A notable fossil site in Utah, where several tyrannosaurs were found buried together, strengthens a theory that grows these fearsome creatures hunted in packs, similar to wolves.
That tyrannosaurs were social hunters is a possibility that paleontologists have been considering for over 20 years.. In 1910, paleontologists working in Alberta, Canada, discovered the remains of 12 tyrannosaurs that appeared to have died. together. This discovery was largely forgotten until Canadian paleontologist Philip Currie, now with the University of Alberta, revisited the old find in 1998, discussing which was evidence of “gregarious behavior” in tyrannosaurs and that these animals were pack hunters.
Seven years later, Currie, along with several colleagues, reported on a similar discovery made in Montana, in which the remains of three tyrannosaurs, belonging to the genus Daspletosaurus, were also found together. And in 2014, paleontologists described fossilized dino footprints found in British Columbia, Canada, that appeared to show three tyrannosaurs moving in the same direction at the same time.
Despite this evidence, scientists have been reluctant to attribute gregarious behavior to tyrannosaurs, claiming that dinosaurs’ limited cognitive abilities could not have allowed it. Critics of this theory will now have to consider a third place of mass death, as described in a new one paper published in PeerJ.
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The fossil site is located inside the Grand Staircase-Escalante National Monument and produced the remains of four, possibly five, tyrannosaurs, which appeared to have died. at the same time. The fossils were buried at the site of an old river, and the authors of the new document said their deaths were likely the result of seasonal flooding.
“Utah’s new site adds to the growing body of evidence showing that tyrannosaurs were complex and large predators, capable of common social behaviors in many of their living relatives, birds,” said Joe Sertich, co-author of document and curator of dinosaurs. at the Denver Museum of Nature & Science, explained in Press release. “This discovery should be the turning point for rethinking how these major carnivores behaved and hunted in the northern hemisphere during the Cretaceous.”
Currie, who did not participate in the new study, said the finding “adds to a growing body of evidence that tyrannosaurids were able to interact as gregarious packets,” as quoted in the press release. , prepared by the Utah Office of Land Management..
The bones of these dinosaurs were found buried in the late Campanian age. Kaiparowits Formation of southern Utah, which is nicknamed the “Rainbow and Quarry of the Unicorns.” Co-author of the study, Alan Titus, del Territory Management Office discovered the site in 2014 and represents the first mass tyrannosaurus death site found in the southern United States.
Titus and his colleagues discovered the remains of several Teratophone, a genus of tyrannosaurus that lived in the Cretaceous approximately 77 million 76 million years ago. This genus is known from a single species, Teratophoneus curriei, the largest members of which measured between 21 and 26 feet (6.4 i 7.9 meters) in length. Tyrannosaurs, or tyrannosaurs, describe a family of large carnivorous dinosaurs that were on two legs, the most famous examples being Tyrannosaurus Rex, Albertosaurus, Daspletosaurus, i Tarbosaurus.
In addition to the Teratophone fossils, Titus and his colleagues discovered several turtles, several species of fish and rays, an almost complete skeleton 12 feet longmeters) Deinosuc alligator and two other species of dinosaurs (none of these animals are believed to have died in the case that killed the Teratophone copies). In addition to these bones, scientists collected fragments of small rocks and sand bar deposits from the ancient Cretaceous river.
“We immediately realized that this place could be used to test the idea of social tyrannosaurs. Unfortunately, the ancient history of the place is complicated, “said Titus. “With the bones that appear to have been exhumed and reburied by the action of a river, the original context in which they were found has been destroyed. However, not everything has been lost.”
In fact, both the physical and chemical evidence recovered from the site allowed the team to make sense of this ancient scene, despite the geological interruptions mentioned. Analysis of stable isotopes of carbon and oxygen, along with concentrations of rare earth elements, gave “a relatively homogeneous signature,” as paleontologists wrote in their paper. This strongly suggests that all fossils came from the same source population and that the animals died and fossilized together. It also suggests that no other animals were introduced to the burial site later.
Scientists suspect a seasonal flood killed tyrannosaurs, washing their bodies in a nearby lake, where they were eventually buried. The team entertained several other possibilities to explain the mass deaths, including poisonings (e.g., drinking water contaminated with cyanobacteria), drought, fire, and even drowning in moving sands. Of these scenarios, flooding is considered the most plausible explanation, according to scientists.
The find in the Rainbows and Unicorns quarry is obviously a big deal, as it is potential evidence of cooperative hunting not just among tyrannosaurs. but sociality in general, which could also be applied to other domains, that is, extended parental care. That said, not everyone is convinced by the new evidence.
“It’s a little harder to be so sure that these data mean these tyrannosaurs lived together in the good old days,” said Kristi Curry Rogers, a biology professor at Macalester College. Associated press. “It’s possible that these animals would have lived in close proximity to each other without traveling together in a social group and gathering around increasingly dwindling resources as times got tougher.”
Fair enough. The fact that these dino bodies were buried together does not mean that they automatically participated in the pack hunt. As Rogers suggests, the Teratophone it is possible for dinosaurs to gather to celebrate a fallen animal, which may or may not have been a typical behavior of these theropods. Vultures, for example, come down in a regular meal, but these birds can hardly be described as pack hunters.
Consequently, other lines of evidence will be needed to support this hypothesis, specifically evidence to show that these animals willingly stayed with each other. and that they did so cooperatively. This will not be easy to prove, but no one said paleontology was easy.
Month: Dinosaurs like it T. rex they were more tyrannical than we realized, research suggests.