Showing papers by "Pablo Vargas published in 2019"
TL;DR: Diversification analyses revealed that nectar spurs are loosely associated with increased diversification rates, which can only be fully explained by the complex interaction of multiple biotic and abiotic factors.
Abstract: Floral nectar spurs are widely considered a key innovation promoting diversification in angiosperms by means of pollinator shifts. We investigated the macroevolutionary dynamics of nectar spurs in the tribe Antirrhineae (Plantaginaceae), which contains 29 genera and 300-400 species (70-80% spurred). The effect of nectar spurs on diversification was tested, with special focus on Linaria, the genus with the highest number of species. We generated the most comprehensive phylogeny of Antirrhineae to date and reconstructed the evolution of nectar spurs. Diversification rate heterogeneity was investigated using trait-dependent and trait-independent methods, and accounting for taxonomic uncertainty. The association between changes in spur length and speciation was examined within Linaria using model testing and ancestral state reconstructions. We inferred four independent acquisitions of nectar spurs. Diversification analyses revealed that nectar spurs are loosely associated with increased diversification rates. Detected rate shifts were delayed by 5-15 Myr with respect to the acquisition of the trait. Active evolution of spur length, fitting a speciational model, was inferred in Linaria, which is consistent with a scenario of pollinator shifts driving diversification. Nectar spurs played a role in diversification of the Antirrhineae, but diversification dynamics can only be fully explained by the complex interaction of multiple biotic and abiotic factors.
29 citations
TL;DR: To investigate factors that explain the spatial pattern of genetic diversity in three closely related species (Linaria glacialis, Linaria nevadensis and Chaenorhinum glareosum) endemic to a fragile high mountain ecosystem, a genome-wide analysis is conducted.
17 citations
TL;DR: The aim is to reconstruct the biogeographical history of the Omphalodeae and to investigate the role of diaspore traits favoring LDD and current geographic distributions, which result is that epizoochorous traits have been the ancestral state of LDD syndromes in most clades.
Abstract: This study was supported by the Fundacion General CSIC and Banco Santander as part ofthe project titled “Do all endangered species hold the samevalue?: origin and conservation of living fossils of floweringplants endemic to Spain
13 citations
12 citations
TL;DR: The results indicate that the earliest divergence events in Cynoglossoideae occurred in the central-northeastern Palearctic during the Paleogene and an epizoochorous trait is ancestral and has been maintained long term, and glochids are correlated with increased diversification rates in two distantly related clades.
Abstract: PREMISE OF THE STUDY Long-distance dispersal (LDD) syndromes, especially endozoochory, facilitate plant colonization of new territories that trigger diversification. However, few studies have analyzed how epizoochorous fruits influence both range distribution and diversification rates. We examined the evolutionary history of a hyperdiverse clade of Boraginaceae (subfamily Cynoglossoideae, eight tribes, ~60 genera, ~1100 species) and the evolution of fruit traits. We evaluated the evolutionary history of diaspore syndromes correlated with geographic distribution and diversification rates over time. METHODS Plastid DNA regions and morphological traits associated with dispersal syndromes were analyzed for 71 genera (226 species). We employed trait-dependent diversification analysis (HiSSE) and biogeographic reconstruction (Lagrange) using a time-calibrated phylogeny. KEY RESULTS Our results indicate that (1) the earliest divergence events in Cynoglossoideae occurred in the central-northeastern Palearctic during the Paleogene (early to middle Eocene); (2) an epizoochorous trait (specialized hooks named glochids) is ancestral and has been maintained long term; and (3) glochids are correlated with increased diversification rates in two distantly related clades (Rochelieae and Cynoglossinae). Rapid speciation occurred for these two groups in the same area (central-eastern Palearctic) and same period (Oligocene-Miocene: Rochelieae, 30.82-13.69 mya; Cynoglossinae, 33.10-15.21 mya). Lower diversification rates were inferred for the remaining four glochid-bearing clades. CONCLUSIONS One more example of "biogeographic congruence" in angiosperms is supported by a shared geographic (central-northeastern Palearctic) and temporal (28.60-21.59 mya, late Oligocene) opportunity window for two main clades' diversification. Epizoochorous traits (fruit glochids) had an effect in higher diversification rates only with the joint effect of other unmeasured factors.
12 citations
TL;DR: Lizards are important seed dispersers throughout the year and across the whole archipelago, regardless of body size, as well as factors other than fruit abundance may be more important drivers of fruit selection.
