Fauna is all of the animal life present in a particular region or time.
The corresponding term for plants is flora. Flora, fauna are collectively referred to as biota. Zoologists and paleontologists use fauna to refer to a typical collection of animals found in a specific time or place, e.g. the "Sonoran Desert fauna" or the "Burgess Shale fauna". Paleontologists sometimes refer to a sequence of faunal stages, which is a series of rocks all containing similar fossils.
Of the estimated 200,000 animal species in Australia, about 96% are invertebrates.