[Animals] These rare fossils reveal a stunning scene from the last days of the dinosaurs

[FNX Magokiler]

The heyday of the dinosaurs ended in flames. About 66 million years ago, an immense asteroid hit ancient Central America and triggered Earth's fifth mass extinction, wiping out 75% of known species.

Most of what we know about this fateful moment in the history of life comes from North America, among the lairs of dinosaurs like T. rex and Triceratops in the American West. Paleontologists know much less about how the catastrophe unfolded further south, but a site of dinosaur bones recently discovered in Argentina could help change this.

According to paleontologist Matthew Lamanna of the Carnegie Museum of Natural History, the Cañadón Tomás quarry has "exceptional potential" to reveal what happened in South America during the mass extinction. The finds include bones from several duck-billed dinosaurs, called hadrosaurs, that may have lived together in a herd, as well as the tooth of a carnivorous dinosaur, a snake vertebra and the jaw of a small mammal. These findings demonstrate that the rocks preserved large and small animals from this prehistoric ecosystem.

Today the area is a bush-covered desert, but about 66 million years ago this part of South America was warm, humid and covered with plants such as ferns and palm trees. According to Noelia Cardozo, a paleontologist at the National University of Patagonia San Juan Bosco, previous research has shown that Cañadón Tomás had a meandering stream that meandered toward the sea surrounded by wide alluvial plains.

 

 

The freshwater habitat allowed creatures found there to be buried and preserved, providing a rare glimpse into life in this part of the world during the late Cretaceous period.

"There are far fewer sites preserving terrestrial vertebrate fossils from the late Cretaceous in the Southern Hemisphere," says Lamanna, who recently described the site at the annual conference of the Geological Society of America.

Although it is more difficult to find fossiliferous rocks of the right age in the Southern Hemisphere, Lamanna explains, experts have spent much more time and effort searching for fossil sites from the end of the Cretaceous in the Northern Hemisphere. "There are fewer researchers, and they are often not as well funded in the southern hemisphere," says University of Chile paleontologist Alexander Vargas, who was not involved in the new research. The result has been a skewed view of what happened before and after the asteroid impact.

The Cañadón Tomás site helps change history. Featuring large herbivores, signs of carnivores and material from smaller animals, the quarry offers a window into an entire ecosystem that thrived at the end of the age of dinosaurs.

 

https://www.nationalgeographic.es/ciencia/2023/10/estos-raros-fosiles-revelan-una-impresionante-escena-de-los-ultimos-dias-de-los-dinosaurios