Search

The casque-headed lophyohyline genus Nyctimantis is widespread in South America, being composed of seven species. A recent molecular and morphological review of the genus found some undescribed species, one of which, from the Brazilian Cerrado, is described in this paper. It is distinguished by its relatively small to medium size, skull without expanded maxillae, paired vocal sacs, toe I without webbing, dark-brown dorsal coloration without longitudinal stripes, and dark-red to brown iris. The new species is the only in the genus occurring in the Brazilian Cerrado, inhabiting swampy forests. [ABSTRACT FROM AUTHOR]

Chironius snakes are typically arboreal or scansorial, usually foraging in trees or forest ground. Herein we report the foraging behavior of the vine snake Chironius brazili while hunting on the large hylid frog Bokermannohyla pseudopseudis on rocky surfaces in open habitats at the Chapada dos Veadeiros, Central Brazil. Snakes were able to locate frogs when they were basking over rock surfaces close to rivers or searching for them on rock crevices even in areas with strong water flux, close to waterfalls. We suggest that scansorial habits and the swimming abilities of Chironius species occurring in rocky montane habitats enable these snakes to feed on these large hylids. [ABSTRACT FROM AUTHOR]

Although hissing is a common strategy of defence used by snakes, especially of the Phytonidae and Boidae families, few studies have described in detail the acoustics components of this behaviour. Here we gathered eight recordings from six different boas from Brazil and extracted acoustic measurements from their hissing sounds. We also examined the potential of our measurements to encode individual identity using discriminant function analyses (DFAs) and to correlate with body length using linear mixed models (LMMs). Boas produce from four to 12 hisses per minute (7.13 ± 3.04) evoked by a negative stimulus, a visual looming stimulus generated by researcher's approach. Each hiss usually has two parts (the first louder part and the second softer part) that are basically broadband white noises split by a short silent interval. The first hiss part also has more frequency modulations and narrower bandwidth than the second hiss part. The DFAs correctly assigned all hisses to their correspondent individuals in the testing data. The first discriminant function explained most of the variance (⩾84%) in the discrimination between groups for the entire hiss and for both hiss parts in the training data subset. Frequency parameters and spectral entropy (for entire hiss and hiss part 1) and the mean frequency and duration (for hiss part 2) were the strongest absolute loadings in the DFAs. Intraspecific morphological traits (e.g. sexual dimorphism and ontogenetic variations) may influence the sound parameters, as detected by individual variations and the tendency for larger individuals to produce lower frequency hisses. Further studies may investigate these aspects in detail, including anatomy of the snake's larynx and experiments with different types of predators. [ABSTRACT FROM AUTHOR]

Rapid adaptive changes can result from the drastic alterations humans impose on ecosystems. For example, flooding large areas for hydroelectric dams converts mountaintops into islands and leaves surviving populations in a new environment. We report differences in morphology and diet of the termite-eating gecko Gymnodactylus amarali between five such newly created islands and five nearby mainland sites located in the Brazilian Cerrado, a biodiversity hotspot. Mean prey size and dietary prey-size breadth were larger on islands than mainlands, expected because four larger lizard species that also consume termites, but presumably prefer larger prey, went extinct on the islands. In addition, island populations had larger heads relative to their body length than mainland populations; larger heads are more suited to the larger prey taken, and disproportionately larger heads allow that functional advantage without an increase in energetic requirements resulting from larger body size. Parallel morphological evolution is strongly suggested, because there are indications that, before flooding, relative head size did not differ between future island and future mainland sites. Females and males showed the same trend of relatively larger heads on islands, so the difference between island and mainland sites is unlikely to be due to greater male-male competition for mates on islands. We thus discovered a very fast (at most 15 y) case of independent parallel adaptive change in response to catastrophic human disturbance.

