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Ovenbirds represent a clade of exclusively Neotropical birds that are exceptionally diverse, despite their rather dull, melanin-based plumage. In general, sexes are considered monomorphic in size and colour, but several authors have reported females of some species within this family as being slightly paler than their conspecific counterparts. Our aim was to assess levels of sexual dichromatism in a set of ovenbird species representing a diversity of genera and plumage patterns; Furnarius rufus, Phleocryptes melanops, Synallaxis spixi and Schoeniophylax phryganophilus. For each species, we quantified sexual differences in brightness and colouration among 8–10 different plumage regions through modelling avian perceptual colour-space distances. To best inform our visual modelling parameters, we successfully sequenced the SWS1 gene fragment (associated with short-wavelength, including ultraviolet, visual sensitivity in birds) for one species, P. melanops, and found it possessed an amino acid sequence consistent with the VS-type SWS1 visual system. This provides further evidence supporting the presence of VS-sensitive opsin in ovenbirds. Among all four species, females were consistently brighter than males in at least one plumage patch, but chromatic colour differences between sexes were significant only for the throat patches of Schoeniophylax phryganophilus. Overall, we interpret ovenbirds to exhibit very low levels of sexual dichromatism, manifest mainly by achromatic colour differences.

Short wavelength visual sensitivity in birds is determined mostly by the type of photopigment present in the short-wavelength sensitive cone 1 (SWS1) which varies between clades and takes two main forms: the violet sensitive type (VS) and ultraviolet sensitive type (UVS). The common ancestor of passerines is thought to have been UVS, but there were at least 8 transitions between both types of visual sensitivity, even within species of the same family (Maluridae). The type of visual system a species has is a key parameter of avian visual models employed to describe chromatic visual perception and assess if colour differences are discernible by birds. Cardinalidae and Thraupidae together include more than 400 very diverse species that were model organisms in many bird colouration studies. However, visual sensitivity has been characterised for only one species of each of these families so far. Here, we obtained partial genetic sequences of the SWS1 opsin gene that determines the spectral sensitivity of the photopigment for a phylogenetically broad species sample of these families. All cardinals and tanagers studied here have SWS1 sequences corresponding with UVS sensitivity, suggesting that this character is conserved in these bird families despite their highly diverse range of plumage colours and habitat types.

A pesar de su importancia, el aporte de decomisos y donaciones a las colecciones biológicas ha sido muy poco cuantificado. El objetivo de este análisis fue evaluar la relevancia de las donaciones y los decomisos de material ornitológico a la Colección Nacional de Tejidos Ultracongelados del Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”. De los 10 288 tejidos de aves depositados en la colección desde su establecimiento en 2003, más de un tercio corresponde a donaciones (22% en total, 13% de particulares y 9% institucionales) y decomisos (12%). Dichos tejidos pertenecen a 28 órdenes y representan más del 50% del total de muestras de 15 de ellos. Passeriformes, Anseriformes y Procellariiformes son los grupos más representados en las donaciones y/o decomisos, aunque hay varios otros órdenes en los que este tipo de muestras son la principal fuente de tejidos, dado que se recolectan pocos ejemplares de manera activa. De las 871 especies presentes en la colección, 156 (18%) están representadas únicamente por muestras provenientes de donaciones y/o decomisos, resaltando así su notoria relevancia. De hecho, más de la mitad de los tejidos de donaciones y alrededor de un cuarto de los decomisados han sido incorporados en al menos 46 estudios científicos. Este análisis evidencia la importancia de las donaciones y los decomisos para las colecciones biológicas y hace hincapié en la necesidad de un trabajo conjunto con instituciones públicas y privadas y de la concientización de la sociedad sobre la significancia de donar materiales biológicos a los museos.

The riverine barrier hypothesis proposes that large rivers represent geographical barriers to gene flow for terrestrial organisms, leading to population differentiation and ultimately allopatric speciation. Here we assess for the first time if the subtropical Paraná Paraguay River system in the Del Plata basin, second in size among South American drainages, acts as a barrier to gene flow for birds. We analysed the degree of mitochondrial and nuclear genomic differentiation in seven species with known subspecies divided by the Paraná Paraguay River axis. Only one species showed genetic differentiation concordant with the current river channel, but another five species have an east/west genetic split broadly coincident with the Paraná River´s dynamic palaeochannel, suggesting this fluvial axis has had a past role in shaping present-day genetic structure. Moreover, dating analyses show that these splits have been asynchronous, with species responding differently to the riverine barrier. Comparisons informed by the geological history of the Paraná River and its influence on the ecological and climatic differences among ecoregions in the study area further bolster the finding that responses to this geographical barrier have been species-specific. Fil: Kopuchian, Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentina Fil: Campagna, Leonardo. Cornell University; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Lijtmaer, Dario Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Cabanne, Gustavo Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: García, Natalia Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina. Cornell University; Estados Unidos Fil: Lavinia Oblanca, Pablo Damián. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Tubaro, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Lovette, Irby. Cornell University; Estados Unidos Fil: Di Giacomo, Adrian Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentina

Coloration traits are central to animal communication; they often govern mate choice, promote reproductive isolation and catalyse speciation. Specific genetic changes can cause variation in coloration, yet far less is known about how overall coloration patterns—which involve combinations of multiple colour patches across the body—can arise and are genomically controlled. We performed genome-wide association analyses to link genomic changes to variation in melanin (eumelanin and pheomelanin) concentration in feathers from different body parts in the capuchino seedeaters, an avian radiation with diverse colour patterns despite remarkably low genetic differentiation across species. Cross-species colour variation in each plumage patch is associated with unique combinations of variants at a few genomic regions, which include mostly non-coding (presumably regulatory) areas close to known pigmentation genes. Genotype–phenotype associations can vary depending on patch colour and are stronger for eumelanin pigmentation, suggesting eumelanin production is tightly regulated. Although some genes are involved in colour variation in multiple patches, in some cases, the SNPs associated with colour changes in different patches segregate spatially. These results suggest that coloration patterning in capuchinos is generated by the modular combination of variants that regulate multiple melanogenesis genes, a mechanism that may have promoted this rapid radiation.

1. The characterisation of energy flow through communities is a primary goal of ecology. Furthermore, predator–prey interactions can influence both species abundance and community composition. The ant subfamily Ponerinae includes many predatory species that range from generalist insectivores to highly specialised hunters that target a single prey type. Given their high diversity and ubiquity in tropical ecosystems, measuring intra‐ and interspecific variation in their trophic ecology is essential for understanding the role of ants as predators of insect communities. 2. The stable isotopic composition of nitrogen of 22 species from the ant subfamily Ponerinae was measured, relative to plants and other predatory and herbivorous insects at two Atlantic Forest sites in Argentina. The study tested the general assumption that ponerine ants are all predatory, and examined intra‐ and interspecific variation in trophic ecology relative to habitat, body size and cytochrome c oxidase subunit 1 sequences (DNA barcoding). 3. Stable isotope analysis revealed that most ponerines occupy high trophic levels (primary and secondary predators), but some species overlapped with known insect herbivores. Species residing at low trophic levels were primarily arboreal and may rely heavily on nectar or other plant‐based resources in their diet. In addition, larger species tend to occupy lower trophic positions than smaller species. 4. Although some of the species were divided into two or more genetic clusters by DNA barcoding analysis, these clusters did not correspond to intraspecific variation in trophic position; therefore, colony dietary flexibility most probably explains species that inhabit more than one trophic level.

