Paris (AFP)

The fossil of an extinct kangaroo species has revealed astonishing tree climbing abilities around 50,000 years ago in an Australian plain, today ... devoid of trees, according to a study released Wednesday.

This doubly incongruous find, described Wednesday in Royal Society Open Science, was made with a new analysis of fossils of small kangaroos, discovered in the immense arid plain of Nullarbor ("no tree" in Latin), in the southwest of Australia.

Paleontologists worked on two nearly complete skeletons - one male, one female - mistakenly classified as "Wallabia kitcheneri", and reclassified them into the newly named subgenus of "Congruus kitcheneri", an extinct species.

By studying its morphology - powerful adduction of the forelegs and hindquarters, sturdy hands with curved claws - they deduced that the 40-pound marsupial was suitable for climbing trees, and moving slowly through them.

A biological curiosity, because Congruus kitcheneri was not strictly speaking an arboreal kangaroo, like the dendrolague, a distant cousin of the marsupials that today inhabit the forests of New Guinea: among the sixty living species of kangaroos, wallabies and other marsupials of the macropodidae family, all of which evolved by leaping onto dry land.

"I remember looking at the bones of the hands and feet, with those big curved claws, and saying to my colleague: + you probably won't believe me, but I think the animal was climb trees! + '"recalls Natalie Warburton, a researcher at the Ecosystem Research Center at Murdoch University in Perth.

What prompted the animal to develop these abilities remains to be elucidated.

"Climbing trees must have required a lot of energy and strong muscles to pull itself up," the researcher told AFP, adding: "there must have been very good food resources in the trees for it to be worth it. penalty. "

The discovery, she said, "also tells us that the habitat and environment in the region over the past 50,000 to 100,000 years were very different from what they are now," a lowland with a near-desert climate.

The fossils have been found in the caves of Thylacoleo, named after the "marsupial lion", an extinct species of carnivorous marsupial mammals that inhabited the region nearly two million years ago, and disappeared around the same time as the climbing kangaroo.

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