Phylogenetic diversity and North Andean block conservation.

Background: The Northern Andean Block (NAB) harbors high biodiversity; therefore, it is one of the most important areas in the Neotropics. Nevertheless, the settlement of several human populations has triggered the rapid transformation of ecosystems, leading to the extinction or endangerment of many species. Methods: Because phylogenetic diversity indices quantify the historical distinctness between species, they are adequate tools for evaluating priority conservation areas. We reconstructed 93 phylogenies encompassing 1,252 species and, utilizing their occurrence data sourced from the Global Biodiversity Information Facility, computed the Average Taxonomic Distinctness Index (AvTD) for each grid cell with a spatial resolution of 0.25° within the NAB. The index values for each grid cell were categorized into quantiles, and grid cells displaying values within the upper quantile (Q5) were identified as the most significant in terms of phylogenetic diversity. We also calculated the contribution of endemic species to overall phylogenetic diversity within the NAB, specifically focusing on areas preserved within protected areas. Results: The NAB Andean region exhibited the highest AvTD, with high AvTD values observed in the middle and southern areas of Cordilleras. Endemic species made a relatively modest contribution to the overall phylogenetic diversity of the NAB, accounting for only 1.2% of the total. Despite their relatively small geographical footprints, protected areas within the NAB have emerged as crucial repositories of biodiversity, encompassing 40% of the total phylogenetic diversity in the region. Discussion: Although the NAB Andean region has been identified as the most crucial area in terms of AvTD, some regions in the Amazonian Piedemonte and Pacific lowlands have high AvTD levels. Interestingly, some protected areas have been found to harbor higher AvTDs than expected, given their smaller size. Although the delimitation of new PAs and species richness have been the primary factors driving the expansion of PAs, it is also essential to consider the evolutionary information of species to conserve all aspects of biodiversity, or at least cover most of them. Therefore, using phylogenetic diversity measures and the results of this study can contribute to expanding the PA network and improving the connectivity between PAs. This approach will help conserve different aspects of biodiversity and preserve evolutionary relationships between species.

Biogeographic evidence supports the Old Amazon hypothesis for the formation of the Amazon fluvial system.

The Amazon has high biodiversity, which has been attributed to different geological events such as the formation of rivers. The Old and Young Amazon hypotheses have been proposed regarding the date of the formation of the Amazon basin. Different studies of historical biogeography support the Young Amazon model, however, most studies use secondary calibrations or are performed at the population level, preventing evaluation of a possible older formation of the Amazon basin. Here, we evaluated the fit of molecular phylogenetic and biogeographic data to previous models regarding the age of formation of the Amazon fluvial system. We reconstructed time-calibrated molecular phylogenies through Bayesian inference for six taxa belonging to Amphibia, Aves, Insecta and Mammalia, using both, nuclear and mitochondrial DNA sequence data and fossils as calibration points, and explored priors for both data sources. We detected the most plausible vicariant barriers for each phylogeny and performed an ancestral reconstruction analysis using areas bounded by major Amazonian rivers, and therefore, evaluated the effect of different dispersal rates over time based on geological and biogeographical information. The majority of the genes analyzed fit a relaxed clock model. The log normal distribution fits better and leads to more precise age estimations than the exponential distribution. The data suggested that the first dispersals to the Amazon basin occurred to Western Amazonia from 16.2-10.4 Ma, and the taxa covered most of the areas of the Amazon basin between 12.2-6.2 Ma. Additionally, regardless of the method, we obtained evidence for two rivers: Tocantins and Madeira, acting as vicariant barriers. Given the molecular and biogeographical analyses, we found that some taxa were fitted to the "Old Amazon" model.

Wing Shape Variation in the Taxonomic Recognition of Species of Diachlorus Osten-Sacken (Diptera: Tabanidae) from Colombia.

We evaluated the directional asymmetry between right and left wings and quantified the intraspecific and interspecific variation of the wing shape of 601 specimens of the genus Diachlorus to determine to what extent the geometrical variation discriminates six species distributed in six protected areas of Colombia. Geometric analyses were performed, integrating Procrustes methods, principal component analyses, cluster analyses, linear and quadratic discriminant analyses, and evaluations of shape changes. In Diachlorus, left and right wings did not present significant asymmetry but a geometrical analysis was allowed for species identification and, in some cases, the origin of the specimens using the variation of wing shape; the best-assigned species was Diachlorus leticia Wilkerson & Fairchild, while the worst was Diachlorus jobbinsi Fairchild, which also had the highest intraspecific variation, while Diachlorus fuscistigma Lutz had the lowest variation. Diachlorus fuscistigma and Diachlorus leucotibialis Wilkerson & Fairchild were the most similar species, while D. leucotibialis and Diachlorus nuneztovari Fairchild & Ortiz were the most disimilar. The specimens with the most different wing shape belonged to Chocó (especially those of D. jobbinsi), the geographically farthest area from the others in the study; however, no correlation was observed between geometric and geographical distances. Linear discriminants were better than nonlinear (quadratic) discriminant analyses in predicting species membership, but the opposite was true for predicting area membership. Based on our data, we hypothesized that other species of Diachlorus could also be discriminated using geometric morphometry of the wing shape.

