Fauna of New Guinea - Origin

Origin

New Guinea is a large island located north of Australia, and south-east of Asia. It is part of the Australian Plate, known as Sahul, and once formed part of the super-continent Gondwana. The origin of most New Guinea fauna is closely linked to Australia. Gondwana began to break up 140 million years ago, and Sahul separated from Antarctica 50 million years ago. As it drifted north, New Guinea moved into the tropics.

Throughout New Guinea's geological history there have been many land connections with Australia. These have occurred during glaciations in various ice ages. Four occurred during the Pleistocene; the last of which was severed 10,000 years ago. At this time, a number species existed on both land masses, and many plants and animals thus crossed from Australia to New Guinea and vice versa. Many later became isolated as the connection ended, then further evolving to the new environment and becoming distinct species.

However, this Australia-New Guinea mixing occurred among a relatively few faunal groups; some New Guinea species have an Asian origin. As New Guinea drifted north, it collided with the Pacific Plate as well as a number of oceanic islands. Although no land connection with Asia was ever formed (see Wallace line), the proximity between the landmasses, via the many small islands of the Indonesian archipelago, allowed some Asian species to migrate to New Guinea. This has resulted in a unique mixture of Australian and Asian species, seen nowhere else in the world. A large percentage of New Guinea's species are endemic to the island.