A new dinosaur with horns over its eyes, the missing link of T. rex

In 2017, paleontologist Jack Wilson spotted a small, flat piece of bone sticking out of the bottom of a towering cliff in Badlands National Park in South Dakota. He soon realized that it belonged to half a tyrannosaur’s nostril. After careful excavation, they were able to extract a complete premaxilla from the rock. But the rest of the jaw of that animal that lived about 76 million years ago was buried under eight meters of sediment. The work was hard, but it was worth it: the almost complete skull of a new species that could be the missing link of the Tyrannosaurus rex came to light. The results of the research have just been published in the journal ‘Paleontology and Evolutionary Science’. The specimen, designated BDM 107, was affectionately nicknamed ‘Sisyphus’ (after the Roman myth that he was forced by Hades to roll a boulder down the mountain for all eternity), due to the challenge involved in removing it from the surrounding rock. However, its formal name is as Daspletosaurus wilsoni , which means ‘Wilson’s Dreadful Reptile’, after John “Jack” P. Wilson (San Diego, California) who discovered the first daspletosaurus , a highly controversial group. A gap in the tyrannosaur story Tyrannosaurids, the family of dinosaurs that includes T. rex, have been known from North America and Asia for more than a century. However, many details of its evolutionary history remain unclear. Since the 1990s, debate has surrounded Daspletosaurus (Greek for ‘dreadful lizard’), a group of large tyrannosaurs discovered between the US and Canada; some studies indicated that it was an ancestor of T. rex, but the lack of good fossils fueled other theories, such as that the tyrannosaurids were actually a group of several closely related species, which, however, did not descend from each other . Related News standard No The ferocious predator that was actually an innocent herbivore: turn in the only dinosaur stampede of which there is record P. Biosca standard Yes De-extinction: what if we resurrected a mammoth and, later, a dinosaur? Miguel Pita This new research indicates that D. wilsoni, which is found in rocks of intermediate age among other tyrannosaurs found in the region, could be the ‘missing link’ between species, since it shows features of Daspletosaurus torosus (which would be an ancestor) and from Daspletosaurus horneri, which probably arose just after it did, between 77 and 75 million years ago. That would explain why this new dinosaur “displays a combination of features found in more primitive tyrannosaurs from older rocks, such as a prominent set of horns around the eye, as well as features known from later members of this group (including T. rex), such as expanded air pockets in the skull,” the authors explain in a statement. The discovery of D. wilsoni suggests that the three daspletosaurs found at the site arrived one after the other, as “consecutive ladder-like steps in a single evolutionary lineage,” rather than diverging from one another as “evolutionary cousins,” the researchers wrote. researchers. That is, previous studies that identified several Daspletosaurus species as a single evolutionary lineage were correct. MORE INFORMATION noticia No The brain of octopuses, more similar to humans than we thought noticia No The discovery of a tiny brain of more than 500 million years defies the textbooks But, where does this finding place the T.Rex? The authors believe that, as has been shown with these three tyrannosaurid species, T.Rex could have arisen in a similar linear fashion, although the researchers acknowledge that much work remains to be done and are planning a new study to explore this idea.