Dry forests characterize many of the biomes of southern South America and the Andes, such as the Chaco and the inter-Andean valley forests, which form a continuous belt (Chaco–Andes dry forest belt). Some of the taxa that inhabit this forest belt present genetic and phenotypic differentiation between edges of the region, which suggests the action of divergent evolutionary processes between forests (i.e., parapatric divergence). In order to test this hypothesis, we studied the morphological and phylogeographic variation of the White-tipped Plantcutter Phytotoma rutila (Cotingidae) and evaluated predictions of genetic and morphological evolutionary processes (e.g., local adaptation). The results supported that the environmental gradient along the Chaco–Andes dry forests might be promoting diversification because we found that body size of the White-tipped Plantcutter varied according to a step cline related to altitude, and thus parapatric processes might be responsible for this pattern. There are other taxa co-distributed across the study region presenting similar patterns of geographic variation, which suggests the action of concerted evolutionary phenomena in the Chaco–Andes dry forest. Fil: Rodríguez Cajarville, María José. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Calderón, Pablo Luciano Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Biología Agrícola de Mendoza. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Instituto de Biología Agrícola de Mendoza; Argentina Fil: Tubaro, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Cabanne, Gustavo Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina

Birds living in riverine environments may show weak population structure because high dispersal abilities required to track habitat dynamics can result in gene flow over broad spatial scales. Alternatively, the configuration of river networks may result in restricted dispersal within river courses or basins, leading to high genetic structure. Although several bird species are riverine specialists in the Andes, no study has extensively evaluated the population genetic structure of any of them. We examined evidence from genetic and morphological data to address questions about the biogeography and taxonomy of the Torrent Duck (Merganetta armata), a riverine specialist bird with a broad distribution in Andean riverine habitats which certainly comprises different subspecies and may comprise more than one species. We found deep subdivisions of Torrent Duck populations from the northern, central and southern portions of the Andes. These lineages, which partly coincide with subspecies described based on plumage variation and body size, do not share mtDNA haplotypes, have private nuclear alleles and exhibit marked differences in morphometric traits. Some geographic barriers presumably restricting gene flow between groups partially coincide with those associated with major genetic breaks in forest species with similar distributions along the Andes, suggesting that bird assemblages including species occupying different habitats were likely affected by common biogeographical events. The three groups of Torrent Ducks may be considered different species under some species definitions and are distinct evolutionary lineages to be conserved and managed separately. Fil: Gutiérrez Pinto, Natalia. University of Nebraska; Estados Unidos. Universidad de los Andes; Colombia Fil: McCracken, Kevin G.. University of Alaska; Estados Unidos. University of Miami; Estados Unidos. University Of Miami. Rosenstiel School Of Marine Atmospheric Science; Estados Unidos Fil: Tubaro, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Kopuchian, Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Astié, Andrea Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Provincia de Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Universidad Nacional de Cuyo. Instituto Argentino de Investigaciones de las Zonas Áridas; Argentina Fil: Cadena, Carlos Daniel. Universidad de los Andes; Colombia

Avian diversity in the Neotropics has been traditionally attributed to the effect of vicariant forces promoting speciation in allopatry. Recent studies have shown that phylogeographical patterns shared among codistributed species cannot be explained by a single vicariant event, as species responses to a common barrier depend on the biological attributes of each taxon. The open vegetation corridor (OVC) isolates Amazonia and the Andean forests from the Atlantic Forest, creating a notorious pattern of avian taxa that are disjunctly codistributed in these forests. Here, we studied and compared the evolutionary histories of Ramphotrigon megacephalum and Pipraeidea melanonota, two passerines with allopatric populations east and west of the OVC that represent different subspecies. These species differ in their biological attributes: R. megacephalum is a sedentary, forest specialist mostly confined to bamboo understorey, whereas P. melanonota is a seasonal migrant and generalist species that ranges in a variety of closed and semi-open environments. We performed genetic and genomic analyses, complemented with the study of coloration and behavioural differentiation, to assess population divergence across the OVC. We found that the evolutionary histories of both R. megacephalum and P. melanonota have been shaped by this environmental barrier. However, these species responded in different and asynchronous manners to the establishment of the OVC and to past connections between the currently isolated South American forests, which can be mostly explained by their distinct ecologies and dispersal abilities. Our results support the fact that the biological attributes of species can make their evolutionary histories idiosyncratic.

We evaluated whether the Andean and the Atlantic forests acted as refugia during the Quaternary, and tested biogeographic hypotheses about the regions involved in the connectivity between those biomes (through the Chaco or the Cerrado). To achieve these goals we selected the Buff-browed Foliage-gleaner Syndactyla rufosuperciliata (Aves, Furnariidae) as a study system, a taxon distributed between the Andean and Atlantic forest. We first explored the historical connectivity between regions through niche modeling. We subsequently used DNA sequences (n = 71 individuals) and genomic analyses (ddRADseq, n = 33 individuals) to evaluate population genetic structure and gene flow within this species. Finally, we performed population model selection using Approximate Bayesian Computation. Our findings indicate that the Andean and the Atlantic forests acted as refugia, and that the populations of the focal species from both regions contacted through the Cerrado region, thus suggesting that the historical dynamics of Andean and Atlantic forests are important for the evolution of forest birds in the region. The results are in agreement with studies of other organisms and may indicate a more general pattern of connectivity among biomes in the Neotropics. Finally, we recommend recognizing both the Andean and the Altantic forests lineages of S. rufosuperciliata as independent species.

Non-iridescent coloration in birds’ plumage is associated with the quasi-ordered nanostructures of short-range order present within the feather barbs. Even though this type of color does not change with the observation direction, a few bird species which exhibit the so called non-iridescent structurally colored feathers, present significant hue variations as the relative angle between incidence and detection directions is varied. Among these, the Swallow Tanager constitutes an excellent system to investigate this phenomenon as its hue changes remarkably from greens to blues as the angle between the illumination and observation directions increases, and independently of feather orientation. In this paper we elucidate the origin of the striking color change of the Swallow Tanager plumage by computing the reflectance spectra of the feathers’ microstructure. We show that the color observed under different illumination-detection conditions can be predicted quite accurately by applying averaging techniques and by considering the air-spheres microstructure of their feathers’ barbs as the main responsible for the observed color change. This work opens up new possibilities for the design of devices with special color characteristics.

The Atlantic Forest harbors 7% of global biodiversity and possesses high levels of endemism, but many of its component taxa remain unstudied. Due to the importance of tropical forests and the urgency to protect them, there is a compelling need to address this knowledge gap. To provide more information on its arthropod fauna, a Malaise trap was deployed for 12 months in a semi-degraded area of the southern Upper Paraná ecoregion of the Atlantic Forest. All specimens were DNA barcoded and the Barcode Index Number (BIN) system was employed to assign each specimen to a species proxy. DNA barcodes were obtained from 75,500 arthropods that included representatives of 8,651 BINs. Nearly 81% of these BINs were first records, highlighting the high rates of endemism and lack of study of arthropods from the Atlantic Forest. Diptera was the most abundant order, followed by Hemiptera, Lepidoptera and Hymenoptera. Diptera was also the most species-rich order, followed by Hymenoptera, Lepidoptera, and Coleoptera, a result consistent with studies in other biogeographic regions. Insects were most abundant in winter and most diverse in autumn and winter. This pattern, however, was caused mainly by the dynamics of dipteran diversity as other orders differed in their seasonal variation. The BIN composition of the insect community varied sharply through the year and also differed between the two consecutive summers included in the sampling period. The study of the 38 commonest BINs showed that seasonal patterns of abundance were not order-specific. Temperature had the strongest impact on seasonal abundance variation. Our results highlight the striking and understudied arthropod diversity of the highly fragmented Atlantic Forest, the predominance of dipterans, and the fact that abundance and richness in this insect community peak in the coolest months. Standardized studies like this generate fast and reliable biodiversity inventories and unveil ecological patterns, thus providing valuable information for conservation programs.

