and though possessed of fur and suckling their young, they lay eggs and have many
other characteristics in common with reptiles. The oldest fossil found in Australia of a
Gondwanan species is the opalized jawbone of a monotreme or platypus-type creature
dated from 110 million years ago and found at Lightning Ridge in New South Wales.
Australia’s unique marsupial fauna evolved to cope with drastically altered climate
and increasing environmental stress. The open forest kangaroos of today may have
evolved from a lineage that began with pygmy possums living in rainforest trees.
These tiny ancestors probably gave rise to the many and diverse marsupials that now
populate the continent, the kangaroos, the wallabies, the wombats, the bandicoots,
the possums and the koalas, which have all spread to fill almost every available
environmental niche and make the continent their own dominion.
In 1894 Robert Broom, a Scottish doctor, discovered some fossils in the Wombeyan
Caves in New South Wales which he believed were two new species of marsupials,
probably possums that lived 15–20 million years ago. The tiny marsupial he named
Burramys parvus excited much scientific interest because, although it seemed to be
possum, its jaw contained high-grooved cheek teeth regarded as characteristic of
kangaroos. In 1966, a Burramys, now known as a mountain pygmy possum, was
found in a ski hut at Mount Hotham in Victoria. Possums live in trees but the mountain
pygmy possum lives on the ground in the boulder fields on the upper slopes of the
high mountains, hibernating there over the winter months. A long-thought-extinct
Platypus, John Lewin, 1808, State Library of NSW18 Where Australia Collides with Asiahttp://www.ebook3000.com