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
Territory of New Guinea the Territory of New Guinea but the Territory of Papua was protected to a large extent by its southern location and the near-impassable Owen Stanley Ranges to the north. The New Guinea campaign opened with the battles for New Britain and New Ireland in the Territory of New Guinea in 1942. Rabaul, the capital of the Territory was overwhelmed on 22–23 January and was established as a major Japanese base from whence they landed on mainland New Guinea and advanced towards Port Moresby and Australia. Having had their initial effort to capture Port Moresby by a seaborne invasion disrupted by