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The influence of geological history on diversification in insular species: Genetic and morphological patterns of Micromeria Benth. (Lamiaceae) in Tenerife (Canary archipelago)

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Abstract

AimUsing phylogenetic and morphometric approaches, our study aims to understand the diversification process of the two groups of Micromeria species in Tenerife: the species restricted to the palaeoislands, and the species widely distributed in the younger part of the island.LocationTenerife, Canary Islands.Methods We calculated a calibrated phylogeny and a Neighbor-Net network based on eight nuclear loci from 37 samples: 22 of the 8 species currently recognized in Tenerife, and 15 of their closest relatives occurring in neighbouring islands and continental populations. We performed a principal components analysis (PCA) of 27 morphological characters from 54 specimens sampled from Tenerife.ResultsOur phylogeny showed that the species from Tenerife can be subdivided into three main clades: one composed of the species inhabiting the palaeoisland of Anaga (M. teneriffae, M. glomerata and M. rivas-martinezii); another composed of the species present in the palaeoisland of Teno (M. densiflora); and a third group that includes all the central species (M. hyssopifolia, M. varia, M. lachnophylla and M. lasiophylla). Morphometric analyses indicated two main groups corresponding to the palaeoisland species and the central ones.Main conclusionsOur study points to a relationship between the diversification in Micromeria and the geological history of Tenerife. We conclude that Micromeria first arrived in Anaga where it diversified, subsequently colonized Teno and from there occupied the central part, presumably after the formation of the Teide volcano. The species of Micromeria in Tenerife constitute an interesting example of how species diversification on oceanic islands can be shaped by the island's geological history, which probably contributed to the high levels of endemism on Tenerife.

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... The islands have different altitudinal gradients depending on their age (Fernández-Palacios et al., 2011), and harbor a range of ecological zones from costal desert, passing through laurel forest, to sub-alpine desert (Juan et al., 2000). The distribution of several species in this island is associated with these ecological zones suggesting that a lot of the diversity found in the Canary Islands arose through adaptive radiation (Meimberg et al., 2006;Puppo et al., 2014. Analogous morphological traits between taxa growing in different islands might have resulted from selective pressures caused by similar ecological conditions. ...
... The history of diversification of Micromeria is highly consistent with the geological history of the Canary Islands (Puppo et al., 2014(Puppo et al., , 2016. Interspecific gene-flow is frequent in Micromeria, especially among species from the same island (Puppo et al., 2016;Curto et al., 2017). ...
... The dataset with the highest amount of missing data contained more loci per individuals and resulted in a tree with higher resolution (Table 1). We observed a division between the Eastern and Western Micromeria lineages, corroborating findings from earlier phylogenetic studies (Puppo et al., 2014. The tree derived from the analysis of the "50% missing data matrix" (Table 1, Supplementary Fig. S1) was less resolved than the tree derived from the analyses of the "90% missing data matrix." ...
Article
As found in other oceanic islands, the Canary Islands include a large number of single island endemic species, some of which form clades that are broadly distributed within the archipelago. The genus Micromeria (Lamiaceae), for instance, includes groups of morphologically similar but ecologically diverse species on each island, representing a great model to investigate niche shifts and adaptation within the Canary Archipelago. Previous attempts to reconstruct phylogenetic relationships within the genus did not lead to robust phylogenies, presumably due to introgression and/or incomplete lineage sorting. In this study, we use a newly developed RAD-sequencing method to improve phylogenetic resolution and to better understand relationships among the Canary Island endemic Micromeria. Overall, we obtained 3571 loci that were genotyped for a total of 46 individuals of Micromeria. Our data reconstructed a highly resolved phylogeny, and corroborated the latest species reclassification of the M. varia s.l. species complex, the taxonomically most complicated group within the genus. Furthermore, taxa occupying similar ecological conditions in different islands, were shown to be closely related. This is the case of taxa from the laurel forest from La Gomera and Gran Canaria, suggesting that the laurel forest likely worked as a filter, only allowing the establishment of colonizers already pre-adapted to these conditions. We also found introgression between these species so it is also possible that the genes that facilitated the adaptation to laurel forest were swapped between Gran Canaria and La Gomera. The observations obtained in this study also allowed us to explain the role of introgression in the origin of M. varia s.l. species complex.
... This has been shown to have a high impact on the evolutionary history of species (i.e. [18][19][20][21][22][23]) that results in species occupying the younger part of the island being more genetically diverse but less differentiated among each other. This had been shown in our study system Micromeria (Lamiaceae) in Tenerife [22,23]. ...
... [18][19][20][21][22][23]) that results in species occupying the younger part of the island being more genetically diverse but less differentiated among each other. This had been shown in our study system Micromeria (Lamiaceae) in Tenerife [22,23]. ...
... (Nepetoideae, Lamiaceae) is composed of shrubs, subshrubs and herbs with monoecious flowers pollinated by insects. Seed dispersal happens mostly by wind, but ants and water also contribute to this process [22,24]. It is a monophyletic genus with ca. ...
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Background Especially on islands closer to the mainland, such as the Canary Islands, different lineages that originated by multiple colonization events could have merged by hybridization, which then could have promoted radiation events (Herben et al., J Ecol 93: 572–575, 2005; Saunders and Gibson, J Ecol 93: 649–652, 2005; Caujapé-Castells, Jesters, red queens, boomerangs and surfers: a molecular outlook on the diversity of the Canarian endemic flora, 2011). This is an alternative to the scenario where evolution is mostly driven by drift (Silvertown, J Ecol 92: 168–173, 2004; Silvertown et al., J Ecol 93: 653–657, 2005). In the former case hybridization should be reflected in the genetic structure and diversity patterns of island species. In the present work we investigate Micromeria from the Canary Islands by extensively studying their phylogeographic pattern based on 15 microsatellite loci and 945 samples. These results are interpreted according to the hypotheses outlined above. ResultsGenetic structure assessment allowed us to genetically differentiate most Micromeria species and supported their current classification. We found that populations on younger islands were significantly more genetically diverse and less differentiated than those on older islands. Moreover, we found that genetic distance on younger islands was in accordance with an isolation-by-distance pattern, while on the older islands this was not the case. We also found evidence of introgression among species and islands. Conclusions These results are congruent with a scenario of multiple colonizations during the expansion onto new islands. Hybridization contributes to the grouping of multiple lineages into highly diverse populations. Thus, in our case, islands receive several colonization events from different sources, which are combined into sink populations. This mechanism is in accordance with the surfing syngameon hypothesis. Contrary to the surfing syngameon current form, our results may reflect a slightly different effect: hybridization might always be related to colonization within the archipelago as well, making initial genetic diversity to be high to begin with. Thus the emergence of new islands promotes multiple colonization events, contributing to the establishment of hybrid swarms that may enhance adaptive ability and radiation events. With time, population sizes grow and niches start to fill. Consequently, gene-flow is not as effective at maintaining the species syngameon, which allows genetic differentiation and reproductive isolation to be established between species. This process contributes to an even further decrease in gene-flow between species.
