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The New World suboscines (Passeriformes and Tyrannides) are one of the biggest endemic vertebrate radiations in South America, including the families Furnariidae and Tyrannidae. Avian brain morphology is a reliable proxy to study their evolution. The aim of this work is to elucidate whether the brains of these families reflect the ecological differences (e.g., feeding behavior) and to clarify macroevolutionary aspects of their neuroanatomy. Our hypotheses are as follows: Brain size is similar between both families and with other Passeriformes; brain morphology in Tyrannides is the result of the pressure of ecological factors; and brain disparity is low since they share ecological traits. Skulls of Furnariidae and Tyrannidae were micro-computed tomography-scanned, and three-dimensional models of the endocast were generated. Regression analyses were performed between brain volume and body mass. Linear and surface measurements were used to build phylomorphospaces and to calculate the amount of phylogenetic signal. Tyrannidae showed a larger brain disparity than Furnariidae, although it is not shaped by phylogeny in the Tyrannides. Furnariidae present enlarged Wulsts (eminentiae sagittales) but smaller optic lobes, while in Tyrannidae, it is the opposite. This could indicate that in Tyrannides there is a trade-off between the size of these two visual-related brain structures.

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BACKGROUND: Metabolic activity and environmental energy are two of the most studied putative drivers of molecular evolutionary rates. Their extensive study, however, has resulted in mixed results and has rarely included the exploration of interactions among various factors impacting molecular evolutionary rates across large clades. Taking the diverse avian family Furnariidae as a case study, we examined the association between several estimates of molecular evolutionary rates with proxies of metabolic demands imposed by flight (wing loading and wing shape) and proxies of environmental energy across the geographic ranges of species (temperature and UV radiation). RESULTS: We found weak evidence of a positive effect of environmental and morphological variables on mitochondrial substitution rates. Additionally, we found that temperature and UV radiation interact to explain molecular rates at nucleotide sites affected by selection and population size (non-synonymous substitutions), contrary to the expectation of their impact on sites associated with mutation rates (synonymous substitutions). We also found a negative interaction between wing shape (as described by the hand-wing index) and body mass explaining mitochondrial molecular rates, suggesting molecular signatures of positive selection or reduced population sizes in small-bodied species with greater flight activity. CONCLUSIONS: Our results suggest that the demands of flight and environmental energy pose multiple evolutionary pressures on the genome either by driving mutation rates or via their association with natural selection or population size. Data from whole genomes and detailed physiology across taxa will bring a more complete picture of the impact of metabolism, population size, and the environment on avian genome evolution.

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The identity of Azara's No. 246 "Trepador remos y cola roxos" and the names Dendrocolaptes miniatus Illiger, 1820 and Dendrocopus rubricaudatus Vieillot, 1818, which are based on it, have never been convincingly elucidated, and previously proposed identifications in the literature are demonstrably incorrect. Azara shot his specimen in a Paraguayan forest and provided a detailed description and measurements of it in his Spanish text. These are sufficient to confirm the identity of the specimen and the names based on it as the Olive Spinetail, long known as Cranioleuca obsoleta (Reichenbach, 1853). Dendrocolaptes miniatus Illiger, 1820 and Dendrocopus rubricaudatus Vieillot, 1818 nevertheless have date priority over that name, but as they have not been used as valid since 1899 they are nomina oblita under Article 23.9.2 of the Code. Cranioleuca obsoleta has been in universal use for this species since Hellmayr (1925), so it qualifies as a nomen protectum under Article 23.9.2, and remains the valid name for the Olive Spinetail.

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South American dry forests have a complex and poorly understood biogeographic history. Based on the fragmented distribution of many Neotropical dry forest species, it has been suggested that this biome was more widely distributed and contiguous under drier climate conditions in the Pleistocene. To test this scenario, known as the Pleistocene Arc Hypothesis, we studied the phylogeography of the Rufous-fronted Thornbird (Phacellodomus rufifrons), a widespread dry forest bird with a disjunct distribution closely matching that of the biome itself. We sequenced mtDNA and used ddRADseq to sample 7,167 genome-wide single-nucleotide polymorphisms from 74 P. rufifrons individuals across its range. We found low genetic differentiation over two prominent geographic breaks - particularly across a 1,000 km gap between populations in Bolivia and Northern Peru. Using demographic analyses of the joint site frequency spectrum, we found evidence of recent divergence without subsequent gene flow across those breaks. By contrast, parapatric morphologically distinct populations in northeastern Brazil show high genetic divergence with evidence of recent gene flow. These results, in combination with our paleoclimate species distribution modelling, support the idea that currently disjunct patches of dry forest were more connected in the recent past, probably during the Middle and Late Pleistocene. This notion fits the major predictions of the Pleistocene Arc Hypothesis and illustrates the importance of comprehensive genomic and geographic sampling for examining biogeographic and evolutionary questions in complex ecosystems like Neotropical dry forests.

