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To characterize the potential for exposure of amphibian terrestrial life stages to plant protection products (PPP), we studied the occurrence and habitat use of adult and metamorph common frogs (Rana temporaria) and common toads (Bufo bufo) in an agricultural landscape in Germany. The four selected study sites were breeding ponds with approximately 80% agricultural land within a 1‐km radius. Adults were monitored by radio tracking for two years, and metamorph numbers were assessed for one summer using pitfall traps alongside drift fences. The results demonstrate that adults were rarely present in arable fields at any of the sites (overall 0.5% and 4% of total observations for frogs and toads, respectively). Metamorph captures in arable fields were more variable, ranging from 1.2% to 38.8% (frogs) and from 0.0% to 26.1% (toads) across study sites. Unsurprisingly, most captures in arable fields for both toad and frog metamorphs occurred at the site where the pond was completely surrounded by arable fields. Overall, the presence of adult amphibians in arable fields was limited and, for the metamorphs, occurred primarily when crops were denser and PPP spray interception higher. Diurnal hiding behavior was observed with the highest activity recorded at night, further reducing the risk of dermal exposure from direct PPP overspraying. In addition, it appeared that alternative habitats, such as woody structures or water bodies in the broader surrounding area, were preferred by the animals over the arable areas. The use of buffer zones around water bodies in agricultural areas would be an effective risk mitigation measure to protect terrestrial adults and metamorphs residing there and would reduce spray drift entry into water bodies during PPP application. It is hoped that these results will contribute to the discussion of risk assessment and mitigation options for amphibians. Integr Environ Assess Manag 2024;20:2218–2230. © 2024 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC). Key Points: Relevant potential exposure for both adult and metamorph anuran amphibians (i.e., common frogs and toads) on agricultural land was assessed.The movement and behavior of both adult and metamorph common frogs and common toads exhibited a preference for nonarable habitats and reduced potential for exposure.Landscape management is an option to protect and support amphibian populations effectively. [ABSTRACT FROM AUTHOR]

Agroforestry, often promoted as a sustainable agriculture practice, is rapidly expanding, often at the cost of primary tropical forests. While agroforestry negatively impacts amphibian diversity, its effects on population demography, microhabitat, use and body condition are relatively understudied. This information is crucial for determining and promoting amphibian‐friendly land‐use practices. We compared habitats, population densities, microhabitat use and body condition of two endemic species of shrub frogs (Pseudophilautus amboli and Raorchestes bombayensis) across (1) elevations (low‐ and high‐elevation forests) and (2) land‐use categories (cashew, rubber and low‐elevation forests) in the northern part of the Western Ghats Biodiversity Hotspot. Using distance sampling, we demonstrated that the abundances of the two shrub frog species differed across elevation categories, with P. amboli more common in low‐elevation forests and R. bombayensis more prevalent in high‐elevation forests. Both species of frogs exhibited extremely skewed, male‐biased sex ratios, with three females for 100 males. P. amboli had lower densities and poor recruitment and exhibited altered microhabitat use in cashew plantations compared to low‐elevation forests. Although adult male P. amboli densities in rubber were similar to those in low‐elevation forests, they exhibited altered microhabitat use and smaller body sizes than in forests, indicating poor body condition. We demonstrate the differential impacts of agroforestry types on shrub frogs. We also demonstrate that distance sampling can be a useful tool for population monitoring of shrub frogs, which comprise almost 25% of the anuran diversity in the Western Ghats. There is a need to identify the drivers of extremely skewed sex ratios, which make these species vulnerable to population crashes. Given the recent downlisting of the two focal species to Least Concern, we advocate for their uplisting to at least Near Threatened status considering their patchy distribution, negative impacts of rapidly expanding agroforestry plantations and extremely skewed sex ratios. [ABSTRACT FROM AUTHOR]

During their development, amphibians undergo various physiological processes that may affect their susceptibility to environmental pollutants. Naturally occurring fluctuations caused by developmental events are often overlooked in ecotoxicological studies. Our aim is to investigate how biomarkers of oxidative stress are modulated at different stages of larval development in the Amazonian amphibian species, Physalaemus ephippifer. The premetamorphosis, prometamorphosis and metamorphic climax stages were used to analyze total antioxidant capacity (ACAP), glutathione S-transferase (GST) activity, lipid peroxidation (LPO) levels and the expression of genes nrf2, gst, gsr (glutathione reductase) and gclc (glycine-cysteine ligase, catalytic subunit). Although there was no difference in ACAP and the genes expression among the studied stages, individuals from the premetamorphosis and prometamorphosis showed higher GST activity than ones under the climax. LPO levels were highest in individuals from the metamorphic climax. The present study suggests that the oxidative status changes during ontogeny of P. ephippifer tadpoles, especially during the metamorphic climax, the most demanding developmental phase. Variations in the redox balance at different developmental stages may lead to a divergent response to pollution. Therefore, we recommend that studies using anuran larvae as biomonitors consider possible physiological differences during ontogeny in their respective analyses. [ABSTRACT FROM AUTHOR]

Studies in evolution, ecology and conservation are increasingly based on genetic and genomic data. With increased focus on molecular approaches, ethical concerns about destructive or more invasive techniques need to be considered, with a push for minimally invasive sampling to be optimised. Buccal swabs have been increasingly used to collect DNA in a number of taxa, including amphibians. However, DNA yield and purity from swabs are often low, limiting its use. In this study, we compare different types of swabs, preservation method and storage, and DNA extraction techniques in three case studies to assess the optimal approach for recovering DNA in anurans. Out of the five different types of swabs that we tested, Isohelix MS‐02 and Rapidry swabs generated higher DNA yields than other swabs. When comparing storage buffers, ethanol is a better preservative than a non‐alcoholic alternative. Dried samples resulted in similar or better final DNA yields compared to ethanol‐fixed samples if kept cool. DNA extraction via a Qiagen™ DNeasy Blood and Tissue Kit and McHale's salting‐out extraction method resulted in similar DNA yields but the Qiagen™ kit extracts contained less contamination. We also found that samples have better DNA recovery if they are frozen as soon as possible after collection. We provide recommendations for sample collection and extraction under different conditions, including budgetary considerations, size of individual animal sampled, access to cold storage facilities and DNA extraction methodology. Maximising efficacy of all of these factors for better DNA recovery will allow buccal swabs to be used for genetic and genomic studies in a range of vertebrates. [ABSTRACT FROM AUTHOR]

Abstract During their development, amphibians undergo various physiological processes that may affect their susceptibility to environmental pollutants. Naturally occurring fluctuations caused by developmental events are often overlooked in ecotoxicological studies. Our aim is to investigate how biomarkers of oxidative stress are modulated at different stages of larval development in the Amazonian amphibian species, Physalaemus ephippifer. The premetamorphosis, prometamorphosis and metamorphic climax stages were used to analyze total antioxidant capacity (ACAP), glutathione S-transferase (GST) activity, lipid peroxidation (LPO) levels and the expression of genes nrf2, gst, gsr (glutathione reductase) and gclc (glycine-cysteine ligase, catalytic subunit). Although there was no difference in ACAP and the genes expression among the studied stages, individuals from the premetamorphosis and prometamorphosis showed higher GST activity than ones under the climax. LPO levels were highest in individuals from the metamorphic climax. The present study suggests that the oxidative status changes during ontogeny of P. ephippifer tadpoles, especially during the metamorphic climax, the most demanding developmental phase. Variations in the redox balance at different developmental stages may lead to a divergent response to pollution. Therefore, we recommend that studies using anuran larvae as biomonitors consider possible physiological differences during ontogeny in their respective analyses.