Virus del dengue de serotipo 1 (DENV-1) de Colombia: su contribución a la presentación del dengue en el departamento de Santander / Dengue virus serotype 1 (DENV-1) from Colombia: its contribution to dengue occurrence in Santander

Introducción. Los cuatro serotipos del virus del dengue circularon en el departamento de Santander entre 1998 y 2008. No existe información sobre el papel del serotipo 1 (DENV-1) en la epidemiología de la enfermedad. Objetivo. Analizar la relación entre el cambio de predominancia del (DENV-1) con su diversificación genética, predominancia de los otros serotipos y presentación del dengue grave. Materiales y métodos. La diversificación genética se estudió por análisis filogenético usando la secuencia del gen E de 12 cepas del virus. Para el análisis se utilizaron datos sobre predominancia de los serotipos obtenidos en estudios previos y datos oficiales de incidencia del dengue. Resultados. Los virus seleccionados se agruparon en el genotipo V junto a (DENV-1) de países de Latinoamérica y se evidenció segregación en cuatro linajes. Los cambios en la predominancia del virus coincidieron con el reemplazo de linaje y esto, a su vez, con incremento en la prevalencia de DENV-2 y DENV-3, e incremento del dengue grave. Conclusión. La diversificación genética podría contribuir a cambios de predominancia de (DENV-1), y la relación del virus con el DENV-2 y DENV-3 en situaciones que favorecen la presentación de casos graves. Se necesitan más estudios para precisar el papel de los serotipos en la epidemiología del dengue.

Introduction: Between 1998 and 2008 all dengue virus serotypes circulated in the Departamento de Santander, an endemic region in northeastern Colombia. No information is available as to the role of serotype 1 (DENV-1) with respect to epidemiology of dengue. Objective: To analyze the relationship between changes in DENV-1 predominance with respect to genetic diversity, prevalence of others serotypes and occurrence of severe dengue. Methods: Virus genetic diversity was studied by phylogenetic analysis comparing E gene sequences from 12 viral strains. Data about serotypes predominance obtained in previous studies and official data about dengue incidence were used for analysis. Results: Selected viruses grouped into genotype V together DENV-1 from Latin America countries, and segregation in four lineages was evidenced. Changes in virus predominance coincided with replacement of lineage, increase in prevalence of DENV-2 and DENV-3 and increase of severe dengue. Conclusion: Genetic divergence could have contributed to changes in DENV-1 predominance. The relationship of the virus with DENV-2 and DENV-3 could create scenarios that promote occurrence of severe cases. More studies are required to ascertain the precise role of serotypes in the epidemiology of dengue.

[Dengue virus serotype 1 (DENV-1) from Colombia: its contribution to dengue occurrence in Santander]. / Virus del dengue de serotipo 1 (DENV-1) de Colombia: su contribución a la presentación del dengue en el departamento de Santander.

INTRODUCTION: Between 1998 and 2008 all dengue virus serotypes circulated in the Departamento de Santander, an endemic region in northeastern Colombia. No information is available as to the role of serotype 1 (DENV-1) with respect to epidemiology of dengue. OBJECTIVE: To analyze the relationship between changes in DENV-1 predominance with respect to genetic diversity, prevalence of others serotypes and occurrence of severe dengue. METHODS: Virus genetic diversity was studied by phylogenetic analysis comparing E gene sequences from 12 viral strains. Data about serotypes predominance obtained in previous studies and official data about dengue incidence were used for analysis. RESULTS: Selected viruses grouped into genotype V together DENV-1 from Latin America countries, and segregation in four lineages was evidenced. Changes in virus predominance coincided with replacement of lineage, increase in prevalence of DENV-2 and DENV-3 and increase of severe dengue. CONCLUSION: Genetic divergence could have contributed to changes in DENV-1 predominance. The relationship of the virus with DENV-2 and DENV-3 could create scenarios that promote occurrence of severe cases. More studies are required to ascertain the precise role of serotypes in the epidemiology of dengue.

Weighted compromise trees: a method to summarize competing phylogenetic hypotheses.

A new consensus method for summarizing competing phylogenetic hypotheses, weighted compromise, is described. The method corrects for a bias inherent in majority-rule consensus/compromise trees when the source trees exhibit non-independence due to ambiguity in terminal clades. Suggestions are given for its employment in parsimony analyses and tree resampling strategies such as bootstrapping and jackknifing. An R function is described that can be used with the programming language R to produce the consensus.