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This article discusses a study that compares the whistles emitted by common bottlenose dolphins in three different regions: Revillagigedo Archipelago in Mexico, Saint Peter and Saint Paul Archipelago in Brazil, and the western Coast of Aragua in Venezuela. The study aims to understand the geographic variation in dolphin whistles in these regions. The study collected acoustic recordings from each location and analyzed the data to provide an overview of whistle variation among the studied areas. The results show that there are differences in whistle characteristics between the locations, suggesting that environmental adaptations, social factors, and genetic divergence may influence dolphin communication. Further research is needed to explore these factors in more detail. [Extracted from the article]

Recent molecular studies have clarified the overarching taxonomy of capuchin monkeys, but intraspecific genetic diversity remains unexplored for most capuchin species. One example is Sapajus nigritus, the southernmost capuchin monkey, found in Brazil and Argentina; its phenotypic diversity has been recognized as two geographic subspecies, but the intraspecific genetic structure of this taxon is poorly known. Here, we sampled across most of this species' geographic distribution, producing a newly sequenced data set for genetic analyses that included 78 individuals from 14 populations. We investigated the intraspecific diversity, genetic structure, and evolutionary history using three mitochondrial markers. Our results indicated that S. nigritus populations exhibited high levels of genetic structure. We found strong support for two monophyletic clades within this species with a deep phylogenetic split, and clear separation from other related taxa. Vicariance events seem to have played a prevalent role in shaping S. nigritus genetic differentiation. The Paraíba do Sul River may have driven the deep divergence between southern and northern clades, whereas the Tietê River may have had a weaker, more recent effect on the divergence of populations within the southern clade. Research Highlights: Using mitochondrial markers we found support for two major clades within Sapajus nigritus; the Paraíba do Sul River probably acted as a barrier to drive this deep phylogenetic split, estimated to have occurred at 1.56 MaWe recovered the southern S. nigritus clade as sister to a clade of other Sapajus species (S. cay, apella, macrocephalus, robustus, flavius) rather than northern S. nigritus, emphasizing southern and northern clades as distinct phylogenetic unitsS. nigritus D‐loop analysis showed high pairwise populational genetic differentiation and geographic structure; this D‐loop database can now be used for to help identify the geographical origin of illegally traded animals [ABSTRACT FROM AUTHOR]

Elasmobranchs are threatened and eDNA metabarcoding is a powerful tool that can help efforts to better understand and conserve them. Nevertheless, the inter‐calibration between optimal methodological practices and its implementation in resource‐limited situations is still an issue. Based on promising results from recent studies, the authors applied a cost‐effective protocol with parameters that could be easily replicated by any conservationist. Nonetheless, the results with fewer elasmobranchs detected than expected reveal that endorsed primers and sampling strategies still require further optimization, especially for applications in resource‐limited conservation programmes. [ABSTRACT FROM AUTHOR]

Aim: The use of landscape resistance maps to model connectivity has become an indispensable tool for species conservation. However, different methods can be used to estimate landscape resistance, but there is no consensus on which is the most reliable one. Therefore, comparing the performance of those methods in predicting resistance can be quite useful to understand their limitations and conservation implications. Our goal was to evaluate the accuracy of two commonly used approaches, habitat suitability modelling and landscape genetics, in estimating landscape resistance to genetic connectivity of two species of Neotropical cats (Leopardus guttulus and L. geoffroyi) across their ranges. Location: South America. Taxon: Felidae—L. guttulus and L. geoffroyi. Methods: For both species, we optimized a landscape genetics resistance surface using a restricted multivariate optimization approach and transformed a habitat suitability map into a resistance layer. We compared landscape resistance models created by these two approaches based on the models' Akaike information criterion scores and evaluated the similarities and differences in their predictions by calculating the correlation between the resistance layers and generating difference maps. Results: The genetic approach greatly outperformed the habitat suitability approach in explaining movement driving gene flow for both species. For the studied species, habitat preference and genetic connectivity are influenced by different landscape features. Habitat alteration imposes great resistance for genetic connectivity, and the presence of natural vegetation remnants within altered environments is essential for their conservation. Main conclusions For the studied species, the transformation of habitat suitability models into resistance surfaces is a poor proxy for permeability to dispersal, and the use of genetic data is more reliable in modelling connectivity for species conservation. Habitat suitability and landscape resistance are not equivalent or even proportional for these species. [ABSTRACT FROM AUTHOR]