Estimating repeatability allows a first approximation that may indicate a potential response to selection of sexual traits. Acoustic sexual signals comprise spectral and temporal variables, where the former generally have lower intra‐individual variation and higher repeatability values. Studies of repeatability in anurans have been conducted mainly in natural conditions, but the stability of laboratory settings allows extended recording intervals, favoring measurement accuracy. We conducted a study of variation and repeatability of the calls of males of Batrachyla taeniata, a frog from the South American temperate forest to evaluate under homogeneous environmental and social conditions: (i) the extent of variation in acoustic properties of calls within and among days, (ii) the extent of temporal variation in the repeatability of call properties, and (iii) differences in repeatability among call variables. Variation of acoustic properties differed within and across days of recording, call rate generally increased within and throughout days, suggesting sensitization processes. Call duration decreased during these time spans, yielding constant calling effort. In contrast, the dominant frequency decreased within days but increased across days. Overall repeatability differs significantly among variables: dominant frequency, call rate, and call duration having the highest, intermediate, and lowest values, respectively. The high repeatability of call rate relative to call duration contrasts with an opposing general tendency in previous studies in anurans. The repeatability of the three variables analyzed increases within days, and the repeatability of call rate also increases throughout days, highlighting the relevance of this variable for individual identity over different time ranges. [ABSTRACT FROM AUTHOR]

Acoustic communication in animals can be affected by multiple biotic (intra and interspecific) and abiotic (e.g., wind and rain) natural noises. In addition, human beings produce additional novel sources of noise, which can reduce or inhibit the reception of acoustic signals by conspecifics, leading to behavioral changes. In this study, we investigated whether sound of conspecifics and road noise additively affect the acoustic parameters of the advertisement call of males of a Yellow Heart‐tongued Frog (Phyllodytes luteolus). We hypothesized that males that vocalize in choruses (males calling nearby) and in areas close to highways (anthropic noise) will increase their temporal and spectral acoustic parameters, respectively, to avoid acoustic signal masking. We recorded the vocalizations of 38 males in environments close (N = 18) to and distant (N = 20) from highways in different social contexts (many or few individuals calling nearby). Contrary to our expectation, the results indicated that males calling in areas close to highways had lower dominant frequency calls than those from natural areas (far from highways), and that the density of males in the chorus had no influence on the acoustic parameters. Furthermore, we found a positive relationship between body size and intensity, indicating that larger individuals can emit calls that can reach greater distances. The advertisement call of Phyllodytes luteolus has a high dominant frequency, with little overlap with the frequency of anthropic noises (roads), which may explain its presence and reproductive success of this species in bromeliads from urbanized areas. [ABSTRACT FROM AUTHOR]

The genus Pristimantis diversified in the tropical Andes mountains and is the most speciose genus of terrestrial vertebrates. Pristimantis are notable among frogs in that they thrive at high elevations (>2,000 m) and are direct developers without a tadpole stage. Despite their ecological significance, little is known about the genetic and physiological traits enabling their success. We conducted transcriptomic analysis on seven Pristimantis species sampled across elevations in the Ecuadorean Andes to explore three hypotheses for their success: (i) unique genes are under selection relative to all other frogs, (ii) common selection occurs across all direct developers, or (iii) common selection occurs across all high-elevation frog clades. Comparative analysis with 34 frog species revealed unique positive selection in Pristimantis genes related to aerobic respiration, hemostasis, signaling, cellular transportation of proteins and ions, and immunity. Additionally, we detected positive selection across all direct developers for genes associated with oxygenase activity and metal ion binding. While many genes under selection in Pristimantis were not positively selected in other high-elevation frog species, we identified some shared genes and pathways linked to lipid metabolism, innate immunity, and cellular redox processes. We observed more positive selection in duplicated- versus single-copy genes, while relaxed purifying selection was prevalent in single-copy genes. Notably, copy number of an innate immunity complement gene was positively correlated with Pristimantis species elevation. Our findings contribute novel insights into the genetic basis of adaptation in Pristimantis and provide a foundation for future studies on the evolutionary mechanisms leading to direct development and coping with high elevations. [ABSTRACT FROM AUTHOR]

Despite the great diversity of Brazilian anuran species, there are still many knowledge gaps about the acoustic communication of these animals. Among the species, those classified as 'Data Deficient' have the greatest gaps in knowledge on their behavior. This is the case of Boana ericae, a species belonging to the Boana pulchella group, endemic to the Chapada dos Veadeiros National Park region, in the northeast of the state of Goiás, Central Brazil. Three distinct call types (A, B, and C) are currently known for B. ericae, with the type A call associated with attracting reproductive partners and the type C call presenting a territorial function. We recorded the vocalizations of 10 individuals of this species and found the presence of vocalizations composing three new note types (D, E, and F). Our results indicate that air temperature and body condition influenced the acoustic parameters of the advertisement and aggressive calls of this species. We also observed that some acoustic parameters of the advertisement calls can be used for individual recognition for showing greater variation among individuals than intra-individually. Our results add new information regarding the vocal repertoire in this species, expanding their known intra-individual classification of the acoustic parameters. [ABSTRACT FROM AUTHOR]

This study aims to characterize the gonads, folliculogenesis, and spermatogenesis processes of male and female Rhinella bergi through anatomical, histological and morphometric analysis. We worked with specimens previously collected in the spring and summer seasons (2014-2015), in which the gonads were studied based on morphological, histological and morphometric analysis. The reproductive system was analyzed using a stereoscopic microscope and a scanning electron microscope (SEM). Histological preparations were made following the conventional protocol of dehydration, inclusion in paraffin and stained with haematoxylin-eosin, Mallory trichrome and PAS histochemical reactions. The anatomical and morphometric characteristics and the gametogenesis in R. bergi agree with what was proposed for other analyzed species of the Bufonidae family. Females with ovaries with oocytes in different stages of maturity and postovulatory females were found. The males presented continuous spermatogenesis. The results of this work serve as a basis for the characterization of the reproductive cycle in R. bergi and, at the same time, provide background information on the analysis of gametogenic activity. Future investigations will be focused on evaluating the reproductive cycle in this species, both in ovaries and testes as well as Bidder's organ, to compare and correlate with the results obtained in this study. [ABSTRACT FROM AUTHOR]

Studying the patterns and properties of biological diversity at multiple geographic scales is essential to answering biogeographical and macroecological questions. Here, we tested the hypothesis that diversity estimates derived from stacked species distribution models (stacked SDMs) would be robust and positively correlated when compared to estimates from well-surveyed areas with species checklists, but potentially more ambiguous when compared to estimates based on species' occurrences. We used these three diversity sources to evaluate alpha and beta diversity, per-site range size, total nestedness and completeness at five geographic scales (1/2°, 1/4°, 1/8°, 1/16°, and 1/32°). Estimates from the species' occurrences dataset and stacked SDMs showed poor positive correlation with alpha diversity in well-surveyed areas (except for stacked SDMs at coarse scales). However, beta diversity in well-surveyed areas exhibited a strong correlation with both the species' occurrence dataset and stacked SDMs at finer scales. The nestedness pattern from stacked SDMs remained relatively constant across all geographic scales; in contrast, nestedness in occurrence datasets was influenced by finer scales, thereby affecting community traits such as incidence and composition of species. Our study demonstrates that stacked SDMs was reliable for inferring effective diversities across multiple geographic scales, whereas occurrence datasets are not and may fail to accurately infer diversity patterns. Even well-surveyed areas with species checklists showed low completeness, sharing similarities with occurrence datasets at 1/4° and 1/16°. We recommend conducting complementary analysis of completeness properties of sample coverage to ensure the reliability of diversity assessments. [ABSTRACT FROM AUTHOR]