Abstract: Frugivory in lizards is often assumed to be constrained by body size; only large individuals are considered capable of consuming fruits, with the potential of acting as seed dispersers. However, only one previous study has tested the correlation of frugivory with body and head size at an archipelago scale across closely related species. All nine lava lizards (Microlophus spp.) were studied on the eleven largest Galapagos islands from 2010 to 2016 to investigate whether frugivory is related to body and head size. We also tested whether fruit abundance influences fruit consumption and explored the effect of seed ingestion on seedling emergence time and percentage. Our results showed that across islands, lava lizards varied considerably in size (64-102 mm in mean snout-vent length) and level of frugivory (1-23%, i.e., percentage of droppings with seeds). However, level of frugivory was only weakly affected by size as fruit consumption was also common among small lizards. Lava lizards consumed fruits throughout the year and factors other than fruit abundance may be more important drivers of fruit selection (e.g., fruit size, energy content of pulp). From 2,530 droppings, 1,714 seeds of at least 61 plant species were identified, 76% of the species being native to the Galapagos. Most seeds (91%) showed no external structural damage. Seedling emergence time (44 versus 118 days) and percentage (20% versus 12%) were enhanced for lizard-ingested seeds compared to control (uningested) fruits. De-pulping by lizards (i.e., removal of pulp with potential germination inhibitors) might increase the chances that at least some seeds find suitable recruitment conditions. We concluded that lizards are important seed dispersers throughout the year and across the whole archipelago, regardless of body size.
10 citations
TL;DR: An integrative study enabled to overcome previous barriers to understanding parapatric speciation by demonstrating the recurrence of progenitor-derivative speciation in plants with gene flow and ecological differentiation, explaining observed parapatry and paraphyly.
Abstract: SUMMARY Traditional classification of speciation modes has focused on physical barriers to gene flow. While allopatry has been viewed as the most common mechanism of speciation, parapatry and sympatry, both entail speciation in the face of ongoing gene flow and thus both are far more difficult to detect and demonstrate. Iberodes (Boraginaceae, NW Europe) with a small number of recently derived species (five) and contrasting morphological traits, habitats and distribution patterns constitutes an ideal system in which to study drivers of lineage divergence and differentiation. To reconstruct the evolutionary history of the genus, we undertook an integrative study entailing: (i) phylogenomics based on restriction-site associated DNA sequencing (RAD-seq), (ii) morphometrics, and (iii) climatic niche modelling. Key results revealed a history of repeated progenitor-derivative speciation, manifesting in paraphyletic pattern within Iberodes. Climatic niche analyses, together with the morphometric data and species distributions, suggest that ecological and geographical differentiation have interacted to shape the diversity of allopatric and parapatric distributions observed in Iberodes. Our integrative study has enabled to overcome previous barriers to understanding parapatric speciation by demonstrating the recurrence of progenitor-derivative speciation in plants with gene flow and ecological differentiation, explaining observed parapatry and paraphyly.
6 citations
TL;DR: Climatic niche analyses, together with the morphometric data and species distributions, suggests that ecological and geographical differentiation interact in concert, in such a way that both allopatric and parapatric have been operating in Iberodes.
Abstract: Traditional classification of speciation modes has been focused on physical barriers to gene flow. Allopatry—geographic separation of populations so that gene flow between them is more or less severed—has as a consequence been viewed as the most common mechanism of speciation (allopatric speciation). By contrast, parapatry and sympatry—no physical barrier is found separating populations (adjacent or overlapped) so that speciation takes place in the face of ongoing gene flow— is more difficult to demonstrate. Iberodes (Boraginaceae) is a primarily Iberian genus that comprises a relatively small number of recently derived species (five) with contrasting diaspore dispersal traits, habitats and distribution patterns. In particular, species distributions of Iberodes offer an ideal system to study drivers of lineage divergence and differentiation in the course of evolution. To reconstruct the evolutionary history of the genus, we addressed an integrative study combining a suitable set of tools: (i) phylogenetics based on restriction-site associated DNA sequencing (RAD-seq), (ii) morphometrics, and (iii) climatic niche modelling. Our robust phylogenetic reconstruction of Iberodes reveals a predominantly budding speciation pattern. Climatic niche analyses, together with the morphometric data and species distributions, suggests that ecological and geographical differentiation interact in concert, in such a way that both allopatric and parapatric have been operating in Iberodes.