Choosy females drive isolation Rapid radiations of recently diverged species represent an excellent opportunity for exploring drivers of speciation. The capuchino seedeaters, a group of South American birds, include a number of species that, in the field, are often discernable only through male plumage and song. Turbek et al. used genomes and behavioral experiments to identify potential isolating factors in two members of this group and found that, though entirely sympatric, females mated only with conspecific males and that only a few genes differed between the species (see the Perspective by Jarvis). Thus, a small reshuffling of genes and reinforcement through mate choice has driven divergence in these overlapping and very similar species. Science , this issue p. eabc0256 ; see also p. 1312

Non-iridescent, structural coloration in birds originates from the feather's internal nanostructure (the spongy matrix) but melanin pigments and the barb's cortex can affect the resulting color. Here, we explore how this nanostructure is combined with other elements in differently colored plumage patches within a bird. We investigated the association between light reflectance and the morphology of feathers from the back and belly plumage patches of male swallow tanagers (Tersina viridis), which look greenish-blue and white, respectively. Both plumage patches have a reflectance peak around 550 nm but the reflectance spectrum is much less saturated in the belly. The barbs of both types of feathers have similar spongy matrices at their tips, rendering their reflectance spectra alike. However, the color of the belly feather barbs changes from light green at their tips to white closer to the rachis. These barbs lack pigments and their morphology changes considerably throughout. Toward the rachis, the barb is almost hollow, with a reduced area occupied by spongy matrix, and has a flattened shape. By contrast, the blue back feathers' barbs have melanin underneath the spongy matrix resulting in a much more saturated coloration. The color of these barbs is also even along the barbs' length. Our results suggest that the color differences between the white and greenish-blue plumage are mostly due to the differential deposition of melanin and a reduction of the spongy matrix near the rachis of the belly feather barbs and not a result of changes in the characteristics of the spongy matrix.

Based on phylogeographic and niche model analyses of the narrow-billed woodcreeper Lepidocolaptes angustirostris, we evaluated the predictions of two diversification hypotheses related to the dry diagonal of South America: (I) isolation by distance (IBD) and (II) landscape heterogeneity. We also investigated the influence of the Pleistocene climatic oscillations on the diversification and population dynamic of this species, and discussed the implications of our findings for the taxonomy of this woodcreeper. We sampled 63 individuals including all subspecies described for L. angustirostris, and compared them using a mitochondrial (ND2) and a nuclear (FIB5) fragments. We performed a Mantel test and spatial autocorrelation analysis, reconstructed the phylogenetic relationships among haplotypes, investigated changes in population size and estimated divergence time among the genetic lineages. We refuted the hypothesis that bird species associated with open environments have shallow geographic differentiation and showed that strong genetic structure observed in L. angustirostris can not be explained by IBD. Paleo-modeling showed strong association between climatic stable areas and the genetic lineages, suggesting that Pleistocene climatic oscillations have primarily driven the intraspecific diversification of this species. In addition, the association between genetic lineages and the dry diagonal biomes supports that landscape heterogeneity may be acting as a secondary barrier restricting gene flow among the lineages. The genetic lineages found in L. angustirostris do not correspond to the subspecies described, indicating that this species can be considered as a single species with strong genetic structure. In conclusion, our data corroborate other studies indicating that Pleistocene climatic oscillations may have had a strong influence in the intraspecific divergence of dry diagonal fauna and that biomes of the dry diagonal should be considered as independent units in further biogeographic studies. Fil: Rocha, A. V.. Universidade do Brasília; Brasil Fil: Cabanne, Gustavo Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Aleixo, A.. Museu Paraense Emilio Goeldi; Brasil Fil: Silveira, L. F.. Universidade de Sao Paulo; Brasil Fil: Tubaro, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Caparroz, R.. Universidade do Brasília; Brasil

Non-iridescent, structurally-based coloration in birds originates from the feather’s internal nanostructure (the keratin spongy matrix), but the presence of melanin and the characteristics of the barb’s cortex can affect the resulting color. Here we investigate how this nanostructure is regulated and combined with other elements in differently-colored plumage patches. To do so, we investigated the association between light reflectance and the morphology of feathers from the back and belly plumage patches of male Swallow Tanagers (Tersina viridis), which look greenish-blue and white, respectively. Both plumage patches have a reflectance peak around 550 nm, but the reflectance spectrum is much less saturated in the belly. The barbs of both types of feathers have similar spongy matrices at their tips which produce similar reflectance spectra. However, the color of the belly feather barbs changes from light green at the tip to white closer to the rachis. These barbs lack pigments and their morphology changes considerably: the spongy matrix is reduced, being almost hollow, and has a different shape towards the rachis. Instead, we observed deposition of melanin underneath the spongy matrix in the back feathers which had a much saturated coloration that was consistent along the barbs’ length. Overall, our results suggest that the color differences between the white and greenish-blue plumage are mostly due to the differential deposition of melanin and a reduction of the spongy matrix in some parts of the belly feather barbs, and not a result of changes in the periodicity of the spongy matrix.

Fil: Attina, Natali. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina

The ~1.97 million egg sets (~5 million eggs) housed in museums have not been used in proportion to their availability. We highlight the wide variety of scientific disciplines that have used egg collections and the geographic locations and sizes of these collections, to increase awareness of the importance of egg collections, improve their visibility to the scientific community, and suggest that they offer a wealth of data covering large spatial scales and long time series for broad investigations into avian biology. We provide a brief history of egg collections and an updated list of museums/institutions with egg collections worldwide. We also review the limitations, challenges, and management of egg collections, and summarize recent literature based on historical and recent museum egg materials.

In this paper, we investigate the unusual color effect exhibited by the plumage of the heads of Cyanerpes cyaneus males, whose color turns from green to turquoise as the angle between the illumination and observation directions is increased. This singular color effect is characteristic of species that have quasi-ordered nanostructures of short-range order within the feather barbs. However, among species of the same family and even within feather patches of the same individual, one can find barbs with different characteristics, both macroscopic (curvature, shape, cross-sectional area) and in their internal microstructure. We apply the Korringa–Kohn–Rostoker method with the averaging technique to model the reflectance spectra for different angles of incidence and explain the dependence of the observed color with the incidence-collection angle. To investigate the influence of the disorder in the optical response of the spongy matrix, we apply the integral method for a two-dimensional cylinder system that simulates the distribution of air cavities within the β -keratin medium. The experimental reflectance was interpreted as the result of multiple reflections in the internal interfaces generated by large air voids present within the spongy matrix. The application of rigorous methods to the study of natural photonic structures is of fundamental relevance for the design of efficient bioinspired artificial materials.

