Dinosaurs are older than we thought, suggests new study

The remains of the first Dinosaurs They could yield without discovering in the Amazon and other equatorial regions of South America and Africa, suggests a modeling study led by researchers from the University College London, which also points to a previous million -year origin.

At present, the oldest dinosaur fossils that are known date from about 230 million years ago and were unearthed further south, in places like Brazil, Argentina and Zimbabue. But the differences between these fossils suggest that dinosaurs had already been evolving for some time, which points to an origin millions of years beforethe researchers point out.

The work, according to the British University (UCL), is a “new turn in the mysterious origin of dinosaurs”; The results are published in Current Biology magazine.

This has taken into account the lagoons existing in the fossil registry, concluding that The first dinosaurs probably arose in a warm equatorial region in what was then the Gondwana supercontinent.

This land area today covers the Amazon, the Congo basin and the Sahara desert, explains a UCL statement.

“Dinosaurs are well studied, but we still don’t really know where they come from. The fossil record presents lagoons so large that it cannot be taken to the letter, ”says Joel Heath.

“Our model suggests that the first dinosaurs could have originated in Gondwana, a western area of ​​low latitude. It is a warmer and more dry environment of what was thought, formed by desert and savannate areas, ”he adds.

Until now, fossils have not been found in the regions of Africa and South America that formed this part of Gondwana. However, “This could be due to the fact that researchers have not yet encountered the right rocks, due to a mixture of inaccessibility and relative lack of research efforts in these areas”.

The modeling study was based on fossils and dinosaur evolutionary trees and their nearby reptile relatives, as well as geography of the time.

At first, the first dinosaurs were widely overcome by number by their reptile cousins, including the ancestors of the crocodiles, the pseudosuquios (an abundant group that included huge species of up to 10 meters in length).

The first dinosaurs were much smaller than their descendants, more the size of a chicken or a dog than a diplodocus. They walked on two legs and it is believed that most were omnivores.

They became dominant after volcanic eruptions ended many of their reptile relatives 201 million years ago.

The new results suggest that dinosaurs and other reptiles could have originated in the Gondwana of low latitude, before irradiar to the south and Laurasia, the adjacent northern supercontinent that was later divided into Europe, Asia and North America.

This origin is based on the fact that it is an intermediate point between the place where the first dinosaurs have been found in southern Gondwana and where the fossils of many of its close relatives to the north have been discovered, in Laurasia, the university emphasizes .

The researchers tested their model with three proposed evolutionary trees.

The model that considered the Silesáurids, traditionally considered cousins ​​of dinosaurs but not diners proper, as ancestors of the ornitiscan dinosaurs was the one that most supported the Gondwanic origin of the dinosaurs at low latitude.

The ornitisquios, one of the three main dinosaurs groups that later included the dining rooms of Stegosaurus and triceratops plants, are mysteriously absent from the fossil record of these first years of the Dinosaurs era. If the Silesáurids are the ancestors of the ornitisquios, this helps to fill this void in the evolutionary tree.

“The definitive proof of our models will be if there are remains of primitive dinosaurs in the Amazon, the Sahara desert and other ancient parts of Gondwana of low latitude,” says Heath.

“Finding them would revolutionize our understanding of the Triassic ecosystems and offered key information about the evolutionary history of the group,” adds a note from the Natural History Museum.