The brushtail possums are the members of the genus Trichosurus in the Phalangeridae, a family of marsupials. They are native to Australia (including Tasmania) and some small nearby islands. Unique among marsupials, they have shifted the hypaxial muscles from the epipubic to the pelvis, much like in placental muscles, meaning that their breathing cycle is more similar to the latter than to that of other non-eutherian mammals. In general, they are more terrestrially oriented than other possums, and in some ways might parallel primates.

The genus contains these species:

• Northern brushtail possum, T. arnhemensis
• Short-eared possum, T. caninus
• Mountain brushtail possum, T. cunninghami
• Coppery brushtail possum, T. johnstonii
• Common brushtail possum, T. vulpecula

John Gould (14 September 1804 – 3 February 1881) was an English ornithologist. He published a number of monographs on birds, illustrated by plates produced by his wife, Elizabeth Gould, and several other artists, including Edward Lear, Henry Constantine Richter, Joseph Wolf and William Matthew Hart. He has been considered the father of bird study in Australia and the Gould League in Australia is named after him. His identification of the birds now nicknamed "Darwin's finches" played a role in the inception of Darwin's theory of evolution by natural selection. Gould's work is referenced in Charles Darwin's book, On the Origin of Species.