The fauna of New Guinea comprises a large number of species of mammals, reptiles, birds, fish, invertebrates and amphibians.
As the world's largest and highest tropical island, New Guinea occupies less than 0.5% of world's land surface, yet supports a high percentage of global biodiversity. Approximately 4,624 vertebrate species inhabit the island of New Guinea and its surrounding waters, which constitutes about 8% of the recognized world vertebrates. This ranges from an estimated 4% of the world's lizards and mammals, to about 10% of the world's fish species.
The numbers of global and New Guinea invertebrate species are poorly known, and thus an accurate comparison is difficult. Butterflies are the best known invertebrate group, and are represented in New Guinea by about 735 species, which is about 4.2% of the world total of 17,500 species.
Nevertheless, despite the rich biodiversity, New Guinea's megafauna diversity is quite low since the Pleistocene extinction event, especially when it comes to apex predators. For example, there are only three terrestrial animals at the top of the food chain. Of the three, two are obligate carnivores, the crocodile monitor and the New Guinea singing dog, whilst one, the cassowary, is actually a frugivore but predatory opportunistically and seasonally. In the air, the only endemic apex predator is the New Guinea harpy eagle, whilst in the riverine systems, there are only two, the saltwater crocodile and the smaller New Guinea crocodile.
Origin History Papua New Guinea is a large island located north of Australia, and south-east of Asia. It is part of the Australian Plate, known as Sahul, and once formed part of the supercontinent Gondwana. The origin of most New Guinea fauna is closely linked to Australia. Gondwana began to break up 140 million years ago, and Sahul separated from Antarctica 50 million years ago. As it drifted north, New Guinea moved into the tropics.
Throughout Papua New Guinea's geological history there have been many land connections with Australia. These have occurred during glaciations in various ice ages. Four occurred during the Pleistocene, the last of which was severed 10,000 years ago. At this time, a number of species existed on both land masses, and many plants and animals thus crossed from Australia to Papua New Guinea and vice versa. Many later became isolated as the connection ended, then further adapted to the new environment and became distinct species.
However, this Australia–Papua New Guinea mixing occurred among a relatively few faunal groups; some Papua New Guinea species have an Asian origin. As Papua New Guinea drifted north, it collided with the Pacific Plate as well as a number of oceanic islands. Although no land connection with Asia was ever formed (see Wallace line), the proximity between the land masses, via the many small islands of the Indonesian archipelago, allowed some Asian species to migrate to Papua New Guinea. This has resulted in a unique mixture of Australian and Asian species, seen nowhere else in the world. A large percentage of Papua New Guinea's species are endemic to the island.
History of study Influential evolutionary biologist Ernst Mayr came to New Guinea (Papua New Guinea ) in 1928 to make collections for the American Museum of Natural History and banker and naturalist Walter Rothschild. Mayr collected several thousand bird skins (he named 26 new bird species during his lifetime) and, in the process, also named 38 new orchid species. He determined that New Guinea's rarest birds-of-paradise were, in fact, hybrid species. During his stay in New Guinea, he was invited to accompany the Whitney South Seas Expedition to the Solomon Islands. Mayr's experience of the fauna of New Guinea informed many of his conclusions about evolution for the rest of his life.Diamond, Jared. 2005. Obituary: Ernst Mayr (1904−2005). Nature 433:700-701.
Mammals
The mammal fauna of New Guinea is composed of all extant subclasses of mammal: the monotremes, placentals and marsupials. New Guinea contains the largest number of monotreme species of any land mass, with only one species absent: the platypus (Ornithorhynchus anatinus). The marsupial fauna of New Guinea is diverse, consisting of the three orders: Dasyuromorphia, Peramelemorphia and Diprotodontia.
The native placental mammals are solely represented by the rodents and bats. There are approximately the same number of placental species as marsupials and monotremes.
Monotremes and marsupials New Guinea's monotremes are restricted to the family Tachyglossidae, also known as echidnas. There are four species of echidnas in two genera: the short-beaked echidna (Tachyglossus aculeatus), the eastern long-beaked echidna (Zaglossus bartoni), the western long-beaked echidna (Zaglossus bruijni) and Sir David's long-beaked echidna (Zaglossus attenboroughi). No living Zaglossus have been seen in Australia, in recent years, and this genus may now be endemic to New Guinea, although a specimen in the natural history museum was collected from the Kimberley region in the early 20th century Helgen, K. M., Miguez R. P., Kohen J. L. and Helgen L. E. 2012. Twentieth Century occurrence of the long-beaked echidna Zaglossus bruijni in the Kimberley region of Australia. ZooKeys 255:103–132 and fossils have been found in Australia.
The native mammal fauna of New Guinea lacks large predators. The carnivorous marsupials, Dasyuromorphia, of New Guinea are all small in comparison to Australian species, and most are insectivorous. The largest is the bronze quoll (Dasyurus spartacus), a rare quoll, first discovered in southern New Guinea in 1979. It reaches a snout to vent length of 36 centimetres (14.2 in). Fossils of larger marsupials have been found, including the carnivorous thylacine (Thylacinus sp.), however evidence of carnivorous megafauna, such as the marsupial lion (Thylacoleo), has not been found.