... In case the selection regime does not stabilize both species, the small ranges will cause the two species to rapidly become one morphospecies. This will be especially pronounced after secondary contact, e.g., by frequent dispersal between current islands or land bridges between paleo-islands (Puppo et al. 2014(Puppo et al. , 2015a. ...
... In the paleo-islands, these four species grow on old rocks and in the southeast, M. teneriffae inhabits the coastal desert. In a phylogenetic analysis of multiple nuclear genes and morphometric analysis, the species associated to the paleo-islands are not only highly morphologically different from those occupying the central area of the island, but are also older (Puppo et al. 2014). Contrary to this, relations among the common species, i.e., those distributed in the younger parts of the island (M. ...
... Contrary to this, relations among the common species, i.e., those distributed in the younger parts of the island (M. varia, M. hyssopifolia, M. lachnophylla, and M. lasiophylla), are less well supported in the phylogeny and further conclusions about their relationships could not be drawn (Puppo et al. 2014). Micromeria varia is distributed along the north part of the island from Teno to Anaga, M. lachnophylla grows in the central highland of the island above 2000 m, and M. lasiophylla is restricted to the southeast rock cliffs of Las Cañadas, above 2000 m (Fig. 1). ...
Article
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Geological history of oceanic islands can have a profound effect on the evolutionary history of insular flora, especially in complex islands such as Tenerife in the Canary Islands. Tenerife results from the secondary connection of three paleo-islands by a central volcano, and other geological events that further shaped it. This geological history has been shown to influence the phylogenetic history of several taxa, including genus Micromeria (Lamiaceae). Screening 15 microsatellite markers in 289 individuals representing the eight species of Micromeria present in Tenerife, this study aims to assess the genetic diversity and structure of these species and its relation with the geological events on the island. In addition, we evaluate the extent of hybridization among species and discuss its influence on the speciation process. We found that the species restricted to the paleo-islands present lower levels of genetic diversity but the highest levels of genetic differentiation suggesting that their ranges might have contracted over time. The two most widespread species in the island, M. hyssopifolia and M. varia, present the highest genetic diversity levels and a genetic structure that seems correlated with the geological composition of the island. Samples from M. hyssopifolia from the oldest paleo-island, Adeje, appear as distinct while samples from M. varia segregate into two main clusters corresponding to the paleo-islands of Anaga and Teno. Evidence of hybridization and intraspecific migration between species was found. We argue that species boundaries would be retained despite hybridization in response to the habitat's specific conditions causing postzygotic isolation and preserving morphological differentiation.
... This position argued against the idea of these massifs as ancient refugia. However, other studies, especially in animals, have reported ages for divergence events between taxa endemic to these palaeo-islands, either at the species or at the intraspecies level (Juan et al. 1996(Juan et al. , 2000Dimitrov et al. 2008;Mac ıas-Hern andez et al. 2013;Puppo et al. 2014) that are contemporaneous or predate the age of merging of the precursor palaeo-islands 3.5 Ma (Ancochea et al. 1990). Few plant studies (G omez et al. 2003;Garc ıa-Verdugo et al. 2010) have focused on patterns of within-island genetic variation for widespread Canarian endemics, and none of them have provided estimates of lineage divergence times, which is necessary to relate within-island patterns to the island geological history. ...
... While in some cases, the divergence between these taxa is found at the species level (e.g. Trechus, Contreras-D ıaz et al. 2007; Pericallis, Jones et al. 2014) and/or predates the merging of the palaeo-islands (Micromeria, Puppo et al. 2014;Pholcus, Dimitrov et al. 2008); in others, it is observed within species (e.g. Tarentola delalandii, G€ ubitz et al. 2000) and/or postdates the merging of the palaeo-islands (Eutrichopus, Moya et al. 2004;Calathus abaxoides, Emerson et al. 1999). ...
... Theoretical predictions of coalescent theory states that high-frequency haplotypes have been present for a long time, and more recent ones are rare and derived from the commonest haplotypes (Posada & Crandall 2001). Additionally, a root haplotype is expected to have a higher number of haplotype Juan et al. (1996) Lizard Gallotia galloti Western/North-eastern lineages 0.7 Ma Mitochondrial cytochrome b Thorpe et al. (1996) Beetle Calathus abaxoides Teno/Anaga 350 000 years Two mitochondrial (COI and COII) Emerson et al. (1999) Skink Chalcides viridanus Teno/Anaga 1.1 Ma Two mitochondrial (12S and 16S) Brown et al. (2000) Gecko Puppo et al. (2014) connections in the network, rather than being close to the tips. However, past extinction of haplotypes can obscure the inference, with younger haplotypes becoming the most prevalent, so accurately identifying the root haplotype is a challenging task. ...
Article
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Geographical isolation by oceanic barriers and climatic stability has been postulated as some of the main factors driving diversification within volcanic archipelagos. However, few studies have focused on the effect that catastrophic volcanic events have had on patterns of within-island diversification in geological time. This study employed data from the chloroplast (cpDNA haplotypes) and the nuclear (AFLPs) genomes to examine patterns of genetic variation in Canarina canariensis, an iconic plant species associated with the endemic laurel forest of the Canary Islands. We found a strong geographic population structure, with a first divergence around 0.8 Ma that has Tenerife as its central axis and divides Canarian populations into eastern and western clades. Genetic diversity was greatest in the geologically stable "paleo-islands" of Anaga, Teno and Roque del Conde; these areas were also inferred as the ancestral location of migrant alleles towards other disturbed areas within Tenerife or the nearby islands using a Bayesian approach to phylogeographic clustering. Oceanic barriers, in contrast, appear to have played a lesser role in structuring genetic variation, with intra-island levels of genetic diversity larger than those between islands. We argue that volcanic eruptions and landslides after the merging of the paleoislands 3.5 million years ago played key roles in generating genetic boundaries within Tenerife, with the paleo-islands acting as refugia against extinction, and as cradles and sources of genetic diversity to other areas within the archipelago.
... These findings suggest that Micromeria might be another example where adaptation to different habitats within an island might be the prevailing mechanism explaining species richness. On the other hand, multi-locus phylogenetic analyses showed that Micromeria species from Tenerife seemed to have undergone at least three phases of diversification, two on the palaeoislands and a more recent one in the young, central part of Tenerife (Puppo et al., 2014). This might indicate that diversification of Micromeria in Tenerife is influenced by ongoing adaptation to relatively recently originated habitats but also by the secondary contact of the palaeoislands caused by the elevation of the central Teide massif (Puppo et al., 2014). ...
... On the other hand, multi-locus phylogenetic analyses showed that Micromeria species from Tenerife seemed to have undergone at least three phases of diversification, two on the palaeoislands and a more recent one in the young, central part of Tenerife (Puppo et al., 2014). This might indicate that diversification of Micromeria in Tenerife is influenced by ongoing adaptation to relatively recently originated habitats but also by the secondary contact of the palaeoislands caused by the elevation of the central Teide massif (Puppo et al., 2014). Micromeria thus is an interesting example where the relative importance of inter-island dispersal and adaptation as explanations for a genus' diversity on an archipelago can be compared. ...
