosaurid genera were at first unclear, with some evidence supporting a hypothesis that Alioramus was closely related to the contemporary species Tarbosaurus. However, the later discovery of Qianzhousaurus indicates that it belongs to a distinct branch of tyrannosaurs, namely the tribe Alioramini. Alioramus were bipedal like all known theropods, and their sharp teeth indicate that they were carnivores. Known specimens were smaller than other tyrannosaurids like Tarbosaurus and Tyrannosaurus rex, but their adult size is difficult to estimate since both Alioramus species are known only from juvenile or sub-adult remains. Originally, Alioramus remotus was estimated at 5 to 6 m (16 to 20 ft) in length when originally described by Paleontologist Sergei Kurzanov in 1976. In 1988, it was given a similar length of 6 m (20 ft) and a weight of 700 kg (1,500 lbs). In 2016 Molina-Pérez and Larramendi estimated A. remotus at 5.5 m (18 ft) and 500 kg (1,100 lb), and A. altai at 5 m (16 ft) and 385 kg (849 lbs). Kurzanov, however, did not correct for lengthening of the skull by deformation during fossilization, which may indicate a shorter overall body length for this individual. If this specimen is a juvenile, then the largest Alioramus specimens would have reached greater lengths of 7 meters, but no confirmed adult specimens are known.