5 citations
TL;DR: The inference analysis does not provide evidence for interactions, indicating that cells migrate by sensing independently the chemokine source, and it is speculated that mature dendritic cells disregard intercellular signals that could otherwise delay their arrival to lymph vessels.
Abstract: Migration of cells can be characterized by two, prototypical types of motion: individual and collective migration. We propose a statistical-inference approach designed to detect the presence of cell-cell interactions that give rise to collective behaviors in cell-motility experiments. Such inference method has been first successfully tested on synthetic motional data, and then applied to two experiments. In the first experiment, cell migrate in a wound-healing model: when applied to this experiment, the inference method predicts the existence of cell-cell interactions, correctly mirroring the strong intercellular contacts which are present in the experiment. In the second experiment, dendritic cells migrate in a chemokine gradient. Our inference analysis does not provide evidence for interactions, indicating that cells migrate by sensing independently the chemokine source. According to this prediction, we speculate that mature dendritic cells disregard inter-cellular signals that could otherwise delay their arrival to lymph vessels.
2 citations
03 Dec 2019
TL;DR: Iberodes M. Serrano, R. Carbajal & S. Ortiz as discussed by the authors is a genero of Boraginaceas subendemico of la peninsula Iberica, with poblaciones disyuntas en Francia (region sureste and costa oeste in el Golfo de Vizcaya).
Abstract: Iberodes M. Serrano, R. Carbajal & S. Ortiz es un genero de Boraginaceas subendemico de la peninsula Iberica, con poblaciones disyuntas en Francia (region sureste y costa oeste en el Golfo de Vizcaya). Este genero comprende cinco especies de plantas anuales (una de ellas con dos subespecies), originalmente consideradas dentro del genero Omphalodes (Serrano et al., 2016). Si tenemos en cuenta la especializacion ecologica de las cinco especies, el genero se puede dividir en dos grupos: por un lado, tres especies de ambientes continentales del interior; y por otro, dos especies litorales que viven sobre dunas costeras. Otra peculiaridad anadida de este genero es que cuatro de las cinco especies estan catalogadas dentro de las categorias de riesgo y amenaza de la UICN, y tres de ellas cuentan con proteccion legal de acuerdo con los catalogos regionales de Castilla y Leon y Galicia, el Catalogo Espanol, la Directiva de Habitats y el Convenio de Berna
11 Oct 2019
TL;DR: Luceno, Mazuecos & P. Vargas as discussed by the authors described a new species of Linaria sect. Supinae, which is a narrow endemic inhabiting the southern hills of the western and central massifs of Sierra de Gredos (Sistema Central mountains, Iberian Peninsula).
Abstract: Una especie nueva de Linaria sect. Supinae en la Sierra de Gredos (Sistema Central, Peninsula Iberica)Linaria vettonica Luceno, Mazuecos & P. Vargas, a new species of Linaria sect. Supinae, is described. It is a narrow endemic inhabiting the southern hills of the western and central massifs of Sierra de Gredos (Sistema Central mountains, Iberian Peninsula). The five populations found occur on siliceous, sandy soils of Quercus pyrenaica woodland clearings and slopes. L. vettonica can be distinguished from Linaria caesia by the densely glandular-pubescent inflorescence, dark purple corolla and brown seeds with tuberculate disc, and from L. aeruginea by its erect fertile stems and dark purple -never blackishcorolla.Key words: Linaria, Sierra de Gredos, narrow endemic, taxonomy, seed micromorphology. ResumenSe describe Linaria vettonica Luceno, Mazuecos & P. Vargas, una nueva especie de Linaria sect. Supinae. Se trata de un endemismo restringido que se distribuye por las vertientes meridionales de los macizos occidental y central de la Sierra de Gredos (Sistema Central, Peninsula Iberica). Las cinco poblaciones encontradas aparecieron sobre suelos arenosos siliceos en claros y laderas de bosques de Quercus pyrenaica. L. vettonica se distingue de L. caesia por sus inflorescencias densamente glandular-pubescentes, corolas de color purpura oscuro y semillas marrones con disco ornamentado con numerosos tuberculos. De L. aeruginea se distingue por sus tallos fertiles erectos y sus flores de color purpura oscuro, nunca negruzcas.Palabras clave: Linaria, sierra de Gredos, endemismo restringido, taxonomia, micromorfologia de semillas.