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Birds in the Huinay area, Los Lagos region, Chile, were studied for parasites. Here we report 2 new genera and species of the family Dilepididae (Cyclophyllidea) found in common local passerines: Janinelliapeebeehi gen. n., sp. n. was found in Elaeniaalbiceps (Tyrannidae) and Huinaylepiselegans gen. n., sp. n. was found in Aphrasturaspinicauda (Furnariidae). Other dilepidid parasites are reported for the first time from Xolmispyrope (Tyrannidae) and from 2 species of Rhinocryptidae. Cotylorhipissureshi Jadhav & Shinde, 1981 is considered a species inquirenda. The very high diversity and endemism of the observed cestode fauna in the Valdivian temperate rain forests is noted.

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Because a broad spectrum of resource use allows species to persist in a wide range of habitat types, and thus permits them to occupy large geographical areas, and because broadly distributed species have access to more diverse resource bases, the resource breadth hypothesis posits that the diversity of resources used by organisms should be positively related with the extent of their geographic ranges. We investigated isotopic niche width in a small radiation of South American birds in the genus Cinclodes. We analysed feathers of 12 species of Cinclodes to test the isotopic version of the resource breadth hypothesis and to examine the correlation between isotopic niche breadth and morphology. We found a positive correlation between the widths of hydrogen and oxygen isotopic niches (which estimate breadth of elevational range) and widths of the carbon and nitrogen isotopic niches (which estimates the diversity of resources consumed, and hence of habitats used). We also found a positive correlation between broad isotopic niches and wing morphology. Our study not only supports the resource breadth hypothesis but it also highlights the usefulness of stable isotope analyses as tools in the exploration of ecological niches. It is an example of a macroecological application of stable isotopes. It also illustrates the importance of scientific collections in ecological studies.

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Relationships among genera in the tribe Synallaxini have proved difficult to resolve. In this study, I investigate relationships among Synallaxis, Certhiaxis and Schoeniophylax using DNA sequences from the mitochondrion and three nuclear regions. I implemented novel primers and protocols for amplifying and sequencing autosomal and sex-linked introns in Furnariidae that resolved basal relationships in the Synallaxini with strong support. Synallaxis propinqua is sister to Schoeniophylax phryganophilus, and together they form a clade with Certhiaxis. The results are robust to analytical approaches when all genomic regions are analyzed jointly (parsimony, maximum likelihood, and species-tree analysis) and the same basal relationships are recovered by most genomic regions when analyzed separately. A sister relationship between S. propinqua, an Amazonian river island specialist, and S. phryganophilus, from the Paraná River basin region, reveals a new biogeographic pattern shared by at least other four pairs of taxa with similar distributions and ecologies. Estimates of divergence times for these five pairs span from the late Miocene to the Pleistocene. Identification of the historical events that produced this pattern is difficult and further advances will require additional studies of the taxa involved and a better understanding of the recent environmental history of South America. A new classification is proposed for the Synallaxini, including the description of a new genus for S. propinqua.

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Triatomines (Hemiptera, Reduviidae) are bloodsucking insects involved in the transmission of Trypanosoma cruzi, the causative agent of Chagas disease, an important public health problem in Latin America. The triatomine species found in sylvatic habitats generally play a limited epidemiological role compared to domestic species, but they may act as a reinfestation source of dwellings after insecticide spraying and have to be carefully considered in control strategies of Chagas disease transmission. The objectives of this work were to carry out a survey of the sylvatic triatomine species colonizing Furnariidae nests in a typical area of the Chaco region of Argentina during the winter and to study the parasites and natural enemies associated with the collected triatomines. Sixty-three triatomine specimens were collected from Furnariidae nests (Coryphistera alaudina and Phacellodomus sibilatrix) randomly selected within the study area. Fifty-four were identified as Psammolestes coreodes, seven as Triatoma platensis, and two as Triatoma infestans. Specimens of T. infestans and T. platensis were found in one nest. The first finding of instar nymphs of T. infestans x T. platensis in a sylvatic habitat is reported. For the first time, sylvatic collected specimens of T. platensis were found infected by T. cruzi. Triatoma virus was found in one Ps. coreodes specimen.

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