Phylogenetic placement and the timing of diversification in Australia’s endemic Vachellia (Caesalpinioideae, Mimosoid Clade, Fabaceae) species

2020 ◽  
Vol 33 (1) ◽  
pp. 103
Author(s):  
D. F. Comben ◽  
G. A. McCulloch ◽  
G. K. Brown ◽  
G. H. Walter
Keyword(s):  
Biological Control ◽  
Molecular Dating ◽  
Long Distance Dispersal ◽  
Monophyletic Clade ◽  
Long Distance ◽  
Australian Species ◽  
Phylogenetic Placement ◽  
Evolutionary Origins ◽  
Species Being ◽  
Relaxed Molecular Clock

The genus Vachellia Wight & Arn. has a pantropical distribution, with species being distributed through Africa, the Americas, Asia and Australia. The relationships among the lineages from Africa and America are well understood, but the phylogenetic placement and evolutionary origins of the Australian species of Vachellia are not known. We, therefore, sequenced four plastid genes from representatives of each of the nine Australian species of Vachellia, and used Bayesian inference to assess the phylogenetic placement of these lineages, and a relaxed molecular clock to assess the timing of diversification. The Australian species of Vachellia form a well-supported monophyletic clade, with molecular-dating analysis suggesting a single dispersal into Australia 6.5 million years ago (95% range 13.9–2.7 million years ago). Diversification of the Australian clade commenced more recently, c. 3.1 million years ago (95% range 9.2–1.2 million years ago), perhaps driven by the increased aridification of Australia at this time. The closest relatives to the Australian Vachellia were not from the Malesian bioregion, suggesting either a long-distance dispersal from Africa, or two separate migrations through Asia. These results not only improve our understanding of the biogeography of Vachellia species, but also have significant implications for the biological control of invasive Vachellia species in Australia.

scholarly journals Diversification history and hybridisation of Dacrydium (Podocarpaceae) in remote Oceania

2011 ◽  
Vol 59 (3) ◽  
pp. 262 ◽  
Author(s):  
Gunnar Keppel ◽  
Peter Prentis ◽  
Ed Biffin ◽  
Paul Hodgskiss ◽  
Susana Tuisese ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
New Caledonia ◽  
The Other ◽  
Evolutionary Relationships ◽  
Restricted Range ◽  
Long Distance Dispersal ◽  
Long Distance ◽  
Low Genetic Diversity ◽  
Cpdna Sequence ◽  
Relaxed Molecular Clock

We examined evolutionary relationships, hybridisation and genetic diversity in species of Dacrydium (Podocarpaceae) in Remote Oceania, where it is restricted to New Caledonia and Fiji. We used cpDNA sequence (trnL–trnF) data to construct a phylogeny and estimate taxon divergence by using a relaxed molecular clock approach. The phylogeny was verified using allozymes, which were also used to investigate genetic diversity of all species and the hybridisation dynamics of two endangered species, D. guillauminii and D. nidulum. Our results suggested that Dacrydium species in Remote Oceania form a monophyletic group that arose and diversified within the last 20 million years through long-distance dispersal and a range of speciation mechanisms. Whereas we detected no hybridisation between the Fijian species D. nausoriense and D. nidulum, we confirmed hybridisation between D. guillauminii and D. araucarioides in New Caledonia and determined introgression to be assymetric from the widespread D. araucarioides into the rare, restricted-range species D. guillauminii. In addition, D. guillauminii had lower genetic diversity than did the other species of Dacrydium studied, which had genetic diversity similar to that of other gymnosperms. Our results provided evidence for the recent and complex diversification of Dacrydium in Remote Oceania. In addition, low genetic diversity of and introgression from D. araucarioides, are of grave concern for the conservation of D. guillauminii.

scholarly journals Jurassic primates, immobile ducks and other oddities: a reply to Heads’ review of The Monkey’s Voyage

2016 ◽  
Vol 29 (6) ◽  
pp. 403 ◽  
Author(s):  
Alan de Queiroz
Keyword(s):  
Fossil Record ◽  
A Priori ◽  
Molecular Dating ◽  
Long Distance Dispersal ◽  
Central Pacific ◽  
Long Distance ◽  
Reasonable Explanation

In The Monkey’s Voyage, I focused on the issue of disjunct distributions, and, in particular, on the burgeoning support from molecular-dating studies for long-distance dispersal over vicariance as the most reasonable explanation for many (but by no means all) distributions broken up by oceans. Michael Heads’ assessment of the book is founded on his long-standing belief, following Croizat, that long-distance dispersal is an insignificant process and, therefore, that disjunctions are virtually always attributable to vicariance. In holding to these notions, Heads offered a series of unsound arguments. In particular, to preserve an ‘all-vicariance’ perspective, he presented a distorted view of the nature of long-distance dispersal, misrepresented current applications of fossil calibrations in molecular-dating studies, ignored methodological biases in such studies that often favour vicariance hypotheses, repeatedly invoked irrelevant geological reconstructions, and, most strikingly, showed a cavalier approach to evolutionary timelines by pushing the origins of many groups back to unreasonably ancient ages. The result was a succession of implausible histories for particular taxa and areas, including the notions that the Hawaiian biota is almost entirely derived from ancient (often Mesozoic) central Pacific metapopulations, that the disjunctions of extremely mobile organisms such as ducks rarely, if ever, result from long-distance dispersal, and that primates were widespread 120 million years before their first appearance in the fossil record. In contrast to Heads’ perspective, a central message of The Monkey’s Voyage is that explanations for disjunct distributions should be evaluated on the basis of diverse kinds of evidence, without strong a priori assumptions about the relative likelihoods of long-distance dispersal and vicariance.

scholarly journals Back to Gondwanaland: can ancient vicariance explain (some) Indian Ocean disjunct plant distributions?

