A pair of giant kangaroos that died about 45,000 years ago have had their DNA extracted by scientists from the University of Adelaide in Australia.
A giant short-faced kangaroo (Simosthenurus occidentalis) and a giant wallaby (Protemnodon anak) were the sample donators. They were found in a cave in Tasmania, and thanks to the cold, dry conditions there, short pieces of DNA were able to be retrieved from their remains.
The material shed some new light on the ancient, huge creatures (the short-faced kangaroo weighed about 260 pounds; the giant wallaby more than 240) and gave the extinct giant wallaby a promotion of sorts.
"The ancient DNA reveals that extinct giant wallabies are very close relatives of large living kangaroos, such as the red and western grey kangaroos," said lead author Dr. Bastien Llamas, senior researcher for the university's Australian Centre for Ancient DNA, 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," Llamas said.
The DNA extraction is welcome news to scientists interested in decoding the evolutionary tangle of Australian megafauna. Poor preservation conditions and the sheer age of remains have most often meant DNA was unobtainable, leaving scientists just bones for analysis.
"In addition to poor DNA preservation, most of the extinct Australian megafauna do not have very close relatives roaming around today, which makes it more difficult to retrieve and interpret the genetic data," said Llamas. "We had to think hard about experimental and bioinformatics approaches to overcome more than 10 million years of divergent evolution between the extinct and living species."
Another happy note concerned family matters. While the short-faced kangaroo does not have any modern descendants, the team was able to report that it does at least have a cousin, in the form of the banded hare-wallaby (Lagostrophus fasciatus). Today, that endangered creature lives only on small, isolated islands off Australia's western coast.
"Our results suggest the banded hare-wallaby is the last living representative of a previously diverse lineage of kangaroos," said co-author Mike Lee, of the South Australian Museum and a professor in the university's School of Biological Sciences. "It will hopefully further encourage and justify conservation efforts for this endangered species."