Land movements and animal distributions in east Wallacea (eastern Indonesia, Papua New Guinea and Melanesia)

Abstract

Four generalized tracks are identified in eastern Indonesia-Papua New Guinea-Melanesia on the basis of animal distribution patterns. Two of these tracks are linked to a Melanesian rift system that developed to the north and east of Australian Gondwana during the late Cretaceous and early Tertiary. The other two tracks are related to Cretaceous rift systems formed off the west/northwest coast of Australian Gondwana. The histories of these rift systems are discussed, their present positions are tentatively located in terms of modern geography, and animal distributional patterns related to their formation and subsequent histories. Wallace's Line is reinterpreted in terms of a boundary between Asian and Australian derived terranes and microcontinents. Distributional patterns that reflect this discontinuity show incongruity with the geological pattern in Sulawesi and the Banda arcs because of the merging of Asian and Australian faunas as a direct result of Australia's collision with Asia. Indo-Australian distributions are interpreted in terms of the distribution of ancestral populations prior to the mid-Mesozoic breakup of the relevant sectors of Gondwana.