Elasmobranchs are apex predators that play a crucial role in marine ecosystems by regulating the dynamics of food webs, as well as connecting different trophic levels across habitats.The large‐scale removal of elasmobranchs impacts the energy transfer in trophic interactions. The pressure of unsustainable fisheries is considerable, as most elasmobranchs have reproductive strategies that render them unable to recover their demographic status after depletion.In Brazil, elasmobranchs are broadly commercialized under the generalist common name of 'cação' (namely, shark meat). This allows threatened species to be commercialized and makes the tracking of different species difficult.DNA barcoding of the Cytochrome c oxidase subunit 1 (COI) gene was applied to identify the different species sold as 'cação' along the coastline of Brazil. Fifty‐seven samples from 33 cities in 15 coastal states of Brazil were purchased and analysed.Bioinformatic analyses revealed the presence of 17 species that were sold as 'cação'. Among them, Prionace glauca (blue shark) was the most abundant. Other species, listed as Endangered under the IUCN Red List of Threatened Species, were also uncovered as being in the shark meat trade, such as Sphyrna lewini (scalloped hammerhead), Isurus paucus (longfin mako shark), and Squatina guggenheim (angular angel shark).These findings have reinforced the necessity to correctly label the commercialized species. Public actions towards species‐specific management plans must be applied, as well as monitoring the supervised allied educational programmes. [ABSTRACT FROM AUTHOR]

Knowledge of how animal species use food resources available in the environment can increase our understanding of many ecological processes. However, obtaining this information using traditional methods is difficult for species feeding on a large variety of food items in highly diverse environments. We amplified the DNA of plants for 306 scat and 40 soil samples, and applied an environmental DNA metabarcoding approach to investigate food preferences, degree of diet specialization and diet overlap of seven herbivore rodent species of the genus Ctenomys distributed in southern and midwestern Brazil. The metabarcoding approach revealed that these species consume more than 60% of the plant families recovered in soil samples, indicating generalist feeding habits of ctenomyids. The family Poaceae was the most common food resource retrieved in scats of all species as well in soil samples. Niche overlap analysis indicated high overlap in the plant families and molecular operational taxonomic units consumed, mainly among the southern species. Interspecific differences in diet composition were influenced, among other factors, by the availability of resources in the environment. In addition, our results provide support for the hypothesis that the allopatric distributions of ctenomyids allow them to exploit the same range of resources when available, possibly because of the absence of interspecific competition. [ABSTRACT FROM AUTHOR]

Description of whistle characteristics and acoustic behavior of I Tursiops i spp. are available throughout the world (Quick and Janik, 2008; Santos, Louro, Couchinho, & Brito, 2005; Schultz & Corkeron, 1994; Steiner, 1981; Wang, Würsig, & Evans, 1995), though most studies have been carried out in the Northern Hemisphere. Mean ± standard deviation, median, and minimum-maximum values of acoustic parameters of whistles of Tursiops truncatus gephyreus (Uruguay, Patos Lagoon estuary and the Tramandaí channel) and of Tursiops truncatus truncatus (Rio de Janeiro). Factor-variable correlations (factor loadings) of acoustic parameters of whistles of Tursiops truncatus gephyreus (Uruguay, Patos Lagoon estuary and the Tramandaí channel) and of Tursiops truncatus truncatus (Rio de Janeiro) with factors 1 and 2 from principal component analysis. Abundance of bottlenose dolphins, Tursiops truncatus (Cetacea: Delphinidae), inhabiting the Patos Lagoon estuary, southern Brazil: Implications for conservation. [Extracted from the article]