Iris patterns in the animal kingdom are incredibly variable, with anurans having some of the most diverse and intricate patterns. Although the shape and colouration of anuran eyes seem to be correlated with ecological factors, the evolution of iris patterns remains unexplored. We used a large-scale phylogenetic comparison with 960 anuran species to examine the evolutionary and ecological correlates of iris patterns. We classified iris patterns into four broad categories: Reticulated, Plain, Dotted, and Lined, and examined whether iris pattern was correlated with diel activity (diurnal, nocturnal, and cathemeral activity) and habit (aquatic, arboreal, terrestrial, and fossorial) or both. Our analysis suggests that reticulated irises are the most common pattern in anurans and are the most likely ancestral character. The evolution of iris patterns across the anuran phylogeny best matched Brownian expectations, with many transitions between the four pattern types. Iris patterns, however, were mostly uncorrelated with diel activity or habit. The only exception was an association between plain irises and diel activity. Specifically, anurans with plain irises were more likely to be diurnal and less likely to be nocturnal; and the evolution of plain irises seemed to have preceded the evolution of diel activity. Overall, iris patterns across anurans are mostly unrelated to ecological factors, suggesting that this trait may be important for other functions, such as inter- or intra-specific interactions, or that the incredible diversity has evolved through neutral processes. Our findings open avenues for further research, especially to understand the potential adaptive value of the striking ornamentation in iris patterns across taxonomic groups. [ABSTRACT FROM AUTHOR]

Microorganisms on amphibian skin reduce disease susceptibility and play an important role in pathogen defense. We hypothesized that anuran skin bacterial communities would change in response to seasonal variation and host species. To test this hypothesis, we used 16S rRNA amplicon sequencing to identify cutaneous bacterial communities of two frogs from the Qinling Mountains of China, Pelophylax nigromaculatus and Nanorana quadranus. We matched the amplicon sequence variants (ASVs) of microbes exhibiting protective effects against the pathogen Batrachochytrium dendrobatidis (Bd), using a database containing over 1900 16S rRNA gene sequences from amphibian skin bacteria. The results showed that seasonal variation had a stronger effect than host species on the structure (alpha-diversity, beta-diversity, species composition and abundance, and biomarkers) and anti-Bd function of cutaneous bacterial communities. These communities were highly dynamic but varied similarly between hosts. Their structural similarities were more consistent at the phylum level, but markedly less so at finer taxonomic levels. The highest relative abundance of anti-Bd reads was observed in P. nigromaculatus during summer, but anti-Bd reads were present in both frog species during different seasons. Therefore, the protective function of cutaneous microbial communities appears to be continuous despite between-species differences in anti-Bd ASV abundance. This observation does not directly explain why Bd infections have not been recorded in the region, butprovides important insight on anuran pathogen defense mechanisms. Our findings also suggest that specific seasons can be periods of high infection risk, with major implications for research on amphibian ecology and conservation.

Abstract Studies in evolution, ecology and conservation are increasingly based on genetic and genomic data. With increased focus on molecular approaches, ethical concerns about destructive or more invasive techniques need to be considered, with a push for minimally invasive sampling to be optimised. Buccal swabs have been increasingly used to collect DNA in a number of taxa, including amphibians. However, DNA yield and purity from swabs are often low, limiting its use. In this study, we compare different types of swabs, preservation method and storage, and DNA extraction techniques in three case studies to assess the optimal approach for recovering DNA in anurans. Out of the five different types of swabs that we tested, Isohelix MS‐02 and Rapidry swabs generated higher DNA yields than other swabs. When comparing storage buffers, ethanol is a better preservative than a non‐alcoholic alternative. Dried samples resulted in similar or better final DNA yields compared to ethanol‐fixed samples if kept cool. DNA extraction via a Qiagen™ DNeasy Blood and Tissue Kit and McHale's salting‐out extraction method resulted in similar DNA yields but the Qiagen™ kit extracts contained less contamination. We also found that samples have better DNA recovery if they are frozen as soon as possible after collection. We provide recommendations for sample collection and extraction under different conditions, including budgetary considerations, size of individual animal sampled, access to cold storage facilities and DNA extraction methodology. Maximising efficacy of all of these factors for better DNA recovery will allow buccal swabs to be used for genetic and genomic studies in a range of vertebrates.

The assessment of amphibian responses as bioindicators of exposure to chemical pollutants is an important tool for conservation of native species. This study aimed to investigate the effects of chronic aluminum (Al) and zinc (Zn) exposure on survival, body size, morphology (malformations), and immune system (leukocyte profile) in P. cuvieri tadpoles. Ecotoxicological analyses were performed utilizing chronic toxicity tests in which 210 tadpoles at the 25th Gosner developmental stage were exposed to Al and Zn. Individuals of P. cuvieri were maintained in glass containers containing various concentrations of aluminum sulfate (0.1, 0.2, or 0.3 mg/L) and zinc sulfate (0.18, 0.27 or 0.35 mg/L), and tests were performed in triplicate. After 14 days, amphibians were weighed, measured and survival rate, malformations in the oral and intestine apparatus, leukocyte profile, and ratio between neutrophils and lymphocytes determined. The differing concentrations of Al and Zn did not produce lethality in P. cuvieri where 95% of the animals survived 326 hr following metal exposure. Individuals exposed to Zn achieved greater body growth and weight gain compared to controls. Aluminum increased weight gain compared controls. These metals also produced malformations of the oral and intestine apparatus and enhanced occurrence of hemorrhages, especially at the highest doses. Lymphocytes were the predominant cells among leukocytes, with lymphopenia and neutrophilia observed following Al and Zn treatment, as evidenced by elevated neutrophil/lymphocyte ratio, an important indicator of stress in animals. Data suggest that further studies need to be carried out, even with metal concentrations higher than those prescribed by CONAMA, to ensure the conservation of this species. [ABSTRACT FROM AUTHOR]

Anuran communication is largely based on acoustic signals, but different sensory modes are also widespread, including visual communication using body color traits as a way of signaling. The Brazilian treefrog, Boana albomarginata, has a complex behavioral repertoire presenting several call types and performing gestures as visual signals. This species has a greenish body color with orange patches on the flanks and thighs. These patches become visible when males are in a calling posture or performing visual signals such as leg kicking and limb lifting, suggesting that they might use the patches as visual cues. We sampled seven populations, using call recordings and photographs to access males call and color traits. We demonstrate that there is variation in color and call properties across populations. Additionally, we observe variation in the relationship between color traits and call properties in different populations, revealing that only two populations exhibit a significant correlation between color and call traits. Further, while call properties and color traits were not related with individual body size, they were associated with body condition. The results indicate a universal pattern across populations for call properties, wherein males in better condition consistently displayed lower-pitched calls, longer calls, and shorter intervals between calls. Regarding color traits, males in better condition in four out of the seven evaluated populations exhibited larger orange patch sizes, lower orange hue values, and higher hue contrasts. Although we observed some level of relation among color, call, and body traits, there is not a universal pattern across all populations. Significance statement: Animal social interactions are mediated by signals transmitted through different sensory modes (i.e., acoustic, chemical, tactile, and visual), and more than one of these modalities can compose the behavioral repertoire of one species. Using photographs and acoustic recordings of Boana albomarginata males in natural environments, we documented geographic variation in both signals, call and color, and investigated their potential to convey individual body size and condition. Our findings reveal that both signals were correlated with individual body condition. In addition, color traits were associated with call properties in some populations. [ABSTRACT FROM AUTHOR]

