In Argentina there is one of the best deposits to study fossils of the first dinosaurs that walked the Earth. In a dry and eroded area, forty years ago the help of a shepherd was key to finding the skeleton of a primitive species of T. rex and Velociraptor.
A lost world in Argentina
The first dinosaurs appeared 230 million years ago. To find fossil remains of the first species we have the Provincial Park of Ischigualasto , in the province of San Juan, Argentina. It is also known as Valle de la Luna, because its landscape seems extraterrestrial. It has that air of a western scene, with stone columns sculpted by the wind, dust and earth with scant vegetation. The Andes rise up on the northwest horizon and to the south the plains expand where the cows that give the famous Argentine meat graze. It is a cattle crossing and, as such, the little population that lives in the area is dedicated to livestock.
Millions of years before humans, large amphibians, cynodonts, dictionodonts and rhynchosaurs, among other species, lived there. The rivers eroded the land and, occasionally, great storms caused the water currents to overflow, dragging dinosaurs and other animals, which were buried in mud: a misfortune for them, but the best way for well-preserved fossils to reach us today. .
The area has remained uninhabited forever and erosion has continued to do its work. So cowboys passing by with their cattle have repeatedly found amazing skeletal remains emerging from the ground. Rumors about these strange bones spread, but it was not until the 1940s that scientists went to study the Ischigualasto fossils.
Fossil I see, fossil I want
One of the first researchers to achieve some success in the area was Alfred Sherwood Romer , an eminence in paleontology. In 1958, Romer drove a vehicle through those drylands when he was already sixty-four years old. He found fossil remains that he extracted from the rocks and protected as much as he could to send them to Buenos Aires and, from there, have them sent to the United States to study them in his laboratory at Harvard. But the fossils were held in Buenos Aires longer than expected. Apparently, Argentines were not very amused when an American took Argentine tests with him to study in his foreign country. Romer could not devote the attention that the fossils required but, over time, it was discovered that the North American paleontologist had found the first dinosaur (by science) in the Valley of the Moon.
But Romer’s attempt served for the Argentines themselves to give importance to Ischigualasto. Osvaldo Reig and José Fernando Bonaparte , Argentine scientists, organized several expeditions starting in 1959. In one of the campaigns in search of fossilized dinosaurs, they met Victorino Herrera , a local shepherd who knew the area perfectly. Herrera led Reig and Bonaparte’s team to an area where he remembered seeing bones. And sure enough, they found bones there, many fossilized bones. Scientists were able to reconstruct the skeleton of an animal the size of a horse. Its morphology implied that it could run on its hind legs, had sharp teeth and powerful claws.
This was the Herrerasaurus
Osvaldo Reig described the fossils as a new species of dinosaurs and named it, after the shepherd, Herrerasaurus . This dinosaur turned out to be a prominent predator in the area, a primitive version of Tyrannosaurus rex or Velociraptor . One of the earliest theropod dinosaurs: agile, intelligent, two-legged predators that were high on the food chain. In addition, the remains found by Romer were also shown to belong to Herrerasaurus as well.
Surprisingly, the finding did not cause dozens of paleontologists to rush to Ischigualasto in search of fossils. The area went unnoticed for two decades and it was not until the end of the 1980s that a new expedition returned to the Valley of the Moon. Paul Sereno and a team, this time made up of Argentines and Americans together, found another Herrerasaurus skeleton and other dinosaur fossils such as Eoraptor and Eodromaeus .
Until now, new discoveries have been described, becoming more than clear that the Ischigualasto Provincial Park has much to offer us to discover the dawn of the dinosaurs.
References:
Brusatte, S. 2019. The rise and fall of the dinosaurs. The New Story of a Lost World . Debate.
Sereno, PC 2010. The skull and neck of the basal theropod Herrerasaurus ischigualastensis. Journal of Vertebrate Paleontology 13, 4, 451-476. DOI: 10.1080/02724634.1994.10011525.
