CANBERRA - Flesh-eating kangaroos, hippopotamus-sized wombats and flightless emu-like ducks weighing 1.5 tonnes freely roamed the vast Australian island continent about 100,000 years ago.
Living off eucalypt forests, grasslands and each other, these giant forebears of today's kangaroos and koalas co-existed for millions of years after the demise of the dinosaurs. But who or what destroyed the massive marsupials, horned turtles and monster ducks - the so-called megafauna which used to dominate ancient Australia - remains a mystery......
......If the dates are right, this questions earlier theories blaming the last ice age 21,000 years ago, or man hunting the animals to extinction after arriving about 60,000 years ago.
Smith says the new dates pointed to a third theory - the "slow burn" - in which the megafauna was gradually wiped out by man changing the landscape plus climate changes.
The first complete skulls of a bizarre "horned" kangaroo are the star finds in the cache of fossils newly unearthed from caves in the Nullarbor Plain, Australia.
The skull of a juvenile shows the ridges (arrowed) from which the horn-like protusions would have grown (Image: Western Australian Museum)
John Long at the Western Australian Museum in Perth and colleagues first excavated the site in 2002. They found an astonishing collection of megafauna fossils, including partial skull fragments of a horned kangaroo, and the first complete skeletons of the thylacoleo, a giant marsupial lion.
The 2003 dig uncovered two complete horned kangaroo skulls and their partial skeletons, as well as two more thylacoleo skeletons and fossils of three species that the team believes are new to science.
"The kangaroo really is bizarre. It doesn't look like any other living or fossil kangaroo yet discovered," Long told New Scientist. "The bony projections right above the eyes stick out laterally, and it has a strange bulbous snout."