Paleontologists have found fossil fragments from a new species of ornithomimosaur (ostrich-mimic dinosaur) that walked the Earth between 84 and 72 million years ago.
Called Aepyornithomimus tugrikinensis, the new dinosaur is a type of ornithomimosaur (Ornithomimidae), a group of theropods that evolved a toothless beak and were likely omnivorous or herbivorous, superficially resembling extant ostriches.
The ancient creature lived in what is now Mongolia during the Campanian, the fifth of six ages of the Late Cretaceous epoch.
The fossil remains of the beast were found in the eolian deposits of the Djadokhta Formation at the Tögrögiin Shiree locality.
They were analyzed by Dr. Chinzorig Tsogtbaatar, a paleontologist from Hokkaido University and the Institute of Paleontology and Geology at the Mongolian Academy of Sciences, and his colleagues from Japan, Mongolia and Canada.
“This is only the third ornithomimosaur specimen reported from the Djadokhta Formation and is the first ornithomimid record from eolian Tögrögiin Shiree locality,” the researchers said.
“It is also the best preserved specimen of all of aforementioned three specimens known to date, and it provides new insight into ornithomimid dinosaur evolution and paleoenvironment.”
“It is possible that Aepyornithomimus tugrikinensis is a transitional form between the basal and derived ornithomimosaurs,” they added.
“The dinosaur could be stratigraphically the oldest known ornithomimid occurrence in the Upper Cretaceous of Asia, and the easternmost occurrence of ornithomimid dinosaurs from the Campanian in the northern hemisphere.”
According to Dr. Tsogtbaatar and co-authors, the discovery of Aepyornithomimus tugrikinensis sheds light on the evolutionary adaptation of ornithomimosaurs to arid environments.
“Aepyornithomimus tugrikinensis is possibly the first evidence of an ornithomimosaur species that could have tolerated more diverse climatic conditions that were shifting from humid to more arid conditions,” they said.
Research describing the new species is published in the journal Scientific Reports.
Chinzorig Tsogtbaatar et al. 2017. First Ornithomimid (Theropoda, Ornithomimosauria) from the Upper Cretaceous Djadokhta Formation of Tögrögiin Shiree, Mongolia. Scientific Reports 7, article number: 5835; doi: 10.1038/s41598-017-05272-6