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
Prehistory of Australia by the first migrants to Australia, widely taken to be ancestors of the modern Aborigines. Migration took place during the closing stages of the Pleistocene, when sea levels were much lower than they are today. Repeated episodes of extended glaciation during the Pleistocene epoch resulted in decreases of sea levels by more than 100 metres in Australasia. People appear to have arrived by sea during a period of glaciation, when New Guinea and Tasmania were joined to the continent of Australia. The continental coastline extended much further out into the Timor Sea, and Australia and New Guinea formed a single