Understanding the factors that influence acoustic activity of anuran species is essential for proper species management and herein, we investigated the influence of landscape metrics (% native vegetation cover and number of patches), latitude and climatic variables (temperature and relative humidity) on the acoustic activity of Physalaemus cuvieri. We used Passive Acoustic Monitoring (PAM) to record the acoustic activity in males of the target species in 29 water bodies distributed throughout the Cerrado, the Brazilian savanna. We investigated whether the rate of call emission by P. cuvieri males is influenced by predictor variables based on generalized linear mixed models. The call rate of P. cuvieri males was influenced only by air temperature variation throughout night. We found a peak of acoustic activity in the warmer hours in the beginning of the night followed by a decrease as the air temperature declines throughout the dawn. Contrary to our expectations, we did not find any significant influence of latitude, relative humidity or landscape metrics (number of fragments or percentage of native vegetation cover) on the acoustic activity of P. cuvieri. The impacts of landscape metrics on the acoustic activity of P. cuvieri are not significant, because it is a species with more generalist ecological requirements, which to allow the individuals to move across the landscape to be successful in colonizing water bodies situated in altered environments. Previous studies have suggested that changes in temperature may affect species phenology, since individuals alter their vocal activity, or their time spent in chorus in response to climate change. In this sense, our results are important because they allow us to predict the impact of future climate change on the acoustic activity of the target species, as well as demographic implications. We tested the influence of latitude, landscape metrics and climatic variables on the acoustic activity of Physalaemus cuvieri. The acoustic activity of Physalaemus cuvieri is strongly influenced by weather conditions, specifically air temperature. Latitude and landscape metrics did not influence the call emission rates of P. cuvieri males. [ABSTRACT FROM AUTHOR]

Locomotion is essential for survival, but it requires resources such as energy and metabolites and therefore may conflict with other physiological processes that also demand resources, particularly expensive processes such as immunological responses. This possible trade-off may impose limits on either the magnitude of immune responses or the patterns of activity and performance. Previous studies have shown that invasive species may have a depressed immune response, allowing them to maintain locomotor function and reproduction even when sick. This may contribute to the ecological success of invasive species in colonization and dispersal. In contrast, noninvasive species tend to reduce activity as a response to infection. Here, we studied the impact of a simulated infection on locomotor performance and voluntary movement in the anurans Xenopus laevis (a globally invasive species) and Xenopus allofraseri (a noninvasive congeneric). We found that a simulated infection reduces locomotor performance in both species, with an accentuated effect on X. allofraseri. Voluntary movement was marginally different between species. Our data suggest that a simulated infection leads to behavioral depression and reduced locomotor performance in anurans and show that this effect is limited in the invasive X. laevis. Contrasting responses to an immune challenge have been reported in the few amphibian taxa analyzed to date and suggest relationships between ecology and immunology that deserve further investigation. Specifically, a depressed immune response may underlie a propension to invasion in some species. Whether this is a general trend for invasive species remains to be tested, but our data add to the growing body of work documenting depressed immune systems in invasive species. [ABSTRACT FROM AUTHOR]

Abstract Acoustic communication in animals can be affected by multiple biotic (intra and interspecific) and abiotic (e.g., wind and rain) natural noises. In addition, human beings produce additional novel sources of noise, which can reduce or inhibit the reception of acoustic signals by conspecifics, leading to behavioral changes. In this study, we investigated whether sound of conspecifics and road noise additively affect the acoustic parameters of the advertisement call of males of a Yellow Heart‐tongued Frog (Phyllodytes luteolus). We hypothesized that males that vocalize in choruses (males calling nearby) and in areas close to highways (anthropic noise) will increase their temporal and spectral acoustic parameters, respectively, to avoid acoustic signal masking. We recorded the vocalizations of 38 males in environments close (N = 18) to and distant (N = 20) from highways in different social contexts (many or few individuals calling nearby). Contrary to our expectation, the results indicated that males calling in areas close to highways had lower dominant frequency calls than those from natural areas (far from highways), and that the density of males in the chorus had no influence on the acoustic parameters. Furthermore, we found a positive relationship between body size and intensity, indicating that larger individuals can emit calls that can reach greater distances. The advertisement call of Phyllodytes luteolus has a high dominant frequency, with little overlap with the frequency of anthropic noises (roads), which may explain its presence and reproductive success of this species in bromeliads from urbanized areas.

In this ecomorphological study, we investigate how the ventral pectoral girdle morphology of anurans correlates with their locomotor modes, habitat preferences, and phylogenetic relationships. We analysed 18 morphometric variables of the pectoral girdle's ventral region across 19 anuran species, encompassing diverse locomotion modes (jumping, hopping, walking, and swimming) and habitats (arboreal, bushy, terrestrial, and aquatic). Our findings, predominantly explained by the Ornstein–Uhlenbeck model, reveal evolutionary adaptations in pectoral girdle morphology driven by habitat‐specific demands. Notably, bushy and walker‐jumper species exhibit large clavicles, coracoids, and sternums, along with a broad medial pectoral girdle and bigger epicoracoid. Terrestrial and arboreal‐ jumpers have a larger omosternum area compared to predominantly swimming species. Arboreal walkers show shorter epicoracoid horns and narrower coracoids. Interestingly, bushy and terrestrial species have a higher proportion of bone tissue in their pectoral girdles. This indicates a potential adaptation to support the additional to adaptation to participate in shock absorption. The patterns recovered underscore the intricate relationship between anatomical evolution and environmental adaptation in anurans. [ABSTRACT FROM AUTHOR]

Morphological studies are useful to develop analysis with taxonomic, phylogenetic, ecological, physiological and evolutionary approaches. During the life cycle, Anurans carry out gas exchange through different structures such as gills, skin and lungs. In general, the development of lungs during the larval period is scarce known and most studies analyse the morphology and ultrastructure of the lung wall at the adult stage. This study describes the development and morphology of the lung of Trachycephalus typhonius during the prometamorphic and metamorphic periods and adult stage. Lung development starts at premetamorphic stages and continues along the prometamorphic and metamorphic periods with the development of the lung wall vascularization and pulmonary septa. There are remarkable differences comparing the lung framework at the end of metamorphosis to the one in the adult stage, regarding different‐order septa and lung wall structure with a well‐developed vascular network. Therefore, the final organization occurs during the juvenile period. This work is the first approach to the study of lung development during larval stages in this species and complements previous studies on lung morphology. Also, contributes to the knowledge of lung morphogenesis and could be useful to interpret the respiratory physiology in different environmental conditions. [ABSTRACT FROM AUTHOR]