... inodora) from the Balearic Islands (Table 2). The latter species, shown to be sister to Micromeria in the Canary Islands in previous phylogenetic analyses (Bräuchler et al., 2005(Bräuchler et al., , 2010Puppo et al., 2014), was used as outgroup. Only one sample from the taxon inhabiting Lanzarote and Fuerteventura (M. ...
Article
Here we reconstruct the evolutionary history of Micromeria in the Canary Islands using eight nuclear markers. Our results show two centers of diversification for Micromeria, one in the eastern islands Gran Canaria and Lanzarote, the other in the western islands, Tenerife, La Palma and El Hierro. Suggested directions of inter-island colonization are the following: Gran Canaria to Lanzarote and La Gomera; Tenerife to La Palma (from the paleoisland of Teno), to El Hierro (from the younger, central part), and to La Gomera and Madeira (from the paleoislands). Colonization of La Gomera probably occurred several times from Gran Canaria and Tenerife. The taxonomic implications of these results are discussed. Incongruence among the different markers was evaluated and, using next generation sequencing, we investigated if this incongruence is due to gene duplication. Copyright © 2015 Elsevier Inc. All rights reserved.
... El género Micromeria Bentham (1829: sub t. 1282) (Lamiaceae) con aproximadamente 70-90 táxones, según autores, es de gran complejidad taxonómica (Puppo et al., 2014, y está distribuido en las regiones templadas y en las montañas tropicales de todo el mundo, desde las regiones mediterránea y macaronésica hasta el sur de África, India y China (Chater, 1971;Chater & Guinea, 1972;Pérez de Paz, 1978;Morales, 1991Morales, , 1993Govaerts, 1999;Harley et al., 2004;Bräuchler et al., 2005Bräuchler et al., , 2008Puppo et al., 2014. ...
... El género Micromeria Bentham (1829: sub t. 1282) (Lamiaceae) con aproximadamente 70-90 táxones, según autores, es de gran complejidad taxonómica (Puppo et al., 2014, y está distribuido en las regiones templadas y en las montañas tropicales de todo el mundo, desde las regiones mediterránea y macaronésica hasta el sur de África, India y China (Chater, 1971;Chater & Guinea, 1972;Pérez de Paz, 1978;Morales, 1991Morales, , 1993Govaerts, 1999;Harley et al., 2004;Bräuchler et al., 2005Bräuchler et al., , 2008Puppo et al., 2014. ...
Article
Micromeria Bentham (1829: sub t. 1282) (Lamiaceae) is a monophyletic and taxonomically intricate genus, represented by nearly 70 species. These are distributed from the Macaronesian-Mediterranean region to southern Africa, India, and China (Morales 1991b, Govaerts 1999, Harley et al. 2004, Bräuchler et al. 2005, 2008; Puppo & Meimberg 2015, Puppo et al. 2014, 2015). Micromeria microphylla (d’Urville) Bentham (1834: 377) was described by d’Urville (1822: 327) as Thymus microphyllus, and is spread in the Mediterranean region (mainland Italy, Sicily, Maltese Islands, Balearic Islands). This species is a pubescent dwarf shrub 10–30 cm, with filiform, procumbent or ascending stems; leaves 3–6 × 2–4 mm, triangular-ovate to elliptical, the upper sometimes narrowly elliptical, rounded or cuneate at base, acute, entire, flat, subsessile; verticillasters with 1-6 usually erect-patent flowers; peduncles or pedicels ca ½ as long as subtending leaves; calyx 2.5–3.5 mm, patentpubescent, villous in throat; teeth ca ½ as long as tube, lanceolate-acuminate to-subulate, unequal; corolla 5–8 mm, purple (Chater & Guinea 1972, Greuter et al. 1986, Mus & Rosselló 1987, Bolòs & Vigo 1996, Morales 1991a, 2010, Pignatti 2018). Bräuchler (in Bräuchler et al. 2008: 393) had previously lectotypified the name Thymus microphyllus using a specimen held at P (see below). However, the type designated by this author is ineffective, being contrary to Art. 9.12 (this and all articles in the following refer to the ICN, Turland et al. 2018). The aim of this paper is revise the typification of the name.
... El género Micromeria Bentham (1829: sub t. 1282) (Lamiaceae) con aproximadamente 70-90 táxones, según autores, es de gran complejidad taxonómica (Puppo et al., 2014, y está distribuido en las regiones templadas y en las montañas tropicales de todo el mundo, desde las regiones mediterránea y macaronésica hasta el sur de África, India y China (Chater, 1971;Chater & Guinea, 1972;Pérez de Paz, 1978;Morales, 1991Morales, , 1993Govaerts, 1999;Harley et al., 2004;Bräuchler et al., 2005Bräuchler et al., , 2008Puppo et al., 2014. ...
... El género Micromeria Bentham (1829: sub t. 1282) (Lamiaceae) con aproximadamente 70-90 táxones, según autores, es de gran complejidad taxonómica (Puppo et al., 2014, y está distribuido en las regiones templadas y en las montañas tropicales de todo el mundo, desde las regiones mediterránea y macaronésica hasta el sur de África, India y China (Chater, 1971;Chater & Guinea, 1972;Pérez de Paz, 1978;Morales, 1991Morales, , 1993Govaerts, 1999;Harley et al., 2004;Bräuchler et al., 2005Bräuchler et al., , 2008Puppo et al., 2014. ...
Article
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Micromeria rodriguezii es una especie endémica de las Islas Baleares (Mediterráneo occidental). Una población de esta especie se ha encontrado en la provincia de Castellón (España), en el margen de un camino forestal. Se proporciona un estudio de la morfología de las plantas de esta población, así como su estado de conservación en la Comunidad Valenciana. Debido a que esta es la única población ibérica conocida hasta el momento, se debe elaborar un plan de manejo y conservación para garantizar su conservación.
... Micromeria Bentham (1829Bentham ( : sub t. 1282) is a taxonomically complex genus (see Bräuchler et al. 2008, Puppo et al. 2014, 2015. It belongs to the family Lamiaceae (subfamily Nepetoideae, tribe Mentheae, and subtribe Menthinae) (Morales 1991a, Harley et al. 2004. ...
... Micromeria s.str. is currently circumscribed as monophyletic and is represented by nearly 70 species in the world (Govaerts 1999;Bräuchler et al. 2008;. The genus is distributed from the Macaronesian-Mediterranean region to southern Africa, India, and China (Morales 1991b, Bräuchler et al. 2008, Puppo et al. 2014, 2015. ...
Article
Some aspects concerning the typification of the Linnaean name Satureja graeca, basionym of Micromeria graeca (Lamiaceae) are discussed. This name had previously been “typified” by Siddiqi in 1985 from a specimen kept at LINN, and also later by Morales in 1991 from another specimen preserved in the same Linnaean herbarium. However, it is not sure that these specimens are part of Linnaeus’s original material so neither cannot be considered a lectotype. An illustration published by Morison in 1699 and cited by Linnaeus in the protologue of Satureja graeca is designated as the lectotype of the name.
