Australia lost nearly 90 per cent of its giant land animals during the Late Pleistocene, and piecing together their family tree has been hampered by the poor survival of ancient DNA in warm climates. A University of Manchester-led international team headed by Dr Michael Buckley turned instead to collagen fingerprinting, a mass spectrometry technique that can read protein signatures in fossils more than 100,000 years old, well beyond the practical limit of DNA methods.
Analysing 51 fossilised marsupial bones from caves and swamps in Tasmania, the team built a molecular phylogeny of Australia's extinct megafauna. The standout result, published in Proceedings of the Royal Society B, is that the koala and the extinct marsupial lion Thylacoleo shared a common ancestor about 25 to 35 million years ago, a closer relationship than previously recognised. The analysis also confirmed the giant herbivores Zygomaturus trilobus and Palorchestes azael as members of Vombatiformes, the wombat and koala group.
The method's real promise lies in what comes next. Because collagen fingerprinting can identify even tiny, otherwise anonymous bone fragments at scale, it could refine extinction timelines and establish how long megafauna overlapped with the first humans in Australia. That evidence bears directly on the long-running and still unresolved debate over whether climate change or human hunting drove the continent's giants to extinction.