Tyrannosaurus rex is arguably the most famous predator among the dinosaurs, but this king of the Late Cretaceous didn’t always hold the top spot. New research describes a deadly predator with serrated teeth like those of a shark that was stomping around before the Tyrannosaurus genus came onto the scene. Named Ulughbegsaurus uzbekistanensis by researchers from the University of Tsukuba, the new genus and species of dinosaur was gleaned from fossil evidence found in the lower Upper Cretaceous Bissekty Formation of the Kyzylkum Desert in Uzbekistan and while there wasn’t much to work with, what it tells us is that this killer was an absolute unit.
Published in Royal Society Open Science, the study was able to estimate the size of U. uzbekistanensis from just a single isolated fossil of the upper jawbone. Among the theropods – a group of three-toed bipedal dinosaurs – maxilla size can be used to estimate their true size in life as it’s been found to correlate to femur length which is a reasonable marker of size (to our knowledge, there aren’t any known dinosaurs with stilts for legs though we’d be delighted to be proven wrong on this one).
Using this rule, the researchers were able to ascertain that U. uzbekistanensis was around 7.5 to 8 meters (24.6 to 26.2 feet) long and weighed around 1,000 kilograms (2,205 pounds). That makes it significantly larger than the Tyrannosauroids that were alive at the time, primitive relatives of T. rex’s Tyrannosaurus genus. One possible competitor could have been Timurlengia, a Tyrannosaurid that lived at the same place and age as U. uzbekistanensis, but measuring just 3 to 4 meters (9.8 to 13 feet) indicates that they probably would have been hunting for different prey.
U. uzbekistanensis joins the Carcharodontosaurs dinosaurs for its teeth, which were serrated like a bread knife. This group of dinosaurs are named after the shark genus Carcharodon, which was inspired by the Greek karchar for "jagged" and odōn for "teeth". Such gnashers would’ve made U. uzbekistanensis a proficient meat eater.
The finding is a fascinating one, not just for introducing a new character into dinosaur-themed disaster movies, but also in that it sheds new light on the role of Carcharodontosaurs as apex predators ruling over the comparatively puny tyrannosaurs that walked among it.
“Our discovery provides evidence that predatory Carcharodontosaur and Tyrannosaur dinosaurs co-existed in the region at that time, and that Carcharodontosaurs were the dominant predators over smaller Tyrannosaurs (which became larger later in the Cretaceous),” said corresponding author Kohei Tanaka to IFLScience.
“We would like to see more fossil materials in Asia in order to understand the evolution and competition of predatory dinosaurs.”