A group of Australian researchers have carried out the most detailed modern analysis of all collected skeletons of the little-studied kangaroo genus Protemnodon. Scientists discovered three new species, as well as plenty of evidence of the different ways these animals move.

Now in the territory of Australia, Tasmania and New Guinea there are many breeds from the kangaroo family (Macropodidae) – actually kangaroos, wallabies (very similar to them, but smaller) and wallabies (smaller than wallabies). It is believed that in the middle of the Pliocene (5,333-2,588 million years ago), in response to the spread of vegetation, these marsupials also began to disperse and acquire grazing features: large body sizes, bipedalism, large incisors. Paleontologists have found other extinct species of kangaroo; For example, the kangaroo genus. ProtemnodonWhat types of diversity were not studied, which subsequently received little attention.

Judging by fossils, mass Protemnodon Their weight ranged from 50 to 150 kilograms, making them the heaviest kangaroos. Different members had different proportions of their hind legs, indicating different modes of locomotion; Some were jumping, some were walking on all fours. Despite the ruins Protemnodon A systematic study of this subject, which has been known for 150 years, has not been done before.

Palaeontologists from Flinders University in South Australia decided to fill the knowledge gap about ancient marsupials and investigated the paleobiology of the species. Protemnodon. They revised their taxonomy and wrote a comprehensive treatise that included a detailed description of the skeleton, lifestyle and movement of these animals. The authors also identified seven Protemnodon species, including three previously unknown. The scientific study was published in the journal mega tax.

All seven species are divided by era by paleontologists: P. snowini, P. dawsonae sp. November , P. otibandus From Pliocene; P.anak, P. mamkurra sp. November , P. viator sp. November , P. tumbuna from the Pleistocene. Last on each list were short bipeds that, unlike the others, relied on their forelimbs to move; these were called facultative quadrupeds. Their skeletons were found mostly in the territory of New Guinea. Other larger species P. tumbuna And P. otibandusThey sometimes relied on a muscular tail, meaning they used five-legged locomotion.

An unusually large and strong ilium and a deep fossa are evidence of the likely quadrupedal nature of the genus. It is not found in other kangaroos, but Protemnodon It was used for ineffective slow jumps. Ancient kangaroos didn’t need wide strides because there were plenty of plants around, the authors of the new study suggest. Slowness was also indicated by short and wide heel bones.

But in sight P. viator found many similarities with modern kangaroos; Including good jumping. Physical appereance P.anak It was a tall animal and fed on leaves higher than its body; this was indicated by the angle of inclination of the cervical vertebrae. That and also P. viator And P.mamkurra they were the heaviest – more than 100 kilograms. According to scientists, the mass of the latter was about 166 kilograms.

In some of the described species, as the authors emphasize, the front legs have short and wide finger phalanges. There is further evidence that Protemnodon’s forearms were strong enough to support body weight; ancient kangaroos were twice as heavy as modern kangaroos. Ultimately, however, the functionality of the broad phalanges remains unclear. Researchers have suggested that different species adapt to the ecological environment in different ways. Representatives of New Guinea preferred quadrupedalism due to dense forests, and in the arid zone of Australia ancient kangaroos led a nomadic lifestyle.

“Our study allows us to assume that the tetrapod belongs to only three or four species ProtemnodonAble to move like a quokka or potor, that is, able to jump sometimes on four legs and sometimes on two legs. The recently described Protemnodon mamkurra is most likely one of them. A large but thick-skinned and strong kangaroo must be quite slow and inefficient. Maybe he only jumped occasionally, maybe only when he was scared,” said Isaac Kerr, author of the scientific paper.