DNA Sheds Light on Mysterious Giant Kangaroo

The giant kangaroo, a species that once roamed the Australian outback over 40,000 years ago, has long been extinct, but thanks to scientists that extracted its DNA for the first time we are learning more about this marsupial megafauna.

A team from the University of Adelaide acquired the ancient DNA from the species Simosthenurus occidentalis and Protemnodon anak, or the giant short-faced kangaroo and giant wallaby, respectively. These well-preserved specimens were found in a Tasmanian cave and died around 45,000 years ago.

In the past, poor preservation conditions and the age of Australian megafaunal remains have prevented retrieval of giant kangaroo DNA. In addition, the lack of modern close relatives to extinct giant kangaroos makes it even more difficult to interpret any genetic data.

But with these specimens, the cave's conditions were able to keep the DNA intact, and researchers successfully reconstructed partial "mitochondrial genomes" - genetic material transmitted from mother to offspring that can shed light on evolutionary relationships.

"The ancient DNA reveals that extinct giant wallabies are very close relatives of large living kangaroos, such as the red and western grey kangaroos," lead author Dr. Bastien Llamas said in a statement. "Their skeletons had suggested they were quite primitive macropods - a group that includes kangaroos, wallabies, pademelons and quokkas - but now we can place giant wallaby much higher up the kangaroo family tree."

On the other hand, short-faced kangaroos are a highly distinct lineage of macropods, with no living descendants. However, it's possible that their closest living cousin is the banded hare-wallaby (Lagostrophus fasciatus), which is now restricted to small isolated islands off the coast of Western Australia.

"Our results suggest the banded hare-wallaby is the last living representative of a previously diverse lineage of kangaroos. It will hopefully further encourage and justify conservation efforts for this endangered species," added co-author Mike Lee.

The research was published in the journal Molecular Biology and Evolution.

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