Recently discovered fossils dating back approximately 85 million years provide rare and valuable insights into the Ornithomimosauria dinosaurs.
Chinzorig Tsogtbaatar, a specialist at the North Carolina Museum of Natural Sciences, along with colleagues, discovered that the ostrich-like dinosaurs known as Ornithomimosauria had developed to a gigantic size in ancient Eastern North America. The new research was published in the journal PLOS ONE on October 19.
Illustration of the Aepyornithomimus dinosaur belonging to the Ornithomimosauria family. (Photo: Masato Hattori/Wikimedia Commons)
At the end of the Cretaceous period, North America was divided into two landmasses by a seaway: Laramidia in the west and Appalachia in the east. However, fossils from Appalachia are extremely rare, making it difficult for scientists to fully understand the ancient ecosystems here. In the new study, Chinzorig and colleagues present newly discovered fossils of Ornithomimosauria from the Eutaw Formation in Mississippi.
The Ornithomimosauria dinosaurs are characterized by their ostrich-like appearance, featuring small heads, long arms, and strong legs. The newly discovered fossils, including foot bones, date back approximately 85 million years, providing rare information about a still-mysterious phase of dinosaur evolution in North America.
By comparing the proportions of these fossils to the developmental patterns within the bones, the research team determined that the fossils may belong to two species of Ornithomimosauria: one relatively small and one very large. They estimate that the larger species weighed over 800 kg, and the specimen studied was likely still in its developmental stage. Thus, this is one of the largest Ornithomimosauria species ever recorded.
The newly discovered fossils shed light on the evolution of Ornithomimosauria. The development of gigantic body sizes and the coexistence of multiple species is a recurring trend of Ornithomimosauria across North America and Asia. Scientists hope that further research in the future will clarify the reasons behind the success of these survival strategies.
