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Aim We tested whether the divergence of South American and Australian Lomatia was the result of the breakup of Gondwana, and assessed the date of divergence between Tasmania and mainland Australia, and across the Hunter River Valley. Location South America (Chile and Argentina) and eastern Australia (Tasmania, Victoria, New South Wales and Queensland). Methods We sequenced one chloroplast (psbA-trnH intergenic spacer) and two nuclear (PHYA and ITS) markers across all 12 species of Lomatia, five species of Telopea and Embothrium coccineum, and included sequences from Gen- Bank for the rest of the tribe Embothrieae. Species relationships were inferred using Bayesian and maximum likelihood analyses, then divergence times estimated using the random local clock in BEAST. Results The chronogram is congruent with geological events: SAm (SAm (SAm (Tas (NEQld (SEAus north of the Hunter + SEAus south of the Hunter))))). South American and Australian species of Lomatia diverged between 35 and 64 Ma. Tasmanian species of Lomatia diverged from mainland Australian taxa c. 32 Ma. Mainland Australian species of Lomatia are mostly not corroborated as monophyletic but show a divergence either side of the Hunter River Valley, dated at 17 Ma. Main conclusions The divergence date between South American Lomatia ferruginea and Australian species cannot exclude Gondwanan vicariance; however, divergences within South America occurred prior to separation of South America and Australia from Antarctica. Tasmanian species diverged from mainland Australia in the early Oligocene. Mainland Australian species of Lomatia are not resolved but form two clades representing populations north and south of the Hunter River Valley, confirming the Hunter River Valley as a significant barrier to gene flow for plants. We suggest that drying events that divided northern and southern floras at the Hunter River Valley occurred at the same time as those that divided eastern and western floras. [ABSTRACT FROM AUTHOR]

Aim Our aim was to implement a molecular dating analysis and assess divergence times among taxa of Winteraceae. This enabled us to test hypotheses of vicariance versus long-distance dispersal to explain intercontinental disjunctions in the family. Location Madagascar, Australia (including Lord Howe Island), New Zealand, New Caledonia and South America. Methods We sampled all Australian species and subspecies of Winteraceae. We also included the monotypic Takhtajania perrieri and at least two species of each genus from New Zealand, New Caledonia and South America. Three sets of sequences were combined into one data matrix, including two internal transcribed spacer ( ITS) data sets and a trnL-F data set. Both ITS data sets included all genera of Winteraceae, and the paralogous genes identified in Zygogynum s.l. in a previous study were sequenced and aligned in separate ITS data sets. A Bayesian molecular phylogenetic tree of extant Winteraceae was used as a backbone constraint in paup* to establish the placement of fossils. Bayesian analyses were performed using beast, implementing fossil priors to fit lognormal distributions, to test a maximum-parsimony phylogeny and assess divergence times. Results Interspecific relationships generally agreed with previous analyses. In particular, Bubbia comptonii was found to be sister to the rest of the Bubbia/ Zygogynum clade, but our analysis has uniquely found sister clades within this group: one from New Caledonia, and one from Australia including Lord Howe Island. The phylogeny yields an age of 91.2 Ma with a 95% confidence interval of 118-67 Ma for crown-group Winteraceae. Main conclusions The estimated age of Takhtajania is consistent with its origin in Madagascar as a result of Gondwanan vicariance - the only angiosperm for which this has been demonstrated with confidence. Differentiation of the rest of this ancient clade is a complicated story of vicariance as a result of the rifting, submergence and exhumation of continents and of long-distance dispersal and extinctions. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Aim The flowering plant family Proteaceae is putatively of Gondwanan age, with modern and fossil lineages found on all southern continents. Here we test whether the present distribution of Proteaceae can be explained by vicariance caused by the break-up of Gondwana. Location Africa, especially southern Africa, Australia, New Zealand, South America, New Caledonia, New Guinea, Southeast Asia, Sulawesi, Tasmania. Methods We obtained chloroplast DNA sequence data from the rbcL gene, the rbcL- atpB spacer, and the atpB gene from leaf samples of forty-five genera collected from the field and from living collections. We analysed these data using Bayesian phylogenetic and molecular dating methods, with five carefully selected fossil calibration points to obtain age estimates for the nodes within the family. Results Four of eight trans-continental disjunctions of sister groups within our sample of the Proteaceae post-date the break-up of Gondwana. These involve independent lineages, two with an Africa-Australia disjunction, one with an Africa–South America disjunction, and one with a New Zealand–Australasia disjunction. The date of the radiation of the bird-pollinated Embothriinae corresponds approximately to the hypothesized date of origin of nectar-feeding birds in Australia. Main conclusions The findings suggest that disjunct distributions in Proteaceae result from both Gondwanan vicariance and transoceanic dispersal. Our results imply that ancestors of some taxa dispersed across oceans rather than rafting with Gondwanan fragments as previously thought. This finding agrees with other studies of Gondwanan plants in dating the divergence of Australian, New Zealand and New Caledonian taxa in the Eocene, consistent with the existence of a shared, ancestral Eocene flora but contrary to a vicariance scenario based on accepted geological knowledge. [ABSTRACT FROM AUTHOR]