Regional patterns of biodiversity in New Guinea animals

Aim To assess regional patterns of biodiversity levels in the New Guinea region by counting numbers of species of different groups in 1degrees grid squares. Location The New Guinea region. Methods Panbiogeographical analysis [Craw, R.C., Grehan, J.R. & Heads, M.J. (1999) Panbiogeography: tracking the history of life. Oxford University Press, New York]. Results The following taxa were analysed: three genera of cicadas (Homoptera), freshwater fishes, snakes, and the four terrestrial orders of mammals in the region - monotremes, marsupials, bats and rodents. A total of 622 species (and subspecies) was analysed and the different centres of diversity in the various groups of animals are related to the three main geological regions of the country: Australian craton, accreted terranes, and Cainozoic volcanic arcs. Main conclusions Freshwater fishes are most diverse in the lower Fly - Merauke region, on the southern, Australian craton portion of New Guinea. Marsupials are the only other group with a main massing on the craton (at the Kubor Mountains area). Snakes are most diverse in the trans-Fly region, like freshwater fishes, and also around Port Moresby. All the other groups have centres of diversity either on the craton margin or outboard of it on different accreted terranes of the New Guinea orogen. In the groups studied, only bats have a significant, albeit secondary, massing on the Bismarck Archipelago. Other terrestrial vertebrates with centres of diversity on the Bismarck Archipelago include the diverse frog genus Platymantis. The regions north and east of New Guinea (Bismarck Sea plate, Solomon Sea plate) are now occupied mainly by sea and volcanic island arcs, but biogeographers and geologists have suggested this as the site of earlier, more extensive land. The different centres of diversity in the different groups are suggested to derive from vicariant locations of early (Mesozoic - early Cainozoic) diversity rather than from different means of dispersal or other aspects of ecology.