... neo-endemics (including SIEs and MIEs). Estimated divergence times of these neo-endemics vary depending on the position in the phylogenetic tree of each lineage (Garc ıa- Maroto et al., 2009;Puppo et al., 2014). Anagenetic SIEs (a category that may include palaeo-endemics) are very rare (5%) in our study. ...
... Divergence times of SIEs belonging to the time calibrated radiated lineages [Lotus (Ojeda et al., 2014), Echium (Garc ıa-Maroto et al., 2009) and Micromeria (Puppo et al., 2014)] indicate an origin of all species congruent with the age of the older parts of the host island, even for those species that are currently more abundant on very young terrain, or that show random distributions. Furthermore, molecular phylogenetic studies have indicated Descurainia gilva and Pericallis multiflora (SIEs from LP and TFE respectively) to be ancestral within their monophyletic lineages, indicating their speciation to have occurred early in the life of each island, notwithstanding that they are currently more frequent on young volcanic substrate (Swenson & Manns, 2003;Goodson et al., 2006). ...
Article
The general dynamic model (GDM) of oceanic island biogeography integrates rates of immigration, speciation and extinction in relation to a humped trajectory of island area, species carrying capacity and topographic complexity through time, based on a simplified island ontogeny. In practice, many islands have more complex ontogenies, featuring surfaces of varying age. Here, we extend the GDM to apply at a local scale within islands, and test the predictions analytically within individual islands. El Hierro, La Palma and Tenerife (Canary Islands). Following the GDM logic, we derive predictions for the distributions and richness of single island endemics (SIEs) across island landscapes of different age. We test these predictions by means of generalized linear models and binominal tests using gridded species occurrence data for vascular plant SIE species and a set of climatic, topographic and terrain age variables. We also examined phylogenetic divergence times for a subset of endemic lineages. Geological age, in interaction with slope, and topographic variables, best explained SIE richness at the landscape scale. About 70% of SIEs had ranges strongly biased to, or largely restricted to old terrain. Available phylogenetic divergence times of SIEs of radiated plant lineages suggested an origin on the older parts of the islands. Metrics of anthropogenic disturbance and habitat availability were unrelated to the observed SIE pattern. Our findings support the hypothesis that SIEs have evolved and accumulated on older and topographically complex terrain, while colonization processes predominate on the youngest parts. These results imply that evolutionary processes shape species distributions at the landscape scale within islands. This opens the perspective of extending the GDM framework to understand processes at a local scale within individual islands.
... only one species, M. varia bentham (1834: 374), is distributed among all islands though different subspecies have been described for each, highlighting the morphological variation present in this species. Phylogenetic evidence (Puppo et al. 2014(Puppo et al. , 2015 however, suggests that M. hyssopifolia plants from Tenerife and el Hierro are not closely related. Similarly, it seems that individuals from la Palma referred to M. lasiophylla are not closely related to those from Tenerife and rather constitute two different taxa. ...
... In this sense, both M. hyssopifolia and M. lasiophylla would be endemic to Tenerife. Similarly, M. varia constitutes an endemic taxon from Tenerife and is not closely related to the plants from other islands of the Canary archipelago and Madeira with which it has been treated as conspecific (Meimberg et al. 2006, Puppo et al. 2014 Fig. 1-a). In la gomera, two species were described: M. lepida Webb & berthelot (1844: 74) with two subspecies: subsp. ...
Article
Based on recent molecular evidence, one new species and one new subspecies of Micromeria are described for the Canary Islands: M. pedro-luisii and M. hierrensis subsp. incana. Six new combinations are proposed: M. canariensis, M. canariensis subsp. meridialis, M. gomerensis, M. rupestris, M. herpyllomorpha subsp. palmensis, and M. hierrensis. Three new hybrids are described for La Gomera: M. lepida subsp. bolleana × M. gomerensis, M. lepida subsp. bolleana × M. pedro-luisii, and M. lepida subsp. lepida × M. pedro-luisii. A new name is also given to the taxon from Madeira: M. maderensis. A revised key to the species present in the Canary archipelago is provided.
... Thus, M. ericifolia (Roth) Bornmüller (1924: 198) becomes the oldest available name for the plants traditionally known as M. hyssopifolia (see Puppo et al. 2014a (Applequist 2016). However, as defined by the lectotype designated by Bräuchler in , that name is associated with the taxon occurring on Madeira which recently has been revealed as specifically distinct from the plants on Tenerife (Puppo et al. 2014b. Furthermore, the name M. thymoides (Sol. ...
Article
Recently, the authors presented a proposal to conserve the names Micromeria varia Bentham (1834: 374) with a conserved type and M. hyssopifolia Webb & Berthelot (1844: 72) against Thymus ericifolius Roth (1800: 50) (Puppo et al. 2014a) to avoid disruption of current usage of these two well established names. This proposal, however, was not recommended by the Nomenclature Committee (Applequist 2016) and subsequently turned down by the General Committee (Wilson 2017). While regretting this decision, we are prepared to accept the taxonomic and nomenclatural implications.
... According to the data of Bräuchler et al. (2010), section Pineolentia and section Micromeria have the same clade, and this shows that they have a common ancestor. The data of Puppo et al. (2014Puppo et al. ( , 2015 contributed to sections Pineolentia and Micromeria. M. pineolens shares the same clade with the Canary Islands section Micromeria specimens. ...
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A new species, Micromeria aybalae H.Duman & Dirmenci (Lamiaceae), Micromeria Benth. sect. Micromeria, is described from Muğla Province in southwestern Turkey. A description, taxonomic note, distribution map, habitat, and nrDNA ITS and cpDNA trnL-F based phylogeny are presented. The differences between the new species and its allies, Micromeria cremnophila Boiss. & Heldr. s.l. and M. hispida Benth., are discussed, and an identification key is provided for the Turkish Micromeria.
... However, as noted above, the microsatellite variation has revealed deep genetic structuring which should be used to inform conservation. The Anaga peninsula has many locally endemic plant taxa, which are interpreted as resulting from geological history, such as Micromeria glomerata and M. rivas-martinezii (Puppo et al. 2014(Puppo et al. , 2016. However, in L. sessilifolius the variation is cryptic in that there are no obvious phenotypic differences. ...
Article
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We developed and characterized microsatellite markers for the genus Lotus, a large genus of leguminous plants containing many endemic species of conservation interest. The marker system was then used to survey patterns of population genetic variation of Lotus sessilifolius, a Canary Island endemic occurring on four islands (La Palma, El Hierro, La Gomera and Tenerife) with the aim of determining whether any of its populations are worthy of special conservation because of genetic distinctiveness. We found strong differentiation between populations with conspicuous geographical signal revealed by population clustering. Generally, populations from each island grouped together. A very striking exception to this pattern is a single population from Tenerife (Tejina-Milán: Anaga Peninsula), which is separated from other Tenerife populations by both genetic clustering and a STRUCTURE analysis, and also shows signs of inbreeding. The genetic distinctiveness of this population deserves especial conservation attention, and may be related to the ancient geological history of the Anaga Peninsula. Importantly, this investigation sets the stage for conservation genetics research in other highly threatened species in the same genus.