The kangaroos, Macropodidae, of New Guinea are highly varied in their ecology and behaviour. Those closely related to the Australian kangaroos, such as the agile wallaby (Macropus agilis), inhabit the open grasslands of New Guinea. However, the tree-kangaroos, which are mostly endemic to New Guinea, are different in appearance and behaviour. As suggested by their name, they are arboreal. They have long, thick tails which enable them to balance in trees, and large, strong forearms for gripping to trees. Two species of tree kangaroos are also found in Australia. They are believed to have migrated from New Guinea during the Pleistocene.
The cuscus, family Phalangeridae, are a family of marsupials closely related to the possums of Australia. The cuscus have evolved in New Guinea, and are found throughout the island. Most species are dark brown or black, however two species, the common spotted cuscus (Spilocuscus maculatus) and black spotted cuscus (Spilocuscus rufoniger), are black, orange and yellow.
Many small, herbivorous possum species are native to New Guinea. These include the families: Acrobatidae, Burramyidae, Petauridae and Pseudocheiridae. Krefft's glider (Petaurus notatus) is one of only two New Guinea possums that are able to glide. It has large flaps of skin between its legs, which it spreads whilst in the air. Three sub-species are found in New Guinea, and they inhabit the entire island.
Placental mammals
The rodents are solely represented by the family Muridae, and within this family, 29 genera are native to New Guinea. They are believed to have migrated to New Guinea during two periods. The first group, called the old endemics, form part of an ancient clade including other old endemics from Australia and the Philippines and likely migrated to New Guinea during the Late Miocene or Early Pliocene. The second group includes a number of species of the genus Rattus. These are believed to have moved to New Guinea later. Most New Guinea species form a monophyletic group with some Moluccan species, which is most closely related to the Australian group (one species of which also occurs on New Guinea) and to the R. xanthurus group of Sulawesi.Musser, G. G. and M. D. Carleton. 2005. Superfamily Muroidea. pp. 894–1531 in Mammal Species of the World a Taxonomic and Geographic Reference. D. E. Wilson and D. M. Reeder eds. Johns Hopkins University Press, Baltimore.Helgen, K.M. 2005. The amphibious murines of New Guinea (Rodentia, Muridae): the generic status of Baiyankamys and description of a new species of Hydromys. Zootaxa 913:1–20.Rowe et al., 2008, Mol. Phyl. Evol. 47:84–101
The old endemics have undergone an adaptive radiation, which produced such distinctive forms as the small, shrew-like Pseudohydromys, the amphibious Hydromys, tree mice of the genus Chiruromys, and several genera of giant rats, of which Mallomys is the largest. This genus contains the largest rat found in New Guinea, the grey black-eared giant rat (Mallomys aroaensis); males can reach a length of 41 centimetres (16.1 in) from snout to vent.
The bats of New Guinea are a very diverse group, comprising six families, and 29 genera. The six families are: Pteropodidae, Emballonuridae, Hipposideridae, Rhinolophidae, Vespertilionidae and Molossidae. Bats migrated to New Guinea on many occasions, with many species being shared with Australia, the Sunda Islands and even mainland Asia. The megabats, or Megachiropterans, of New Guinea are highly adapted, and many are endemic to New Guinea and surrounding islands. While most megabats are herbivorous, and eat fruit, nectar and flowers, some species within New Guinea have adapted to also eat insects whilst in flight; an ecological niche usually filled by microbats. Some species also forage on the ground, an adaptation not seen in areas with large predators.
The microbats show much less endemism than the megabats. Only one genus and a few species are endemic to New Guinea and surrounding islands; this suggests a much later migration to New Guinea.
The colonisation of New Guinea by humans (Homo sapiens) occurred at least 40,000 years ago. Since their original colonisation, many mammals have been introduced, both by accident and on purpose. The wild boar (Sus scrofa) was introduced to New Guinea at least 6,000 years ago, though may have been introduced 12,000 years ago. It is abundant throughout the island, and more common in areas where humans grow sweet potato as their primary food source. The wild boar is a large forager, and disturbs the forest floor whilst looking for food. This disturbance may have an effect on the native flora and fauna.
The domestic dog (Canis familiaris) was introduced to New Guinea about 2,000 years ago. There is also an endemic wild dog, the New Guinea singing dog, Canis lupus hallstromi, that is closely related to the Australian dingo. It arrived on the island at least 6,000 years ago. Its common name comes from the way these dogs harmonize during chorus howls. The New Guinea singing dogs live in the remote mountains, above human habitation level, and whilst cassowaries still remain the island's largest opportunistic terrestrial predator by technicality, the singing dogs are New Guinea's largest obligate full-time land predator ecosystem-wise.Koler-Matznick et al., 2003, 2007
Many murid species have been introduced to New Guinea. These include: the Polynesian rat (Rattus exulans), the Himalayan field rat (Rattus nitidus), the black rat (Rattus rattus), the ricefield rat (Rattus argentiventer), the brown rat (Rattus norvegicus) and the house mouse (Mus musculus). Most of these have not caused much damage, and most have only established in human settlements. R. nitidus and R. argentiventer have very limited distributions on the island. The house mouse is the most widespread of the introduced murids, and is found in settlements and grassland. It is the only introduced murid to reach the central region of Telefomin.