Agence France-PresseMarch 25, 2021 11:44:59 IST
The most notable thing about the near-perfect fossils was not that they belonged to 40-pound kangaroos that mysteriously evolved to climb trees, though that was remarkable enough. What really stunned paleontologists was that the Nullarbor Plain in southwestern Australia, the site of the discovery, was a treeless shrub and was thought to be so even when the newly named Congruus kuhneri bounced – and apparently climbed – beyond its reach before some 50,000 years. The name derived from the Latin language says it all: “Null” for “none”, and “arbor” for “tree”.
The barren snail-shaped area – 1,100 kilometers (700 miles) from head to tail – is even under the control of road signs that say in big letters, “THE END OF THE UNHAPPY PLANE.”
“I remember looking at the bones on my arms and legs with my big, curved claws and saying to a colleague,‘ You probably won’t believe me, but I think it was climbing trees! ’” Recalled Natalie Warburton, a researcher at the Center for Climate-Affected Terrestrial Ecosystems. Murdoch University in Perth.
“Extremely unexpected” behavior of climbing a tree, described in detail in a magazine on Wednesday The open science of the Royal Society, it is certainly significant, she told AFP.
Except for distant relatives in the tropical canopy of New Guinea, about sixty living species of kangaroos, wallabies and other marsupial families macropodidae – all the descendants of the ancestors who lived on the trees, resembling an opsum – have long since evolved to break through to the terra firma.
But the finding, Warburton added, “also tells us that the habitat and environment in the area over the last 50,000 to 100,000 years have indeed been different from what they are now, and perhaps different from what we could previously interpret at the time. based on geological and botanical evidence “.
Overall, the fossils are “completely inconsistent” with expected behavior and ecology.
Strictly speaking, Warburton and her colleague Gavin Prideaux, a paleontologist at Flinders University in Adelaide, were not the first fossil hunters to dig up this unusual roof.
But an earlier specimen of the same species was mistakenly inserted into a taxonomic support based on several partial teeth and a fragment of the upper jaw.
With two full skeletons to work with – one male, one female – Warburton and Prideaux managed to reclassify what were Wallabia kuhneri into Congruus kuhneri, a sub-genus so far occupied by one species, also extinct.
It is unknown exactly what pushed these big-bone creatures to the evolution of ancient skills.
“Climbing a tree would take a lot of energy and big muscles to lift,” Warburton said.
Zoo of megafauna
“There must have been pretty good food sources on the trees that would be worth doing.”
Fossils were found in the Thylacoleo Caves, named after the lion-like baggy carnivores that ruled the region for nearly two million years, until they became extinct at about the same time as the kangaroo that climbed the trees.
Exactly why the megafauna menagerie that inhabited Australia’s sun-scorched landscape – including giant wombats, tonal bag animals and croc-sized lizards – are almost all extinct at the same time is the subject of heated debate.
Dramatic climate change has long been thought to be the main culprit, but recent research following the movements of early humans across the continent suggests they are to blame.
The Nullarbor lowlands – historically occupied by indigenous Australian peoples – have a desert-like climate, daily temperatures close to 50 degrees Celsius (122 Fahrenheit) in summer and winter nights that can fall below zero.
Current mammals include the southern hairy nose, which is protected from the hot sun by drowning in the sand, as well as red kangaroos and dingoes.