Reptiles stand upright after the Fermi extinction

Reptile animals have changed the way of moving from ground-to-ground to perpendicular to the ground right after the end of the Permian extinction event, the largest extinction event in paleontological history that took place about 250 years ago. Millions of years have erased 90% of species on Earth.

In a detailed survey of 460 reptile fossils that lived before and after the extinction event, Tai Kubo and Professor Mike Benton from Bristol University discovered that before this event, all reptiles They all move with both hands and feet in the shape of a crawl, like the iguana and lizard today.

After the mass extinction event, medium and large reptiles in the Triassic period then moved with their legs perpendicular to the body and the ground like mammals today.

 

Moschop dinosaurs existed before the end of the Permian-early Triassic extinction event. (Photo: © Jim Robins )

Professor Benton said : 'Dinosaurs - and then mammals - succeeded in standing upright. An upright animal such as an elephant or a Diplodocus dinosaur can reach a very large size due to its weight being driven directly to the ground through its legs that act as pillars. In addition, other upright animals, such as monkeys, can use their hands to climb or pick food. '

Straight walking has great advantages - it means longer strides and less pressure on the knee and elbow joints. Going straight is the key to the success of the dinosaurs that appeared 25 million years after the great extinction. The first dinosaurs had two legs and they gradually grew into very large sizes. Conversely, ground-level cows cannot reach large bodies, otherwise their legs will not be able to withstand body weight.

In the past, the transition from horizontal to upright cattle was considered a long process, in about 20-30 million years, but new evidence shows that the event actually happened much faster, and perhaps starting from the great Fermi era.

This new information also changes other evolutionary hypotheses.'If the replacement of cattle animals is equal to straight-up animals is a long process, then we are studying a competitive alternative,' said Professor Benton.

The shape of the foot of the previous reptile (pictured below) and later (pictured above) of the great extinction 252 million years ago. (Photo: © Simon Powell)

'However, new evidence from footprints shows a much more rapid type of substitution, in which animals that cross each of the Permian ecosystems nearly wiped out, and groups. newly evolved after the great extinction are straight-up animals. All of the competitive interactions here seem to take place only for a very short period of time. '

Detailed research published in Palaeontology published yesterday, September 15.