Papua New Guinea notable feature in common for the two landmasses is the existence of several species of marsupial mammals, including some kangaroos and possums, which are not found elsewhere. Papua New Guinea is a megadiverse country. Many of the other islands within PNG territory, including New Britain, New Ireland, Bougainville, the Admiralty Islands, the Trobriand Islands, and the Louisiade Archipelago, were never linked to New Guinea by land bridges. As a consequence, they have their own flora and fauna; in particular, they lack many of the land mammals and flightless birds that are common to New Guinea and Australia. Australia and New
Fauna of New Guinea four species of echidnas in two genera: the short-beaked echidna ("Tachyglossus aculeatus"), the eastern long-beaked echidna ("Zaglossus bartoni"), the western long-beaked echidna ("Zaglossus bruijni") and Sir David's long-beaked echidna ("Zaglossus attenboroughi"). No living "Zaglossus" have been seen in Australia, in recent years, and this genus may now be endemic to New Guinea, although a specimen in the natural history museum was collected from the Kimberley region in the early 20th century and fossils have been found in Australia. The native mammal fauna of New Guinea lacks large predators. The carnivorous marsupials, Dasyuromorphia, of New Guinea are all small in comparison