Digging up new species of Australia and New Guinea’s giant fossil kangaroos

Paleontologists from Flinders College have described three uncommon new species of big fossil kangaroo from Australia and New Guinea, discovering them extra numerous in form, vary and hopping technique than beforehand thought.

The three new species are of the extinct genus Protemnodon, which lived from round 5 million to 40,000 years in the past—with one about double the dimensions of the biggest purple kangaroo residing at present.

The analysis follows the invention of a number of full fossil kangaroo skeletons from Lake Callabonna in arid South Australia in 2013, 2018 and 2019. These extraordinary fossils allowed lead researcher Dr. Isaac Kerr, then a Ph.D. scholar, to unpick a virtually 150-year-long puzzle across the identities of the species of Protemnodon.

The article, “Systematics and palaeobiology of kangaroos of the late Cenozoic genus Protemnodon (Marsupialia, Macropodidae)” by Isaac AR Kerr, Aaron B Camens, Jacob D van Zoelen, Trevor H Worthy and Gavin J Prideaux has been printed in Megataxa.

The brand new Flinders College examine reviewed all species of Protemnodon, discovering that they have been fairly totally different from each other. The species tailored to dwell in differing environments and even hopped in several methods.

Protemnodon would have appeared one thing like a grey kangaroo, however have been usually extra squat and muscular. Whereas some species have been round 50 kg, others have been a lot bigger than any residing kangaroo.

Nevertheless, one new species named as a part of the newest examine—named Protemnodon viator—was a lot greater, weighing as much as 170 kg. That is about twice as a lot as the biggest male purple kangaroos.

Protemnodon viator was well-adapted to its arid central Australian habitat, residing in related areas to the purple kangaroos of at present. It was a long-limbed kangaroo that might hop pretty rapidly and effectively. Its identify, viator, is Latin for “traveler” or “wayfarer.”

The Australian researchers found two different new species—Protemnodon mamkurra and Protemnodon dawsonae—whereas additionally revisiting the work of earlier researchers together with British naturalist Sir Richard Owen who coined the time period “dinosaur” in Victorian England.

The primary species of Protemnodon have been described in 1874 by British paleontologist Owen who adopted the frequent method of the time, to focus mainly on fossil tooth. He noticed slight variations between the tooth of his specimens, and described six species of Protemnodon.

Successive research have whittled away at a few of these early descriptions; nonetheless, the brand new Flinders College examine agrees with one in all his species, Protemnodon anak. This primary specimen described, referred to as the holotype, nonetheless resides within the Pure Historical past Museum in London.

Dr. Kerr says it beforehand was instructed that some or all Protemnodon have been quadrupedal. “Nevertheless, our examine means that that is true of solely three or 4 species of Protemnodon, which can have moved one thing like a quokka or potoroo—that’s bounding on 4 legs at instances, and hopping on two legs at others.

“The newly described Protemnodon mamkurra is probably going one in all these. A big however thick-boned and sturdy kangaroo, it was most likely pretty slow-moving and inefficient. It could have hopped solely not often, maybe simply when startled.”

Dr. Kerr says the perfect fossils of this species come from Inexperienced Waterhole Collapse southeastern South Australia, on the land of the Boandik individuals. The species identify, mamkurra, was chosen by Boandik elders and language specialists within the Burrandies Company. It means “nice kangaroo.”

It is uncommon to have a single genus of kangaroo dwell in such diverse environments, he says. “For instance, the totally different species of Protemnodon at the moment are recognized to have inhabited a broad vary of habitats, from arid central Australia into the high-rainfall, forested mountains of Tasmania and New Guinea.”

The third of the new species, Protemnodon dawsonae, is understood from fewer fossils than the opposite two, and is extra of a thriller. It was almost certainly a mid-speed hopper, one thing like a swamp wallaby.

It was named in honor of the analysis work of Australian paleontologist Dr. Lyndall Dawson, who studied kangaroo systematics and the fossil materials from “Massive Sink,” the a part of the Wellington Caves in NSW, from which the species is usually recognized.

To assemble information for the examine, Dr. Kerr visited the collections of 14 museums in 4 international locations and studied “nearly each piece of Protemnodon there may be.”

“We photographed and 3D-scanned over 800 specimens collected from throughout Australia and New Guinea, taking measurements, evaluating and describing them. It was fairly the enterprise.

“It feels so good to lastly have it out on the earth, after 5 years of analysis, 261 pages and greater than 100,000 phrases. I actually hope that it helps extra research of Protemnodon occur, so we will discover out extra of what these kangaroos have been doing.

“Dwelling kangaroos are already such exceptional animals, so it is superb to assume what these peculiar big kangaroos may have been getting as much as.”

Whereas Protemnodon fossils are pretty frequent throughout Australia, they’ve traditionally been discovered “remoted,” or, as particular person bones with out the remainder of the animal. This has hampered paleontologists’ examine of Protemnodon prior to now, making it tough to say what number of species there have been, how you can inform them aside—and the way the species differed in measurement, geographic vary, motion and diversifications to their pure environments.

By about 40,000 years in the past, all Protemnodon have been extinct on mainland Australia, perhaps lingering some time longer in New Guinea and Tasmania. This extinction occurred regardless of their variations in measurement, diversifications, habitat and geographic vary.

For causes not but clear the identical didn’t occur to many related and intently associated animals, similar to wallaroos and grey kangaroos. This query could quickly be answered by additional analysis aided in some half by this examine.

“It is nice to have some readability on the identities of the species of Protemnodon,” says Flinders Professor Gavin Prideaux, a co-author of the main new article in Megataxa.

“The fossils of this genus are widespread and so they’re discovered repeatedly, however most of the time you don’t have any means of being sure which species you are taking a look at. This examine could assist researchers really feel extra assured when working with Protemnodon.”