New findings from Grand-Staircase Escalante indicate tyrannosaurs may have hunted and lived in groups – St George News

ST. GEORGE – Popular media outlets like “Jurassic Park”, “The Land Before Time” and “King Kong” have always portrayed large carnivorous dinosaurs such as the Tyrannosaurus rex as solitary and fiercely competitive hunters. As scary as it is to imagine even one of those giant carnivores chasing you as prey, it’s even more terrifying to consider escaping many of them at the same time. However, recent research suggests this may have been the case.

In 2014, paleontologists working at the Grand Staircase-Escalante National Monument found a wealth of fossils including four tyrannosaurs. Over the next seven years, the research team carefully excavated and studied numerous fossils under the direction of Dr. Alan Titus, a paleontologist with the Bureau of Land Management.

In a press conference held Monday morning, Titus and some of his colleagues studied the Teratophoneus remains announced that at least some of these ancient carnivores were social and may have lived and hunted in groups.

“I’ve talked to many tyrannosaurus researchers, and a few in particular maintain that these animals simply did not have the brain capacity to engage in advanced social interaction,” Titus said. “With tyrannosaurs, you are looking at a unique line of predatory dinosaurs, the Coelurosauria.”

Titus said one of the main features of the Coelurosauria is an enlarged brain.

“They actually have a greater skull volume than their opponents or ancestors,” he said. “We interpret that as opening the door to potentially increased computing power, if you will, in the brain and the evolution of some social behaviors.”

You might wonder why such a large and powerful predator would need help with a hunt. A contributing researcher, Dr. Joseph Sertich of the Denver Museum of Nature and Science said social behavior may have helped dinosaurs hunt larger prey and reduce individual risk.

The same rocks that bury this Teratophoneus group also bury amazing horned dinosaurs such as Kosmoceratops and Utahceratops and very large hadrosaurs such as Gryposaurus and the Crested Parasaurolophus, ”said Sertich. “Being in a social unit, these tyrannosaurs might have had a better chance of tackling some of these really big or really dangerous herbivores.”

Unraveling the mystery

The project at Grand Staircase-Escalante National Monument became an international research effort, and the research team published its findings in the open access scientific journal PeerJ.

Fossils from the site were excavated, cleaned and examined by BLM paleontologists including Titus and lab manager Katja Knoll. In-depth research revealed that the fossils came from many individual tyrannosaurs of varying ages and sizes, as well as other prehistoric fauna such as ancient turtles, fish and an almost complete Deinosuchus skeleton.

“One of these things is definitely not like the other, and that would be the tyrannosaurs,” said Titus. So how did these tyrannosaurs get into a lake? That became the first mystery we had to solve. “

By analyzing the soil of the excavation site and comparing it to the minerals and rocks trapped in the fossils, the researchers concluded that the dinosaurs were not initially buried on that layer and may have been re-buried after environmental changes.

That led researchers to question whether the remains of the tyrannosaurus had simply accumulated in the riverbed over time, which wouldn’t support theories of their social behavior, Titus said.

Dr. Celina Suarez of the University of Arkansas, along with Dr. Daigo Yamamura did a geochemical analysis of all fossils to compare them and find out if they differed in significant ways.

“We can look at the diet, temperature, and even the type of water or isotopic composition of the water that different animals drank,” Suarez said. “The Teratophoneus, the fish, turtles, crocodilians, and carbonate nodules (rock samples from the same soil layer) all have very similar patterns of rare earth elements, suggesting that they all died and were fossilized together. “

Using these geochemical tools, the fossils were also dated to about 76 million years ago. Knowing that the fossils belonged together and were not deceptively grouped, the researchers wondered what could have brought them together.

Titus said the remains and apparent cause of death – floods – were remarkably similar to the earliest discovered and perhaps best-known evidence for social tyrannosaurs.

In the late 1990s, Dr. Phil Currie, a Canadian paleontologist, excavating the Dry Island Buffalo Jump site in the province of Alberta. There he discovered the remains of at least 12 tyrannosaurs of different ages that appeared to have been killed in another mass event. He theorized that the find was evidence of social behavior, although it was the exact opposite of popular scientific theory, Titus said.

The discovery at the Grand Staircase-Escalante National Monument is the first of its kind in the Southwestern United States, but it adds to a growing body of evidence that Dr. Currie seems to confirm. Tyrannosaurs may have been more intelligent and social than previously thought.

Insight into the research site

The fossils were discovered in the Kaiparowits sub-unit of the National Monument, at a site now known as the “Rainbows and Unicorns Quarry”. Titus said the name came up during a telephone conversation between two of his colleagues.

“A former employee of mine … thought I was a little too excited about every fossil site I had ever found.”

Titus said colleagues often jokingly accused him that every location, including at the Grand Staircase-Escalante National Monument, was “rainbows and unicorns all the time.”

In this case, however, Titus’s colleagues agreed that the location at the monument was really as good as it seemed.

“And so the name just stood out.”

The researchers even brought a stuffed, rainbow-colored unicorn toy to the dig as a mascot.

Secretary of the Interior Deb Haaland recently visited the Grand-Staircase Escalante National Monument, where she visited with Titus and treated some fossil specimens. While the Biden administration has not taken official action to restore Utah’s national monuments to their pre-Trump size, the president made many promises during his 2020 campaign.

The Rainbows and Unicorns site remains within the confines of the shrunken monument, but some conservationists fear that many such sites are beyond current boundaries and could be vulnerable to exploitation or unwitting destruction.

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