Patterns of univariate trait variation across metacommunities are widely explored, as are searches for their underlying causes. Surprisingly, patterns of multivariate shape remain unknown, and the search for drivers of functional traits of communities often neglect the biogeographical distribution of phylogenetic clades. Our aim was to investigate multivariate shape distribution across metacommunities and to determine the main environmental drivers of shape beyond/taking into account the phylogenetic distribution of lineages. We obtained mean skull and mandible shape for 228 species of Neotropical sigmodontine rodents through geometric morphometrics (GM), and then calculated mean shapes for 1° × 1° cells across the Neotropics based on the incidence of sigmodontines. We investigated the effects of lineage distribution on mean trait variation by using phylogenetic fuzzy weighting to calculate principal coordinates of phylogenetic structure (PCPS). Effects of environmental variables on shape variation incorporating phylogenetic composition were realized through redundancy analysis. We found that the different distributions of major lineages throughout the Neotropics were responsible for much of the mean shape variation. The association of landscape features with tribal groupings (Oryzomyini with Amazonia and Phyllotini and Abrotrichini with the Andes) were standouts. Environmental variables and lineage distribution explain the same (i.e. shared) portion of shape variation, suggesting phylogenetic niche conservatism at the metacommunity level. Seasonality in temperature and land cover were the best environmental predictors of mean shape: larger tympanic bullae, incisive foramina, and check teeth are all associated with highly seasonal and less vegetated areas. Our new approach of using GM shape across metacommunities was demonstrably useful in understanding large-scale biogeographical patterns of shape variation and identifying its underlying causes. The overlap between environmental variables and phylogenetic lineage distribution suggests that a process of niche conservatism is likely: the phenotype-environment correlation is mediated by the differential biogeographical distribution of the main clades. [ABSTRACT FROM AUTHOR]

Aim We describe patterns of skull size and shape variation in an Atlantic forest endemic rodent to test the influence of genetic structure, historical and environmental variables upon intraspecific morphological variability. Location South America, Brazil, Atlantic forest. Methods We analyse subtle differences in skull morphology of Akodon cursor through geometric morphometrics applied to 324 individuals from 12 localities distributed throughout the species range. Using cytochrome- b gene (cyt- b) sequences from 125 individuals (38 localities), we describe underlying patterns of genetic structure and transform them into distance measures that are included in our morphological analyses. We estimate the relative importance of genetic structure, historical variables and environmental variables on skull size and shape through mixed model selection and Akaike's information criterion. Results Geographical patterns in skull size are mainly explained by non-random factors related to primary productivity and precipitation, whereas spatial shifts in shape correlate with mitochondrial divergence. Cytochrome- b data revealed a phylogeographic break around the Jequitinhonha River, yet striking morphological shifts were observed further south. Differences in palaeostability between regions, and the configuration of rivers, appear as secondary sources of explanation for observed patterns. Main conclusions Multiple forces explain morphological variation within A. cursor. Teasing apart the effects of local adaptation and gene flow may be difficult, but is a key to improve our understanding of the drivers of intraspecific morphological variation. Our findings support the view that size is a more labile feature than shape, and that it may more easily break away from constraints imposed by gene flow. The combination of random and non-random factors, together with documented breaks in the distribution of the Atlantic forest over the Late Quaternary, accounts for the majority of morphological differences observed in A. cursor. [ABSTRACT FROM AUTHOR]

Aim Body size variation in animal assemblages is a widely addressed pattern in biogeographical studies, and is affected by both environmental gradients and phylogenetic constraints. However, no study has yet explored to what extent the association between body size variation and environmental gradients across broad spatial scales is influenced by the biogeographical distribution of different phylogenetic lineages. In this study, we discriminate the influences of environmental variables and phylogenetic community composition on body size variation in South American sigmodontine rodents. Location South America. Methods We computed the mean body mass of sigmodontine species co-occurring in 1 × 1° cells across South America. For each cell we recorded mean values for three environmental variables. We characterized the phylogenetic composition of sigmodontine assemblages within each cell using phylogenetic fuzzy-weighting and principal coordinates of phylogenetic structure ( PCPS). We then partitioned out the influence of environmental factors and the phylogenetic community composition on mean body size. Results Mean body size variation was mostly explained by shared influence of phylogenetic community composition ( PCPS) and environmental factors (68%), while exclusive influence of PCPS was low (19%), and of environment was even lower (0.47%). Increases in body size were related to increases in annual mean temperature, and the influence of environment on body size was mediated by the distribution of sigmodontine lineages across South America. Main conclusions Environment alone was not sufficient to explain body size variation in sigmodontine assemblages. Rather, environmental gradients interacted with historical processes to determine body size variation in the Neotropical assemblages. These results have implications for the way we think of body size gradients across species assemblages, because any gradient in a trait may be a result of differences in the biogeographical distribution of lineages across space, which should be considered in an explicit context. [ABSTRACT FROM AUTHOR]

