“Shadow of death”: in Argentina, a predatory dinosaur reveals some secrets

published on Wednesday, May 04, 2022 at 11:41 am

Three years after its discovery in southern Argentina, the fossil of a dinosaur is gradually revealing its secrets: 70 million years old, measuring 10 meters long, it was a large predator that eviscerated its prey at using sharp, curved claws.

The remains of this “megaraptor”, a carnivorous dinosaur with large hind legs and small upper limbs, were discovered in March 2019 in the south of the province of Santa Cruz in Patagonia, 30 km south of the tourist town of El Calafate .

Mauro Aranciaga, a 29-year-old paleontologist who works in the Comparative Anatomy Laboratory at the Museum of Natural Sciences of Argentina, directed by Fernando Novas, discovered the first piece of the skeleton while participating in his first campaign of excavations in 2019.

“When I lifted the vertebra I saw that it had the characteristics of a megaraptor. It was really a huge emotion, I saw a giant vertebra and that meant that we were dealing with a giant megaraptor “, recalls the young researcher.

“I realized a childhood and adult dream!” He told AFP in the laboratory premises in Buenos Aires.

Three years later, after a tedious work of extraction, transport, cleaning and long months of laboratory studies, the first conclusions concerning “Maip macrothorax”, its name, have just been published in the scientific journal Nature.

“It was a large animal, according to the measurements and comparisons we made (…) It is also one of the last megaraptors to have inhabited the planet before the extinction of the dinosaurs , about 66 million years ago”, explains Fernando Novas, the director of the laboratory.

– Shred the prey –

This Argentinian paleontologist has a long history of discovery behind him.

In 1996, he found the remains of the very first representative of the megaraptor group 1,400 km away, in the province of Neuquen (south).

Others were then discovered in Australia, Thailand, Japan, he says.

Far from the titanosaurs, the largest known dinosaurs, which can measure about thirty meters and weigh 70 tons, the megaraptors listed so far measured between 8 and 9 meters long.

“This one measured between 9 and 10 meters long and weighed around 6 tonnes”, the largest of the megaraptors known to date, explains Mauro Aranciaga, who also points out that he was “at the top of the food chain” in its ecosystem.

Several vertebrae, ribs, hip, tail and arm pieces were found.

The researchers were also “surprised to discover that megaraptors had huge claws on their thumb and index finger.

They had three fingers on their hands, but their claws were nearly forty centimeters long,” says Novas.

“Obviously, these claws were to be used to capture prey, tear them apart and rummage through their innards,” he adds.

Hence its baptismal name: “Maip” is a Tehuelche word, an indigenous people of southern Argentina, which refers to an evil spirit or “the shadow that death leaves after its passage”.

As for its thorax, it measured up to 1.20 meters wide, for 1.50 meters long, according to the researchers.

“Maip had such a large thorax that the insertions of the ligaments that connect the vertebrae to the ribs were preserved. This allows us to go a little further and reconstruct parts that are usually not preserved”, explains Mauro Aranciaga.

Fernando Novas says that the discovery took place in an “extraordinary deposit which turns out to be one of the most important in South America”. It dates from the Cretaceous (-145 to -66 million years) “when there were neither the Andes nor the glaciers, but rather tropical forests in which a great diversity of animals lived”.

The first clues to the presence of a fossil deposit in the area appeared in 1980 thanks to the work of Argentine geologist Francisco Nulo, but the first real campaign was launched in 2019 by Fernando Novas’ team.

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