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It turns out that ancient species of kangaroos in Australia have more in common with giant pandas than modern macropods.
According to D Rex Mitchell of the University of New England, author of a study published in the newspaper PLOS ONE about the long-extinct Simosthenurus occidentalis.
Still hoping about 42,000 years ago, S. occidentalis was a sthenurine kangaroo, sometimes called a "short face" kangaroo – an entirely extinct group characterized in part by its strongly constructed skull, large jaws and teeth, and shortened snout.
The heavyweight of the subfamily was Procoptodon goliah, the biggest macropod to have ever lived – a murderer over 200 kilograms and over two meters tall, which probably disappeared about 50,000 years ago.
With an average body mass estimated at about 118 kilograms, S. occidentalis was several sizes of shoes on P. goliah, but always heavier than the largest living macropod, the red kangaroo (Macropus rufus), which reaches about 90 kilograms.
Previous research has suggested that the robust skull characteristics of stenurines indicate that these animals have a strong jaw adapted to a diet that includes tough foods such as mature leaves, stems, and branches.
Mitchell hypothesized that if this is true, the skulls of kangaroos should also be constructed to withstand the forces that such powerful bites would exert on the bones and joints of the skull.
He created a digital model of a S. occidentalis skull, performed a series of bite simulations, and then compared them to the koala bite (Phascolarctos cinereus) – the existing animal considered to have the most similar ecology and type of skull.
The differences between the two include the positioning of S. occidentalis teeth of the cheek. They extend further back on the bones of the jaw than do the koalas. They would have exerted much more force on the articulation of the jaw and increased the risks of dislocation of the jaw.
Simulations revealed that S. occidentalis could produce and withstand comparatively heavy forces when he was biting unilaterally – particularly when he was inserting very hard materials into the cheek teeth on one side of the mouth, much like a giant panda with a bamboo stalk.
S. occidentalis Mitchell found that the cheekbones, supported by large muscles, would prevent his jaw from being dislocated during strong bites, and that the bones of the front and roof of the skull would form a circular arc that would withstand the forces torsion caused by bites.
These attributes support the suggestion that kangaroo sthenurine skulls were well adapted to production and bore strong bite forces, which would have allowed them to eat tough, low-nutritious foods that could have been inaccessible to their teeth. other species.
Mitchell notes that S. occidentalis – an extinct species – seems more able to exploit tough food than any living Australian herbivore, which means that these kangaroos represent a feeding behavior and an ecology that we no longer observe on the continent.
"The extinct kangaroo skull studied here differs from that of current kangaroos in many ways compared to the skull of a giant panda compared to other bears," says Mitchell.
"So, it seems that the strange skull of this kangaroo looked, in a functional sense, less like a modern day kangaroo and more like a giant panda."
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