Reproductive strategies are one of the more fascinating aspects of Anuran biology and are likely affected by species habitat use and availability of reproductive sites. The Cerrado endemic Pithecopus oreades is a habitat specialist that reproduces in seasonal high-altitude rocky streams in Central Brazil. Herein, we describe its reproductive behavior based on observations made during two consecutive reproductive seasons in a high-altitude stream located in an open field area in Central Brazil. The reproductive activity of P. oreades occurs during the rainy season, from the very first rains, and lasts about 3 months. The species is nocturnal, showing a vocalization peak between 20:00 h and 21:00 h. Its vocalization activity was related to total precipitation. The nests, composed by only one folded leaf, are placed on shrubs along streams. The nests, which hang over the stream pools, contain approximately 30 eggs that last about 13 days of incubation, producing about 25 tadpoles per spawning. Males are territorial, remaining in the same places for more than 60 days, defending them through vocalizations and eventual physical combats. Males with a higher body condition usually stay longer in the same territory. We also recorded males displaying satellite behavior. [ABSTRACT FROM AUTHOR]

Understanding the variability of acoustic signals is a first important step for the comprehension of the evolutionary processes that led to current diversity. Herein, we evaluate the variability of the advertisement call of the phyllomedusid species from the genera Phyllomedusa Wagler, 1830 and Pithecopus Cope, 1866 at different levels: intra-individual, intra-population, inter-population, intra-species, and inter-specific. An analysis of coefficients of variation showed a continuum of variability between the acoustic parameters analyzed, from static to highly dynamic. The majority of the variation was attributed to the inter-specific level, while call parameters at the intra-individual level varied the least. However, each parameter behaved differently with call interval being the most variable across all levels. Most temporal acoustic parameters were affected by environmental temperature, while pulse rate and dominant frequency were strongly influenced by body size. Only pulse rate was correlated to the geographic distance between populations, while all parameters presented a significant phylogenetic signal. Based on these results, we discuss the possible importance of different evolutionary forces and the usage of vocalizations for taxonomic purposes. Key words: acoustic communication, evolution, Pithecopus, Phyllomedusa, phylogenetic signal, trait diversification, variation. La compréhension de la variabilité des signaux acoustiques est une première étape importante pour comprendre les processus évolutifs qui ont mené à la diversité actuelle. Nous évaluons la variabilité des chants d'appel des espèces de phyllomédusidés des genres Phyllomedusa Wagler, 1830 et Pithecopus Cope, 1866 aux différentes échelles suivantes : chez un même individu, au sein de la population, entre populations, au sein de l'espèce et entre espèces. Une analyse des coefficients de variation montre un continuum de variabilité entre les paramètres acoustiques analysés, qui vont de statiques à hautement dynamiques. La majeure partie de la variation est attribuée à l'échelle interspécifique, alors que les paramètres du chant pour un même individu présentent la plus faible variation. Tous les paramètres se comportent toutefois différemment, l'intervalle entre les chants étant le paramètre le plus variable à toutes les échelles. La température ambiante influence la plupart des paramètres acoustiques temporels, alors que la taille du corps influence fortement le rythme des impulsions et la fréquence dominante. Seul le rythme des impulsions est corrélé à la distance géographique entre populations, alors que tous les paramètres présentent un signal phylogénétique significatif. À la lumière de ces résultats, nous discutons de l'importance possible de différentes forces évolutives et de l'utilisation de vocalisations à des fins taxonomiques. [Traduit par la Rédaction] Mots-clés : communication acoustique, évolution, Pithecopus, Phyllomedusa, signal phylonétique, diversification des caractères, variation., Introduction Understanding variability is fundamental for the comprehension of evolution (Hallgrimsson and Hall 2011). Darwin's observations on phenotypic variation were the basis for the development of the concept of natural [...]