Anuran species are some of the good environmental indicators of habitat quality and condition in ecosystems. This is due to their amphibious life modes and sensitivity to environmental change caused by rapid expansion of agricultural activities, advancement of forest destruction, climate change and emerging infectious diseases. Understanding their diversity and distribution patterns is crucial for the development and implementation of effective species and habitat conservation strategies. The study aimed at assessing and comparing anuran biodiversity and distribution patterns between a protected (North Nandi Forest Reserve) and a non-protected area (Kingwal swamp) to provide additional baseline information, both being among the underexplored areas in Kenya. Data were gathered in both dry and wet seasons, between October 2022 and June 2023 by employing standard sampling techniques for anurans(Visual encounter and pitfall traps with a drift fence) to maximise detection. Three habitat types-farmland, intermediate land and forest were exploited. A total of 1649 individuals from 21 different species, belonging to nine different genera and nine different families were recorded. Ptychadenidae was the most abundant family from the recorded anurans, while Dicroglossidae, Arthroleptidae, Pyxicephalidae and Ranidae were the least. High biodiversity was observed in the forest habitat (Protected) and least in the farmland (non-protected). The wet season had high species abundance, diversity and richness compared to the dry season. There was a significant difference (p <0.05) in diversity between the habitats in wet season, but no significance difference during dry season (p >0.05) except for forest and farmland (p <0.05). There was a significant difference in species abundance between seasons (p <0.05), and between habitats (p <0.05) in all seasons except for farmland and intermediate (p >0.05), as well as farmland and forest (p >0.05) during the wet season. Habitat type and season had no influence (p >0.05) on species richness. Anuran biodiversity is a function of habitat diversity and season, with the associated differences in microhabitat structure providing diverse niches and ways of exploring resources. The modest sampling indicates that Kingwal Swamp and North Nandi Forest Reserve are rich and support anuran species, and the differences in anuran biodiversity between the 3 habitats demonstrates that conservation efforts continue to be a priority. [ABSTRACT FROM AUTHOR]

In this study, we evaluated the effect of changes in natural wetlands on the amphibian diversity at differing spatial and temporal scales. We sampled 10 wetland sites along floodplains in southern Brazil. We classified the sites as reference or altered ponds according to the preservation degree and presence of human impact. The amphibian monitoring was conducted through calling surveys performed between 2015/2016 using an automated recording system that identified the calling male species. We identified 23 species, mainly distributed in the families Hylidae (43%) and Leptodactylidae (34.8%). The altered ponds had lower diversity and higher species dominance. Even ponds with the greatest landscape change revealed a high degree of resilience concerning the amphibian species composition. However, only Boana pulchella was dominant in altered ponds and B. pulchella and Pseudopaludicola falcipes were dominant in reference ponds. A reduction of amphibian richness was driven by the expansion of the urban area and loss of flooding areas. From 1999 to 2016 all sampled sites had their wetland area reduced as the surrounding urban area increased, contributing to the combined loss of habitat and reproductive sites of anurans in subtropical wetlands. [ABSTRACT FROM AUTHOR]

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In a fast-changing environment, it is important to keep track of biodiversity. In Mexico, new herpetofauna is described every year. Vocalisations can portray ecological and evolutionary characteristics for better understanding of species. Here, we lay out the current state of knowledge on advertisement calls of Mexican anurans, as well as the publication trends and the use of metadata through an exhaustive literature review and bibliometric analysis. We obtained 174 documents with advertisement call descriptions of 58.4% of Mexican anuran species published between 1940–2021. We identified that most of the species with call descriptions are distributed in the Neotropics and belong to endemic and endangered categories. Anuran call descriptions in publications are frequently accompanied by associated data such as relative humidity, call frequency, or recording format. The mean number of recorded characteristics per description was 12.568 (of 38). Although almost half of the Mexican species have associated advertisement call descriptions, we identified several knowledge gaps, particularly in the degree of information that each description contains. Furthermore, most of the identified studies were performed outside of Mexico by foreign researchers, despite the high level of anuran endemism in the country. We highlight the need for more detailed descriptions published by Mexican researchers. [ABSTRACT FROM AUTHOR]

Olfaction is a crucial capability for most vertebrates and is realized through olfactory receptors in the nasal cavity. The enormous diversity of olfactory receptors has been created by gene duplication, following a birth-and-death model of evolution. The olfactory receptor genes of the amphibians have received relatively little attention up to now, although recent studies have increased the number of species for which data are available. This study analyzed the diversity and chromosomal distribution of the OR genes of three anuran species (Engystomops pustulosus, Bufo bufo and Hymenochirus boettgeri). The OR genes were identified through searches for homologies, and sequence filtering and alignment using bioinformatic tools and scripts. A high diversity of OR genes was found in all three species, ranging from 917 in B. bufo to 1194 in H. boettgeri, and a total of 2076 OR genes in E. pustulosus. Six OR groups were recognized using an evolutionary gene tree analysis. While E. pustulosus has one of the highest numbers of genes of the gamma group (which detect airborne odorants) yet recorded in an anuran, B. bufo presented the smallest number of pseudogene sequences ever identified, with no pseudogenes in either the beta or epsilon groups. Although H. boettgeri shares many morphological adaptations for an aquatic lifestyle with Xenopus, and presented a similar number of genes related to the detection of water-soluble odorants, it had comparatively far fewer genes related to the detection of airborne odorants. This study is the first to describe the complete OR repertoire of the three study species and represents an important contribution to the understanding of the evolution and function of the sense of smell in vertebrates. [ABSTRACT FROM AUTHOR]

The germes gene is a marker of germ plasm and primordial germ cells (PGC). It is described for the African clawed frog Xenopus laevis. Overexpression of its mutant form negatively affects the formation and migration of PGC. However, it was unknown until now how widely this gene is represented in animals of different phylogenetic groups. For this work, the authors performed bioinformatic analysis of genomic and transcriptome sequences of animals with germ plasm. We found out that the germes homologs are present only in representatives of the genera Xenopus and Hymenochirus of the family Pipidae (order Anura). The obtained results were confirmed by RT-PCR analysis of the expression of the germes orthologs in the ovaries of six representatives of different Anura families. Phylogenetic analysis of cloned sequences of the germes homologs suggests the appearance of this gene in the ancestors of Pipidae and its secondary loss in the genus Pseudohymenochirus. It is also shown that the amino acid sequences of the functional domains of the Germes protein are rather conservative. [ABSTRACT FROM AUTHOR]

Frog population declines have already been observed in the central Amazon even for common species that are considered not to be in danger of extinction. The Amazon is close to its limit of tolerated deforestation, and parts of the forest have already been modified by climate change, which raises questions about how the fauna in these areas would adapt to climate changes by the middle and the end of this century. In this study we used population density data on seven species of Amazonian frogs and analyzed the relationship between the activity of these species and temperature, precipitation, and relative humidity. We also used the least-squares method with logarithmic models to assess whether climate change projected by the Intergovernmental Panel on Climate Change (IPCC) would be an indicator of the population dynamics of these species. Our results suggest that even common species may be may experience population declines and extinction in the next decades due to climate changes. [ABSTRACT FROM AUTHOR]

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Climate change is one of the key drivers of the dramatic erosion of global biodiversity. Poikilothermic organisms, such as amphibians, are particularly prone to alterations in temperature and precipitation and are therefore expected to be severely impacted by global climate change. We evaluated: i) the potential effects of climate change on taxonomic and functional richness of amphibians in the Atlantic Forest of Brazil, and ii) tested whether forest-dependent and open area species responded differently to climatic stressors. We applied an ensemble forecasting approach using point locality data to establish predictive maps of taxonomic and functional richness for different IPCC AR5 scenarios with two Representative Concentration Pathway trajectories (RCP 4.5 and RCP 8.5) at two temporal projections (2050 and 2070). A significant decline in both taxonomic and functional richness of Atlantic Forest amphibians is expected over the coming decades under the evaluated climate scenarios. The core areas projected to maintain significantly high anuran richness in both components were in coastal high-altitude localities. We found negative effects (losses) to be more pronounced for taxonomic richness. Model outcomes indicate significant losses in both forest and open area species. A few remaining high-altitude sites will then play an important role as potential climatic refuges to safeguard anuran diversity, requiring a dynamic landscape approach as conservation strategy.

