Home About us Contact | |||

## Ancestral Range (ancestral + range)
## Selected Abstracts## Climate cooling promoted the expansion and radiation of a threatened group of South American orchids (Epidendroideae: Laeliinae) BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 3 2010ALEXANDRE ANTONELLIThe Brazilian Cerrado is the most species-rich tropical savanna in the world. Within this biome, the Campos Rupestres (,rocky savannas') constitute a poorly studied and highly threatened ecosystem. To better understand how plants characteristic of this vegetation have evolved and come to occupy the now widely-separated patches of rocky formations in eastern Brazil, we reconstruct the biogeographical history of the rare orchid genus Hoffmannseggella. We apply parsimony and Bayesian methods to infer the phylogenetic relationships among 40 out of the 41 described species. Absolute divergence times are calculated under penalized likelihood and compared with estimates from a Bayesian relaxed clock. Ancestral ranges are inferred for all nodes of the phylogeny using Fitch optimization and statistical dispersal vicariance analysis. In all analyses, phylogenetic uncertainty is taken into account by the independent analysis of a large tree sample. The results obtained indicate that Hoffmannseggella underwent rapid radiation around the Middle/Late Miocene (approximately 11,14 Mya). The region corresponding today to southern Minas Gerais acted as a main source area for several independent range expansions north- and eastwards via episodic corridors. These results provide independent evidence that climate cooling following the Middle Miocene Climatic Optimum (approximately 15 Mya) led to important vegetational shifts in eastern Brazil, causing an increase in the dominance of open versus closed habitats. Polyploidy following secondary contact of previously isolated populations may have been responsible for the formation of many species, as demonstrated by the high ploidy levels reported in the genus. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100, 597,607. [source] ## Evolution of the second orangutan: phylogeny and biogeography of hominid origins JOURNAL OF BIOGEOGRAPHY, Issue 10 2009John R. GrehanAbstract Aim, To resolve the phylogeny of humans and their fossil relatives (collectively, hominids), orangutans (Pongo) and various Miocene great apes and to present a biogeographical model for their differentiation in space and time. Location, Africa, northern Mediterranean, Asia. Methods, Maximum parsimony analysis was used to assess phylogenetic relationships among living large-bodied hominoids (= humans, chimpanzees, bonobos, gorillas, orangutans), and various related African, Asian and European ape fossils. Biogeographical characteristics were analysed for vicariant replacement, main massings and nodes. A geomorphological correlation was identified for a clade we refer to as the ,dental hominoids', and this correlation was used to reconstruct their historical geography. Results, Our analyses support the following hypotheses: (1) the living large-bodied hominoids represent a monophyletic group comprising two sister clades: humans + orangutans, and chimpanzees (including bonobos) + gorillas (collectively, the African apes); and (2) the human,orangutan clade (dental hominoids) includes fossil hominids (Homo, australopiths, Orrorin) and the Miocene-age apes Hispanopithecus, Ouranopithecus, Ankarapithecus, Sivapithecus, Lufengpithecus, Khoratpithecus and Gigantopithecus (also Plio-Pleistocene of eastern Asia). We also demonstrate that the distributions of living and fossil genera are largely vicariant, with nodes of geographical overlap or proximity between Gigantopithecus and Sivapithecus in Central Asia, and between Pongo, Gigantopithecus, Lufengpithecus and Khoratpithecus in East Asia. The main massing is represented by five genera and eight species in East Asia. The dental hominoid track is spatially correlated with the East African Rift System (EARS) and the Tethys Orogenic Collage (TOC). Main conclusions, Humans and orangutans share a common ancestor that excludes the extant African apes. Molecular analyses are compromised by phenetic procedures such as alignment and are probably based on primitive retentions. We infer that the human,orangutan common ancestor had established a widespread distribution by at least 13 Ma. Vicariant differentiation resulted in the ancestors of hominids in East Africa and various primarily Miocene apes distributed between Spain and Southeast Asia (and possibly also parts of East Africa). The geographical disjunction between early hominids and Asian Pongo is attributed to local extinctions between Europe and Central Asia. The EARS and TOC correlations suggest that these geomorphological features