Paleontologists have identified a previously unknown species of koala that roamed Western Australia until roughly 30,000 years ago, expanding the diversity of these marsupials before human arrival.
The discovery comes from fossil remains that reveal at least two distinct koala species inhabited Australia when humans first reached the continent. One lineage survived to the present day. The other, documented through skeletal fragments, vanished as Western Australia transitioned to an arid climate during the late Pleistocene epoch.
Researchers analyzed dental and jaw structures from the extinct species, distinguishing it from Phascolarctos cinereus, the modern koala. The fossils show the ancient koala occupied different ecological niches than its surviving relative, likely adapted to the wetter conditions that characterized Western Australia before desertification accelerated around 30,000 years ago.
Climate shifts drove the extinction rather than human hunting, the evidence suggests. As rainfall decreased and vegetation changed, the specialized koala population could not adjust to the new landscape. The surviving koala species persisted in eastern and central Australian forests where moisture remained more stable.
This finding reflects a broader pattern of megafauna extinctions and species turnover across Australia during the Pleistocene. Many large animals disappeared around the same time, though scientists continue debating whether climate change, human predation, or both factors triggered these losses.
The research underscores how little we still understand about Australia's prehistoric mammal communities. Modern koalas represent just one branch of a more complex evolutionary tree. Understanding these lost lineages helps reconstruct ancient Australian ecosystems and provides perspective on how climate change reshapes wildlife distributions over millennia.
THE TAKEAWAY: Australia's koala diversity was greater before climate aridification eliminated a specialized Western Australian species 30,000 years ago.