The tyrant‐flycatchers (Tyrannidae) are the largest family of birds in the New World. Although their phylogenetic relationships have been deeply studied based on phenotypic and genetic characters, several systematic uncertainties still exist. In particular, the affinities within the South American genus Ramphotrigon and its close relationship with the Mexican‐endemic Deltarhynchus flammulatus remain unresolved. Here we performed a taxonomic assessment of this intriguing relationship including, for the first time, representatives of all three Ramphotrigon species and the monotypic Deltarhynchus. We carried out phylogenetic analyses based on three mitochondrial markers and one autosomal nuclear intron, and complemented the genetic evidence with the study of morphological and plumage coloration differentiation, in order to provide a more in‐depth reassessment of the Ramphotrigon–Deltarhynchus relationship in general and the genus Ramphotrigon in particular. Genetic data showed that Ramphotrigon is paraphyletic as currently defined, with R. fuscicauda and R. ruficauda being more closely related to D. flammulatus than to R. megacephalum. This paraphyletic relationship was recovered with maximum support based on mitochondrial and nuclear markers. Ramphotrigon megacephalum evidenced a deep genetic divergence from its two congeners and D. flammulatus, comparable to that between the first one and other tyrannids. Ramphotrigon megacephalum was also significantly different from D. flammulatus, R. fuscicauda and R. ruficauda in external morphology and plumage coloration. On the other hand, D. flammulatus, R. fuscicauda and R. ruficauda showed almost no differences in the morphological variables analyzed. In this context, we believe that a taxonomic reorganization of this group is necessary. One possibility would be to transfer D. flammulatus to the genus Ramphotrigon and to assign R. megacephalum to a new genus with at least two species. Lastly, we propose a biogeographic model for the evolutionary history of Ramphotrigon and Deltarhynchus in South and Middle America over the past 12 million years.

The central Andean rainforests and the Atlantic Forest are separated by the Chaco and the Cerrado domains. Despite this isolation, diverse evidence suggests that these rainforests have been connected in the past. However, little is known about the timing and geographic positions of these connections, as well as their effects on diversification of species. In this study, we used the Black-goggled Tanager (Trichothraupis melanops, Thraupidae) as a model to study whether the Andean and the Atlantic forests have acted as a refugia system, and to evaluate biogeographic hypotheses of diversification and connection between these rainforests. We compared alternative biogeographic scenarios by using Approximate Bayesian Computation (ABC), modeled range shifts across time, and assessed niche divergence between regions. The results indicated that the major phylogeographic gap within T. melanops is located between these rainforests. The ABC analysis supported peripatric diversification, with initial dispersal from the Atlantic Forest to the Andes during the Mid-Pleistocene. Also, the results supported an Andean-Atlantic forests connection through the current Cerrado-Chaco transition, linking the southern Atlantic Forest with the central Andes. Our findings, taken together with other studies, support that the connection between these biomes has been recurrent, and that has occurred mostly through the Cerrado and/or the Cerrado-Chaco transition. The data also support that the connection dynamic has played an important role in the biological diversification, by promoting peripatric divergence in some forest taxa restricted to both biomes. Fil: Trujillo Arias, Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina Fil: Calderón, Pablo Luciano Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Biología Agrícola de Mendoza. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Instituto de Biología Agrícola de Mendoza; Argentina Fil: Santos, Fabricio R.. Universidade Federal de Minas Gerais; Brasil Fil: Miyaki, Cristina Yumi. Universidade de Sao Paulo; Brasil Fil: Aleixo, Alexandre. Museu Paraense Emilio Goeldi; Brasil Fil: Witt, Christopher C.. University of New Mexico; Estados Unidos Fil: Tubaro, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina Fil: Cabanne, Gustavo Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina

Ciertas señales vocales pueden ser difíciles de producir debido a restricciones en los mecanismos vocales. En el caso del canto de las aves, se ha visto que tanto el tamaño corporal como la morfología del pico restringen parámetros espectrales y temporales del canto. Por lo tanto, la variación dentro de un clado en ambos caracteres morfológicos puede ejercer un importante efecto en la evolución vocal y su diversidad. Sin embargo, dada la relación alométrica entre el tamaño del cuerpo y del pico, no siempre es fácil separar los efectos que cada uno pueda tener. Además, diferentes hábitats imponen diferentes fuentes de atenuación y degradación del sonido, y el canto de las aves parece haberse adaptado a minimizar la degradación acústica específica a su hábitat. Aquí analizamos la variación vocal en relación tanto al tamaño corporal como a la morfología del pico en 13 de las 14 especies del clado “azul” de la familia Cardinalidae, controlando por las características del hábitat. Por un lado, encontramos la correlación negativa predicha entre el tamaño corporal y las frecuencias del canto, pero ningún efecto del tamaño corporal en las variables temporales. Por otro lado, no encontramos ninguna relación entre las dimensiones del pico (corregidas por el tamaño corporal) y las frecuencias del canto, pero encontramos que el largo del pico correlaciona negativamente con la tasa de notas y positivamente con la duración del intervalo entre notas. Previamente se encontraron resultados similares, pero principalmente en especies con trinos, donde las notas son iguales y producidas a tasa constante. Nuestros resultados muestran que diferentes variables morfológicas, incluso si están fuertemente correlacionadas, pueden ejercer diferentes restricciones en un carácter comportamental complejo como es el canto. Un mejor entendimiento de la relevancia de estos factores próximos en la evolución vocal es fundamental para entender las causas de la diversidad vocal aviar. Certain vocal signals can be difficult or challenging to produce due to constraints on vocal mechanics. In the case of birdsong, both body size and beak morphology have been shown to constrain spectral and temporal song parameters. Therefore, variation within a clade in both these morphological traits could exert an important effect in vocal evolution and diversity. However, given the allometric relationship between body size and beak size, it is not always easy to separate the effects they may have. Additionally, different habitats impose different sources of sound attenuation and degradation, and birdsong seems to be adapted to minimize habitat-specific sound degradation. Here, we analyze vocal variation in relation to both body size and beak morphology in 13 of 14 species in the "blue" clade of the Cardinalidae, controlling for habitat characteristics. On one hand, we found the predicted negative correlation of body size with song frequencies, but no effect of body size on temporal variables. On the other hand, we found no relationship between different beak dimensions (corrected by body size) and song frequencies, but we found that beak length was correlated negatively with note rate and positively with the duration of the interval between notes. Similar results have been found previously, but mostly in species with trilled songs, in which notes are equal and produced at a constant rate. Our results show that different morphological variables, even if strongly correlated, can exert differential constraints in a complex behavioral trait such as song. A better understanding of the relevance of these proximate factors in shaping vocal evolution is fundamental to understanding the causes of avian vocal diversity. Fil: García, Natalia Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina Fil: Tubaro, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina

At least four mitogenome arrangements occur in Passeriformes and differences among them are derived from an initial tandem duplication involving a segment containing the control region (CR), followed by loss or reduction of some parts of this segment. However, it is still unclear how often duplication events have occurred in this bird order. In this study, the mitogenomes from two species of Neotropical passerines (Sicalis olivascens and Lepidocolaptes angustirostris) with different gene arrangements were first determined. We also estimated how often duplication events occurred in Passeriformes and if the two CR copies demonstrate a pattern of concerted evolution in Sylvioidea. One tissue sample for each species was used to obtain the mitogenomes as a byproduct using next generation sequencing. The evolutionary history of mitogenome rearrangements was reconstructed mapping these characters onto a mitogenome Bayesian phylogenetic tree of Passeriformes. Finally, we performed a Bayesian analysis for both CRs from some Sylvioidea species in order to evaluate the evolutionary process involving these two copies. Both mitogenomes described comprise 2 rRNAs, 22 tRNAs, 13 protein-codon genes and the CR. However, S. olivascens has 16,768 bp showing the ancestral avian arrangement, while L. angustirostris has 16,973 bp and the remnant CR2 arrangement. Both species showed the expected gene order compared to their closest relatives. The ancestral state reconstruction suggesting at least six independent duplication events followed by partial deletions or loss of one copy in some lineages. Our results also provide evidence that both CRs in some Sylvioidea species seem to be maintained in an apparently functional state, perhaps by concerted evolution, and that this mechanism may be important for the evolution of the bird mitogenome. Fil: Caparroz, Renato. Universidade do Brasília; Brasil Fil: Rocha, Amanda V.. Universidade do Brasília; Brasil Fil: Cabanne, Gustavo Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina Fil: Tubaro, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina Fil: Aleixo, Alexandre. Museu Paraense Emílio Goeldi; Brasil Fil: Lemmon, Emily M.. Florida State University; Estados Unidos Fil: Lemmon, Alan R.. Florida State University; Estados Unidos

