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Lamont et al. (2016) concluded that the Australian sclerophyllous genus Hakea (Proteaceae) arose 18 million years ago in the South West of Western Australia (SWA) and dispersed 18 times to eastern (EA) and central Australia (CA) only 12 million years ago (mid-Miocene). Their explanation of the biogeographic history of Hakea was based on the following: accepting a fully resolved molecular phylogenetic tree, although ∼40% of nodes had posterior probability values below 0.95; using all nodes including geographically paralogous nodes to determine ancestral area probabilities; and applying a strict clock to estimate clade divergence times. Our re-analyses of the same dataset using a relaxed clock model pushes the age of Hakea to 32.4 (21.8–43.7) million years ago relative to its nearest outgroups, and the age of the divergence of two major clades (A and B) to 24.7 (17.2–33.7) million years ago. Calibration based on a new finding of Late Cretaceous fossil Banksia pushes these dates to 48.0 (24.3–75.2) million years ago and 36.6 (18.5–55.4) million years ago respectively. We confirm that each of the two main clades includes lineages in SWA, CA and EA. At the basal node of Clade A, two eastern Australian species form the sister group to three SWA scrub–heath–Eremaean species. These two groups together are sister to a large, mostly unresolved clade of SWA, CA and EA taxa. Similarly, at the base of Clade B is a polytomy of lineages from the SWA, CA and EA, with no resolution of area relationships. There is no evidence of a centre of origin and diversification of the genus is older than the mid-Miocene, being at least Oligocene, and probably older, although calibration points for molecular dating are too far removed from the ingroup to provide any great confidence in the methodology. Consideration should be given to the possibility of vicariance of multiple, widespread ancestral lineages as an explanation for lineages now disjunct between EA and SWA.
Matt A. M. Renner, Margaret M. Heslewood, Mahwash Jamy, Simon D. F. Patzak, John J. Engel, David S. Glenny, Matt J. von Konrat, Alfons Schäfer-Verwimp, Jochen Heinrichs
On the basis of variation in molecular sequence data and morphology, three species are recognised within Dinckleria. The generitype D. pleurata is widespread in Tasmania and New Zealand and has outlier populations in Victoria, and in rainforests around the New South Wales–Queensland border. Dinckleria fruticella is endemic to New Zealand, records of this species from Tasmania and Queensland are based on misidentifications. The widespread Malesian species Plagiochila singularis is transferred to Dinckleria, and newly reported for Australia and Vanuatu. In Australia, this species is known by two collections, one from the Atherton Tableland the other from the Paluma Range. Dinckleria can be distinguished from other genera of Plagiochilaceae by the presence of papillae on leaf-cell surfaces in combination with monomorphic leafy shoots arising from a basal stolon, the stolons originating by ventral-intercalary branching, presence of cell surface wax, and the restriction of rhizoids to the ventral merophyte.
Three-taxon statement matrices can be analysed using the maximum-likelihood method. In the present paper, it is demonstrated that groups based solely on putative reversals are always recognisable after maximum-likelihood analysis of three-taxon statement matrices, even without a priori recoding of the putative reversals as new character states or fractional weighting of three-taxon statements. Parametric implementations of three-taxon statement analysis still require more investigation. However, it must be highlighted that a focus on the set of hypotheses, rather than on the ‘actual data’, is required.
The genus Banksieaephyllum, originally erected for cuticle-bearing fossil leaves of subtribe Banksiinae (Proteaceae subfamily Grevilleoideae, tribe Banksieae), is reassessed. Of the 18 described species, nine are accepted within Banksia, including Banksieaephyllum obovatum Cookson & Duigan, which is synonymised with B. laeve Cookson & Duigan on the basis of new cuticular preparations. Two other species are transferred to Banksieaefolia gen. nov., a genus erected for Banksieae of uncertain affinities, and which presently includes only fossils that probably belong to subtribe Musgraveinae. The seven other Banksieaephyllum species lack definitive characters of Proteaceae (i.e. brachyparacytic stomata and annular trichome bases) and do not have Banksieae-type cylindrical trichome bases. These species are, therefore, not accepted as Proteaceae and are transferred to Pseudobanksia gen. nov., together with another fossil Banksia-like leaf species, Phyllites yallournensis Cookson & Duigan. Lectotypes are chosen for Banksia fastigata H.Deane, Banksieaephyllum acuminatum Cookson & Duigan, Banksieaephyllum angustum Cookson & Duigan and Banksieaephyllum laeve Cookson & Duigan. Implications arising from the re-assessment of Banksieaephyllum include clarification of biome conservatism in Banksieae; Banksia has long had an association with relatively open, sclerophyllous vegetation, and Musgraveinae with rainforest. Pseudobanksia and Banksia share convergent traits, but in contrast to Banksia, Pseudobanksia failed to survive the drying climates and increased fire-frequencies of the Neogene.
The tribe Tigridieae (Iridoideae: Iridaceae) is a New World group with centres of diversity in Mexico and Andean South America. North America harbours 67 of the 172 species recognised within the tribe, 54 being endemic. Our aims were to identify areas of endemism of the North American Tigridieae using endemicity analysis (EA) and to infer their relationships using parsimony analysis of endemicity (PAE). A data matrix with 2769 geographical records of Tigridieae was analysed. The EA allowed to identify six consensus areas of endemism in Mexico. The PAE resulted in one cladogram with four clades and the following five biotic components: northern Mexico, western Mexico, central Mexico, southern Mexico and central–southern Mexico. The richness analysis of these areas of endemism indicated that the greatest concentration of species is located in central Mexico, with 14 species in one grid-cell. Grid-cells with 12 species each were identified in low western Mexico, high western Mexico, southern Mexico and central–southern Mexico. This last area is characterised by the greatest endemism, including nine species. The formation of the Transmexican Volcanic Belt seems to have been a key element to explain the diversification of North American Tigridieae.
Species-level relationships within the pantropical, largely rainforest genus Cryptocarya R.Br (Lauraceae) and allied groups have long been problematic. Here, we utilise nuclear RPB2 and plastid trnL–trnF sequence data to reconstruct the phylogenetic relationships among Australian Cryptocarya species. We relate our findings to the previous two disparate attempts to resolve species-level relationships on the basis of traditional taxonomic tools. Our results showed that an early diversification gave rise to two lineages present in Australia and globally. The loss of cataphylls (bract-like leaves in seedlings) seems to be a derived state only found in the larger of these two clades. Ruminate cotyledons is another potentially informative character; however, it is highly likely that this condition arose through convergent or parallel evolution. Little or no molecular variation was observed between many species, which suggests recent diversification. Furthermore, the close relationships between species from two geographically disjunct centres of rainforest diversity within Australia suggests that loss of between-region connectivity is recent. A global revision of the group, incorporating molecular analyses and seedling and fruit morphology, is needed to untangle the complex evolutionary relationships within this genus.
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