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 Papua and New Guinea "Strategically the northern islands (such as New Guinea) encompass Australia like fortresses. They are as necessary to Australia as water to a city." Article 22 of the Treaty of Versailles provided for the division of Germany and the Central Powers' imperial possessions among the victorious Allies of World War I and German New Guinea, the Bismarck Archipelago and Nauru were assigned to Australia as League of Nations Mandates: territories "formerly governed [by the Central Powers] and which are inhabited by peoples not yet able to stand by themselves under the strenuous conditions of the modern world". Shortly after the start