Differing impact of a major biogeographic barrier on genetic structure in two large kangaroos from the monsoon tropics of Northern Australia
Article first published online: 28 JAN 2014
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Ecology and Evolution
Volume 4, Issue 5, pages 554–567, March 2014
How to Cite
Ecology and Evolution 2014; 4(5):554–567
- Issue published online: 4 MAR 2014
- Article first published online: 28 JAN 2014
- Manuscript Accepted: 5 DEC 2013
- Manuscript Revised: 4 DEC 2013
- Manuscript Received: 30 OCT 2013
- Australia and Pacific Science Foundation
- Tropical Savannas Cooperative Research Centre
- WV Scott Foundation
- Australian Museum
- Macropus antilopinus ;
- Macropus robustus ;
- mitochondrial DNA;
- Northern Australia;
- tropical savanna;
Tropical savannas cover 20–30% of the world's land surface and exhibit high levels of regional endemism, but the evolutionary histories of their biota remain poorly studied. The most extensive and unmodified tropical savannas occur in Northern Australia, and recent studies suggest this region supports high levels of previously undetected genetic diversity. To examine the importance of barriers to gene flow and the environmental history of Northern Australia in influencing patterns of diversity, we investigated the phylogeography of two closely related, large, vagile macropodid marsupials, the antilopine wallaroo (Macropus antilopinus; n = 78), and the common wallaroo (Macropus robustus; n = 21). Both species are widespread across the tropical savannas of Australia except across the Carpentarian Barrier (CB) where there is a break in the distribution of M. antilopinus. We determined sequence variation in the hypervariable Domain I of the mitochondrial DNA control region and genotyped individuals at 12 polymorphic microsatellite loci to assess the historical and contemporary influence of the CB on these species. Surprisingly, we detected only limited differentiation between the disjunct Northern Territory and Queensland M. antilopinus populations. In contrast, the continuously distributed M. robustus was highly divergent across the CB. Although unexpected, these contrasting responses appear related to minor differences in species biology. Our results suggest that vicariance may not explain well the phylogeographic patterns in Australia's dynamic monsoonal environments. This is because Quaternary environmental changes in this region have been complex, and diverse individual species’ biologies have resulted in less predictable and idiosyncratic responses.