Fauna of New Guinea - Amphibians

Amphibians

The amphibians of New Guinea consist of a highly diverse group of species, with over 320 described species, and many species still to be described. The amphibians of New Guinea, like most Gondwanan continents, are restricted to those of the order Anura, known as frogs and toads. There are six families represented in New Guinea. Four of these: Myobatrachidae, Hylidae, Ranidae and Microhylidae are native. Two specimens of Rhacophoridae, a family well represented in Asia, were discovered in 1926. They were thought to be introduced by humans, and to have become extinct on the island. The other family, Bufonidae, is only represented by two species: the Cane Toad (Chaunus marinus) and the Common Asiatic Toad (Duttaphrynus melanostictus). The Cane Toad was introduced from Australia in 1937 to control hawk moth larvae, which were eating sweet potato crops; they have since become common in non-forested areas. The Common Asiatic Toad was accidentally introduced, and is very abundant in a small area in the north-west, and may be spreading further throughout the island.

Frogs from the family Myobatrachidae are highly diverse and widespread in Australia. However, only seven described species have established in New Guinea. In Australia, the largest diversiy is seen in the subtropical and semi-arid environments, with the greatest diversity in the tropics occurring in savannah. New Guinea, however, is mostly covered in dense rainforest. The most common Myobatrachid in New Guinea is the Wokan Cannibal Frog (Lechriodus melanopyga). It is a small ground-dwelling frog found throughout New Guinea. The Lechriodus genus, 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 has reached Australia. Nyctimystes are arboreal frogs, which lay their eggs in fast flowing streams, behind a rock to avoid it being flushed away. The tadpoles have modified mouths, which use suction to stick to rocks.

Ranidae, also known as true frogs, are the most widely distributed family of frogs on earth, however, they are not well represented in Australia or New Guinea. New Guinea and Australia have been absent of Ranids for most of their history, however since the continent's collision with Asia, species have begun to move across. The Ranids in New Guinea are only represented with one genus, Rana.

Although the origins of Microhylidae in New Guinea are very similar to the Ranids, there is much more diversity. The Microhylids are represented by twelve genera in New Guinea, four of which are endemic.