It belongs to the family of dinosaurs known as carcarodontosaurs, best known for their shark-like teeth. Named Ulughbegsaurus uzbekistanensis, it was at least seven meters long and weighed more than a ton (1,000 kilograms) and would have traveled across Central Asia about 90 million years ago.
The jaw fossil was believed to have been unearthed in the 1980s and found its way to the Tashkent State Geological Museum, Uzbekistan, but its importance was not recognized until 2019, said Darla Zelenitsky, an associate professor of paleobiology of dinosaurs at the University of Calgary in Canada.
Researchers in Canada, Japan and Uzbekistan named the new genus and species Ulughbegsaurus (oo-LOOG-bek-SAW-Russian) uzbekistanensis, in honor of the 15th-century mathematician and astronomer Ulugh Beg.
“More than 90 million years ago, the apex predators of Asian and American ecosystems were often large species of carcodontosaurs known as shark-tooth dinosaurs, which were later replaced by large, tyrannosaurous species, similar to T. rex, sometime around 80 (million) 90 million years ago, “Zelenitsky said in a statement.
“Both groups of dinosaurs were meat eaters that had sharp teeth and walked on two legs, although in general tyrannosaurs were stronger.”
The evolution of tyrannosaurs to replace carcodontosaurs at the top of the food chain in these regions is not well understood due to an irregular fossil record in the early part of the Late Cretaceous about 80 to 100 million years ago. . Apex predators are usually less numerous Zelenitsky explained that predatory animals, which could explain why their fossil remains are harder to find in some ancient ecosystems.
Zelenitzky said Ulughbegsaurus would have shared the ecosystem with a small species of tyrannosaurus called Timurlengia.
“All the evidence suggests that carcarodontosaurus species were oversized or” kept “tyrannosaurus species in ecosystems in Asia and probably in North America even before their extinction about 90 million years ago,” Zelenitsky said in an email.
The extinction of carcodontosaurs allowed tyrannosaurus species to take on the role of apex predators in Asia and North America 80 to 90 million years ago. They persisted in large forms like T. rex until a massive asteroid hit Earth about 66 million years ago, condemning most dinosaurs to extinction.