Abstract Background Amphibians, particularly anurans, display an enormous variation in genome size. Due to the unavailability of whole genome datasets in the past, the genomic elements and evolutionary causes of anuran genome size variation are poorly understood. To address this, we analyzed whole-genome sequences of 14 anuran species ranging in size from 1.1 to 6.8 Gb. By annotating multiple genomic elements, we investigated the genomic correlates of anuran genome size variation and further examined whether the genome size relates to habitat types. Results Our results showed that intron expansions or contraction and Transposable Elements (TEs) diversity do not contribute significantly to genome size variation. However, the recent accumulation of transposable elements (TEs) and the lack of deletion of ancient TEs primarily accounted for the evolution of anuran genome sizes. Our study showed that the abundance and density of simple repeat sequences positively correlate with genome size. Ancestral state reconstruction revealed that genome size exhibits a taxon-specific pattern of evolution, with families Bufonidae and Pipidae experiencing extreme genome expansion and contraction events, respectively. Our result showed no relationship between genome size and habitat types, although large genome-sized species are predominantly found in humid habitats. Conclusions Overall, our study identified the genomic element and their evolutionary dynamics accounting for anuran genome size variation, thus paving a path to a greater understanding of the size evolution of the genome in amphibians.

Abstract Background Parotoid gland secretion of bufonid toads is a rich source of toxic molecules that are used against predators, parasites and pathogens. Bufadienolides and biogenic amines are the principal compounds responsible for toxicity of parotoid secretion. Many toxicological and pharmacological analyses of parotoid secretions have been performed, but little is known about the processes related to poison production and secretion. Therefore, our aim was to investigate protein content in parotoids of the common toad, Bufo bufo, to understand the processes that regulate synthesis and excretion of toxins as well as functioning of parotoid macroglands. Results Applying a proteomic approach we identified 162 proteins in the extract from toad’s parotoids that were classified into 11 categories of biological functions. One-third (34.6%) of the identified molecules, including acyl-CoA-binding protein, actin, catalase, calmodulin, and enolases, were involved in cell metabolism. We found many proteins related to cell division and cell cycle regulation (12.0%; e.g. histone and tubulin), cell structure maintenance (8.4%; e.g. thymosin beta-4, tubulin), intra- and extracellular transport (8.4%), cell aging and apoptosis (7.3%; e.g. catalase and pyruvate kinase) as well as immune (7.0%; e.g. interleukin-24 and UV excision repair protein) and stress (6.3%; including heat shock proteins, peroxiredoxin-6 and superoxide dismutase) response. We also identified two proteins, phosphomevalonate kinase and isopentenyl-diphosphate delta-isomerase 1, that are involved in synthesis of cholesterol which is a precursor for bufadienolides biosynthesis. STRING protein-protein interaction network predicted for identified proteins showed that most proteins are related to metabolic processes, particularly glycolysis, stress response and DNA repair and replication. The results of GO enrichment and KEGG analyses are also consistent with these findings. Conclusion This finding indicates that cholesterol may be synthesized in parotoids, and not only in the liver from which is then transferred through the bloodstream to the parotoid macroglands. Presence of proteins that regulate cell cycle, cell division, aging and apoptosis may indicate a high epithelial cell turnover in parotoids. Proteins protecting skin cells from DNA damage may help to minimize the harmful effects of UV radiation. Thus, our work extends our knowledge with new and important functions of parotoids, major glands involved in the bufonid chemical defence.

Environmental seasonality can promote the evolution of larger brains through cognitive and behavioral flexibility but can also hamper it when temporary food shortage is buffered by stored energy. Multiple hypotheses linking brain evolution with resource acquisition and allocation have been proposed for warm-blooded organisms, but it remains unclear how these extend to cold-blooded taxa whose metabolism is tightly linked to ambient temperature. Here, we integrated these hypotheses across frogs and toads in the context of varying brumation (hibernation) durations and their environmental correlates. We showed that protracted brumation covaried negatively with brain size but positively with reproductive investment, likely in response to brumation-dependent changes in the socio-ecological context and associated selection on different tissues. Our results provide novel insights into resource allocation strategies and possible constraints in trait diversification, which may have important implications for the adaptability of species under sustained environmental change.

The gut microbiome composition of terrestrial vertebrates is known to converge in response to common specialized dietary strategies, like leaf-eating (folivory) or ant- and termite-eating (myrmecophagy). To date, such convergence has been studied in mammals and birds, but has been neglected in amphibians. Here, we analysed 15 anuran species (frogs and toads) representing five Neotropical families and demonstrated the compositional convergence of the gut microbiomes of distantly related myrmecophagous species. Specifically, we found that the gut microbial communities of bufonids and microhylids, which have independently evolved myrmecophagy, were significantly more similar than expected based on their hosts' evolutionary divergence. Conversely, we found that gut microbiome composition was significantly associated with host evolutionary history in some cases. For instance, the microbiome composition of Xenohyla truncata, one of the few known amphibians that eat fruits, was not different from those of closely related tree frogs with an arthropod generalist diet. Bacterial taxa overrepresented in myrmecophagous species relative to other host families include Paludibacter, Treponema, and Rikenellaceae, suggesting diet-mediated selection and prey-to-predator transmission likely driving the observed compositional convergence. This study provides a basis for examining the roles of the gut microbiome in host tolerance and sequestration of toxic alkaloids from ants and termites. [ABSTRACT FROM AUTHOR]

Preference‐performance theory predicts that females should select breeding sites that maximize offspring performance. Amphibians have been a model system for investigating habitat selection, yet most studies have focused on habitat selection in response to predators and conspecifics. We investigated female oviposition site selection and larval performance in eastern gray treefrogs (Hyla versicolor) among pools with and without one of two ecologically distinct heterospecific larvae, the green frog (Rana clamitans) and the American bullfrog (Rana catesbeiana). Pools without heterospecifics were used on more nights and had more eggs deposited compared to pools with heterospecifics. In a competition experiment, treefrog larval performance matched this female preference: tadpoles developed faster and grew larger in the absence of either heterospecific. Although we hypothesized that bullfrogs would more strongly affect female treefrog preference and offspring performance because of previous work demonstrating that bullfrogs had stronger negative effects on other tadpoles, both heterospecifics elicited similar responses. The effects of heterospecifics on anuran breeding site selection are understudied and not well understood, and our results demonstrate that female selection of breeding sites is an adaptive behavior for offspring in the presence of heterospecific competitors. [ABSTRACT FROM AUTHOR]

