Multiple biogeographical barriers identified across the monsoon tropics of northern Australia: phylogeographic analysis of the brachyotis group of rock‐wallabies

Abstract

The monsoon tropics of northern Australia are a globally significant biodiversity hotspot, but its phylogeography is poorly known. A major challenge for this region is to understand the biogeographical processes that have shaped the distribution and diversity of taxa, without detailed knowledge of past climatic and environmental fluctuations. Although molecular data have great potential to address these questions, only a few species have been examined phylogeographically. Here, we use the widely distributed and abundant short-eared rock-wallaby (Petrogale brachyotis; n = 101), together with the sympatric monjon (P. burbidgei; n = 11) and nabarlek (P. concinna; n = 1), to assess historical evolutionary and biogeographical processes in northern Australia. We sequenced ∼1000 bp of mitochondrial DNA (control region, ND2) and ∼3000 bp of nDNA (BRCA1, ω-globin and two anonymous loci) to investigate phylogeographic structuring and delineate the time-scale of diversification within the region. Our results indicate multiple barriers between the Top End (Northern Territory) and Kimberley (Western Australia), which have caused divergence throughout the Plio-Pleistocene. Eight geographically discrete and genetically distinct lineages within the brachyotis group were identified, five of which are separated by major river valleys (Ord, Victoria, Daly), arid lowlands and discontinuous sandstone ranges. It is likely that these barriers have similarly influenced genetic structure in other monsoonal biota.

A new species of Velvet Gecko (Oedura: Diplodactylidae) from the limestone ranges of the southern Kimberley, Western Australia

“…Finally, when the resources required for fieldwork in the Kimberley are available (especially for wet season work), researchers have until recently tended to focus on the more diverse and topographically complex mesic regions of the north-west Kimberley (Miles & Burbidge 1975;Burbidge & McKenzie 1978;Doughty et al 2012;Palmer et al 2013). Although the Kimberley is widely recognised as a centre of biological endemism (Cracraft 1991;Slatyer et al 2007;Bowman et al 2009;Powney et al 2010), a sense of how complex and varied patterns of intraregional diversity in this area are only just beginning to develop (Oliver et al 2012b(Oliver et al , 2014Potter et al 2012;Catullo et al 2014). Recent molecular work suggests that in addition to O. murrumanu sp.…”

Phylogeography of the antilopine wallaroo (Macropus antilopinus) across tropical northern Australia

“…2011; Potter et al. 2012). Many studies have highlighted the importance of the Carpentarian barrier in shaping species distribution and diversification (Cracraft 1986; Cardinal and Christidis 2000; Jennings and Edwards 2005; Lee and Edwards 2008; Kearns et al.…”

“…2012). The regional climate is characterized by dry winters and wet summers, which has a strong effect on the distribution of plant and animals species (Bowman et al.…”

“…2010), Daly River Drainage Barrier (Potter et al. 2012), and the Victoria River Drainage Barrier (Joseph and Omland 2009). Eldridge et al.…”

Biogeographic patterns on Kimberley islands, Western Australia

“…Potter et al (2012) recently identified a new potential biogeographic barrier in the central Kimberley -the East-West Kimberley Divide. Adolphus is the only island we sampled that is located on the eastern side of this barrier (see Eldridge et al 2011).…”