Super-muscular, 374-pound kangaroos once stomped through Australia and New Guinea

The Earth used to be absolutely teeming with more megafauna. The fossil record is full of enormous birds like those of New Zealand Heracles inexpectatus, giant lemurs from Madagascar, large marine reptiles that would put today’s sea snakes to shame. Paleontologists have now found evidence for three unusual new species of giant fossil kangaroo in what is now Australia and New Guinea. The creatures are described in a study published April 14 in the journal Megataxa and indicate that these species were probably much more diverse in form, habitat and jumping method.

“Living kangaroos are such remarkable animals, so it’s amazing to think what these peculiar giant kangaroos could have been up to,” study co-author and Flinders University PhD student Isaac Kerr. said in a statement.

Meet the giant kangaroos

The three new species belong to one extinct genus of giant kangaroos Protemnodon who lived from five million to about 40,000 years ago. They would have looked about the same modern gray kangaroos, but were generally stockier and more muscular. Some species weighed around 50 kilos, but others were up to twice the size of today’s largest living kangaroos.

Protemnodon are fossils quite common throughout Australia, but historically they have been found as individual bones rather than in complete skeletons. This has made it difficult for scientists to determine how many species there were and how they differed in geographic range, movement and size.

[Related: What prehistoric poop reveals about extinct giant animals.]

“The fossils of this genus are widespread and regularly found, but more often than not you can’t be sure which species you are looking at,” study co-author and Flinders University paleontologist Gavin Prideaux. said in a statement.

For this study, the team was able to use several complete fossilized kangaroo skeletons Lake Callabonna in South Australia, which could give scientists a clearer picture of these giant kangaroos. Researchers also assessed all known species Protemnodon and discovered that they were all very different from each other. The animals also adapted to living in different environments and even had different ways of jumping.

A very heavy, traveling kangaroo

One of the new species has a name Protemnodon viator. The word viator resources ‘traveller’ or ‘traveller’ in Latin. So was this wandering marsupial much larger than other known giant kangaroos weighing up to 374 pounds. According to the team, this is roughly twice as much as the largest living male red kangaroos.

Protemnodon viator was also probably well adapted to its arid habitat in central Australia. It lived in a smaller geographic area than today’s red kangaroos. He also had long limbs and could jump quickly and efficiently.

A ‘robust’ creature and a swamp wallaby-like kangaroo

Another new species has been given a name Protemnodon mamkurra and it connects today’s paleontologists with a famous scientist from the past. British paleontologist and naturalist Sir Richard Owen famous coin of the term ‘dinosaur’ in 1842but also described the first kind of Protemnodon in 1874.

When he first found these giant kangaroo fossils, he took a common scientific approach at the time. He focused mainly on fossilized teeth and noticed small differences between the teeth of his specimens. Ultimately he described six species Protemnodon and further research has dispelled some of Owen’s early descriptions. He also suggested that some or all Protemnodon have four legs. While not all of them have, this study agrees one of its kind-Protemnodon anak–probably had four legs.

[Related: Giant beasts once roamed Madagascar. What happened to them?]

“However, our study suggests that this applies to only three or four species of Protemnodon, which may have moved something like a quokka or potoroo – which sometimes jumps on four legs and at others jumps on two legs,” Kerr said. . “The newly described Protemnodon mamkurra is probably one of these. It was a large, robust, thick-boned kangaroo, which was probably quite slow and inefficient. He may have jumped only rarely, perhaps only when startled.’

The best of these fossil species come from the Green Waterhole Cave in southeastern Australia, on the land of the Boandik people. The species name mamakurrameans ‘big kangaroo’ and was chosen by Boandik elders and language experts in the Burrandies Corporation.

According to Kerr, it is unusual for a single kangaroo genus to live in such varied environments. “For example, the different types Protemnodon They are now known to have inhabited a wide range of habitats, from arid central Australia to the rain-covered, forested mountains of Tasmania and New Guinea.”

The third new species is mentioned Protemnodon dawsonae. It is known from fewer fossils than the other two, so it is more of a mystery. The team believes it was likely a medium speed hopper and possibly similar to the live swamp wallaby. It was named in honor of the Australian paleontologist Lyndall Dawson.

Although most species became extinct on mainland Australia about 40,000 years ago, they are still active potentially lived longer in New Guinea and Tasmania. Future studies could shed more light on their extinction, as it is still an enduring paleontological mystery.