... This is true regardless of the frequently cited comments from Mayr (1967) that islands are natural laboratories for the study of evolution. Different components of the biology of island plants have been studied, including exemplary studies of reproductive biology (e.g., Sun & Ganders, 1988;McMullen, 1990;Weller et al., 1998;Anderson et al., 2001Anderson et al., , 2006Bernardello et al., 2001;Sakai et al., 2006), phylogeny (Francisco-Ortega et al., 1997;Baldwin et al., 1998;Baldwin, 2003;Carine et al., 2004), eco-physiology (Givnish et al., 2004;Givnish & Montgomery, 2014), fertility of interspecific hybrids (Gillett & Lim, 1970;Carr & Kyhos, 1986;Carr, 2003), and biogeography (Puppo et al., 2014;Otto et al., 2016). However, integrated studies focused on processes and not just patterns, have rarely, if ever, been carried out on an island lineage. ...
Article
Oceanic islands have long been called natural laboratories for studying evolution because they are geologically young, isolated, dynamic areas with diverse habitats over small spatial scales. Volcanic substrates of different ages permit the study of different stages of divergence and speciation within plant lineages. In addition to divergence, the dynamic island setting is conducive to hybridization. Discussion will focus on the potential of systematic/ecological studies, in combination with genomic data from high throughput sequencing and an ever-increasing array of analytical techniques, for studying evolution in island plants. These studies may include: generation of highly resolved phylogenies to clarify the biogeography of speciation and whether divergence has occurred with or without gene flow; identification of the barriers to gene flow (extrinsic vs. intrinsic) of importance during divergence; documentation of historical and current hybridization events within island lineages; and elucidation of the genomic composition and ecology of hybrid populations in order to infer the evolutionary consequences of hybridization, such as the origin of stabilized homoploid hybrid species.
... In addition to islands of different ages in archipelagos such as the Canary and Hawaiian Islands, there are substrates of varying ages on single islands, as well as areas of natural and human-mediated disturbances on individual islands (e.g., Sherrod, 2009;Carracedo, 2011). In essence, there may be islands within islands, with species or cryptic species, occurring on different substrates on islands with complex geological histories, such as Tenerife in the Canary Islands (e.g., Puppo et al., 2014). More recent lava flows (even in historical times), natural landslide areas, and areas of human disturbance provide open areas for colonization and subsequent divergence, as well as the potential for the generation of novelty by hybridization (Otto et al., 2016). ...
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Plant species on oceanic islands comprise nearly 25% of described vascular plants on only 5% of the Earth`s land surface yet are among the most rare and endangered plants. Conservation of plant biodiversity on islands poses particular challenges because many species occur in a few and/or small populations, and their habitats on islands are often disturbed by the activity of humans or by natural processes such as landslides and volcanoes. In addition to described species, evidence is accumulating that there are likely significant numbers of "cryptic" species in oceanic archipelagos. Plant systematists, in collaboration with others in the botanical disciplines, are critical to the discovery of the subtle diversity in oceanic island floras. Molecular data will play an ever increasing role in revealing variation in island lineages. However, the input from plant systematists and other organismal biologists will continue to be important in calling attention to morphological and ecological variation in natural populations and in the discovery of "new" populations that can inform sampling for molecular analyses. Conversely, organismal biologists can provide basic information necessary for understanding the biology of the molecular variants, including diagnostic morphological characters, reproductive biology, habitat, etc. Such basic information is important when describing new species and arguing for their protection. Hybridization presents one of the most challenging problems in the conservation of insular plant diversity, with the process having the potential to decrease diversity in several ways including the merging of species into hybrid swarms or conversely hybridization may generate stable novel recombinants that merit recognition as new species. These processes are often operative in recent radiations in which intrinsic barriers to gene flow have not evolved. The knowledge and continued monitoring of plant populations in the dynamic landscapes on oceanic islands are critical to the preservation of their plant diversity.
... 3Á5 Mya (Ancochea et al., 1990). Indeed, there are a few examples that indicate a biogeographic split among sister taxa or populations of a single species that date back to the Miocene (Juan et al., 1996;Dimitrov et al., 2008;Maci as-Hern andez et al., 2013;Puppo et al., 2014); however, various documented and time-calibrated biogeographic splits have been placed in the Pleistocene (e.g. Kondraskov et al., 2015). ...
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Background and Aims Macaronesian laurel forest is among the worldwide hotspots of threatened biodiversity. With increasing evidence that woodland composition on the Canary Islands changed dramatically during the last few thousand years, the aim of this study was to find evidence for substantial recent population dynamics of two representative species from laurel forest. Methods Amplified fragment length polymorphism (AFLP) was used to evaluate fine-scaled genetic variation of the paradigmatic tree Laurus novocanariensis (Lauraceae) and a long-lived herbaceous gentian from core laurel forest, Ixanthus viscosus (Gentianaceae), on Tenerife. Bioclimatic variables were analysed to study the respective climate niches. A chloroplast DNA screening was performed to evaluate additional genetic variation. Key Results Genetic diversity of the laurel tree showed severe geographic partitioning. On Tenerife, fine-scaled Bayesian clustering of genetic variation revealed a western and an eastern gene pool, separated by a zone of high admixture and with a third major gene pool. Compared with genetic clusters found on the other Canary Islands, the East–West differentiation on Tenerife seems to be more recent than differentiation between islands. This is substantiated by the finding of extremly low levels of chloroplast DNA-based polymorphisms. Ixanthus showed no geographic structuring of genetic variation. Conclusions Genetic data from Tenerife indicate contemporary gene flow and dispersal on a micro/local scale rather than reflecting an old and relic woodland history. In particular for Laurus, it is shown that this species occupies a broad bioclimatic niche. This is not correlated with its respective distribution of genetic variation, therefore indicating its large potential for contemporary rapid and effective colonization. Ixanthus is more specialized to humid conditions and is mostly found in the natural Monteverde húmedo vegetation types, but even for this species indications for long-term persistence in the respective bioclimatically differentiated regions was not find.
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The Earth's islands harbor a distinct, yet highly threatened, biological and cultural diversity that has been shaped by geographic isolation and unique environments. Island systems are key natural laboratories for testing theory in ecology and evolution. However, despite their potential usefulness for research, a quantitative description of island environments and an environmental classification are still lacking. Here, we prepare a standardized dataset and perform a comprehensive global environmental characterization for 17,883 of the world's marine islands >1 km(2) (∼98% of total island area). We consider area, temperature, precipitation, seasonality in temperature and precipitation, past climate change velocity, elevation, isolation, and past connectivity-key island characteristics and drivers of ecosystem processes. We find that islands are significantly cooler, wetter, and less seasonal than mainlands. Constrained by their limited area, they show less elevational heterogeneity. Wet temperate climates are more prevalent on islands, whereas desert climates are comparatively rare. We use ordination and clustering to characterize islands in multidimensional environmental space and to delimit island ecoregions, which provides unique insights into the environmental configuration and diversity of the world's islands. Combining ordination and classification together with global environmental data in a common framework opens up avenues for a more integrative use of islands in biogeography, macroecology, and conservation. To showcase possible applications of the presented data, we predict vascular plant species richness for all 17,883 islands based on statistically derived environment-richness relationships.