espanolEl color del plumaje de las aves se debe tanto a la presencia de pigmentos como a efectos estructurales selectivos en frecuencia producidos por la interaccion de la luz con la microestructura fotonica que constituye las barbas de las plumas. El plumaje de la especie Tersina viridis, de la familia Thraupidae, presenta dicromatismo sexual: los machos tienen plumaje azul y las hembras son verdes. Ademas, las plumas muestran una reflectancia iridiscente que varia con el angulo entre la direccion de incidencia y la de observacion. Para investigar los mecanismos de generacion de color en las plumas de Tersina viridis estudiamos su respuesta electromagnetica. En primer lugar, se obtuvieron imagenes TEM de la seccion transversal de las barbas, las cuales revelaron una microestructura formada por cavidades cuasi-esfericas de aire inmersas en una matriz de β-queratina. Para obtener sus parametros geometricos relevantes, se realizo un analisis estadistico detallado de las imagenes. Dichos parametros, junto con las propiedades opticas de los materiales involucrados, determinan el comportamiento electromagnetico de la estructura. Para calcular la reflectancia de la barba se utilizaron dos metodos teoricos. En primer lugar, se aplico un modelo simplificado basado en el analisis de Fourier que solo tiene en cuenta eventos de esparcimiento simple. Este metodo provee informacion util acerca de la posicion espectral del pico de reflectancia dominante en la zona visible del espectro. Sin embargo, este analisis no considera las interacciones entre las esferas, las cuales podrian afectar significativamente la respuesta optica. Para tener esto en cuenta, se aplico el metodo conocido como Korringa-Kohn-Rostoker (KKR), que es un formalismo teorico riguroso para el calculo de la reflectancia de estructuras formadas por apilamientos de esferas inmersas en un medio material. Se realizaron simulaciones numericas prestando especial atencion a la influencia de las caracteristicas geometricas de la microestructura. Las curvas obtenidas muestran un pico de reflectancia en la zona del UV, tal como muestran las mediciones de los espectros de reflectancia de la especie. Estos resultados muestran el potencial del metodo KKR para reproducir en forma precisa la respuesta electromagnetica de estructuras naturales y para reproducir caracteristicas que no pueden ser explicadas utilizando el metodo de Fourier. Los resultados obtenidos confirman que la estructura fotonica cuasi-periodica de la barba produce esparcimiento coherente y por lo tanto es la responsable del color de la especie Tersina viridis. EnglishThe colour of birds’ plumage is due to the presence of pigments as well as to frequency selective structural effects produced by the interaction of light with the photonic microstructure that constitutes the feather barbs. The species Swallow Tanager, of the family Thraupidae, exhibits sexual dichromatism: males have blue plumage and females green. In addition, the feathers show an iridescent reflectance, which changes as the angle between the directions of incidence and observation is varied. In order to investigate the mechanisms of colour generation in the feathers of the Swallow Tanager species, we study their electromagnetic response. First, we obtained TEM images of the barbs’ cross section, which revealed a microstructure consisting of quasi-spherical air cavities embedded in a β-keratin matrix. To obtain the relevant geometric parameters of the structure, we performed a detailed statistical analysis of the images. These parameters, together with the optical properties of the constituent materials, determine the electromagnetic behaviour of the structure. To calculate the reflectance of a barb, we used two theoretical approaches. First, we applied a simplified model based on Fourier analysis, which relies on the single-particle scattering hypothesis. This method provides useful information about the spectral position of the dominant reflectance peak in the visible region of the spectrum. However, this approach does not account for multiple scattering effects which could produce additional features. Then, we investigate the optical response by applying the Korringa-Kohn-Rostoker (KKR) method, which is a rigorous theoretical formalism for the calculation of the reflectance of structures formed by a stack of spheres embedded in a material medium. We performed numerical simulations, paying special attention to the influence of the geometrical characteristics of the microstructure on the optical response of the barbs. The KKR curves exhibit an enhancement in the UV region, which is in agreement with the measured reflectance of Swallow Tanager. These results evidence the potential of the KKR formalism to accurately reproduce the electromagnetic response of natural structures and to reveal features that cannot be explained using the Fourier approach. The results obtained confirm that the quasi-ordered spongy structure produces coherent scattering and therefore is the responsible for the colour of the Swallow Tanager.

In this work we study the sound production mechanism of the raspy sounding song of the white-tipped plantcutter (Phytotoma rutila), a species with a most unusual vocalization. The biomechanics involved in the production of this song, and scaling arguments, allowed us to predict the precise way in which body size is encoded in its vocalizations. We tested this prediction through acoustic analysis of recorded songs, computational modeling of its unusual vocal strategy, and inspection of museum specimens captured across southeastern and south-central South America. Fil: Uribarri, Gonzalo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina Fil: Rodríguez Cajarville, María José. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Tubaro, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Goller, Franz. University Of Utah. Department Of Biology; Estados Unidos Fil: Mindlin, Bernardo Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina

The tropical and subtropical Andes have among the highest levels of biodiversity in the world. Understanding the forces that underlie speciation and diversification in the Andes is a major focus of research. Here we tested two hypotheses of species origins in the Andes: 1. Vicariance mediated by orogenesis or shifting habitat distribution. 2. Parapatric diversification along elevational environmental gradients. We also sought insights on the factors that impacted the phylogeography of co-distributed taxa, and the influences of divergent species ecology on population genetic structure. We used phylogeographic and coalescent analyses of nuclear and mitochondrial DNA sequence data to compare genetic diversity and evolutionary history of two frog species:Pleurodema borellii(Family: Leiuperidae, 130 individuals; 20 sites), andHypsiboas riojanus(Family: Hyllidae, 258 individuals; 23 sites) across their shared range in northwestern Argentina. The two showed concordant phylogeographic structuring, and our analyses support the vicariance model over the elevational gradient model. However,Pleurodema borelliiexhibited markedly deeper temporal divergence (≥4 Ma) thanH. riojanus(1-2 Ma). The three main mtDNA lineages ofP. borelliiwere nearly allopatric and diverged between 4-10 Ma. At similar spatial scales, differentiation was less in the putatively more habitat-specializedH. riojanusthan in the more generalistP. borellii. Similar allopatric distributions of major lineages for both species implies common causes of historical range fragmentation and vicariance. However, different divergence times among clades presumably reflect different demographic histories, permeability of different historical barriers at different times, and/or difference in life history attributes and sensitivities to historical environmental change. Our research enriches our understanding of the phylogeography of the Andes in northwestern Argentina.

The central Andean rainforests and the Atlantic Forest are two similar biomes that are fully isolated by xerophytic and open-vegetation regions (the Chaco and Cerrado, respectively). Even though there is evidence suggesting that these rainforests have been connected in the past, their dynamics of connection, the geographic areas that bridged these regions, and the biological processes that have promoted diversification between them remain to be studied. In this research, we used three passerine species (Poecilotriccus plumbeiceps, Phylloscartes ventralis and Cacicus chrysopterus) as models to address whether the Andean and the Atlantic forests have acted as a refugia system (macrorefugia), and to evaluate biogeographic hypotheses of diversification and connection between them. In order to achieve these goals, we performed traditional phylogeographic analyses and compared alternative biogeographic scenarios by using Approximate Bayesian Computation. Additionally, we performed morphological analyses to evaluate phenotypic divergence between these regions. Our findings support that both rainforest regions acted as refugia, but that the impact of their isolation was stronger on the genetic than on the morphologic characters. Our results provided evidence that both geographic isolation as well as ecological factors have modeled the external traits of forest organisms in the region. Regarding the connection routes between the Andes and the Atlantic Forest, the genetic data rejected the hypothesis of a Chaco connection in the tested species, providing evidence for a connection through the Cerrado or through the transition between the Cerrado and Chaco, in a process that could have started as early as the Late Miocene.

