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
Geography of Papua New Guinea divides the island of New Guinea. Across the 820 km (509 mi) border, the western half of New Guinea is officially known as Papua province, governed by Indonesia. Papua New Guinea's border with Indonesia is not straight; the border loops slightly to the west in the south-central part of New Guinea. Papua New Guinea's Western Province contains that loop. There are maritime borders with Australia to the south and Solomon Islands to the southeast. Papua New Guinea has a total area of 462 840 km², of which 452 860 km² is land and 9 980 km² is water. Its coastline