A newly identified branch of the marsupial family tree is adding a surprising twist to the history of Australia's most distinctive mammals. The finding suggests that their evolution was more complicated, and more mysterious, than scientists previously understood.
Marsupials first reached Australia more than 55 million years ago. Since then, they have spread into an astonishing range of habitats and lifestyles. Today, they include about 160 species, from High Country animals (thumb-sized possums that sleep through the winter), to desert specialists in the Red Center, including tiny moles with pink fur and no eyes that spend their lives underground.
Yet despite their success, scientists still do not fully understand how marsupials diversified across Australia. Major gaps in the fossil record have left long stretches of their early history almost invisible.
Now, in a new paper published in the Journal of Paleontology, researchers from UNSW report three newly identified species that may belong to an ancient and previously unknown order of marsupials. The discovery offers a rare look at some of the earliest stages of marsupial evolution on the continent.
"Not only is it a new order, it could also be the most ancient lineage of all Australian marsupials," says UNSW paleontologist Dr. Tim Churchill.
