Iconic tyrannosaurids like Tiranosaurio King they dominated the top of the food web at the end of the reign of the dinosaurs. But they did not always occupy that first place. In a new study published in the Royal Society Open Science, a research team led by the University of Tsukuba described a new genus and species belonging to Carcharodontosauria., a group of medium to large-sized carnivorous dinosaurs that preceded the tyrannosaurids as apex or alpha predators.
The new dinosaur, named Ulughbegsaurus uzbekistanensis, was found in the Lower Upper Cretaceous Bissekty Formation of the Kyzylkum Desert in Uzbekistan, and therefore lived about 90 million years ago. Two separate evolutionary analyzes support the classification of the specimen as the first definitive carcharodontosaurus discovered in the Upper Cretaceous of Central Asia.
“We describe this new genus and species based on a single isolated fossil, a left maxilla or upper jaw,” the first author of the study explained in a statement. Assistant Professor Kohei Tanaka. “Among theropod dinosaurs, the size of the maxilla can be used to estimate the size of the animal because it correlates with the length of the femur, a well-established indicator of body size. Therefore, we were able to estimate that Ulughbegsaurus uzbekistanensis had a mass of more than 1000 kilos, and an approximate length of 7.5 to 8 meters, greater than the length of an adult African elephant ”.
This size far exceeds that of any other known carnivore of the Bissekty Formation, including the small tyrannosauroid Timurlengia described in the same formation. Therefore, the newly named dinosaur probably spearheaded the food web in its early Upper Cretaceous ecosystem.
The genus namesake is appropriately regal; Ulughbegsaurus is named after Ulugh Beg, the 15th century mathematician, astronomer, and sultan of the Timurid Empire of Central Asia. The species is named after the country where the fossil was discovered.
Before the Upper Cretaceous, Carcharodontosaurs like Ulughbegsaurus disappeared from the paleocontinent that included Central Asia. This extinction is believed to have been related to the emergence of tyrannosaurids as alpha predators., but this transition remains poorly understood due to the scarcity of relevant fossils.
Lead author Professor Yoshitsugu Kobayashi at the Hokkaido University Museum noted: “The discovery of Ulughbegsaurus uzbekistanensis fills a major gap in the fossil record, revealing that Carcharodontosaurs spread across the continent from Europe to eastern Europe. Asia. As one of the last survivors in Laurasia, the coexistence of this large predator with a smaller tyrannosauroid reveals important limitations in the transition of the apex predator niche in the Upper Cretaceous “.