Mitochondrial DNA evolution and population history of the Tenerife skink Chalcides viridanus

School of Biological & Earth Sciences, Liverpool John Moores University, UK.
Molecular Ecology (Impact Factor: 6.49). 09/2000; 9(8):1061-7. DOI: 10.1046/j.1365-294x.2000.00962.x
Source: PubMed


Recent studies of island lizards have suggested that historical vicariance as a result of volcanism may have played an important role in shaping patterns of within-island genetic diversity. The skink, Chalcides viridanus, shows variation in morphology within the volcanic island of Tenerife. Two mitochondrial DNA (mtDNA) fragments (from the 12S and 16S rRNA regions) were sequenced in individuals from 17 sites to evaluate the relationship between current phylogeography and the geological history of the island. Three main clades were detected. The two most basal clades were restricted to areas representing the ancient precursor islands of Teno and Anaga in the northwest and northeast of Tenerife, respectively. The third clade showed a widespread geographical distribution and provided evidence of a recent rapid expansion after a bottleneck. Within-island cladogenesis appears to have taken place during a recent period of volcanic activity and long after the ancient islands had been united by the eruptions that led to the formation of the Canadas edifice. Evidence of similar biogeographical histories are found in other species in the Canary archipelago, supporting the volcanism scenario as a potentially widespread cause of within-island differentiation in reptiles.

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Available from: Jose Pestano, May 28, 2014
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    • "Alternatively, Anaga's eastern and western populations may have different origins, with the former populations being formed by the original local individuals and the latter being the result of colonizations from central Tenerife (see following paragraphs). Evidence for phylogeographic structure associated with Tenerife's precursor islands has been found in the gecko Tarentola delalandii (Gübitz et al. 2000), the skink Chalcides viridanus (Brown et al. 2000), the lizard G. galloti (Thorpe et al. 1996), and a species complex within the darkling beetle Pimelia (Juan et al. 1996). For G. galloti and Pimelia, the Anaga populations are the most divergent, whereas the Teno and South populations are closely related or undifferentiated. "
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    ABSTRACT: Geological processes and ecological adaptation are major drivers of diversification on oceanic islands. Although diversification in these islands is often interpreted as resulting from dispersal or island hopping rather than vicariance, this may not be the case in islands with complex geological histories. The island of Tenerife, in the Canary Islands, emerged in the late Miocene as 3 precursor islands that were subsequently connected and reisolated by volcanic cycles. The spider Dysdera verneaui is endemic to the island of Tenerife, where it is widely distributed throughout most island habitats, providing an excellent model to investigate the role of physical barriers and ecological adaptation in shaping within-island diversity. Here, we present evidence that the phylogeographic patterns of this species trace back to the independent emergence of the protoislands. Molecular markers (mitochondrial genes cox1, 16S, and nad1 and the nuclear genes ITS-2 and 28S) analyzed from 100 specimens (including a thorough sampling of D. verneaui populations and additional outgroups) identify 2 distinct evolutionary lineages that correspond to 2 precursor islands, each with diagnostic genital characters indicative of separate species status. Episodic introgression events between these 2 main evolutionary lineages explain the observed incongruence between mitochondrial and nuclear markers, probably as a result of the homogenization of their ITS-2 sequence types. The most widespread lineage exhibits a complex population structure, which is compatible with either secondary contact, following connection of deeply divergent lineages, or alternatively, a back colonization from 1 precursor island to another.
    Full-text · Article · Mar 2013 · The Journal of heredity
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    • "We used individuals that had been collected for previous research projects (e.g., Pestano and Brown 1999; Brown et al. 2000); see Brown and Pestano (1998) for more information and La Gomera-El Hierro divergence. One individual was used from each site, unless otherwise stated: "
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    ABSTRACT: Delimitation of species is an important and controversial area within evolutionary biology. Many species boundaries have been defined using morphological data. New genetic approaches now offer more objective evaluation and assessment of the reliability of morphological variation as an indicator that speciation has occurred. We examined geographic variation in morphology of the continuously distributed skink Chalcides mionecton from Morocco and used Bayesian analyses of nuclear and mitochondrial DNA (mtDNA) loci to examine: (i) their concordance with morphological patterns, (ii) support for species delimitation, (iii) timing of speciation, and (iv) levels of gene flow between species. Four digit individuals were found at sites between Cap Rhir (in the south) and the northern extreme of the range, whereas five-digit individuals were found in two disjunct areas: (i) south of Cap Rhir and (ii) the north of the range where they were often syntopic with four-digit individuals. The pattern of variation in generalized body dimensions was largely concordant with that in digit number, suggesting two general morphotypes. Bayesian analyses of population structure showed that individuals from sites south of Cap Rhir formed one genetic cluster, but that northern four- and five-digit individuals clustered together. Statistical support for delimitation of these genetic clusters into two species was provided by a recent Bayesian method. Phylogenetic-coalescent dating with external time calibrations indicates that speciation was relatively recent, with a 95% posterior interval of 0.46-2.66 mya. This postdates equivalent phylogenetic dating estimates of sequence divergence by approximately 1 Ma. Statistical analyses of a small number of independent loci provide important insights into the history of the speciation process in C. mionecton and support delimitation of populations into two species with distributions that are spatially discordant with patterns of morphological variation.
    Full-text · Article · Dec 2012 · Ecology and Evolution
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    • " , 2000 ; Moya et al . , 2004 ) . Thus , it is also possible that later within - island vicariance has caused the pattern . The Gu¨ı´mar valley was massively affected by a landslide approximately 0 . 8 My ago , which is thought to have fragmented the ranges of the Gallotia lizards ( 0 . 8 My ; Brown et al . , 2006 ) , Chalcides skinks ( 1 . 1 My ; Brown et al . , 2000 ) and Eutrichopus beetles ( 0 . 7 My ; Moya et al . , 2004 ) . This would correspond to the pattern found in Arminda , where the branches of the five westernmost taxa have approximately the same length ( note that El Hierro is approximately 1 . 2 My old ) . It is reasonable to suggest that unvegetated young lava flows represent strong b"
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    ABSTRACT: Volcanic archipelagos represent excellent areas to study colonization and speciation processes. The grasshopper genus Arminda is one of many endemic taxa of the Canary Islands. It consists of seven wingless species, most of which are singleisland endemics.We sequenced twomitochondrial (12s rRNA, ND5) and two nuclear gene fragments (28s rRNA, ITS2) to reconstruct the colonization pattern of the genus. Our results are in accordance with a stepping-stone colonization model from east to west, corresponding to the prevailing ocean currents, but alternative hypotheses cannot be fully rejected. The populations of A. brunneri from Tenerife belong to two different lineages (east and west) consistent with the geological history of the island. It remains to be tested whether these lineages represent different species and whether further lineages exist on this island. The five clades of the four western islands (A. brunneri group) have approximately similar branch lengths. The short internodes between these lineages resulted in a poorer phylogenetic resolution. Specimens from La Palma were genetically distinct and are subsequently described as a new species, Arminda palmae sp.n. Our results suggest in situ speciation on Gran Canaria, which was accompanied by a stronger degree ofmorphological diversification than the interisland speciation processes. The aberrant species A. canariensis has formerly been assigned to a monotypic subgenus Chopardminda, which is now synonymized with Arminda syn.n. based on its phylogenetic position. Gran Canaria seems to be the only island where Arminda species occur sympatrically, although allopatric speciation seems likely due to the long history of volcanism and erosion on the island.
    Full-text · Article · Jan 2009 · Systematic Entomology
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