If you happened to be living on this planet 250 million years ago, you probably wanted to spend your vacations in Antarctica.

Scientists paint a vivid picture of the tropical paradise that the frozen continent once was — and perhaps what the continent will be like again: verdant grasslands, gushing rivers and forests as far as the eye could see.

Warm, wet and only rarely below freezing, the South Pole was fit for a king. Namely, the Antarctic king.

That's how researchers at the Field Museum are describing a newly discovered reptile that once prowled those lush lands.

Scientifically dubbed Antarctanax shackletoni — a combination of "Antarctic king" and the name of intrepid explorer Ernest Shackleton — this lizard probably didn't come off as particularly stately. At least in size.

Its dimensions, based on an incomplete fossil skeleton found this week, put it somewhere in the neighborhood of a modern-day iguana.

"This new animal was an archosaur, an early relative of crocodiles and dinosaurs," Field Museum researcher Brandon Peecook notes in a press release. "On its own, it just looks a little like a lizard, but evolutionarily, it's one of the first members of that big group. It tells us how dinosaurs and their closest relatives evolved and spread."

And despite its humdrum appearance, Antarctanax lived in strange times indeed, according to the study published this week in the Journal of Vertebrate Paleontology.

Hints of a unique ecosystem

Fossilized remains of Arctic king The fossilized remains of Antarctanax shackleton include vertebrae, ribs and the right foot. (Photo: Brandon Peecook, Field Museum)

Peecook, who was lead author of the study, says the fossil goes a long way toward painting Antarctica as an unlikely cradle for sprawling diversity of life — from winged insects to four-legged reptilian herbivores to some of the dinosaurs' earliest relatives.

"The more we find out about prehistoric Antarctica, the weirder it is," Peecook explains. "We thought that Antarctic animals would be similar to the ones that were living in southern Africa, since those landmasses were joined back then. But we're finding that Antarctica's wildlife is surprisingly unique."

And while the Antarctic king reveals much about diversity of the once-unfrozen continent, it also reveals a stunning bounce back from one of the biggest mass extinctions in the planet's history.

At the time, animals were just crawling out from the apocalyptic period known as the end-Permian mass extinction, when sustained volcanic activity ended almost all the life on the planet.

Archosaurs, like the Antarctic king, were among the leftovers that managed to rise from those tumultuous times and thrive.

"A pattern we see over and over again with mass disturbances like the end-Permian mass extinction is that some of the animals who managed to survive quickly filled in the empty ecospaces," Peecook tells Gizmodo. "Archosaurs are a great example — a group of animals that were able to do practically everything."

Roughly 10 million years later, the dinosaurs horned their way onto the scene, Peecook adds. But not before an upstart king helped lay the groundwork for their empire.

This 'king' once ruled the green, lush forests of Antarctica
Newly discovered remains of the Antarctic king, Antarctanax shackletoni, paint a lush picture of the Antarctica of 250 million years ago.