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Quantum mechanical/molecular mechanics (QM/MM) methods are interesting to model the impact of a complex environment on the spectroscopic properties of a molecule. In this context, a FROm molecular dynamics to second harmonic Generation (FROG) code is a tool to exploit molecular dynamics trajectories to perform QM/MM calculations of molecular optical properties. FROG stands for "FROm molecular dynamics to second harmonic Generation" since it was developed for the calculations of hyperpolarizabilities. These are relevant to model non-linear optical intensities and compare them with those obtained from second harmonic scattering or second harmonic generation experiments. FROG's specificity is that it is designed to study simple molecular liquids, including solvents or mixtures, from the bulk to the surface. For the QM/MM calculations, FROG relies on the Dalton package: its electronic-structure models, response theory, and polarizable embedding schemes. FROG helps with the global workflow needed to deal with numerous QM/MM calculations: it permits the user to separate the system into QM and MM fragments, to write Dalton's inputs, to manage the submission of QM/MM calculations, to check whether Dalton's calculation finished successfully, and finally to perform averages on relevant QM observables. All molecules within the simulation box and several time steps are tackled within the same workflow. The platform is written in Python and installed as a package. Intermediate data such as local electric fields or individual molecular properties are accessible to the users in the form of Python object arrays. The resulting data are easily extracted, analyzed, and visualized using Python scripts that are provided in tutorials. [ABSTRACT FROM AUTHOR]

Predator-prey interactions have been suggested as drivers of diversity in different lineages, and the presence of anti-predator defences in some clades is linked to higher rates of diversification. Warning signals are some of the most widespread defences in the animal world, and there is evidence of higher diversification rates in aposematic lineages. The mechanisms behind such species richness, however, are still unclear. Here, we test whether lineages that use aposematism as anti-predator defence exhibit higher levels of genetic differentiation between populations, leading to increased opportunities for divergence. We collated from the literature more than 3000 pairwise genetic differentiation values across more than 700 populations from over 60 amphibian species. We find evidence that over short geographical distances, populations of species of aposematic lineages exhibit greater genetic divergence relative to species that are not aposematic. Our results support a scenario where the use of warning signals could restrict gene flow, and suggest that anti-predator defences could impact divergence between populations and potentially have effects at a macro-evolutionary scale.

The objective of this study was to describe the intraocular pressure (IOP) findings in a population of Chinese edible frogs (Hoplobatrachus rugulosus) sold in wet markets across Hong Kong and to characterize the influence of sex and anesthesia. One hundred animals were evaluated, and 96 were included in this study. All frogs included appeared ophthalmologically normal upon gross examination. Intraocular pressure was evaluated with rebound tonometry (TonoVet Plus® setting "d") on conscious frogs and under anesthesia. General anesthesia was induced with MS-222 (tricaine methanesulfonate) 2 g/L by immersion. After IOP measurements, the frogs were euthanized with intravenous pentobarbital (200 mg/ml) and sex was confirmed on postmortem examination. Mean (± SD) IOP values were significantly decreased under MS-222 anesthesia in males (14.7 ± 2.8 mmHg; P < 0.0001) and females (14.7 ± 2.4 mmHg; P < 0.0001) compared to conscious readings (16.3 ± 2.1 mmHg and 16.3 ± 2.1 mmHg, respectively). There was no significant difference in IOP found between males and females before or after anesthesia. There was no significant difference between the right and left eye in males and females before or after anesthesia. The results of this study establish a normal range of IOP for this species and are comparable to previous published reports of IOP in anurans. [ABSTRACT FROM AUTHOR]

Calls are the most conspicuous form of communication in anurans. They are generally species specific, mediate mating behavior and, as such, are often emitted during the breeding season. The calls of Thoropa, an endemic genus to the Brazilian Atlantic Forest and Campo Rupestre, are known from the type localities of six valid species. However, recent molecular analyses revealed a greater number of molecular lineages within the T. miliaris species group than previously recognized. Here we aimed to investigate the advertisement calls of 12 individuals of T. miliaris and 5 individuals of T. taophora. Whenever possible, these were assigned to the recognized molecular lineages through Sanger sequences of the final portion of the 16S ribosomal mitochondrial gene. The sampled individuals are from different localities and associated with different lineages. We conducted the acoustic characterization based on 15 (T. miliaris) and 11 (T. taophora) recordings. We identified three types of calls: Type 1 and Type 2 calls of T. miliaris, and a third call type, exclusive to T. taophora. Type 1 of T. miliaris is usually formed by an introductory and a long note, followed by a more frequently emitted (i.e., common) note. Type 2 of T. miliaris is composed of an introductory note, followed by a long note, and followed by relatively high and low amplitude alternated notes. The call of T. taophora is formed by a peculiar note, with low and high relative amplitude portions on the same note. It is worth noting that syntopic lineages exhibit similar calls. Also, recorded calls from far localities of the same lineages are similar. This study is the first to analyze calls of different lineages and populations T. miliaris and T. taophora. [ABSTRACT FROM AUTHOR]