In this work we build a convolutional neural network capable of identifying individual birds by their songs. Since the actual data available from each individual is very limited, we use a dynamical system capable of synthesizing realistic songs, to generate surrogate-training data. The different synthetic songs are the result of integrating the dynamical system with slightly varied parameters. We show that a data set built in this way allows us to train the network to successfully identify the different individuals in our study. In this way, we present a novel way to perform data augmentation using dynamical systems. Fil: Tubaro, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Mindlin, Bernardo Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina

The Andes constitute one of the main factors that have promoted diversification in the Neotropics. However, the role of other highland regions in the southern cone of South America has been barely studied. We analyzed the level of endemism in the avifauna of the Central Sierras in Córdoba, a high region in central Argentina, to evaluate the effect of its geographic isolation from the Andes. There are 11 species with endemic subspecies in this region, all of them described based only on differences in morphology (mainly plumage color) with no genetic evidence. We performed the first genetic analyses of seven of these species using mitochondrial DNA obtained from fresh tissue and toe pad samples. Our results show that for three of these species, Catamenia inornata, Phrygilus unicolor and Cinclodes atacamensis, the population in the Central Sierras is clearly differentiated from those of other regions, and the first two of them also show divergence among Andean subspecies. In the remaining species we found a varying degree of differentiation, ranging from a small divergence in Muscisaxicola rufivertex to the presence of different haplotypes but with an apparent lack of phylogeographic structure in Phrygilus plebejus and Sturnella loyca (being the latter the only species with a continuous distribution between the Central Sierras and the Andes) to haplotype sharing in Asthenes modesta. While further analyses including additional markers, morphological characters and vocalizations are needed, our results show that some of the species that have disjunct distributions, with a population in the Central Sierras isolated geographically from the Andes, possess distinct genetic lineages in the Central Sierras that suggest an evolutionary isolation from other populations. These findings highlight the importance of montane regions in general, and the Central Sierras in particular, as drivers of diversification in the Neotropics. Fil: Bukowski Loináz, María Belén. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Lavinia Oblanca, Pablo Damián. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Trujillo Arias, Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Kopuchian, Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentina Fil: Tubaro, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Lijtmaer, Dario Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina

Ants are abundant and ecologically dominant insects in most terrestrial communities. In subtropical ecosystems, there is a high turnover of species from the canopy to the top layers of the soil. Additionally, ant communities are often influenced by inter-specific competition. Collectively, these two processes (abiotic filtering and competition) make ants ideal for studies of community structure. We examined composition, co-occurrence, and species interactions in a sub-tropical forest ant community to examine how ground-foraging ant species partition microhabitats. We used four methods: Pitfall traps, litter samples, surface baits, and subterranean baits. Surface baiting was employed at three different time periods to examine how foraging activity and species interactions at baits varied with time of day and temperature. Each method sampled a particular assemblage of the 97 total ant species. Pitfall traps shared ~50% of species with surface baits and litter samples. Subterranean baits had the fewest total species but included some uncommonly sampled ants. The majority of interactions between species at baits were neutral, but a few agonistic interactions were also observed when bait occupancy was highest. Species co-occurrence patterns suggest that this ant community may not be heavily influenced by interspecific competition. Our results reinforce the advantages of applying complementary sampling techniques to examine ant community structure, and suggest that competition and dominance is best considered in the context of resource type, foraging strategy and time of sampling. Finally, we discuss the lack of two conspicuous Neotropical groups in our samples, leaf-cutting ant and army ants. Fil: Hanisch, Priscila Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina Fil: Suarez, Andrew V.. University of Illinois. Urbana - Champaign; Estados Unidos Fil: Tubaro, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina Fil: Paris, Carolina Ivon. Universidad de Buenos Aires; Argentina

The plumage of birds often exhibits attractive color effects produced by the interaction of light with the photonic microstructure present in the feather barbs and barbules. This microstructure constitutes a natural photonic crystal that rejects radiation of wavelengths contained within the band gap, which significantly alters the observed coloration depending on the incidence conditions. In spite of the high degree of regularity exhibited by the barb's microstructure of many species, the disorder present in these natural photonic crystals might modify the reflected response. In this paper, we address the problem of modeling the electromagnetic response of a quasiordered photonic structure, using an electromagnetic method only suitable for strictly periodic structures. In particular, we simulate the reflected response of the plumage of the Swallow Tanager (Tersina viridis) by two different approaches. On the one hand, we compute the reflected response by averaging reflectance spectra calculated by the Korringa-Kohn-Rostoker method for different geometrical parameters. We also apply the inner extinction approximation, which represents imperfections in the structure by adding a small imaginary part to the dielectric constant of the inclusions. The agreement between the experimental and the simulated results evidences the potential of the proposed methods to reproduce the electromagnetic response of natural photonic structures.

Behavioural characters that are learned can show temporal variation due to changes in a population across generations that are not due to changes in the same individual. The song of the Rufous-collared Sparrow, Zonotrichia capensis, shows significant geographic variation associated with habitat vegetation, defining song dialects. To study the temporal stability or change of Rufous-collared Sparrow dialects at a microgeographical scale, we compared the recordings made in Estancia ?El Destino? (in the northeast coast of Buenos Aires province, Argentina) during 1987 and 2000 with a set of recordings made during 2010 and 2011. We found that the dialect boundaries of the Rufous-collared Sparrow remained stable over a period of 24 years. Since we did not detect gross changes in the habitat characteristics, we concluded that habitat structure is an important factor for dialect distribution. When we consider each dialect separately, the variation detected in some traits between 1987 and 2000 persisted while other traits showed reversal across time. These findings are consistent with the hypothesis that some changes in song were the result of neutral variation, whereby changes due to random factors such as copying error, for example, could have been maintained or introduced across generations. Fil: García, Natalia Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Arrieta, Ramiro Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Kopuchian, Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentina Fil: Tubaro, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina

Understanding patterns of species diversity rely on accurate taxonomy which can only be achieved by long-term natural history research and the use of complementary information to establish species boundaries among cryptic taxa. We used DNA barcoding to characterize the ant diversity of Iguazú National Park (INP), a protected area of the Upper Paraná Atlantic Forest ecoregion, located at the southernmost extent of this forest. We assessed ant diversity using both cytochrome c oxidase subunit 1 (COI) sequences and traditional morphological approaches and then compared the results of these two methods. We successfully obtained COI sequences for 312 specimens belonging to 124 species, providing a DNA barcode reference library for nearly 50% of the currently known ant fauna of INP. Our results evidenced a clear barcode gap for all but two species, with a mean intraspecific divergence of 0.72%, and an average congeneric distance of 17.25%. Congruently, the library assembled here was remarkably useful for the discrimination of the ants of INP and even allowed us to link unidentified males and queens to their worker castes. To detect overlooked diversity, we classified the DNA barcodes into Molecular Operational Taxonomic Units (MOTUs) using three different clustering algorithms and then compared their number and composition to that of reference species identified based on morphology. The MOTU count was always higher than that of reference species regardless of the method, suggesting that the diversity of ants at INP could be between 6% and 10% higher than currently recognized. Lastly, our survey contributed with 78 new barcode clusters to the global DNA barcode reference library, and added 36 new records of ant species for the INP, being 23 of them new citations for Argentina. Fil: Hanisch, Priscila Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Lavinia Oblanca, Pablo Damián. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Suarez, Andrew. University of Illinois; Estados Unidos Fil: Lijtmaer, Dario Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Leponce, Maurice. Royal Belgian Institute of Natural Sciences; Bélgica Fil: Paris, Carolina Ivon. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina Fil: Tubaro, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina

The evolution of complex behavior is driven by the interplay of morphological specializations and neuromuscular control mechanisms [1-3], and it is often difficult to tease apart the respective contributions of these two factors. Avian vocal learning and its associated neural adaptations are thought to have played a major role in the diversification of birds [4-8], whereas the functional significance of the substantial morphological diversity of the vocal organ itself remains largely unexplored. Within the most species rich order, Passeriformes, ?tracheophones? are a suboscine group that, unlike their oscine sister taxon, does not exhibit vocal learning [9] and are thought to phonate with a pair of tracheal membranes [10, 11] instead of the two independent sources found in other passerines [12-14]. Here we provide direct videoscopic evidence that tracheophones possess three sound sources, two oscine-like labial pairs in addition to the unique tracheal membranes, which collectively represent the largest described number of sound sources for a vocal organ. Birds with experimentally disabled tracheal membranes were still able to phonate. Instead of being the main sound source, the tracheal membranes constitute a morphological specialization, which, through interaction with the labia, contributes to the generation of different acoustic features such as spectral complexity, amplitude modulation and enhanced sound amplitude. In contrast, these same features arise in oscines from neuromuscular control of the two labial sources [15-17]. These findings are supported by a modeling approach and provide a clear example for how a morphological adaptation of the tracheophone vocal organ can generate specific, complex sound features. Morphological specialization therefore constitutes an alternative path in the evolution of acoustic diversity to that of oscine vocal learning and complex neural control. Fil: García, Sarah M.. University Of Utah. Department Of Biology; Estados Unidos Fil: Kopuchian, Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales ; Argentina Fil: Mindlin, Bernardo Gabriel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentina Fil: Fuxjager, Matthew. Wake Forest Universit. Department Of Biology; Estados Unidos Fil: Tubaro, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales ; Argentina Fil: Goller, Franz. University Of Utah. Department Of Biology; Estados Unidos

Acoustic signals among newly diverged taxa have the potential to convey species identity, information that is key to reducing hybridization. Capuchino seedeaters constitute a remarkable example of recently radiated endemic species from the grasslands of South America. They are sexually dimorphic and show striking differences in male plumage coloration and song. Contrasting with this divergence in phenotype most species show extremely low neutral genetic differentiation and lack of reciprocal monophyly, which is interpreted to be a product of recent common ancestry and hybridization. Here we use field-based playback experiments to test for the first time if males of two species, Sporophila hypoxantha and S. palustris, discriminate between conspecific and heterospecific song. Using various measures of behavior we find that both species react more strongly to their own songs. The response to playback from another southern capuchino cannot be differentiated from that of a control song from a more distantly related Sporophila species. Additionally, we did not find evidence for reinforcement as the response of S. hypoxantha did not differ between individuals that co-occur with S. palustris and those that do not. Our finding suggests that song, a culturally inherited trait, may help maintain reproductive isolation between species in the rapid and explosive capuchino radiation.

1 * Understanding how genetic and phenotypic differences that arise in geographically isolated populations influence the outcome of secondary contact advances our knowledge of speciation. In the present study, we investigate the secondary contact between divergent lineages of a widespread Neotropical songbird, the Rufous-collared sparrow (Zonotrichia capensis). Zonotrichia capensis is morphologically and behaviourally diverse, and shows a pattern of lineage diversification produced by a Pleistocene expansion and colonization of South America from a probable Central American origin. Consistent with previous results, we find three lineages throughout the species range, showing between 1.5% and 2.5% divergence in mitochondrial control region sequences. These lineages come into secondary contact in the Dominican Republic, La Paz (Bolivia), and North-eastern Argentina. We use DNA microsatellite data to study a broad secondary contact zone in North-eastern Argentina, finding that Bayesian clustering analyses do not assign individuals to their respective mitochondrial lineages. Overall, we did not observe nuclear genetic discontinuities in the study area. We conclude that, if genetic, morphological, and/or cultural differences accumulated among lineages during isolation, they were insufficient to prevent gene flow after secondary contact. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 111, 863-868.

Consistent responses by various organisms to common environmental pressures represent strong evidence of natural selection driving geographical variation. According to Bergmann's and Allen's rules, animals from colder habitats are larger and have smaller limbs than those from warmer habitats to minimize heat loss. Although evidence supporting both rules in different organisms exists, most studies have considered only elevational or latitudinal temperature gradients. We tested for the effects of temperature associated with both elevation and latitude on body and appendage size of torrent ducks (Merganetta armata), a widespread species in Andean rivers. We found a negative relationship between body size and temperature across latitude consistent with Bergmann's rule, whereas there was a positive relationship between these variables along replicate elevational gradients at different latitudes. Limb-size variation did not support Allen's rule along latitude, nor along elevation. High-elevation ducks were smaller and had longer wings than those inhabiting lower elevations within a river. We hypothesize that temperature is likely a major selective pressure acting on morphology across latitudes, although hypoxia or air density may be more important along elevational gradients. We conclude that the effect of temperature on morphology, and hence the likelihood of documenting ecogeographical ‘rules’, depends on the environmental context in which temperature variation is examined. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 111, 850–862.

Along many decades, protected environments were targeted by the scientific community for ecological research and for the collection of scientific information related to environmental aspects and biodiversity. However, most of the territory in hotspot regions with weak or even non legal protection has been left aside. These non-protected areas (NPA) could host high biodiversity values. This paper addresses how scientific effort on a NPA (CIAR) of 700 ha from the Atlantic Rain Forest, generates new information and tools for large-scale environmental and biodiversity management in NPAs. Information published during the last decade was summarized and complemented with subsequent novel data about biodiversity (new species, first records, DNA and chemical analyses, etc.). The results showed: 1 new genus (arachnid), 6 new species and several putative new species (fish and arthropod), 6 vulnerable species (bird and mammal) and 36 first records for Argentina (fish, arthropod, platyhelminth and fungi). When compared with protected natural areas of the same biome, the CIAR showed highly valuable aspects for fauna and environment conservation, positioning this NPA as a worldwide hotspot for some taxa. Indeed, when compared to international hotspots in a coordinated Malaise trap program, the CIAR showed 8,651 different barcode index numbers (∼species) of arthropods, 80% of which had not been previously barcoded. Molecules like Inoscavin A, with antifungal activity against phytopathogens, was isolated for the first time in Phellinus merrillii fungi. The study of major threats derived from anthropic activities measured 20 trace elements, 18 pesticides (i.e. endosulfans, chlorpyrifos, DDTs, HCHs) and 27 pharmaceuticals and drugs (i.e. benzoylecgonine and norfluoxetine) in different biotic and abiotic matrices (water, sediment, fish and air biomonitors). This integrated data analysis shows that biodiversity research in NPA is being undervalued and how multidisciplinary and multi-taxa surveys creates a new arena for research and a pathway towards sustainable development in emerging countries with biodiversity hotspots. Fil: Avigliano, Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Unidad Ejecutora de Investigaciones en Producción Animal. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Unidad Ejecutora de Investigaciones en Producción Animal; Argentina. Fundacion Bosques Nativos Argentinos Para la Biodiversidad.; Argentina Fil: Rosso, Juan Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Lijtmaer, Dario Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Ondarza, Paola Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Piacentini, Luis Norberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Pque. Centenario. Museo Argentino de Ciencias Naturales "bernardino Rivadavia". Departamento de Invertebrados; Argentina Fil: Izquierdo, Matías Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentina Fil: Cirigliano, Andrea. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina Fil: Romano, Gonzalo Matías. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Núñez Bustos, Ezequiel Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Pque. Centenario. Museo Argentino de Ciencias Naturales "bernardino Rivadavia". Departamento de Invertebrados; Argentina Fil: Porta, Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Mabragaña, Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Grassi, Emanuel Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentina Fil: Palermo, Jorge Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad de Microanálisis y Métodos Físicos en Química Orgánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Unidad de Microanálisis y Métodos Físicos en Química Orgánica; Argentina Fil: Bukowski Loináz, María Belén. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Tubaro, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Schenone, Nahuel Francisco. Fundacion Bosques Nativos Argentinos Para la Biodiversidad.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentina

