São João do Polêsine (Brazil) (AFP)
Several million years before the appearance of the Tyrannosaurus Rex, star of the Jurassic Park saga of Steven Spielberg, the Gnathovorax, another terrible predator, shredded its prey with its sharp teeth in the south of Brazil.
Measuring almost 3 meters, it was the largest dinosaur of its time and also the fiercest, which placed it at the top of the food chain, like the T-Rex.
Its scientific name, Gnathovorax cabreirai, means "ravenous jaws". He was the king of the Triassic period before the Jurassic, 250 to 200 million years ago.
"In the Triassic ecosystem, he occupied a position similar to that of lions today," Rodrigo Temp Muller, a 26-year-old paleontologist from the University of Santa Maria (UFSM) in the state, told AFP. from Rio Grande do Sul, on the border with Argentina and Uruguay.
This region with splendid pampas landscapes is the eldorado of paleontology enthusiasts, a sort of "Trias Park" which conceals a hundred excavation sites which expose the red earth on the sides of green hills.
- "Hooked claws" -
The first skeleton of Gnathovorax was found in 2014 in São João do Polesine, about 300 km west of Porto Alegre.
Dating back over 230 million years, it is one of the oldest and best-preserved dinosaur fossils in the world.
"The fact that it is so well preserved allowed us to obtain a large amount of information on its anatomy. We even managed to reproduce parts of its brain thanks to tomographies," reveals the researcher.
"It was a bipedal dinosaur, which walked on its hind legs and had hooked claws to catch its prey", describes Rodrigo Temp Muller.
He was as formidable as the tyrannosaurus, which appeared more than 150 million years later in North America and could measure more than 12 meters, but is not its distant cousin.
The Gnathovorax is part of another family of dinosaurs, that of the herrerassauridae, the great predators of the Triassic, and is related to other species whose fossils have been found in Brazil and Argentina.
During this period, the continents had not yet separated and the dinosaurs were smaller than those which appeared later, in the Jurassic, then in the Cretaceous.
In place of the pampas, we found a real jungle, with a floor covered with moss.
Most of the dinosaurs present in this area disappeared during major floods of sediment-laden rivers and were thus fossilized.
"We have discovered many fossils throughout the region and there will surely be others. The type of sediment we have here preserves the fossils well, the future is bright," said Rodrigo Temp Muller.
- Giant with long neck -
On the campus of the UFSM Paleontological Research Center in Sao Joao do Polesine (CAPPA), the skeleton of the Gnathovorax is exposed in a display case.
The skull is particularly well preserved and we can notably observe the powerful jaw which gives it its name.
Once extracted from the ground, the fossils are examined with extreme meticulousness using tools that resemble a dental bur. In some cases, the work can take years.
Gnathovorax is not the only species studied by Brazilian researchers.
They also found impressive skeletons of Macrocollum itaquii, the oldest long-necked dinosaur in the world, which lived 225 million years ago.
His fossil was found in 2012, on a vacant lot by a road in Agudo, 20 km from Sao Joao de Polesine.
"It was a biped, like Gnathovorax, but it was herbivorous. Its dentition was adapted to the food of plants which it would seek in the heights thanks to its long neck", explains Rodrigo Temp Muller.
"It is one of the first dinosaurs of which we found the complete skeleton in Brazil," added the young paleontologist.
Treasures that bear witness to the rich palaeontological heritage of Brazil, a country bruised in September 2018 by the fire of the National Museum in Rio, which set apart invaluable collections in smoke, including impressive dinosaur skeletons.
© 2019 AFP