Antarctanax shackleton during the early Triassic period, it engages the insect on the banks of the Antarctic River.
Credits: Copyright Adrian Stroup / Museum Museum
Millions of years before the earth was submerged in the footsteps T. rex – the so-called "King of the Dinosaurs" – the forested Antarctica was home to the iguana lizard king.
This ancient reptile was an arhosaur – part of the same group that would later include dinosaurs, pterosaurs and crocodiles. Scientists have recently discovered a partial liver skeleton dating back 250 million years ago when Antarctica was full of plant and animal life.
Not only does the fossil of this former "king" give a sharper picture of the forest landscape in ancient Antarctica, it also helps explain the evolutionary landscape after the largest mass extinction in Earth's history, scientists reported in the new study. [Antarctica: The Ice-Covered Bottom of the World (Photos)]
Although the fossil lizard was incomplete, scientists could discover on the conjugated vertebrates that the animal was adult reptile and probably measured the length of 1.2 to 1.5 meters. They called him Antarctanax Shackleton: The first part of the name derives from the Greek words for "the king of Antarctica"; the second part is patron of British pioneer polar researcher Ernest Shackleton, who called the Beardmore glacier – where many Antarctic fossils, including Antarctanax, was recently found – after the expedition of 1908.
The subtle lines in the spine and leg skeletons have shown that it is a new type, and the shape of the foot suggests that it lives on the ground, wandering through the woods, said author of study Brandon Peecook, a journalist at Meeker's Natural History Museum in Chicago, said Live Science.
"In the legs there are no adjustments that would make us think that he lived on a tree or that he was a puppet," Peecook said.
This tree is hard to imagine if you imagine Antarctica as it is today: a frozen, mostly lifeless, ice-covered desert. But some hundreds of millions of years ago, Antarctica hosted a warm, wet environment where temperatures rarely, if ever, were dipped below freezing temperatures, the authors said.
"We have evidence of widespread forests all over the place and large rivers that move through those forests," Peecook said. The walk among the trees and rivers were amphibians, mammalian mothers called "cinodonti", other predators like mammals called dicinodonti that had ticks and beak, and reptiles like Antarctanaxhe added.
But this fossil also contributes to an important evolutionary story. With the discovery of this unknown ancient reptile, the researchers compile the unexpected variety of arhosaurs that emerged shortly after the mass extinction of the Perma – cataclysmic event 252 million years ago, which destroyed about 96 percent of all marine species and about 70 percent of all marine species. terrestrial vertebrates. Scientists previously thought that after this global event of extinction, animals needed millions of years to diversify and fill empty niches. But Antarctanax shows that archeologists began to diversify within just a few million years after extinction of the perma.
"If you look at the oldest rocks of the Thracian, arthrosis and other groups explode," Peecook told Live Science. While Antarctanaxa body similar to a iguana may not seem particularly dramatic, some Thracian reptiles developed into the sky as pterosaurs, while others returned to the sea and finally evolved into huge Ihtiosaurs and Plesiosaurs – and their ancestors probably appeared at the same time as Antarctanaxhe explained.
"Existence." Antarctanax in the early trials it implies that all these other crazy lines already existed at this time, even if we do not have good fossil record of them from that time, "Peecook said.
The findings are now published online (January 31st) in the Paleontology of Vertebrate.
Originally posted on the day Live Science.