A new iguana-sized fossil found in the mountains of Antarctica represents an extinct cousin of dinosaurs and crocodiles—and it likely once lived on forest floors in temperate climates.
The fossil, dated to the early Triassic Period around 250 million years ago, represents a much different time in the history of Antarctica. Higher latitudes and warmer overall global temperatures meant that our frozen continent was a temperate forest many, many yesterdays ago.
The reptile, named Antarctanax, was announced today in the Journal of Vertebrate Paleontology. It represents a close cousin of crocodiles and dinosaurs, but has no living relatives. It also predates the earliest known dinosaurs or crocodiles by about 10 million years. It was small, likely eating amphibians and small proto-mammals, and, given the structure of its bones, most likely spent most of its time on the forest floor. That forest today just so happens to be in one of the most inhospitable places on Earth.
“Where there’s no plants or animals for hundreds of miles around, here’s a forest,” Brandon Peecook, a researcher at the Field Museum of Natural History and author on the paper, says. That forest is long gone, of course. All that remains the fossils of some of its animals and some petrified wood. “This was a warm forest at the bottom of the world—not quite where Antarctica is now, but pretty far south.”
Peecook and colleagues initially found the fossil on a 2010-2011 expedition to Graphite Peak, which is slightly inland on the continent and several thousand miles south of New Zealand. The group went mountaintop to mountaintop hunting for fossils, finding quite a few—but nothing that seemed all that new. But as they chipped away rock from one specimen, “it became quickly obvious that this was a new animal,” Peecook says.
The Antarctanax came from a time just 2 million years after the extinction event that ended the Permian period, where 70 percent of all terrestrial species and 96 percent of ocean species died off. What came next was a glut of new species to repopulate the Earth, with amphibians, reptiles, and mammal relatives all scrambling to fit in the niche eventually dominated by dinosaurs.
“It’s a new discovery for sure, and it’s reaffirms something paleontologists have known for years, which is how many forms were radiating out right after this mass extinction,” Peecook says.
Antarctanax just wasn’t one of the lucky ones to make the eventual cut. But some of its cousins, like the crocodiles and alligators, persist today, as do the descendants of dinosaurs, birds. It’s just one piece of a big puzzle as to what the world was like 250 million years ago—and more of the puzzle pieces may be hiding where it’s really, really cold.
Originally posted on Popular Mechanics