BUENOS AIRES (CTYS-UNLAM AGENCY).- Researchers from the Argentine Museum of Natural Sciences found a large carnivorous dinosaur about 70 million years old in the southwest of the province of Santa Cruz. Vertebrae, ribs and part of what would be the chest and shoulder girdle of this specimen were recovered.

For 15 days, rescue tasks were carried out to extract this megaraptor. Surely, from these fossils, researchers will be able to present in society a new large species within this group of carnivorous dinosaurs with lethal characteristics to attack their preys.

Paleontologist Mauro Aranciaga Rolando told the CTyS-UNLaM Agency: "We have found a very large specimen of a new megaraptorid, which were formidable carnivorous dinosaurs, because they had a set of adaptations for hunting that was really spectacular".

"Unlike the Tyrannosaurus rex, the megaraptors were slimmer animals, more prepared for the race, with long tails that allowed them to maintain balance, at the same time that they had muscular legs, but elongated to be able to take long steps", said Aranciaga Rolando, CONICET fellow at the Argentine Museum of Natural Sciences (MACN).

The megaraptors had several characteristics that allow to describe them as lethal. According to Aranciaga, "the main weapons of the megaraptors were in their arms, because they were extremely long and muscular, while they had scythe-like claws on their thumbs, which had a sharp edge and reached 40 centimeters in length, reason why it is probable that this animal has conferred deep hurts against its preys”.

Dr. Fernando Novas, head of the MACN Laboratory of Comparative Anatomy and CONICET researcher, commented to the CTyS-UNLaM Agency that "this new finding will allow us to know what these dinosaurs were like in this corner of Patagonia and to know their relations of kinship with the megaraptors found in other parts of the world”.

The paleontologist Novas was the one who discovered the first specimen of this group of dinosaurs in 1996, in the province of Neuquén, and it was he who coined the name Megaraptor ("great raptor") for this creature.

Megaraptors were large predatory dinosaurs that thrived and diversified during the Cretaceous period, primarily in the southern hemisphere, until the mass extinction that occurred some 65 million years ago. Also, megaraptors were found in Australia and Asia.

"For me, it was a great satisfaction that, since we made that first discovery in Neuquén, cousins of the Megaraptor were found in other regions of the world," said Novas. And he highlighted: "Now, we add another megaraptor from Patagonia".

Aranciaga Rolando asserted that "this possible new species of about 10 meters long, in addition to its importance due to its size, represents one of the most modern specimens of the megaraptors family, since those that were known so far were some millions of years older".

Another of the characteristics that Aranciaga Rolando indicated as favorable for the predatory aptitude of the megaraptors is that they had an elongated neck and skull, which surely helped them to reach their prey more easily.

Dinosaur racing
The posibility to sprint would have been very important for the megaraptors. The paleontologist Sebastián Rozadilla of the MACN and CONICET indicated that "these carnivorous dinosaurs would not have fed on the sauropods, which are those large long-necked dinosaurs that also lived in that area, but on other herbivorous dinosaurs of which was finded in the Chorrillo formation, west of Santa Cruz”.

"These herbivorous dinosaurs could reach between five and six meters in length and belonged to the Isasicursor species, which were bipeds and great runners", said Rozadilla. Hence, the speed of the megaraptors would have been an important factor in being able to hunt them down.

These herbivorous dinosaurs lived in large groups, including young and adults. "They lived similarly to the way gazelles or antelopes do today in the African savannah", Rozadilla described.

The rescue of this great predator
The smallest known megaraptors measure about five meters, while the largest are similar to this specimen found southwest of Santa Cruz during the last campaign carried out in March.

To extract this animal, which was in extremely hard rock, it was necessary to use appropriate machinery such as the rock cutter.

In a task that took about two weeks, with chisels and hammers, paleontologists removed the rock surrounding the specimen in order to remove each of the bones. "Finally, the rock that contained the fossil was covered with plaster and bandages, so that it would not be destroyed during its transportation to Buenos Aires", said Aranciaga.

For these weeks, this formidable predator is duly fulfilling his quarantine at the MACN Laboratory of Comparative Anatomy, waiting for the researchers to continue with their preparation and study. Subsequently, this sprinter will make his trip back to the province of Santa Cruz to enrich the collections of the “Padre Molina” Museum, in Río Gallegos.