Translocating amphibians to alternative, suitable habitat is a climate adaptation strategy aimed at minimizing the risk of extinction due to projected global warming and drying. Projected conditions could undermine their physiological performance, and thus survival and reproduction. Translocations minimize risks of extinction by increasing spatial redundancy across climate-resilient habitats, particularly for dispersal-limited species. However, outcomes of amphibian translocation attempts are poorly documented, and their effectiveness remains unclear. We released and tracked 34 Eleutherodactylus coqui to determine early postrelease survival of a control (nontranslocated) group (n = 14) and experimental (translocated) group (n = 20) moved 0.8 km from their capture location in west-central Puerto Rico in 2021. We defined "initial" as the first 17 d postrelease, a period during which we hypothesized that experimental individuals would have lower survival rates because they transitioned from known-familiar to novel-unfamiliar habitat. We found no evidence in the data to support our hypothesis. Daily survival rates were better explained by a model with no group effect but negatively influenced by in situ temperature. However, the effect of in situ temperature (proxy of operative temperature) was weak (95% confidence intervals overlapped 0). After 17 d, all but one of the recaptured frogs lost weight for a combined weight loss of 0.28 ± 0.13 g. However, weight loss was significantly higher in translocated frogs (0.81 ± 0.33 g). Average daily movements did not hinder survival even though experimental individuals traveled farther (∼ eight times) than control ones. Our findings suggested that managed translocations have the potential to become a useful conservation tool, not an additive source of mortality. We outline challenges that remain before translocations of Eleutherodactylus species can be broadly applied. [ABSTRACT FROM AUTHOR]

The Pallas' spadefoot Pelobates vespertinus is a frog species native to eastern Europe and west Siberia. This species resists harsh winter conditions by moving up to 2 m underground. This amphibian is the first species known to withstand extreme air hypoxia. In this study, we investigated the metabolome of liver, heart, and brain of the Pallas' spadefoot after a month-long exposure of hypoxia, with oxygen levels reduced to approximately one-tenth of the air normal content. Surprisingly, our findings revealed a limited impact of hypoxia on the metabolomic profiles. Concentrations of glycolysis end products (lactate and alanine) increased only slightly compared to other amphibians under hypoxia, and no accumulation of succinate was observed. Furthermore, there were no notable changes in the content of adenosine phosphates. These results are consistent with a previous study, which indicated that the Pallas' spadefoot possesses relatively small glycogen and fat reserves before the winter compared to other frogs. It appears that this species conserves energy during winter by minimizing its metabolic activity. These findings corroborated the hypothesis that the survival of P. vespertinus under hypoxic conditions primarily relies on metabolic suppression rather than substantial energy reserves. [ABSTRACT FROM AUTHOR]

As is true of many complex tasks, the work of discovering, describing, and understanding the diversity of life on Earth (viz., biological systematics and taxonomy) requires many tools. Some of this work can be accomplished as it has been done in the past, but some aspects present us with challenges which traditional knowledge and tools cannot adequately resolve. One such challenge is presented by species complexes in which the morphological similarities among the group members make it difficult to reliably identify known species and detect new ones. We address this challenge by developing new tools using the principles of machine learning to resolve two specific questions related to species complexes. The first question is formulated as a classification problem in statistics and machine learning and the second question is an out-of-distribution (OOD) detection problem. We apply these tools to a species complex comprising Southeast Asian stream frogs (Limnonectes kuhlii complex) and employ a morphological character (hind limb skin texture) traditionally treated qualitatively in a quantitative and objective manner. We demonstrate that deep neural networks can successfully automate the classification of an image into a known species group for which it has been trained. We further demonstrate that the algorithm can successfully classify an image into a new class if the image does not belong to the existing classes. Additionally, we use the larger MNIST dataset to test the performance of our OOD detection algorithm. We finish our paper with some concluding remarks regarding the application of these methods to species complexes and our efforts to document true biodiversity. [ABSTRACT FROM AUTHOR]

