It helps tie together a few enigmatic species that have been puzzling palaeontologists for several decades."The exact path that birthed Australia's marsupial diversity will likely never be known.But with global warming opening inaccessible parts of Antarctica and South America, Dr Archer says breakthroughs are imminent."Palaeontologists are quietly rubbing their hands together to get at new fossil deposits that have never been seen before It'll be under that ice," he said."We know there is a very big story here and we're just beginning to get the first inklings of just how big this story is."I think the only way forward now is for collaboration between Australian and South American palaeontologists to tackle this whole problem."