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 frog found throughout New Guinea. "Lechriodus" is the only myobatrachid genus with greater diversity in New Guinea than Australia. Excluding "Lechriodus", the rest of the myobatrachids are mostly restricted to savannah in the southern Fly and Digul River plains. Tree frogs, of the family Hylidae, have successfully inhabited New Guinea. They are the most diverse family of frogs in New Guinea with over 100 species, and many more to be described. There are two genera represented in New Guinea, "Litoria" and "Nyctimystes". "Litoria" are found throughout both Australia and New Guinea, however, only one of the 24 species of "Nyctimystes"