Aspects of the results of studies of the fossil-rich Cainozoic deposits of Riversleigh, northwestern Queensland, are reviewed. A summary of five selected Riversleigh faunas representing the primary periods of the region's Cainozoic history is provided. Faunal and environmental changes over the last 25 000 000 years in the Riversleigh region are identified and changes in Australia's rain forest mammal communities over the same period are discussed. Evidence for the origin of Australia's modern mammal groups from ancestors now known to have lived in the Tertiary rainforests of northern Australia is reviewed. The geological record for Riversleigh's more than 100 local faunas is considered. At least three primary intervals of Oligo-Miocene deposition, one of Pliocene and many of Pleistocene and Holocene deposition are identified. An appendix is provided in which the principal faunal assemblages from Riversleigh are allocated to these depositional intervals. The evidence for correlating Riversleigh local faunas with faunal assemblages in the rest of Australia and the world is reviewed. Oligo-Miocene, Pliocene and Pleistocene marsupial and monotreme fossils correlate Riversleigh's local faunas with others from central and eastern Australia; bats correlate them with faunal assemblages in Europe; rodents correlate them with Pliocene assemblages in eastern Australia.

Around 88 large vertebrate taxa disappeared from Sahul sometime during the Pleistocene, with the majority of losses (54 taxa) clearly taking place within the last 400,000 years. The largest was the 2.8-ton browsingDiprotodon optatum, whereas the ∼100- to 130-kg marsupial lion,Thylacoleo carnifex, the world’s most specialized mammalian carnivore, andVaranus priscus, the largest lizard known, were formidable predators. Explanations for these extinctions have centered on climatic change or human activities. Here, we review the evidence and arguments for both. Human involvement in the disappearance of some species remains possible but unproven. Mounting evidence points to the loss of most species before the peopling of Sahul (circa 50–45 ka) and a significant role for climate change in the disappearance of the continent’s megafauna.