Phylogeographic patterns in reptiles on the New England Tablelands at the south-western boundary of the McPherson Macleay Overlap

Aim To investigate the impact of climatic oscillations and recognized biogeographic barriers on the evolutionary history of the garden skink (Lampropholis guichenoti), a common and widespread vertebrate in south‐eastern Australia. Location South‐eastern Australia. Methods Sequence data were obtained from the ND4 mitochondrial gene for 123 individuals from 64 populations across the entire distribution of the garden skink. A range of phylogenetic (maximum likelihood, Bayesian) and phylogeographic analyses (genetic diversity, Tajima’s D, ΦST, mismatch distribution) were conducted to examine the evolutionary history and diversification of the garden skink. Results A deep phylogeographic break (c. 14%), estimated to have occurred in the mid–late Miocene, was found between ‘northern’ and ‘southern’ populations across the Hunter Valley in northern New South Wales. Divergences among the geographically structured clades within the ‘northern’ (five clades) and ‘southern’ (seven clades) lineages occurred during the Pliocene, with the location of the major breaks corresponding to the recognized biogeographic barriers in south‐eastern Australia. Main conclusions Climatic fluctuations and the presence of several elevational and habitat barriers in south‐eastern Australia appear to be responsible for the diversification of the garden skink over the last 10 Myr. Further molecular and morphological work will be required to determine whether the two genetic lineages represent distinct species.

Section: Discussionmentioning

confidence: 72%

Biogeographic barriers in south-eastern Australia drive phylogeographic divergence in the garden skink, Lampropholis guichenoti

Chapple

Thompson

2011

“…Species that have more restricted distributions within the major regions also show similar patterns of genetic structure, e.g. reptiles on the central coast (Colgan et al. , 2009).…”

Section: Resultsmentioning

confidence: 99%

Decline of a biome: evolution, contraction, fragmentation, extinction and invasion of the Australian mesic zone biota

Byrne¹,

Steane²,

Joseph³

et al. 2011

366

351

Aim The mesic biome, encompassing both rain forest and open sclerophyllous forests, is central to understanding the evolution of Australia's terrestrial biota and has long been considered the ancestral biome of the continent. Our aims are to review and refine key hypotheses derived from palaeoclimatic data and the fossil record that are critical to understanding the evolution of the Australian mesic biota. We examine predictions arising from these hypotheses using available molecular phylogenetic and phylogeographical data. In doing so, we increase understanding of the mesic biota and highlight data deficiencies and fruitful areas for future research.Location The mesic biome of Australia, along the eastern coast of Australia, and in the south-east and south-west, including its rain forest and sclerophyllous, often eucalypt-dominated, habitats.Methods We derived five hypotheses based on palaeoclimatic and fossil data regarding the evolution of the Australian mesic biota, particularly as it relates to the mesic biome. We evaluated predictions formulated from these hypotheses using suitable molecular phylogenies of terrestrial plants and animals and freshwater invertebrates.Results There was support for the ancestral position of mesic habitat in most clades, with support for rain forest habitat ancestry in some groups, while evidence of ancestry in mesic sclerophyllous habitats was also demonstrated for some plants and herpetofauna. Contraction of mesic habitats has led to extinction of numerous lineages in many clades and this is particularly evident in the rain forest component. Species richness was generally higher in sclerophyllous clades than in rain forest clades, probably due to higher rates of net speciation in the former and extinction in the latter. Although extinction has been prominent in rain forest communities, tropical rain forests appear to have experienced extensive immigration from northern neighbours. Pleistocene climatic oscillations have left genetic signatures at multiple levels of divergence and with complex geographical structuring, even in areas with low topographical relief and few obvious geographical barriers.Main conclusions Our review confirms long-held views of the ancestral position of the Australian mesic biome but also reveals new insights into the complexity of the processes of contraction, fragmentation, extinction and invasion during the evolution of this biome.

“…The Brush‐tailed rock‐wallaby ( Petrogale penicillata ) and the Hastings River mouse ( Pseudomys oralis ) also appear to have distinct lineages across this region (Jerry et al ., ; Rowe et al ., ; Hazlitt et al ., ). Our estimates of early Pleistocene divergence is older than that observed in Petrogale penicillata (Hazlitt et al ., ) and Pseudomys oralis (Rowe et al ., ) but similar in timing to divergences in some reptiles across this region (Colgan et al ., ).…”

Section: Discussionmentioning

confidence: 97%

Evolutionary and contemporary responses to habitat fragmentation detected in a mesic zone marsupial, the long‐nosed potoroo (Potorous tridactylus) in south‐eastern Australia

Frankham

Handasyde

Eldridge

2015

Aim Outside of Australia's Wet Tropics, studies of the biogeographical patterns of unglaciated Southern Hemisphere mesic environments are limited, and have primarily focused on herpetofauna. In this study mitochondrial DNA (mtDNA) and microsatellite (nuDNA) analyses were used to investigate the impact of biogeographical barriers on the evolutionary history of the widespread Australian marsupial Potorous tridactylus, as well as the effect of recent human‐mediated habitat fragmentation. Location Australia; Queensland, New South Wales, Victoria, and Tasmania. Methods Three hundred and fifty‐four individuals from 39 sites (representing 16 regional populations) across the species range were assessed for mtDNA Control Region and microsatellite (10 loci) variation. Genetic diversity, phylogeographical relationships and population structure were examined, as well as evidence for isolation by distance and past population expansion. Results Three highly divergent and reciprocally monophyletic mtDNA lineages were resolved (two mainland, one Tasmanian). A deep phylogeographical break, not associated with any obvious biogeographical barrier, was present on the mainland. Within the northern mainland and Tasmanian lineages, sub‐structuring was coincident with the presence of physical barriers to gene flow. Fine‐scale structuring was also present, with regional populations highly differentiated. Main conclusions This study expands on previous studies of Australia's mesic biome. Major phylogeographical breaks were identified, that dated to the Miocene (within the mainland) and Pliocene (isolation of Tasmanian), and differed from those described for the region's herpetofauna in age or location. The major mainland break appears species specific within this topographically complex region of Australia. Tasmanian populations were isolated from the mainland well before the most recent flooding of Bass Strait. Minor phylogenetic breaks within Tasmanian and northern NSW were associated with known biogeographical barriers. An absence of sub‐structuring within the southern mainland lineage suggests extensive historical connectivity. The presence of regional population structure suggests that post‐European settlement, local populations have become isolated and differentiated.