A MULTI‐GENE ESTIMATE OF HIGHER‐LEVEL PHYLOGENETIC RELATIONSHIPS AMONG NIGHTJARS (AVES: CAPRIMULGIDAE)

ABSTRACT ∙ The higher‐level phylogenetic relationships of the nightjars and nighthawks (Caprimulgidae) have been challenging for traditional systematics due to their cryptic plumage and conservative morphology. We explored these relationships by combining two previously published molecular datasets with new data to generate a complete matrix (7,104 bp) of evolutionarily disparate sequence elements from four genes for 36 taxa. We analyzed each of the genes separately for base composition heterogeneity and heterozygosity. We analyzed the concatenated matrix in a likelihood framework using seven different partitioning schemes. As the number of subsets in a given partitioning scheme increased, tree length and likelihood score also increased; however, the branching topology was little affected by increasingly complex partitioning schemes. Our best maximum likelihood tree has increased bootstrap support at 13 of 30 ingroup nodes compared with previous analyses, a result likely due to doubling the length of the sequence data. Coalescent‐based species tree inference produced a tree congruent with all strongly supported nodes in the maximum likelihood tree. This topology agrees with previous molecular studies in identifying three small, early branching Old World genera (Eurostopodus, Lyncornis, and Gactornis) and four more speciose terminal clades, representing the New World nighthawks (genus Chordeiles) and three nightjar radiations centered in South America, Central America and the Old World, respectively. Increased node support across the tree reinforces a historical scenario with origins in the region surrounding the Indian Ocean, followed by diversification in the New World and subsequent recolonization and radiation in the Old World. Future work on this group should incorporate additional members of the genera Lyncornis and Eurostopodus, to determine which is the basal lineage of Caprimulgidae.RESUMEN ∙ Relaciones filogenéticas de más alto nivel de los atajacaminos (Aves: Caprimulgidae) en base a un análisis multigénico Las relaciones filogenéticas de más alto nivel de los atajacaminos y añaperos (Caprimulgidae) son un reto para la sistemática tradicional, debido a que el grupo posee morfología poco variable y plumajes crípticos. Exploramos relaciones filogenéticas en el grupo combinando dos conjuntos de datos moleculares ya publicados con nuevos datos. La matriz completa (7,104 bp) se generó con cuatro genes y 36 taxones, incluyendo marcadores con distintos modelos de evolución. Se examinó cada uno de los genes por separado para determinar heterocigosidad y heterogeneidad de la composición de bases. Se analizó la matriz concatenada en un marco de máxima verosimilitud utilizando siete particiones diferentes. La longitud de los árboles filogenéticos y su verosimilitud aumentaron a la par del número de subconjuntos en una partición particular; sin embargo, la topología del árbol varió poco entre particiones. En comparación con topologías publicadas, nuestro árbol de máxima verosimilitud tuvo mejor soporte para 13 de los 30 nodos internos, resultado que podría deberse al uso del doble de los datos de secuencias. El método de árboles de especies basado en coalescencia produjo una topología congruente con la obtenida por máxima verosimilitud. Esta topología concuerda con previos estudios moleculares, identificando tres pequeños géneros del Viejo Mundo como basales en la filogenia (Eurostopodus, Lyncornis y Gactornis), y cuatro clados terminales con más especies. Estos clados terminales representan los atajacaminos del Nuevo Mundo del género Chordeiles, y otras tres radiaciones de América del Sur, Central y del Viejo Mundo. Nuestros resultados sugieren un escenario histórico con orígenes del grupo en la región circundante al Océano Indico, seguido por la diversificación en las Américas y la posterior recolonización y radiación en el Viejo Mundo. Futuros estudios en este grupo deben incorporar miembros adicionales de los géneros Lyncornis y Eurostopodus, lo que permitirá estudiar cuál es el linaje basal de Caprimulgidae