mediated establishment of the ancestral range. [source] ## Estimating ancestral distributions of lineages with uncertain sister groups: a statistical approach to Dispersal,Vicariance Analysis and a case using Aesculus L. (Sapindaceae) including fossils JOURNAL OF SYSTEMATICS EVOLUTION, Issue 5 2009A.J. HARRISAbstract, We propose a simple statistical approach for using Dispersal,Vicariance Analysis (DIVA) software to infer biogeographic histories without fully bifurcating trees. In this approach, ancestral ranges are first optimized for a sample of Bayesian trees. The probability P of an ancestral range r at a node is then calculated as where Y is a node, and F(rY) is the frequency of range r among all the optimal solutions resulting from DIVA optimization at node Y, t is one of n topologies optimized, and Pt is the probability of topology t. Node Y is a hypothesized ancestor shared by a specific crown lineage and the sister of that lineage "x", where x may vary due to phylogenetic uncertainty (polytomies and nodes with posterior probability <100%). Using this method, the ancestral distribution at Y can be estimated to provide inference of the geographic origins of the specific crown group of interest. This approach takes into account phylogenetic uncertainty as well as uncertainty from DIVA optimization. It is an extension of the previously described method called Bayes-DIVA, which pairs Bayesian phylogenetic analysis with biogeographic analysis using DIVA. Further, we show that the probability P of an ancestral range at Y calculated using this method does not equate to pp*F(rY) on the Bayesian consensus tree when both variables are <100%, where pp is the posterior probability and F(rY) is the frequency of range r for the node containing the specific crown group. We tested our DIVA-Bayes approach using Aesculus L., which has major lineages unresolved as a polytomy. We inferred the most probable geographic origins of the five traditional sections of Aesculus and of Aesculus californica Nutt. and examined range subdivisions at parental nodes of these lineages. Additionally, we used the DIVA-Bayes data from Aesculus to quantify the effects on biogeographic inference of including two wildcard fossil taxa in phylogenetic analysis. Our analysis resolved the geographic ranges of the parental nodes of the lineages of Aesculus with moderate to high probabilities. The probabilities were greater than those estimated using the simple calculation of pp*F(ry) at a statistically significant level for two of the six lineages. We also found that adding fossil wildcard taxa in phylogenetic analysis generally increased P for ancestral ranges including the fossil's distribution area. The ,P was more dramatic for ranges that include the area of a wildcard fossil with a distribution area underrepresented among extant taxa. This indicates the importance of including fossils in biogeographic analysis. Exmination of range subdivision at the parental nodes revealed potential range evolution (extinction and dispersal events) along the stems of A. californica and sect. Parryana. [source] ## Genetic subdivision, glacial refugia and postglacial recolonization in the golden-striped salamander, Chioglossa lusitanica (Amphibia: Urodela) MOLECULAR ECOLOGY, Issue 6 2000J. AlexandrinoAbstract The golden-striped salamander (Chioglossa lusitanica) is an ecologically specialized species, endemic to north-western Iberia. Patterns of genetic variation were assessed at seven polymorphic enzyme loci and one mitochondrial DNA (mtDNA) marker (cytochrome b) in 17 populations across its range. Estimates of enzyme genetic diversity revealed a high degree of genetic subdivision (FST = 0.68), mainly attributable to the existence of two groups of populations. The groups were located, respectively, north and south of the Mondego River, indicating that this river coincided with a major historical barrier to gene flow. A significant decrease in genetic variability from the Mondego northwards was associated with the Douro and Minho rivers. mtDNA sequence variation revealed a congruent pattern of two haplotype groups (d = 2.2%), with a geographical distribution resembling that of allozymes. The pattern and depth of genetic variation is consistent with the following hypotheses: (i) subdivision of an ancestral range of the species prior to the middle Pleistocene; (ii) secondary contact between populations representing historical refugia; (iii) relatively recent range expansion giving rise to the northern part of the species range; and (iv) loss of genetic variation through founder effects during range expansion across major rivers. [source] ## A LIKELIHOOD FRAMEWORK FOR INFERRING THE EVOLUTION OF GEOGRAPHIC RANGE ON PHYLOGENETIC TREES EVOLUTION, Issue 11 2005Richard H. ReeAbstract