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The extent of mass wasting along the north flank of Tenerife has been mapped using swath bathymetry, GLORIA side-scan sonar, and 3.5-kHz echo sounder data. The marine surveys show that, north of Tenerife, a giant landslide is exposed over an area of 5500 km2 of the seafloor, more than twice the surface area of the island. The landslide truncates an older ridge and valley topography that is associated with the shield building basalts on Tenerife. We interpret the ridge and valley topography as the result of subaerial erosion. The landslide is estimated to have a length of 100 km, a width of up to 80 km, and a volume of about 1000 km3. It extends onshore into the Orotava and Icod valleys which have been interpreted as of landslide origin. K-Ar dating of basaltic flows in the steep headwall of Orotava suggests an age of formation for the valley is younger than 0.78 Ma and may even be younger than 0.27 Ma. The Icod valley is located immediately to the north of the most recent volcano on Tenerife, Las Cañadas, and has been associated with the collapse of its caldera, between 1.2 and 0.2 Ma.A young age for the landslide is supported by the 3.5-kHz echo sounder data which show that the landslide is draped by a thin (
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Micromeria Benth. (Lamiaceae, Nepetoideae) is a very common genus in the Mediterranean region. To test the monophyly of the genus and to elucidate its phylogenetic placement within subtribe Menthinae (Dumort) Endl. of tribe Mentheae Dumort we performed parsimony analysis of trnK intron sequence data of 51 accessions representing 15 genera of Nepetoideae and two genera of subfamily Ajugoideae. Tree topology reveals a well-supported "core group" indicating four distinct lineages. The first one comprises three species of Satureja L. s.str., the second one includes taxa of the genus Clinopodium L. from both the Old and the New World, paraphyletic with respect to Monarda L. and two species of Micromeria section Pseudomelissa Benth. A third group contains all samples of the remaining Micromeria species. Within this monophyly, a western lineage including taxa from NW Africa, the Balearic, and the Canary Islands, is sister to an eastern lineage with species distributed from SE Asia to the western Mediterranean. In a further clade the genera Thymbra L., Thymus L., and Origanum L. are grouped together. Combined analysis using a reduced dataset of trnK/trnL-F sequences increased support for the infrageneric resolution within Micromeria. Based on the phylogenetic reconstructions there is evidence that the genus as currently circumscribed is polyphyletic. Results are discussed in the context of morphology, karyology, and biogeography, outlining the necessity of removing section Pseudomelissa from Micromeria.
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The use of single copy nuclear markers is of increasing importance in plant phylogenetics. The generally higher level of variability compared to chloroplast DNA and the ability to use incongruence in a multilocus analysis to determine reticulation patterns makes these kinds of sequence based markers especially useful for species level investigations. However, the prevalence of gene duplication that results from the high frequency of polyploidization events during the evolution of higher plants can impede marker development especially for groups lacking model organisms. Here, we present the strategy and results of marker development for phylogenetic analysis in Micromeria, using publicly available DNA sequences and ESTs from related genera from Lamiaceae, subfamily Nepetoideae. By eliminating markers with signatures of duplication during four steps of marker development, we were able to select 19 primer pairs that resulted in orthologous products for all the species studied. This corresponds to 23% of the initial 84 primer pairs designed. Using an initial sampling of eight individuals, we tested the markers for support of phylogenetic hypotheses related to the evolution of Micromeria on the Canary Islands. While some hypotheses were supported by all markers, an east west split, with a closer relationship between the species of Tenerife and Madeira on one hand and the ones from Gran Canaria and the eastern islands on the other is supported by 12 markers but contradicted by the remaining seven. This indicates that reticulation and inter-island gene flow played a role in the evolution of Micromeria.
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Computational evolutionary biology, statistical phylogenetics and coalescent-based population genetics are becoming increasingly central to the analysis and understanding of molecular sequence data. We present the Bayesian Evolutionary Analysis by Sampling Trees (BEAST) software package version 1.7, which implements a family of Markov chain Monte Carlo (MCMC) algorithms for Bayesian phylogenetic inference, divergence time dating, coalescent analysis, phylogeography and related molecular evolutionary analyses. This package includes an enhanced graphical user interface program called Bayesian Evolutionary Analysis Utility (BEAUti) that enables access to advanced models for molecular sequence and phenotypic trait evolution that were previously available to developers only. The package also provides new tools for visualizing and summarizing multispecies coalescent and phylogeographic analyses. BEAUti and BEAST 1.7 are open source under the GNU lesser general public license and available at http://beast-mcmc.googlecode.com and http://beast.bio.ed.ac.uk
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Most evolutionary studies of oceanic islands have focused on the Pacific Ocean. There are very few examples from the Atlantic archipelagos, especially Macaronesia, despite their unusual combination of features, including a close proximity to the continent, a broad range of geological ages, and a biota linked to a source area that existed in the Mediterranean basin before the late Tertiary. A chloroplast DNA (cpDNA) restriction site analysis of Argyranthemum (Asteraceae: Anthemideae), the largest endemic genus of plants of any volcanic archipelago in the Atlantic Ocean, was performed to examine patterns of plant evolution in Macaronesia. cpDNA data indicated that Argyranthemum is a monophyletic group that has speciated recently. The cpDNA tree showed a weak correlation with the current sectional classification and insular distribution. Two major cpDNA lineages were identified. One was restricted to northern archipelagos--e.g., Madeira, Desertas, and Selvagens--and the second comprised taxa endemic to the southern archipelago--e.g., the Canary Islands. The two major radiations identified in the Canaries are correlated with distinct ecological habitats; one is restricted to ecological zones under the influence of the northeastern trade winds and the other to regions that are not affected by these winds. The patterns of phylogenetic relationships in Argyranthemum indicate that interisland colonization between similar ecological zones is the main mechanism for establishing founder populations. This phenomenon, combined with rapid radiation into distinct ecological zones and interspecific hybridization, is the primary explanation for species diversification.
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Argyranthemum coronopifolium (Willd.) C. J. Humphries, a rare endemic of Ten–erife in the Canary Islands, has a disjunct distribution which coincides with the two largest Tertiary basalt massives, Teno and Anaga. No morphological differentiation was found between the Teno and Anaga populations. The disjunction is believed to be due to barriers caused by lava flows in the intermediate region of North Tenerife. A. coronopifolium is shown to be hybridizing with the widespread A. frutescens (L.) Schultz Bip. in both Anaga and Teno. The hybridization was analysed phenetically by Wells' distance method and principal coordinate analysis. Geographical barriers between the species are shown to be broken down by road side immigration of A. frutescens into the area of A. coronopifolium, and the possibility of swamping is discussed. The trend of increasing hybridization is connected to the development of tourism in the Canary Islands.