Aim Subterranean rodents of the genus Ctenomys are widespread in open habitats; the collared tuco-tuco, C. torquatus, has a wide range crossed by large water-courses. Based on a phylogeographical approach to investigate the riverine barrier hypothesis, we evaluated the strength of a river as a barrier and characterized the effect of large rivers in structuring distinct populations of the collared tuco-tuco. Location Grasslands of southern Brazil. Methods Sampling included 294 individuals from 33 localities throughout the geographical range of C. torquatus, especially around the main rivers. Phylogeographical patterns were estimated through two mitochondrial DNA sequences (control region and COI). Additionally, 22 microsatellite loci were surveyed to estimate the effect of rivers on population divergence through the FST index of genetic differentiation and AMOVAs. Spatial autocorrelation analyses were performed for both molecular markers. Molecular rates of change for mitochondrial DNA were estimated using fossil records and applied to Bayesian demographic analysis to test the relationship with the river geological data. Results Molecular-clock analysis estimated the time to most recent common ancestor ( TMRCA) to be c. 200 kyr and indicated a pattern of recent demographic expansion for C. torquatus. Fu's F S neutrality test was significant and negative (−13.7). High and significant FST and AMOVA among-population comparisons ( FSC) revealed highly differentiated populations, although no AMOVA groupings considering rivers as a segregating factor were significant. Spatial autocorrelation analysis revealed that isolation by distance was detected over approximately 200 km. Main conclusions The effect of the river was not proportionally larger from the headwaters to the mouth, and no population differentiation was observed after the later events of dispersal over the river or the formation of a water channel. This finding could result from the recent history of the occupation of C. torquatus in that region, combined with a dry Pleistocene climate and lower river levels. [ABSTRACT FROM AUTHOR]

Pardiñas, Valenzuela, and Salazar-Bravo (2017) are concerned that eventual differences in species mean body masses and in the phylogenetic hypothesis used in Maestri et al. (2016)-compared with those available on other potential sources-could affect the results of our original article. Here, we used a new phylogenetic hypothesis to conduct the same analyses of the original article, and we randomly sampled 1000 values of body mass within approximately 35% upper and lower intervals around the mean body mass for each species included in our database. We show that our previous results and conclusions are robust and valid, and they persist despite uncertainty in mean body mass estimation. We argue that sampling variation and uncertainty in both species mean body mass estimation and phylogenetic hypothesis are to be expected and should not always be confused with inaccuracies. [ABSTRACT FROM AUTHOR]

Since evolutionary processes, such as dispersal, adaptation and drift, occur in a geographical context, at multiple hierarchical levels, biogeography provides a central and important unifying framework for understanding the patterns of distribution of life on Earth. However, the advent of molecular markers has allowed a clearer evaluation of the relationships between microevolutionary processes and patterns of genetic divergence among populations in geographical space, triggering the rapid development of many research programmes. Here we provide an overview of the interpretation of patterns of genetic diversity in geographical and ecological space, using both implicit and explicit spatial approaches. We discuss the actual or potential interaction of phylogeography, molecular ecology, ecological genetics, geographical genetics, landscape genetics and conservation genetics with biogeography, identifying their respective roles and their ability to deal with ecological and evolutionary processes at different levels of the biological hierarchy. We also discuss how each of these research programmes can improve strategies for biodiversity conservation. A unification of these research programmes is needed to better achieve their goals, and to do this it is important to develop cross-disciplinary communication and collaborations among geneticists, ecologists, biogeographers and spatial statisticians. [ABSTRACT FROM AUTHOR]

The crab-eating fox is a medium-sized Neotropical canid with generalist habits and a broad distribution in South America. We have investigated its genetic diversity, population structure and demographic history across most of its geographic range by analysing 512 base pairs (bp) of the mitochondrial DNA (mtDNA) control region, 615 bp of the mtDNA cytochrome b gene and 1573 total nucleotides from three different nuclear fragments. MtDNA data revealed a strong phylogeographic partition between northeastern Brazil and other portions of the species’ distribution, with complete separation between southern and northern components of the Atlantic Forest. We estimated that the two groups diverged from each other c. 400 000–600 000 years ago, and have had contrasting population histories. A recent demographic expansion was inferred for the southern group, while northern populations seem to have had a longer history of large population size. Nuclear sequence data did not support this north–south pattern of subdivision, likely due at least in part to secondary male-mediated historical gene flow, inferred from multilocus coalescent-based analyses. We have compared the inferred phylogeographic patterns to those observed for other Neotropical vertebrates, and report evidence for a major north–south demographic discontinuity that seems to have marked the history of the Atlantic Forest biota. [ABSTRACT FROM AUTHOR]