Kangaroo fossil points to previously unknown species in New Guinea

Kangaroo fossil points to previously unknown species in New Guinea | Pro Club Bd

  • Paleontologists have described a new genus of fossil giant kangaroos, named Nombe after the Nombe Rockshelter archaeological site where the fossil was originally found in Papua New Guinea.
  • The find was an accidental discovery since Ph.D. Candidate Isaac Kerr reexamined a jawbone found in the 1970s that was originally thought to belong to the extinct genus Protemnodon, the cousin of modern-day eastern gray and red kangaroos found in Australia.
  • To date, there has been limited archaeological research on the island of New Guinea and the fossil record is patchy.
  • The team hopes further research will provide insight into the evolution of the island’s outstanding modern biodiversity, much of which is endemic.

A previously unknown genus of primitive giant kangaroos that once roamed the rainforests of New Guinea has been described by a team of paleontologists from Flinders University in Australia.

The researchers hope the results, released in June, will revitalize the field of paleontological research on New Guinea and help uncover the island’s history, leading to a better understanding of its diverse and often unique modern flora and fauna.

The serendipitous discovery came about when lead author Isaac Kerr, a Ph.D. Flinders University candidate, re-examined a fossilized jawbone thought to belong to a giant kangaroo from the extinct genus Protemnodona cousin of today’s eastern gray and red kangaroos (Macropus giganteus and Macropus rufus) found in Australia and the focus of Kerr’s research. A closer look reveals clear differences Protemnodon in the molars led the research team to believe that it was in fact a previously undiscovered genus, most likely unique to New Guinea.

Flinders University paleontology researcher Isaac Kerr with an Australian kangaroo jaw bone and a fossil jaw of Australian megafauna used in the latest Royal Society study. Image courtesy of Flinders University.

The jawbone was originally found during an expedition led by Mary Jane Mountain in the 1970s at an archaeological site called the Nombe Rockshelter in central Papua New Guinea. Kerr and his colleagues named the new genus nome then the locality and the type species are mentioned Nombe Nombe.

“The fauna of New Guinea is strange and unique, and the fossil evidence suggests it is,” Kerr said in an email to Mongabay.

In 2020, a collaborative study between 99 different botanists found that New Guinea had the most plant species of any island on earth – surpassing Madagascar’s record of 11,832 species for a total of 13,634 plant species. Even more incredible, two-thirds of the plant species found on the island are endemic, meaning they are found only in New Guinea.

The fauna of New Guinea is similarly diverse and in many cases unique, such as the critically endangered western long-beaked hedgehog (Zaglossus bruijnii), an egg-laying mammal or the colorful birds of paradise like the Raggiana (Paradisaea raggiana), national bird of Papua New Guinea.

Artist's rendering of Nombe Rockshelter's megafauna
Artist’s rendering of the Nombe Rockshelter megafauna with the Nombe kangaroo at right. Image courtesy of Peter Schouten.

The reason for the high level of endemism in New Guinea is its isolation. The island was connected to mainland Australia by a land bridge around 5 to 8 million years ago when sea levels were lower, but was separated when the area now known as Torres Strait was flooded. Once cut off, species that previously roamed Australia and New Guinea—like the now-extinct kangaroos—began to follow different evolutionary paths. For example, Kerr says, the marsupials found on New Guinea are often smaller and stockier than their Australian counterparts because they live in a dense forest habitat, as opposed to Australia’s arid grasslands.

“If we want to fully understand our modern ecosystems, we need to understand how they formed,” says Gilbert Price, a University of Queensland paleontologist unaffiliated with the study. “Just think, without these fossils, we would have no idea New Guinea even had this species of kangaroo.”

To date, there has been limited paleontological research on New Guinea, and the fossil record is patchy, in part due to the challenges of working on New Guinea and finding research funding, Price says.

“It’s like a new frontier for paleontologists,” he says. “There are also lessons to be learned, especially if we can understand how and why organisms like Nombe Nombe lived and died out.”

3D rendering of the fossilized PNG kangaroo jawbone used in the new Flinders University study. Image courtesy of Kerr, Flinders University.

Kerr and his colleagues hope their discovery will give new impetus to paleontological research in New Guinea. The team recently received a grant to conduct three excavations at two sites in central and east Papua New Guinea over the next three years.

“We will be working with curators from the Museum and Art Gallery of Papua New Guinea and other contacts in Papua New Guinea,” said Gavin Prideaux, a Flinders University paleontologist and co-author of the paper, in a press release. “We hope to generate local interest in New Guinea paleontology.”

Banner Image: An artist’s rendering of the Nombe kangaroo. Image courtesy of Peter Schouten.

Citation:

Kerr, IA, & Prideaux, GJ (2022). A new kangaroo genus (Marsupialia, Macropodidae) from the late Pleistocene of Papua New Guinea. transactions of the Royal Society of South Australia, 1-24 doi:10.1080/03721426.2022.2086518

Animals, Archeology, Biodiversity, Environment, Extinction, Fossils, Islands, Marsupials, New Discovery, New Species, Rainforest Biodiversity, Research, Science

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