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Islands have long provided model systems in which ecologists and evolutionary biologists have develo-ped, tested and refined models for species diversity (Whittaker and Fernández-Palacios 2007). In two recent papers, Emerson and Kolm (2005a, b) have presented and discussed multiple regression analyses from two oceanic archipelagos, the Canaries and Hawaii, demon-strating for plants and arthropods that islands of greater species richness also have higher proportions of single island endemics (SIEs). They claim this as evidence that higher species richness of a taxon drives higher rates of diversification in that taxon, i.e. that ''diversity begets diversity''. Their analysis is interesting, but given that it is an analysis of proportions of SIEs not rate of species production, it is ultimately inconclusive as to mechan-isms leading to the relationship. It might tell us, as inferred by Emerson and Kolm (2005a, b), that high species richness creates the conditions for high rates of speciation through: 1) competitive interactions, 2) genetic drift due to small population sizes, and 3) greater community structural complexity. But it could also be that the relationship is a by-product of circum-stances not adequately captured in their analyses. Herein, we develop an alternative model, positing that the opportunities for speciation have a broadly predictable relationship to the life cycle of oceanic islands. We term our model the island immaturity Á speciation pulse (IISP) model of island evolution. Intrinsic to this model is that opportunity drives speciation rate and that opportunity is greatest at a relatively early stage of an island's life cycle, when intrinsic carrying capacity exceeds species richness by the greatest margin, i.e. when there is greatest ''vacant niche space''. As islands mature, both richness and endemism increase in tandem, but as islands decline in their old age, opportunities for speciation diminish, in tandem with a reduced carrying capacity (and reduced numbers of SIEs). Our argument is that the mechanisms identified by Emerson and Kolm (2005a, b), whilst each having a role in island evolution, make for an incomplete set of key island mechanisms and that in particular they neglect the likely importance of compe-titive release early in the life cycle of an island, and of the subsequent decline in carrying capacity, for the propor-tions of single island endemics (see Peck et al. 1999). In setting out the IISP model, we describe the observations on which it is based, and then examine what we expect in terms of critical rates, and emergent patterns of SIEs, comparing our model with that put forward by Emerson and Kolm (2005a, b). We illustrate our model with reference to data for the arthropods and plants of the Canary Islands (cf. Emerson and Kolm 2005a).
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Aim MacArthur and Wilson’s dynamic equilibrium model of island biogeography provides a powerful framework for understanding the ecological processes acting on insular populations. However, their model is known to be less successful when applied to systems and processes operating on evolutionary and geological timescales. Here, we present a general dynamic model (GDM) of oceanic island biogeography that aims to provide a general explanation of biodiversity patterns through describing the relationships between fundamental biogeographical processes – speciation, immigration, extinction – through time and in relation to island ontogeny.
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Premise of the study: The mint family (Lamiaceae) is the sixth largest family of flowering plants, with the tribe Mentheae containing about a third of the species. We present a detailed perspective on the evolution of the tribe Mentheae based on a phylogenetic analysis of cpDNA and nrDNA that is the most comprehensive to date, a biogeographic set of analyses using a fossil-calibrated chronogram, and an examination of staminal evolution. Methods: Data from four cpDNA and two nrDNA markers representing all extant genera within the tribe Mentheae were analyzed using the programs BEAST, Lagrange, S-DIVA, and BayesTraits. BEAST was used to simultaneously estimate phylogeny and divergence times, Lagrange and S-DIVA were used for biogeographical reconstruction, and BayesTraits was used to infer staminal evolution within the tribe. Key results: Currently accepted subtribal delimitations are shown to be invalid and are updated. The Mentheae and all five of its subtribes have a Mediterranean origin and have dispersed to the New World multiple times. The vast majority of New World species of subtribe Menthinae are the product of a single dispersal event in the mid-late Miocene. At least four transitions from four stamens to two stamens have occurred within Mentheae, once in the subtribe Salviinae, once in the subtribe Lycopinae, and at least twice in the subtribe Menthinae. Conclusions: Worldwide cooling trends probably played a large role in the diversification and present day distribution of the tribe Mentheae. Additional work is needed to ascertain relationships within some Mentheae genera, especially in the subtribe Menthinae.
Article
New age determinations from Tenerife, together with those previously published (93 in all), provide a fairly comprehensive picture of the volcanic evolution of the island. The oldest volcanic series, with ages starting in the late Miocene, are formed mainly by basalts with some trachytes and phonolites which appear in Anaga, Teno and Roque del Conde massifs. In Anaga (NE), three volcanic cycles occurred: one older than 6.5 Ma, a second one between 6.5 and 4.5 Ma, with a possible gap between 5.4 and 4.8 Ma, and a late cycle around 3.6 Ma. In Teno (NW), after some undated units, the activity took place between 6.7 and 4.5 Ma, with two main series separated by a possible pause between 6.2 and 5.6 Ma. In the zone of Roque del Conde (S), the ages are scattered between 11.6 and 3.5 Ma. Between 3.3 and 1.9 Ma, the whole island underwent a period of volcanic quiescence and erosion.
Article
Dike complexes, which are increasingly accepted as a common feature in the growth of most oceanic volcanoes, are well represented in the Canary Islands, where their deep structure can be readily observed through hundreds of infiltration galleries excavated for water mining. These intrusive complexes have their surficial representation as narrow, clearly aligned clusters of emission centers that, cumulatively, form steep topographic ridges. In the subsoil, a narrow band of tightly packed parallel dikes runs through the center of the structure. These volcanotectonic features behave as true active polygenetic volcanoes and show clear rift affinities. The geometry of these rift zones is either single or three-branched. The two-branched stage, probably transitional, has not been observed. The rift zones play a key role in the mass wasting and destruction of mature oceanic volcanoes. Cumulative gravitational stresses related to the growth of the volcanic edifices increase their instability. More ephemeral mechanisms associated with intense eruptive phases, such as dike wedging, increase of slope angles and strong local seismicity associated with magma movement can finally trigger massive landslides. Massive landslides, enhanced by later erosion, may be the explanation for the origin of numerous horseshoe-type valleys and calderas in the Canary Islands. The “least-effort” geometry of complex rift zones seems to fit some mechanism of magma-induced upwelling, such as a hotspot, in the explanation of the genesis of the Canarian Archipelago. The rift zones play a major role in the distribution of historic volcanism in the Canary Islands and, therefore, in their volcanic hazards assessment.
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1 Large endemic plant taxa found on oceanic archipelagos are frequently monophyletic, indicating that they originate from a single colonization event. 2 Colonization is a two-stage process requiring both dispersal and establishment to be successful. Accordingly, once-only colonization may be explained either by dispersal barriers limiting colonization, or by the first successful colonization of an island inhibiting the establishment of later arrivals through niche pre-emption and interspecific competition. 3 Using the endemic flora of the Canaries and Macaronesia as a test case, I argue that barriers to dispersal are low and that niche pre-emption is therefore the more likely explanation for the monophyly of large endemic groups in these islands.