Amphibians are the most threatened species-rich vertebrate group, with species extinctions and population declines occurring globally, even in protected and seemingly pristine habitats. These 'enigmatic declines' are generated by climate change and infectious diseases. However, the consequences of these declines are undocumented as no baseline ecological data exists for most affected areas. Like other neotropical countries, Costa Rica, including Área de Conservación Guanacaste (ACG) in north-western Costa Rica, experienced rapid amphibian population declines and apparent extinctions during the past three decades. To delineate amphibian diversity patterns within ACG, a large-scale comparison of multiple sites and habitats was conducted. Distance and time constrained visual encounter surveys characterised species richness at five sites--Murciélago (dry forest), Santa Rosa (dry forest), Maritza (mid-elevation dry-rain forest intersect), San Gerardo (rainforest) and Cacao (cloud forest). Furthermore, species-richness patterns for Cacao were compared with historic data from 1987-8, before amphibians declined in the area. Rainforests had the highest species richness, with triple the species of their dry forest counterparts. A decline of 45% (20 to 11 species) in amphibian species richness was encountered when comparing historic and contemporary data for Cacao. Conservation efforts sometimes focus on increasing the resilience of protected areas, by increasing their range of ecosystems. In this sense ACG is unique containing many tropical ecosystems compressed in a small geographic space, all protected and recognised as a UNESCO world heritage site. It thus provides an extraordinary platform to understand changes, past and present, and the resilience of tropical ecosystems and assemblages, or lack thereof, to climate change. [ABSTRACT FROM AUTHOR]

As an alternative to antibiotics, Antimicrobial Peptides (AMPs) possess unique properties including cationic, amphipathic and their abundance in nature, but the exact characteristics of AMPs against bacterial membranes are still undetermined. To estimate the structural stability and functional activity of AMPs, the Pseudin AMPs (Pse-1, Pse-2, Pse-3, and Pse-4) from Hylid frog species, Pseudis paradoxa, an abundantly discovered source for AMPs were examined. We studied the intra-peptide interactions and thermal denaturation stability of peptides, as well as the geometrical parameters and secondary structure profiles of their conformational trajectories. On this basis, the peptides were screened out and the highly stable peptide, Pse-4 was subjected to membrane simulation in order to observe the changes in membrane curvature formed by Pse-4 insertion. Monomeric Pse-4 was found to initiate the membrane disruption; however, a stable multimeric form of Pse-4 might be competent to counterbalance the helix-coil transition and to resist the hydrophobic membrane environment. Eventually, hexameric Pse-4 on membrane simulation exhibited the hydrogen bond formation with E. coli bacterial membrane and thereby, leading to the formation of membrane spanning pore that allowed the entry of excess water molecules into the membrane shell, thus causing membrane deformation. Our report points out the mechanism of Pse-4 peptide against the bacterial membrane for the first time. Relatively, Pse-4 works on the barrel stave model against E. coli bacterial membrane; hence it might act as a good therapeutic scaffold in the treatment of multi-drug resistant bacterial strains. [ABSTRACT FROM AUTHOR]

After polyploid species are formed, interactions between diploid and polyploid lineages may generate additional diversity in novel cytotypes and phenotypes. In anurans, mate choice by acoustic communication is the primary method by which individuals identify their own species and assess suitable mates. As such, the evolution of acoustic signals is an important mechanism for contributing to reproductive isolation and diversification in this group. Here, we estimate the biogeographical history of the North American grey treefrog complex, consisting of the diploid Hyla chrysoscelis and the tetraploid Hyla versicolor, focusing specifically on the geographical origin of whole genome duplication and the expansion of lineages out of glacial refugia. We then test for lineage‐specific differences in mating signals by applying comparative methods to a large acoustic data set collected over 52 years that includes >1500 individual frogs. Along with describing the overall biogeographical history and call diversity, we found evidence that the geographical origin of H. versicolor and the formation of the midwestern polyploid lineage are both associated with glacial limits, and that the southwestern polyploid lineage is associated with a shift in acoustic phenotype relative to the diploid lineage with which they share a mitochondrial lineage. In H. chrysoscelis, we see that acoustic signals are largely split by Eastern and Western lineages, but that northward expansion along either side of the Appalachian Mountains is associated with further acoustic diversification. Overall, results of this study provide substantial clarity on the evolution of grey treefrogs as it relates to their biogeography and acoustic communication. [ABSTRACT FROM AUTHOR]

The decline of biodiversity is an urgent concern that raises significant alarm today. Several species vanish without their biology being understood, or sometimes, even without awareness of their existence. Due to the significance that the Inselbergs has to biodiversity and nature, as they have been recognized as genuine evolutionary laboratories, they present a unique opportunity to enhance our understanding of biologically unexplored species. Our study presents the first information regarding the body size, age and growth pattern of Scinax fuscovarius, Odontophrynus asper, and Melanophryniscus atroluteus, the three most frequently encountered anuran species in the Inselbergs outcrops of northeastern Argentina. We have demonstrated that the variations in body size cannot be attributed to the effect of the specific hill where the species inhabit. We discovered that sexual dimorphism in age and the analyzed morphological variables is expressed differently in the three examined species. We also demonstrated that the observed differences in body size between populations of M. atroluteus of Inselbergs and the Atlantic Forest of Argentina can be attributed to differences in age at sexual maturity and growth patterns. However, we believe that other proximate mechanisms should be taken into account, such as the effects of the environment and inter- and intra-specific competition experienced during the larval stages, for a better understanding of the population differences in adult body size and age. Our findings will assist in the evaluation of species management and conservation strategies within their habitat. [ABSTRACT FROM AUTHOR]

Local inventories provide primary key information on diversity and distribution of species for conservation purposes. Here we describe the composition and conservation status of anuran fauna in flooded habitats eastern Amazon and evaluate to preference and the level of association of species with the flooded habitats in a poorly known area of the flooded forest present in the Ariri district, state of Amapá, North Brazil. Four nocturnal sampling events were carried out during the rainy season: beginning of the rainy season (March-May 2014 and December 2014-February 2015), mid rainy season (June-August 2014), and end of rainy season (September-November 2014), using visual encounter survey. We identified 29 anuran species. According to flooded habitat preference, the highest richness of species was found in high várzea (22 species, 75.9%, H' = 3.091), and 16 species (55.2%) was recorded with high association with flooded habitats. Including all flooded habitats, a greater number of constant species were found, followed by accessory and accidental species. Species accumulation curve showed a tendency toward stabilization of species richness only in the end of rainy season. Our study provides important data on the local anuran fauna and the presence of species typical of flooded and non-flooded habitats demonstrates a certain degree of similarity between species composition, reinforcing the importance of flooded habitats for the preservation of anurans of the Amazonia Forest in north Brazil. [ABSTRACT FROM AUTHOR]

Since 2000 I have been collecting and recording observations about the amphibians that inhabit Anglers Park and Dan Daniel Park in the City of Danville. During this period fourteen species of anurans and seven species of salamanders were found. This paper covers calling dates, egg laying dates, habitat associations, activity periods, parasites, physical anomalies, and additional natural history information collected on each species. [ABSTRACT FROM AUTHOR]