El género Neotropical Sporophila contiene un grupo de ocho especies conocido coloquialmente como los capuchinos del sur. Dicho grupo muestra una marcada variación fenotipica (principalmente en la coloración y el canto de los machos) que contrasta con la falta de monofilia a nivel de especie y bajos niveles de diferenciación en marcadores genéticos neutros. Este patrón ha sido atribuido al origen reciente del grupo y a la hibridacion e introgresion entre especies. Una revision taxonómica reciente de la única especie politípica, S. bouvreuil (la cuál contenía cuatro subespecies), designó a S. bouvreuil y S. pileata como nuevas especies en base a patrones de coloración y distribución geográfica. En el presente estudio utilizamos secuencias de ADN y frecuencias de alelos de ADN microsatélite para corroborar la designación de dichas especies y estudiar por primera vez la relación entre ellas y con respecto a los demas capuchinos del sur. Utilizando análisis filogenéticos y herramientas de genetica de poblaciones mostramos que S. bouvreuil y no S. minuta, como se creia anteriormente, es la especie hermana del grupo, al cuál pertenece S. pileata. Posiblemente el ancestro de los capuchinos del sur provino del norte de América del Sur y comenzó a radiar durante el Pleistoceno inferior o medio en al menos ocho especies en los pastizales del noreste Argentino, este de Paraguay, y sur de Brasil. Como en estudios previos, no fue posible distinguir entre capuchinos del sur utilizando marcadores genéticos neutros, un resultado esperable en el contexto de una radiación rápida y reciente. Within the Neotropical genus Sporophila, a group of eight species known colloquially as “southern capuchinos” shows remarkable phenotypic variation despite lack of (species level) mitochondrial DNA monophyly and extremely low differentiation in other putatively neutral genetic markers. Previous studies have interpreted this as reflecting recent common ancestry and, perhaps, ongoing hybridization and introgression. A recent taxonomic revision of the only polytypic southern capuchino species, Sporophila bouvreuil (with four previously recognized subspecies), prompted the designation of S. bouvreuil and S. pileata as two distinct species on the basis of plumage color and geographic distribution. We used DNA sequence and microsatellite data to corroborate these new species designations and explored for the first time the relationship between these taxa and the remaining southern capuchinos. Phylogenetic and population genetic analyses showed that S. bouvreuil and not S. minuta, as was previously thought, is the sister species to the core radiation of which S. pileata is part. Our data suggest that the ancestor of the southern capuchinos is derived from northern South America and began to radiate during the lower to middle Pleistocene into at least eight species within the grasslands of northeastern Argentina, eastern Paraguay, and southern Brazil. Consistent with earlier studies, we could not distinguish among southern capuchino species using neutral genetic markers, an expected signature of a rapid and recent radiation. Fil: Campagna, Leonardo. Queens University; Canadá. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Silveira, Luis Fabio. Universidade de Sao Paulo; Brasil Fil: Tubaro, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Lougheed, Stephen C.. Queens University; Canadá

Fil: Arrieta, Ramiro Santiago. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales; Argentina

DNA barcodes of birds are currently available for 41% of known species and for many different geographic areas; therefore, they are a rich data source to answer evolutionary questions. We review studies that have used DNA barcodes to investigate evolutionary processes in birds using diverse approaches. We also review studies that have investigated species in depth where taxonomy and DNA barcodes present inconsistencies. Species that showed low genetic interspecific divergence and lack of reciprocal monophyly either are the result of recent radiation and (or) hybridize, while species with large genetic splits in their COI sequences were determined to be more than one independent evolutionary unit. In addition, we review studies that employed large DNA barcode datasets to study the molecular evolution of mitochondrial genes and the biogeography of islands, continents, and even at a multi-continental scale. These studies showed that DNA barcodes offer high-quality data well beyond their main purpose of serving as a molecular tool for species identification. Fil: Barreira, Ana Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales ; Argentina Fil: Lijtmaer, Dario Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales ; Argentina Fil: Tubaro, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales ; Argentina

Vocal communication is an unique example,where the nonlinear nature of the periphery can giverise to complex sounds even when driven by simple neuralinstructions. In this work we studied the case of twoclose-related bird species, Patagioenas maculosa and Patagioenaspicazuro, whose vocalizations differ only in thetimbre. The temporal modulation of the fundamental frequencyis similar in both cases, differing only in the existenceof sidebands around the fundamental frequency in theP. maculosa. We tested the hypothesis that the qualitativedifference between these vocalizations lies in the nonlinearnature of the syrinx. In particular, we propose that theroughness of maculosa?s vocalizations is due to an asymmetrybetween the right and left vibratory membranes,whose nonlinear dynamics generate the sound. To test thehypothesis, we generated a biomechanical model for vocalproduction with an asymmetric parameter Q with which wecan control the level of asymmetry between these membranes.Using this model we generated synthetic vocalizationswith the principal acoustic features of both species. In addition, we confirmed the anatomical predictions bymaking post mortem inspection of the syrinxes, showingthat the species with tonal song (picazuro) has a more symmetricalpair of membranes compared to maculosa. Fil: Alonso, Rodrigo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina Fil: Kopuchian, Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Amador, Ana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina Fil: Suarez, María de los Angeles. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina Fil: Tubaro, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Mindlin, Bernardo Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física. Laboratorio de Sistemas Dinámicos; Argentina

The increasing availability of molecular phylogenies has highlighted the issue that genotypic and phenotypic patterns of variation are not always congruent, particularly below the species level. This has led to an ongoing discussion on the validity of the subspecies category and on the use of molecular data to help revise traditional classifications based on phenotypic data. We compared patterns of spatial diversification in genotype and phenotype in the Blue-black Grosbeak Cyanocompsa cyanoides, a Neotropical songbird with four recognised subspecies. Variation in phenotype and genotype are partially congruent among the four subspecies. The more genetically divergent subspecies C. c. rothschildii is strongly differentiated from the other subspecies in meristic characters, plumage colo uration and song . W e suggest that this taxon be accorded full species status as C. rothschildii. Regarding the remaining diversity within C. cyanoides, both phenotypic and genetic markers suggests that it could be divided into two subgroups, but the boundaries of genetic lineages do not coincide with those of subspecies defined using phenotypic data. Lack of complete congruence between phenotypic and molecular markers may be expected, since they are subject to different evolutionary processes. The discordance could also be due to a methodological problem, as subspecies ? geographic boundaries were defined on the basis of phenotypic descriptions that were not systematically evaluated. We consider the subspecies to be an informative taxonomic entity , but note that many current subspecific designations for diverse species need extensive reassessment. Fil: García, Natalia Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Barreira, Ana Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Lavinia Oblanca, Pablo Damián. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Tubaro, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina