A fossil discovered in Montana in 2017 by a team of researchers would actually be a new type of tyrannosaurus, according to a study published on November 25 in the specialized journal PeerJ. This discovery would therefore make it possible to make links between various species of tyrannosaurs, especially with the famous T-Rex.
Contrary to what one might think, the T-Rex is not the only tyrannosaur monster that existed. And it is not a discovery of 2017 that will say the opposite. Indeed, that year a team of American paleontologists unearthed a small piece of bone in Montana (United States), which appeared to be the middle part of a nostril of a tyrannosaurus. Subsequent excavations in 2020 and 2021 uncovered a skull and part of the skeleton believed to date from around 76.5 million years ago, belonging to the Cretaceous period. According to a study published on November 25 in the specialized journal PeerJ, it is a species belonging to a line of tyrannosaurids – a family of dinosaurs – of the genus Daspletosaurus, which scientists named Daspletosaurus wilsoni. .
An ancestor of the T-Rex?
According to the researchers, this species was the descendant of Daspletosaurus torosus and the predecessor of Daspletosaurus horneri, which probably arose between 77 and 75 million years ago, the journal Live Science tells. By studying the anatomy of this new species, the researchers confirmed the idea that the Daspletosaurus line would be the ancestors of the famous Tyrannosaurus Rex, more commonly known as T.Rex. “The three species of daspletosaurus belong to the family Tyrannosauridae, which consists of nine genera, including Tyrannosaurus,” explains Live Science.
A vague genealogy
Until this new discovery, the Tyrannosauridae lineage remained difficult to disentangle, making it difficult “to determine the precise evolutionary relationships between the various species,” Live Science reports. “Many researchers disagree on whether tyrannosaurids represent a single lineage that evolved in place, or several closely related species that did not descend from each other,” write the study’s co-authors.
But the very specific characteristics that Daspletosaurus wilsoni shares with older tyrannosaurs suggest that it “could be a good candidate to be a transitional species between D. torosus and D. horneri”. The three species would then have arrived one after the other as “successive ladder-like steps in a single evolutionary lineage”, rather than branching off from each other as “evolutionary cousins” the researchers explain in their study.
Daspletosaurus wilsoni would therefore be a “half way” or a “missing link” between older and younger tyrannosaur species.
If these species evolved one after the other, the scientists suggest that the rest of the tyrannosaurids, including T. rex, “may also have emerged in a similarly linear fashion.” Research continues to try to confirm this idea.
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