The New Guinea-Australia Nexus: Using molecular approaches to probe biogeographical relationships between Australian and New Guinean freshwater turtles

A project undertaken at The Institute of Applied Ecology, University of Canberra, and supervised by A Georges

They total 30 species (more when we consider that some are species complexes), achieve their highest diversity in the lowlands of New Guinea, have populations or closely related species in both New Guinea and northern Australia, and show the classic trend of declining diversity with increasing latitude.

Add to this the recurrent pattern of interconnection and isolation of these land masses, injecting vicariance into the equation, and we have a unique natural backdrop to study the biogeographic drivers of evolution and speciation in our region.

This project will yield greater understanding of the freshwater turtle fauna of Australia and New Guinea, the diversity of forms, the way this biodiversity is distributed, and the contemporary and historical drivers of diversification. The project will specifically address the role of the tropics both as a repository of global biodiversity (even for a group of clear southern continental origin), and as the cradle of biodiversity, with tropical New Guinea providing fodder for diversification of freshwater turtles in Australia.

We will resolve species complexes of Elseya and, should some of the new species turn out to be threatened, will bring them to the attention of formal processes established nationally and internationally for their protection. We will clarify the role of the history of interconnection between Australia and New Guinea on diversification of the Australian freshwater turtle fauna, knowledge of benefit to science in both Australia and PNG. In particular, understanding the evolutionary impact of the historical interconnections between the two land masses is essential for understanding the natural history of the Australian fauna.

The project will also yield improved capacity for biological science within PNG through both the generation of knowledge relevant to the management of the biota and its utilisation, and through the engagement of NGO officers and local communities in the work and in publications. This will build upon excellent linkages with PNG nationals and organisations during prior studies in the Transfly and Kikori.

The project will contribute to a solid foundation for future study of concordant patterns of genetic substructuring across disparate taxonomic groups in freshwaters, as a basis for defining natural freshwater bioregions. Development of molecular markers in this project are also will be useful in monitoring wildlife trade, a serious issue for New Guinea and adjacent southeast Asia.