Article
Recently, the Canary Islands have become a focus for studies of the colonization and the diversification of different organisms. Some authors have considered Canarian endemisms as relicts of Tertiary origin, but new molecular data suggest a general pattern of continental dispersion followed by in situ speciation. Recent phylogeographic studies are revealing variants of the simple stepping-stone colonization model that seems to hold for many Hawaiian groups. Many factors can generate deviations from such a pattern: the stochastic nature of colonization, competitive exclusion, phylogenetic constraints on adaptive evolution and extinction. An understanding of island colonization and diversification can best be developed from an ecosystem level synthesis as more data for the Canarian archipelago come to hand.
Article
Current routine genotyping methods typically do not provide haplotype information, which is essential for many analyses of fine-scale molecular-genetics data. Haplotypes can be obtained, at considerable cost, experimentally or (partially) through genotyping of additional family members. Alternatively, a statistical method can be used to infer phase and to reconstruct haplotypes. We present a new statistical method, applicable to genotype data at linked loci from a population sample, that improves substantially on current algorithms; often, error rates are reduced by > 50%, relative to its nearest competitor. Furthermore, our algorithm performs well in absolute terms, suggesting that reconstructing haplotypes experimentally or by genotyping additional family members may be an inefficient use of resources.
Article
Abstract A molecular phylogenetic study of Bystropogon L'Her. (Lamiaceae) is presented. We performed a cladistic analysis of nucleotide sequences of the internal transcribed spacers (ITS), of the nuclear ribosomal DNA, and of the trnL gene and trnL-trnF intergenic spacer of the chloroplast DNA. Bystropogon odoratissimus is the only species endemic to the Canary Islands that occurs in the three palaeo-islands of Tenerife. This species is not part of an early diverging lineage of Bystropogon and we suggest that it has a recent origin. This phylogenetic pattern is followed by most of the species endemic to the palaeo-islands of Tenerife. The two sections currently recognized in Bystropogon form two monophyletic groups. Taxa belonging to the section Bystropogon clade show interisland colonization limited to the Canary Islands with ecological shifts among three ecological zones. Taxa from the section Canariense clade show interisland colonization both within the Canary Islands and between the Canary Islands and Madeira. Speciation events within this clade are mostly limited to the laurel forest. The genus has followed a colonization route from the Canaries towards Madeira. This route has also been followed by at least five other plant genera with species endemic to Macaronesia. Major incongruences were found between the current infrasectional classification and the molecular phylogeny, because the varieties of Bystropogon origanifolius and Bystropogon canariensis do not form two monophyletic groups. The widespread B. origanifolius appears as progenitor of the other species in section Bystropogon with a more restricted distribution.
Article
The evolutionary history of a set of taxa is usually represented by a phylogenetic tree, and this model has greatly facilitated the discussion and testing of hypotheses. However, it is well known that more complex evolutionary scenarios are poorly described by such models. Further, even when evolution proceeds in a tree-like manner, analysis of the data may not be best served by using methods that enforce a tree structure but rather by a richer visualization of the data to evaluate its properties, at least as an essential first step. Thus, phylogenetic networks should be employed when reticulate events such as hybridization, horizontal gene transfer, recombination, or gene duplication and loss are believed to be involved, and, even in the absence of such events, phylogenetic networks have a useful role to play. This article reviews the terminology used for phylogenetic networks and covers both split networks and reticulate networks, how they are defined, and how they can be interpreted. Additionally, the article outlines the beginnings of a comprehensive statistical framework for applying split network methods. We show how split networks can represent confidence sets of trees and introduce a conservative statistical test for whether the conflicting signal in a network is treelike. Finally, this article describes a new program, SplitsTree4, an interactive and comprehensive tool for inferring different types of phylogenetic networks from sequences, distances, and trees.
Article
The Canary Islands have been a focus for phylogeographic studies on the colonization and diversification of endemic angiosperm taxa. Based on phylogeographic patterns, both inter island colonization and adaptive radiation seem to be the driving forces for speciation in most taxa. Here, we investigated the diversification of Micromeria on the Canary Islands and Madeira at the inter- and infraspecific level using inter simple sequence repeat PCR (ISSR), the trnK-Intron and the trnT-trnL-spacer of the cpDNA and a low copy nuclear gene. The genus Micromeria (Lamiaceae, Mentheae) includes 16 species and 13 subspecies in Macaronesia. Most taxa are restricted endemics, or grow in similar ecological conditions on two islands. An exception is M. varia, a widespread species inhabits the lowland scrub on each island of the archipelago and could represent an ancestral taxon from which radiation started on the different islands. Our analyses support a split between the "eastern" islands Fuerteventura, Lanzarote and Gran Canaria and the "western" islands Tenerife, La Palma and El Hierro. The colonization of Madeira started from the western Islands, probably from Tenerife as indicated by the sequence data. We identified two lineages of Micromeria on Gomera but all other islands appear to be colonized by a single lineage, supporting adaptive radiation as the major evolutionary force for the diversification of Micromeria. We also discuss the possible role of gene flow between lineages of different Micromeria species on one island after multiple colonizations.
Article
We present Neighbor-Net, a distance based method for constructing phylogenetic networks that is based on the Neighbor-Joining (NJ) algorithm of Saitou and Nei. Neighbor-Net provides a snapshot of the data that can guide more detailed analysis. Unlike split decomposition, Neighbor-Net scales well and can quickly produce detailed and informative networks for several hundred taxa. We illustrate the method by reanalyzing three published data sets: a collection of 110 highly recombinant Salmonella multi-locus sequence typing sequences, the 135 "African Eve" human mitochondrial sequences published by Vigilant et al., and a collection of 12 Archeal chaperonin sequences demonstrating strong evidence for gene conversion. Neighbor-Net is available as part of the SplitsTree4 software package.
Revisi on del g enero Micromeria Bentham (Lamiaceae–Stachyoideae) en la Regi on Maca-ron esica
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The theory of island biogeography Molecular evidence for adaptive radiation of Micromeria Benth. (Lamiaceae) on the Canary Islands as inferred from chloroplast and nuclear DNA sequences and ISSR fingerprint data
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Revisi on del g enero Micromeria Bentham (Lamiaceae-Stachyoideae) en la Regi on Macaron esica. Instituto de Estudios Canarios
  • P Erez De Paz
P erez de Paz, P.L. (1978) Revisi on del g enero Micromeria Bentham (Lamiaceae-Stachyoideae) en la Regi on Macaron esica. Instituto de Estudios Canarios, Monograf ıas, 16, 1-306.
Bioclimatic and physical characterization of the world's islands
  • P Weigelt
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Weigelt, P., Jetz, W. & Kreft, H. (2013) Bioclimatic and physical characterization of the world's islands. Proceedings of the Natural Academy of Sciences of Philadelphia, 110, 15307-15312.
jModelTest 2: more models, new heuristics and parallel computing
  • Darriba
Hybridization and distribution of Argyranthemum coronopifolium (Asteraceae-Arthemideae) in the Canary Islands
  • Brochman
The island immaturity - speciation pulse model of island evolution: an alternative to the “diversity begets diversity” model
  • Whittaker
Revisión del género Micromeria Bentham (Lamiaceae-Stachyoideae) en la Región Macaronésica
  • Pérez de Paz