Estudio comparativo de los nuevos anticoagulantes orales

El tratamiento anticoagulante con Antagonistas de la Vitamina K (AVK) es muy complejo. Los nuevos anticoagulantes orales han supuesto una alternativa a los fármacos inhibidores de la vitamina K, presentando un mayor margen terapéutico así como una menor variabilidad intrae interindividual. Por otra parte, pueden administrarse a dosis fijas sin necesidad de una monitorización tan estrecha como requieren los AVK. Los nuevos anticoagulantes orales se clasifican en dos grupos atendiendo a su mecanismo de acción: inhibidores directos del factor X activado (FXa) (rivaroxabán, apixabán y edoxabán) y un inhibidor directo de la trombina (dabigatrán). Se han finalizado con resultados positivos diversos ensayos de fase III en profilaxis del tromboembolismo venoso en cirugía ortopédica, tratamiento del tromboembolismo venoso, o prevención del ictus en pacientes con fibrilación auricular. Para establecer una dosificación adecuada de estos fármacos, dado que las pruebas de laboratorio disponibles no son precisas ni permiten conocer el grado de anticoagulación, es necesario considerar otros factores como las interacciones farmacológicas y el estado de la función renal de cada paciente. En el futuro, las preferencias del paciente y las características farmacológicas serán relevantes para optimizar el tratamiento. Por todo ello, estos nuevos fármacos representan un nuevo paradigma en el tratamiento anticoagulante, aportando grandes ventajas, pero no exentos de inconvenientes

NOTES ON THE BIRDS OF THE SIERRA DE UNTURAN SOUTHERN VENEZUELA

Volume: 110Start Page: 167End Page: 16

Biochemical studies of the higher level systematics of birds

Volume: 122AStart Page: 39End Page: 5

How Many Kinds of Birds Are There and Why Does It Matter?

Estimates of global species diversity have varied widely, primarily based on variation in the numbers derived from different inventory methods of arthropods and other small invertebrates. Within vertebrates, current diversity metrics for fishes, amphibians, and reptiles are known to be poor estimators, whereas those for birds and mammals are often assumed to be relatively well established. We show that avian evolutionary diversity is significantly underestimated due to a taxonomic tradition not found in most other taxonomic groups. Using a sample of 200 species taken from a list of 9159 biological species determined primarily by morphological criteria, we applied a diagnostic, evolutionary species concept to a morphological and distributional data set that resulted in an estimate of 18,043 species of birds worldwide, with a 95% confidence interval of 15,845 to 20,470. In a second, independent analysis, we examined intraspecific genetic data from 437 traditional avian species, finding an average of 2.4 evolutionary units per species, which can be considered proxies for phylogenetic species. Comparing recent lists of species to that used in this study (based primarily on morphology) revealed that taxonomic changes in the past 25 years have led to an increase of only 9%, well below what our results predict. Therefore, our molecular and morphological results suggest that the current taxonomy of birds understimates avian species diversity by at least a factor of two. We suggest that a revised taxonomy that better captures avian species diversity will enhance the quantification and analysis of global patterns of diversity and distribution, as well as provide a more appropriate framework for understanding the evolutionary history of birds

New records of birds from auyan-tepui, Estado Bolivar, Venezuela

Volume: 117Start Page: 194End Page: 19

Distribution of natal dispersal distances and the genetic structure of Spruce Grouse (Falcipennis canadensis) populations

Natal dispersal distances are difficult to measure, yet important for estimating the genetic structure and demographic connectedness of natural populations. Here we provide estimates of the distributions of male and female natal dispersal distances from a long-term study of Spruce Grouse (Falcipennis canadensis (L., 1758)) in southwestern Alberta, Canada, based on individuals marked as brood chicks and re-observed as adults during subsequent breeding seasons. The mean distance dispersed by females (2.33 km) was twice that of males (1.13 km), and both dispersal distributions were leptokurtic. Given estimates of population density and survivorship, we estimated the genetic effective neighborhood size of this population as approximately 541 individuals. We computed equivalent estimates for two additional long-term studies of this species, based on data available in the literature; mean natal dispersal distances, averaged across sexes, ranged from 1.73 km to 2.73 km for the three populations; effective deme sizes ranged from 541 to 890. Consequently, three widespread populations of Spruce Grouse yielded roughly similar estimates of demographic and genetic structure.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author