Diet studies of cracids have highlighted the group's significance as seed dispersers and the impact of their disappearance from natural environments. However, the diet of Penelope jacucaca remains largely unknown, limiting our understanding of its natural history and potential ecosystem services. In this study, we investigated the diet of P. jacucaca in two Caatinga fragments with varying levels of preservation using fecal material analysis. The diet of the species consisted primarily of fruits, flowers, and leaves, comprising a total of 22 food items. The number of seeds found in individual fecal samples exhibited a negative correlation with individual seed masses. The species demonstrated a preference for zoocoric fruits of different sizes from the local vegetation. The diet varied between the sampled areas, suggesting that P. jacucaca exhibits dietary flexibility based on local vegetation. However, it is also possible that fragmentation affects the nutritional value of the species' diet. Due to its large body size, the White-browed guan can ingest a wide variety of fruits, including larger ones, incorporating seeds that are rarely explored by other birds. We propose that plant species with "large" seeds (> 15 mm), such as Ziziphus joazeiro, Brosimum gaudichaudii, and Ximenia americana, would be mainly negatively affected by the absence of P. jacucaca in the studied areas. The decline in the population of this important seed disperser in the region is likely to have negative implications for the viability of many zoocoric plants, thereby posing a threat to the vegetation of the studied fragments. [ABSTRACT FROM AUTHOR]

Lizards are commonly preyed by a great variety of predators, including vertebrates and invertebrates. Therefore, it is expected that lizards have developed a wide range of antipredator traits, increasing their chances of successful survival during agonistic events. Defence against predation involves two levels of behavioural strategies, commonly named primary and secondary defence traits. Primary defences relate to predator detection or interest and include as responses immobility, mimicry, aposematism, and cryptic colouration. Secondary defences occur after predator detection and attack, including traits that aim to prevent or interrupt predators. These defences encompass traits such as frightening (e.g., scratching or biting the predator), tail lashing, flouncing vigorously the body, cloacal discharge, agony vocalisations, and tail autotomy. In this review, we gathered information from 206 scientific publications, including peer-reviewed journals, short communications, scientific notes, and books. This compilation resulted in 22 defence traits, 23% passive and 77% active defences. Lizard species deal with a wide diversity of predators, but the number of field records, experiments, and antipredator studies remain scarce. We reviewed the defence traits presented by Neotropical lizards, using a phylogenetic approach in order to track evolutionary process behind these traits. Thanatosis, crypsis, and tail autotomy are symplesiomorphic for lizards, whereas venom and emetic substances are autapomorphic, and aposematism seems to be rare. We also present a novel case of defence trait where the dark colour helps lizards to be camouflaged in the burned vegetation. Our character mapping provides valuable information about the evolution of defensive traits in Neotropical lizards, combining natural history and phylogenetics. Trivial observations about any animal behaviour, including those provided by social networks and citizen science pages, might be important, and we strongly recommend that ethological observations describe the event in all possible details. [ABSTRACT FROM AUTHOR]

Recent studies have argued that changes in fire regimes in the 21st century are posing a major threat to global biodiversity. In this scenario, incorporating species' physiological, ecological, and evolutionary traits with their local fire exposure might facilitate accurate identification of species most at risk from fire. Here, we developed a framework for identifying the animal species most vulnerable to extinction from fire-induced stress in the Brazilian savanna. The proposed framework addresses vulnerability from two components: (1) exposure, which refers to the frequency, extent, and magnitude to which a system or species experiences fire, and (2) sensitivity, which reflects how much species are affected by fire. Sensitivity is based on biological, physiological, and behavioral traits that can influence animals' mortality "during" and "after" fire. We generated a Fire Vulnerability Index (FVI) that can be used to group species into four categories, ranging from extremely vulnerable (highly sensible species in highly exposed areas), to least vulnerable (low-sensitivity species in less exposed areas). We highlight the urgent need to broaden fire vulnerability assessment methods and introduce a new approach considering biological traits that contribute significantly to a species' sensitivity alongside regional/local fire exposure. [ABSTRACT FROM AUTHOR]