It is rare these days for a new species of possum to be discovered in Australia. The last recorded discovery was of the Daintree River Ringtail Possum, Pseudochirulus cinereus, in 1945.
However, Dr David Lindemayer, a regular associate of the Australian Museum, and colleagues from the Australian National University recently discovered that the well known Mountain Brushtail Possum, Trichosurus caninus, was in fact not one species, but two.
The Mountain Brushtail Possum occurs in the wet sclerophyll and sub-tropical forests from Victoria to central Queensland, and for many years has been the subject of detailed ecological studies by Dr Lindenmayer. The studies showed distinct differences in external body measurements between northern and southern populations of Mountain Brushtail Possum, which led the team to investigate further by extracting DNA from blood samples in order to examine genetic differences between the populations.
The results indicated that the northern Mountain Brushtail Possum from New South Wales and Queensland was indeed a different species from the southern Mountain Brushtail Possum found in Victoria.
As a result, the existing species, Trichosurus caninus, was renamed the Short-eared Possum, and the southern population was identified as a new species. The new southern species, Trichosurus cunninghamii, retains the common name Mountain Brushtail Possum.
The type specimens of the Mountain Brushtail Possum now reside in the Australian Museum mammal collection.