A phylogenetic reappraisal of the birdwing genus Ornithoptera (Lepidoptera: Papilionidae: Troidini) and a new theory of its evolution in relation to Gondwanan vicariance biogeography

The troidine papilionid genus Ornithoptera is shown to be distinct from Troides In order to reappraise the interrelationships of the member species of Ornithoptera, and to test the resultant theory of their evolution against biogeographical data, the genus is revised using Hennigian cladistic methodology through computer analysis. The input data for this was drawn equally from immature stages and adult characters. A single cladogram hypothesising the likely phylogeny of the Ornithoptera species was generated. With minor weighting of a single important adult character, a further two cladograms were generated, one of which is similar to hypotheses proposed by previous workers. Based on these findings, and on ecological data, notably larval foodplant relations with Aristolochiaceae, as well as present-day biogeographical data, a new theory of the origin and evolution of Ornithoptera is presented which fits well Gondwanan vicariance events ascertained by geological studies: essentially that Ornithoptera evolved on northward drifting Australia, allopatrically from Troides on the Indian plate, and therefore that Ornithoptera did not reach the Australian Subregion via Troides-like ancestors in Southeast Asia as has been previously postulated. As ‘living fossils’ representative of an ancient, Gondwanaland-derived, austral faunal element, the Ornithoptera should be regarded even more highly in terms of their ‘conservation value’.