2015 ◽  
Vol 11 (6) ◽  
pp. 20150086 ◽  
Author(s):  
Michael D. Pirie ◽  
Glenn Litsios ◽  
Dirk U. Bellstedt ◽  
Nicolas Salamin ◽  
Jonathan Kissling
Keyword(s):  
Indian Ocean ◽  
Paradigm Shift ◽  
Indian Subcontinent ◽  
Continental Drift ◽  
Molecular Dating ◽  
Long Distance Dispersal ◽  
Long Distance ◽  
Strong Assumption ◽  
Plant Groups ◽  
Age Constraints

Oceans, or other wide expanses of inhospitable environment, interrupt present day distributions of many plant groups. Using molecular dating techniques, generally incorporating fossil evidence, we can estimate when such distributions originated. Numerous dating analyses have recently precipitated a paradigm shift in the general explanations for the phenomenon, away from older geological causes, such as continental drift, in favour of more recent, long-distance dispersal (LDD). For example, the ‘Gondwanan vicariance’ scenario has been dismissed in various studies of Indian Ocean disjunct distributions. We used the gentian tribe Exaceae to reassess this scenario using molecular dating with minimum (fossil), maximum (geological), secondary (from wider analyses) and hypothesis-driven age constraints. Our results indicate that ancient vicariance cannot be ruled out as an explanation for the early origins of Exaceae across Africa, Madagascar and the Indian subcontinent unless a strong assumption is made about the maximum age of Gentianales. However, both the Gondwanan scenario and the available evidence suggest that there were also several, more recent, intercontinental dispersals during the diversification of the group.

An expanded molecular phylogeny of the southern bluebells (Wahlenbergia, Campanulaceae) from Australia and New Zealand

2012 ◽  
Vol 25 (1) ◽  
pp. 11 ◽  
Author(s):  
Jessica M. Prebble ◽  
Heidi M. Meudt ◽  
Phil J. Garnock-Jones
Keyword(s):  
New Zealand ◽  
Dna Markers ◽  
Long Distance Dispersal ◽  
Long Distance ◽  
Australian Species ◽  
Chloroplast Markers ◽  
Its Regions ◽  
Variable Species ◽  
Low Levels ◽  
Chloroplast Dna Markers

We used nuclear and chloroplast DNA markers to examine relationships and test the current morphology-based taxonomy of several species and subspecies of Australian and New Zealand Wahlenbergia. We sampled nuclear ribosomal ITS regions and the chloroplast regions trnL–F and trnK–psbA from 105 individuals, representing 29 of the 46 species and subspecies currently recognised in New Zealand and Australia. Our phylogeny was incompletely resolved because of low levels of genetic variation in all three markers and some conflict between ITS and chloroplast markers. The New Zealand rhizomatous species appear to have radiated in New Zealand after a single long-distance dispersal event from Australia, but it is unclear to which species in Australia they are most closely related. The New Zealand radicate species do not form a clade; instead they are shown to be very closely related to many Australian radicate species. The four species in the New Zealand lowland radicate W. gracilis complex may all belong to the same morphologically variable species. In contrast, the other New Zealand radicate species, W. vernicosa, is probably a separately evolving lineage, and is not conspecific with the W. gracilis complex, nor the Australian W. littoricola, as previously hypothesised. Two of the New Zealand rhizomatous species, W. albomarginata and W. pygmaea, may be conspecific. By contrast, the morphologically distinctive New Zealand rhizomatous W. cartilaginea, W. matthewsii and W. congesta subsp. haastii each formed monophyletic groups. Samples of two recently described Australian species (W. rupicola and W. telfordii) formed monophyletic groups consistent with their recognition.

Cytotaxonomic observations on Villarsia (Menyanthaceae)

1974 ◽  
Vol 22 (3) ◽  
pp. 513 ◽  
Author(s):  
R Ornduff
Keyword(s):  
Indian Ocean ◽  
Distribution Pattern ◽  
South African ◽  
Seed Size ◽  
Ploidy Level ◽  
Climatic Conditions ◽  
Long Distance Dispersal ◽  
Chromosome Counts ◽  
Long Distance ◽  
Australian Species

Chromosome counts for five species of Villarsia indicate that x = 9 for the genus. In Australia one species is diploid, two species are hexaploid, and one species has tetraploid and hexaploid races. The South African V. capensis is tetraploid. Seed size differences in V. reniformis are not correlated with differences in ploidy level. One Australian species and V. capensis are distylous and strongly self-incompatible. Two homostylous species in Australia are self-compatible, but V. albiflora is homostylous and self-incompatible. Villarsia capensis is morphologically variable, but seems closely related to eastern Australian species. The amphi-Indian Ocean distribution pattern exhibited by this genus is an unusual one, and it seems doubtful if it can be accounted for by long-distance dispersal. The present range was perhaps achieved at a time when continental positions and climatic conditions were more favourable for overland migration than they are at present.

scholarly journals Relaxed Molecular Clock Provides Evidence for Long-Distance Dispersal of Nothofagus (Southern Beech)

PLoS Biology ◽  
2005 ◽  
Vol 3 (1) ◽  
pp. e14 ◽  
Author(s):  
Michael Knapp ◽  
Karen Stöckler ◽  
David Havell ◽  
Frédéric Delsuc ◽  
Federico Sebastiani ◽  
...  
Keyword(s):  
Molecular Clock ◽  
Long Distance Dispersal ◽  
Long Distance ◽  
Southern Beech ◽  
Relaxed Molecular Clock
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