Hybridization among animal species has recently become more recognized as an important phenomenon, especially in the context of recent radiations. Here we show that complex hybridization has led to contrasting patterns of genomic composition among closely related species of the Neotropical cat genus Leopardus. We show strong evidence of ancient hybridization and introgression between the pampas cat (L. colocolo) and northeastern populations of tigrina (L. tigrinus), leading to remarkable cytonuclear discordance in the latter. In contrast, southern tigrina populations show recent and continuing hybridization with Geoffroy's cat (L. geoffroyi), leading to extreme levels of interspecific admixture at their contact zone. Finally, we demonstrate that two seemingly continuous Brazilian tigrina populations show no evidence of ongoing gene flow between them, leading us to support their formal recognition as distinct species, namely L. tigrinus in the northeast and L. guttulus in the south.

Intraguild predation (IGP) and interspecific killing (IK) have been recently acknowledged as important ecological forces that could influence community structure. Not only can carnivores influence prey community composition, they might also impact the populations of other carnivores. The goal of the current study was to assess the role of IGP and IK as significant forces influencing carnivoran assemblages in South America. To this end, we compiled the available records on 35 species of terrestrial carnivorans in the subcontinent, to investigate the potential and actual extent of IGP/IK as widespread ecological forces. We considered potential intraguild predators those having >20 % range overlap and body mass 2-5.4 times greater than that of other guild members and likely-potential intraguild predators those that, in addition, were also hypercarnivorous. The potential number of intraguild predators for those species evaluated ranged from zero to 18 (mean=5.35±SE 0.74). IGP/IK events (n =116) included 52 pairs of Neotropical carnivorans, 13 of which were killers and 25 were victims. Confirmed intraguild predator species (n =13) accounted for 37.1 % of the assemblage, nearly the same value predicted to be likely potential predators (n = 14). IGP and IK were highly associated with the hypercarnivorous felids, whereas victim species were most often the omnivorous procyonids and skunks. The results indicate jaguars, pumas, and ocelots as the species most likely to have significant impact on the guild. IGP and IK are not random and reflect widespread interactions that influence carnivoran community structure in South America.

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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.

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Entre janeiro de 2005 e dezembro de 2006 foram realizados estudos sobre a composição e abundância relativa dos mamíferos de médio e grande porte do Parque Estadual do Turvo. Para tanto, foram utilizados registros de armadilhas fotográficas além de visualizações e dados sobre presença e ausência de pegadas ao longo de transectos pré-determinados. No total foram registradas 29 espécies de mamíferos de médio e grande porte, das quais Dasyprocta azarae Lichtenstein, 1823 e Sylvilagus brasiliensis (Linnaeus, 1758) foram as espécies com maior número de registros. No que se refere a Carnivora, Nasua nasua (Linnaeus, 1766) e Leopardus pardalis (Linnaeus, 1758) tiveram os maiores índices de registro, enquanto Leopardus tigrinus (Schreber, 1775), Leopardus wiedii (Schinz, 1782) e Galictis cuja (Molina 1782) os menores. Entre os ungulados apenas Pecari tajacu (Linnaeus, 1758) mostrou-se freqüente, sendo a quarta espécie em número de registros. Algumas espécies comuns em outros ambientes apresentaram baixos índices de registro no Parque Estadual do Turvo, tais como Dasypus novemcinctus Linnaeus, 1758 e Didelphis albiventris Lund, 1840. Finalmente, constata-se a provável extinção local de Tayassu pecari (Link, 1795), uma vez que não foram obtidos registros de sua presença ao longo do estudo. A conservação dos mamíferos de médio e grande porte do Parque está fortemente associada à preservação do "Corredor Verde de Misiones", que provavelmente representa uma área fonte para diversas espécies.

Vertebrates are a vital ecological component of Amazon forest biodiversity. Although vertebrates are a functionally important part of various ecosystem services they continue to be threatened by anthropogenic impacts throughout the Amazon. Here we use a standardized, regularly spaced arrangement of camera traps within 25km2 to provide a baseline assessment of vertebrate species diversity in a sustainable use protected area in the eastern Brazilian Amazon. We examined seasonal differences in the per species encounter rates (number of photos per camera trap and number of cameras with photos). Generalized linear models (GLMs) were then used to examine the influence of five variables (altitude, canopy cover, basal area, distance to nearest river and distance to nearest large river) on the number of photos per species and on functional groups. GLMs were also used to examine the relationships between large predators [Jaguar (Panthera onca) and Puma (Puma concolor)] and their prey. A total of 649 independent photos of 25 species were obtained from 1,800 camera trap days (900 each during wet and dry seasons). Only ungulates and rodents showed significant seasonal differences in the number of photos per camera. The number of photos differed between seasons for only three species (Mazama americana, Dasyprocta leporina and Myoprocta acouchy) all of which were photographed more (3 to 10 fold increase) during the wet season. Mazama americana was the only species where a significant difference was found in occupancy, with more photos in more cameras during the wet season. For most groups and species variation in the number of photos per camera was only explained weakly by the GLMs (deviance explained ranging from 10.3 to 54.4%). Terrestrial birds (Crax alector, Psophia crepitans and Tinamus major) and rodents (Cuniculus paca, Dasyprocta leporina and M. acouchy) were the notable exceptions, with our GLMs significantly explaining variation in the distribution of all species (deviance explained ranging from 21.0 to 54.5%). The group and species GLMs showed some novel ecological information from this relatively pristine area. We found no association between large cats and their potential prey. We also found that rodent and bird species were more often recorded closer to streams. As hunters gain access via rivers this finding suggests that there is currently little anthropogenic impact on the species. Our findings provide a standardized baseline for comparison with other sites and with which planned management and extractive activities can be evaluated.

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