Freshly discovered fossils from dozens of caves across the South West prove WA was once home to its own species of koalas.
The newly discovered Phascolarctos sulcomaxilliaris species is believed to have vanished around 28,000 years ago during a major climate shift which devastated eucalyptus forests.
Previously, koala fossils were long assumed to have been related to the east-coast species, but further research which looked at the bone structures of the fossils found they belong to a separate species all together.
The research was led by Dr Kenny Travouillon, Curator of Mammals at the WA Museum, and Adjunct Research Fellow at Curtin University School of Earth and Planetary Sciences.
He said the examination began after a fossil of a skull was found from Moondyne Cave in Margaret River.
“The fossil displayed characteristics we don’t see in modern koalas, which prompted further investigation,” Dr Travouillon said.
Researchers continued their analysis and inspected almost 100 bones from fossil specimens within the museums collection – comparing skulls, teeth, and skeletons with the modern koala from Australia’s east coast.
Dr Travouillon said the species, nicknamed the dimpled koala, differed from modern koalas in several striking ways.
“Deep grooves in the cheekbone housed a large facial muscle, suggesting the animal may have had unusually large, mobile lips, possibly for manipulating eucalyptus leaves.”
“Its skeleton was likely less agile than modern koalas and may have spent less time moving between trees.”
The research suggests the koalas would instead flare their nostrils to enhance their sense of smell and detect food from greater distances.
Extinction came with a major late-Pleistocene climate event, which is thought of as one of the five ice ages.
Fossils of the dimpled koala have now been identified at sites like Yanchep, Margaret River and the Roe Plain near Madura, proving that these koalas once occupied a far broader range than previously recognised.
