2024-01-13 20:57:00
New species of tyrannosaur found in New Mexico, possibly predating T. rex. (Illustrative image Infobae)
Researchers have found a new species of tyrannosaurus in New Mexico, which is believed to have lived between five and seven million years before its iconic relative Tyrannosaurus Rex. According to the work published in Scientific Reports, cited by Asher Elbein in The New York Times, this discovery suggests that the history of the evolution of T. rex must be revised and expanded.
You may be interested: A group of miners in North Dakota discovered a mammoth tusk between 10,000 and 100,000 years old
“Most species don’t last more than a million years,” says Spencer Lucas, curator of paleontology at the New Mexico Museum of Natural History and Science and co-author of the study. This evidence, added to the anatomical differences found, suggests that the skull examined belongs to a different species, named Tyrannosaurus mcraeensis in honor of the geological formation where it was discovered.
In the 1980s, museum employees collected a partial skull of a large adult tyrannosaur at Elephant Butte Reservoir, initially assuming the fossils belonged to a T. rex. However, Sebastián Dalman, a paleontologist at the museum, noticed subtle but consistent differences in the specimen when he began his analysis in 2013. These differences included a thinner lower jaw and teeth with different characteristics, as well as the absence of a prominent bony crest. behind the eye, characteristics of an adult T. rex.
Initially, the rock strata from which the fossil came—the McRae Formation of New Mexico—were believed to be contemporaneous with the well-known Hell Creek Formation of the Great Plains, which dates back to 66 to 68 million years ago, the same period. of T. rex. However, more recent dating of the rocks suggests that the McRae Formation is five to seven million years older, indicating that the specimen found comes from an earlier relative of T. rex.
The need to review the evolution of T. rex following the discovery of Tyrannosaurus mcraeensis. (Illustrative image Infobae)
This finding has been received with interest by the scientific community. Dave Hone, a paleontologist at Queen Mary University of London and not involved in the study, said, “This is going to receive a lot more scrutiny than the average newly named dinosaur.” Although there has been reluctance in the past to split such an iconic and well-studied species without overwhelming evidence, some outside researchers have reacted more warmly toward T. mcraeensis, acknowledging that the authors have made a reasonable and compelling case.
The discovery, the NYT article notes, also has interesting implications for the timeline of tyrannosaur evolution. Throughout the late Cretaceous period, tyrannosaur relatives ranged across what is now western North America, from Alaska to Mexico, but in the final million years of the dinosaurs’ reign, the largest T. rex replaced these lines.
Traditionally, it had been argued that Tyrannosaurus represented a specific group that crossed a land bridge from Asia, given its closeness to its better-known relatives from Mongolia. However, the new find suggests that the Tyrannosaurus line appeared in North America much earlier than expected, and may have originated in the southwest before spreading north.
As Thomas R. Holtz Jr., a paleontologist at the University of Maryland, said, “there is obviously more going on than just a northward movement, given that we also have the Asian lines.” Likewise, if Tyrannosaurus appeared in the southwest, the genus may have evolved in giant size to hunt the huge herbivores of the region.
However, what caused a landscape of giants to appear in a specific region of North America remains a mystery. “I think we need to spend more time looking at the southwest,” said Nick Longrich, a paleontologist at the University of Bath in England and co-author of the paper. “There are many understudied areas where we are going to find new things,” concludes the evidence presented by Asher Elbein in her article for The New York Times.
1705184841
#Discovery #Mexico #redefines #evolution #Tyrannosaurus #rex