The majority of the amphibian larvae spend their early life stage in aquatic medium. In such system, they respond to a broad array of stimuli (tactile, chemical and visual cues) and exhibit suitable behavioural responses. The ability of detection of food and predator was studied in the tadpoles of the Indian skipper frog Euphlyctis cyanophlyctis in the laboratory setup by using a rectangular glass test tank with end compartments (stimulus zones) providing exclusively visual and and (or) chemical food (either boiled spinach or tadpoles of Duttaphrynus melanostictus) and predator (tadpoles of Hoplobatrachus tigerinus). A test tadpole E. cyanophlyctis was held at the centre of the test tank for 5 min (acclimation) to perceive visual and (or) chemical food or predator cues. Then it was released from the centre of the test tank and allowed to associate or stay away from the caged stimulus subjects (food or predator), which were placed at one end of the test tank either in a glass beaker (visual cues) or in a mesh cage wrapped with cheese cloth (chemical cues) for a period of 10 min. The test tadpoles failed to detect either food or predator through visual cues. They spent almost an equal amount of time in the zone housing food or predator in a glass beaker as compared to the opposite zone, which was kept empty. However, they detected both food and predator solely through chemical cues. In tests with chemical food cues (either boiled spinach or tadpoles of D. melanostictus), they spent the majority of their time (67.25 % of total time) near chemical food cues rather than empty or visual food cues. In contrast, in tests with chemical predator cues (tadpoles of H. tigerinus), they spent the majority of their time (68.89 % of total time) away from the chemical predator cues. Therefore, the findings show that E. cyanophlyctis tadpoles detect both food and predator through chemical sensory mechanism rather than visual ones. [ABSTRACT FROM AUTHOR]

We present an updated checklist of amphibians and reptiles of Querétaro, Mexico. The herpetofauna of Querétaro is composed of 136 species, 35 amphibians (seven caudates and 28 anurans) grouped in nine families and 20 genera; 101 reptiles (five turtles, 33 lizards, and 63 snakes) grouped in 20 families and 59 genera. We did not include 13 previous records that do not have adequate evidence. We include three newly reported species for Querétaro: Coniophanes imperialis (Baird & Girard, 1859), Scaphiodontophis annulatus (Duméril, Bibron & Duméril, 1854), and Xenosaurus newmanorum (Taylor, 1949). A total of 69 species (51% of the total species) are endemic to Mexico, while one species, Sceloporus exsul (Dixon, Ketchersid & Lieb, 1972), is endemic to the state. According to Mexican law (SEMARNAT NOM-059), 50 species are threatened or under special protection, while according to the IUCN red list, only 11 species are under some category of risk. We suggest that a greater survey effort for amphibians and reptiles is required to discover unrecorded species in those areas that have not been sufficiently sampled.

Amphibians are the most threatened species-rich vertebrate group, with species extinctions and population declines occurring globally, even in protected and seemingly pristine habitats. These ‘enigmatic declines’ are generated by climate change and infectious diseases. However, the consequences of these declines are undocumented as no baseline ecological data exists for most affected areas. Like other neotropical countries, Costa Rica, including Área de Conservación Guanacaste (ACG) in north-western Costa Rica, experienced rapid amphibian population declines and apparent extinctions during the past three decades. To delineate amphibian diversity patterns within ACG, a large-scale comparison of multiple sites and habitats was conducted. Distance and time constrained visual encounter surveys characterised species richness at five sites—Murciélago (dry forest), Santa Rosa (dry forest), Maritza (mid-elevation dry-rain forest intersect), San Gerardo (rainforest) and Cacao (cloud forest). Furthermore, species-richness patterns for Cacao were compared with historic data from 1987–8, before amphibians declined in the area. Rainforests had the highest species richness, with triple the species of their dry forest counterparts. A decline of 45% (20 to 11 species) in amphibian species richness was encountered when comparing historic and contemporary data for Cacao. Conservation efforts sometimes focus on increasing the resilience of protected areas, by increasing their range of ecosystems. In this sense ACG is unique containing many tropical ecosystems compressed in a small geographic space, all protected and recognised as a UNESCO world heritage site. It thus provides an extraordinary platform to understand changes, past and present, and the resilience of tropical ecosystems and assemblages, or lack thereof, to climate change.

Ectothermic inhabitants of tropical forests are subjected to constant environmental temperatures, which determine their passive thermoregulatory strategies. We observe these trends during the summer of 2017, in the anurans Dendropsophus bifurcus, Rhinella marina, and Scinax ruber, in a tropical rainforest from the Upper Amazon Basin of Ecuador. D. bifurcus and S. ruber showed a tendency to tigmothermy, whereas R. marina presented tendencies towards heliothermy. Body temperatures (Tbs) did not differ between D. bifurcus and R. marina, but S. ruber presented a lower Tb. Our results suggest that thermal environment is influencing different thermoregulatory strategies as tigmothermy and heliothermy of frogs and toads distributed in tropical environments at low elevation.

Simple Summary: The size of an organism's organs not only relates to its body size and physiological function, but also offers important evidence of its adaptation to environmental changes. This study specifically investigated the geographical variation in organ size within the Asian common toad (Duttaphrynus melanostictus). Our findings revealed significant differences in the relative sizes of nine selected organs among various populations. Furthermore, we examined the effects of the geographical gradient on organ size, uncovering a positive correlation between the relative size of the testes and altitude and/or latitude. Adaptive evolution is the process by which organisms change their morphological, physiological and biochemical characteristics to adapt to different environments during long-term natural selection. Especially, researching variation in organ size can provide important insights into morphological adaptation in amphibians. In this study, we comparatively studied differences in organ sizes (heart, lungs, liver, gallbladder, kidneys, spleen, digestive tract, testes and brain) among five geographical populations of the Asian common toad Duttaphrynus melanostictus. Our results revealed significant variations in the size of these nine specific organs among the populations. Notably, we observed a significant positive correlation between the relative size of the testes and latitude and/or altitude. However, no correlation was found between the relative size of the heart and the length of the digestive tract with altitude across populations, respectively, contradicting Hesse's rule and the digestion theory. These findings suggest that our study does not provide substantial theoretical support for the adaptive evolution of organ size in this particular toad species, but rather contributes to the understanding of the evolution and adaptations of species' different environmental conditions. Further research is warranted to delve deeper into the factors influencing organ size in amphibian populations. [ABSTRACT FROM AUTHOR]

During the breeding season, hundreds of anurans agglomerate at spawning sites, where a diversity of social contexts arise. In this scenario, anurans may alter their vocal repertoire according to the immediate social context, to overcome intraspecific competition. To evaluate the acoustic response of Boana goiana to successive interactions with a conspecific competitor, the present study was based on comparing the repetition rates of advertisement and aggressive calls of B. goiana focal males exposure to repeated artificial advertisement calls in 10 playback sessions. We observed that B. goiana males altered their acoustic behaviour in response to the simulated arrival of a new competitor. Males emitted less advertisement calls and more aggressive calls with the arrival of the competitors. Temperature and body condition were not important predictors of continuity of males in the experiment or the call repetition rates in the pre-playback session. However, the body condition influenced the total delta advertisement calls (differences in the call rate emission between end and the beginning of the experiment), indicating that higher values of body conditions allow males to show smaller reductions in the emission of advertisement calls over time in the presence of a competitor. [ABSTRACT FROM AUTHOR]