Theropod Dinosaurs of the Nemegt Formation (Upper Cretaceous) of Mongolia

Presented by Dr. Philip Currie of the University of Alberta, March 21, 2024.
The similarities between the Late Cretaceous faunas of Asia and North America have been noted since the 1920s. Despite the distance, dinosaur fossils from the Late Cretaceous found in both Asia and North America bear similarities. The first “raptor” (Dromaeosauridae) was collected in Alberta in 1915, but until Velociraptor was collected in Mongolia in 1923, the unique anatomical features of these animals were not known. Similarly, the large tyrannosaur from Mongolia, Tarbosaurus, is considered as another species of Tyrannosaurus by some researchers. Most theropod species known from the Nemegt Formation have close relatives from the Late Cretaceous of Alberta. There are exceptions, however, such as the tyrannosaur-sized Deinocheirus from Mongolia. This strange animal was only known from 1965 on the basis of a pair of 2 m-long arms with huge claws. The mystery of the relationships of this animal was only solved after our expeditions recovered two more mostly complete skeletons (with skulls) in Mongolia in 2016 and 2018. In spite of the bizarre appearance of this dinosaur, it is actually derived from the ostrich-mimic dinosaurs of Alberta, Mongolia, and other Upper Cretaceous ornithomimids.