At a time when historical biogeography appears to be again expanding its scope after a period of focusing primarily on discerning area relationships using cladograms, new inference methods are needed to bring more kinds of data to bear on questions about the geographic history of lineages. Here we describe a likelihood framework for inferring the evolution of geographic range on phylogenies that models lineage dispersal and local extinction in a set of discrete areas as stochastic events in continuous time. Unlike existing methods for estimating ancestral areas, such as dispersal-vicariance analysis, this approach incorporates information on the timing of both lineage divergences and the availability of connections between areas (dispersal routes). Monte Carlo methods are used to estimate branch-specific transition probabilities for geographic ranges, enabling the likelihood of the data (observed species distributions) to be evaluated for a given phylogeny and parameterized paleogeographic model. We demonstrate how the method can be used to address two biogeographic questions: What were the ancestral geographic ranges on a phylogenetic tree? How were those ancestral ranges affected by speciation and inherited by the daughter lineages at cladogenesis events? For illustration we use hypothetical examples and an analysis of a Northern Hemisphere plant clade (Cercis), comparing and contrasting inferences to those obtained from dispersal-vicariance analysis. Although the particular model we implement is somewhat simplistic, the framework itself is flexible and could readily be modified to incorporate additional sources of information and also be extended to address other aspects of historical biogeography. [source] ## Estimating ancestral distributions of lineages with uncertain sister groups: a statistical approach to Dispersal,Vicariance Analysis and a case using Aesculus L. (Sapindaceae) including fossils JOURNAL OF SYSTEMATICS EVOLUTION, Issue 5 2009A.J. HARRISAbstract, We propose a simple statistical approach for using Dispersal,Vicariance Analysis (DIVA) software to infer biogeographic histories without fully bifurcating trees. In this approach, ancestral ranges are first optimized for a sample of Bayesian trees. The probability P of an ancestral range r at a node is then calculated as where Y is a node, and F(rY) is the frequency of range r among all the optimal solutions resulting from DIVA optimization at node Y, t is one of n topologies optimized, and Pt is the probability of topology t. Node Y is a hypothesized ancestor shared by a specific crown lineage and the sister of that lineage "x", where x may vary due to phylogenetic uncertainty (polytomies and nodes with posterior probability <100%). Using this method, the ancestral distribution at Y can be estimated to provide inference of the geographic origins of the specific crown group of interest. This approach takes into account phylogenetic uncertainty as well as uncertainty from DIVA optimization. It is an extension of the previously described method called Bayes-DIVA, which pairs Bayesian phylogenetic analysis with biogeographic analysis using DIVA. Further, we show that the probability P of an ancestral range at Y calculated using this method does not equate to pp*F(rY) on the Bayesian consensus tree when both variables are <100%, where pp is the posterior probability and F(rY) is the frequency of range r for the node containing the specific crown group. We tested our DIVA-Bayes approach using Aesculus L., which has major lineages unresolved as a polytomy. We inferred the most probable geographic origins of the five traditional sections of Aesculus and of Aesculus californica Nutt. and examined range subdivisions at parental nodes of these lineages. Additionally, we used the DIVA-Bayes data from Aesculus to quantify the effects on biogeographic inference of including two wildcard fossil taxa in phylogenetic analysis. Our analysis resolved the geographic ranges of the parental nodes of the lineages of Aesculus with moderate to high probabilities. The probabilities were greater than those estimated using the simple calculation of pp*F(ry) at a statistically significant level for two of the six lineages. We also found that adding fossil wildcard taxa in phylogenetic analysis generally increased P for ancestral ranges including the fossil's distribution area. The ,P was more dramatic for ranges that include the area of a wildcard fossil with a distribution area underrepresented among extant taxa. This indicates the importance of including fossils in biogeographic analysis. Exmination of range subdivision at the parental nodes revealed potential range evolution (extinction and dispersal events) along the stems of A. californica and sect. Parryana. [source] |