Urban growth negatively impacts biodiversity through species loss and biotic homogenization. However, cities continue to grow and there are species with certain functional traits that bypass the urban environmental filters persisting in different urban niches. Our objective was to describe taxonomic and functional groups of amphibians and analyze alpha and beta diversity, relating them to environmental variables that characterize fourteen urban green sites with different types and degrees of urbanization, in the metropolitan area of Santa Fe city, Province of Santa Fe, Argentina. We registered 26 species that belong to 13 genera grouped in 5 families: Microhylidae (1), Odontophrynidae (1), Bufonidae (2), Leptodactylidae (10), Hylidae (12). The fourteen surveyed sites were grouped into five categories with similar urbanistic characteristics. Species richness varied from 4 to 15 species per site and between 12 and 19 species per urban green space category. Species corresponded to 10 functional groups and each urban green spaces categories harbor between 7 and 9 functional groups. Beyond the moderate to low beta diversity values, we found that the different urban green spaces categories are complementary as reservoirs of amphibians, since some categories harbor exclusive species or functional groups, while other urban green spaces categories, without exclusive species or functional groups, shelter numerous populations of some species or functional groups. [ABSTRACT FROM AUTHOR]

Foothill yellow‐legged frogs (Rana boylii) are a declining species, and methodologies for assessing population occupancy have been associated with only diurnal work on the species. Diurnal visual encounter surveys are typically used to determine presence within suitable habitat; however, studies of ecologically similar species indicate a potential advantage of nocturnal surveys. At 5 sites in 4 counties in California, USA, we compared diurnal and nocturnal surveys (n = 53 paired surveys) for foothill yellow‐legged frogs, conducted 2016‐2023, to determine the value of each survey period. Generally, occupancy probabilities increased 1–22 times, detection probabilities 1–69 times, and estimated abundances 3–12 times during nocturnal versus diurnal surveys. Associated standard errors were also lower in nocturnal versus diurnal surveys. However, we noted 2 locations where diurnal surveys yielded higher detection probability or higher estimates densities compared to nocturnal surveys. We suggest that both diurnal and nocturnal surveys be required when assessing occupancy of foothill yellow‐legged frogs. [ABSTRACT FROM AUTHOR]

Temporally variable climates are expected to drive the evolution of thermal physiological traits that enable performance across a wider range of temperatures (i.e. climate variability hypothesis, CVH). Spatial thermal variability, however, may mediate this relationship by providing ectotherms with the opportunity to behaviourally select preferred temperatures (i.e. the Bogert effect). These antagonistic forces on thermal physiological traits may explain the mixed support for the CVH within species despite strong support among species at larger geographical scales. Here, we test the CVH as it relates to plasticity in physiological upper thermal limits (critical thermal maximum—CTmax) among populations of coastal tailed frogs (Ascaphus truei). We targeted populations that inhabit spatially homogeneous environments, reducing the potentially confounding effects of behavioural thermoregulation. We found that populations experiencing greater temporal thermal variability exhibited greater plasticity in CTmax, supporting the CVH. Interestingly, we identified only one site with spatial temperature variability and tadpoles from this site demonstrated greater plasticity than expected, suggesting the opportunity for behavioural thermoregulation can reduce support for the CVH. Overall, our results demonstrate one role of climate variability in shaping thermal plasticity among populations and provide a baseline understanding of the impact of the CVH in spatially homogeneous thermal landscapes. [ABSTRACT FROM AUTHOR]

Apple is a significant economic crop in China, and leaf diseases represent a major challenge to its growth and yield. To enhance the efficiency of disease detection, this paper proposes an Adaptive Cross-layer Integration Method for apple leaf disease detection. This approach, built upon the YOLOv8s architecture, incorporates three novel modules specifically designed to improve detection accuracy and mitigate the impact of environmental factors. Furthermore, the proposed method addresses challenges arising from large feature discrepancies and similar disease characteristics, ultimately improving the model's overall detection performance. Experimental results show that the proposed method achieves a mean Average Precision (mAP) of 85.1% for apple leaf disease detection, outperforming the latest state-of-the-art YOLOv10s model by 2.2%. Compared to the baseline, the method yields a 2.8% increase in mAP, with improvements of 5.1%, 3.3%, and 2% in Average Precision, Recall, and mAP50-95, respectively. This method demonstrates superiority over other classic detection algorithms. Notably, the model exhibits optimal performance in detecting Alternaria leaf spot, frog eye leaf spot, gray spot, powdery mildew, and rust, achieving mAPs of 84.3%, 90.4%, 80.8%, 75.7%, and 92.0%, respectively. These results highlight the model's ability to significantly reduce false negatives and false positives, thereby enhancing both detection and localization of diseases. This research offers a new theoretical foundation and direction for future advancements in apple leaf disease detection. [ABSTRACT FROM AUTHOR]

Ex situ conservation is a complementary strategy to in situ efforts and is vital for safeguarding endangered species through maintenance and breeding in captivity with potential for reintroductions into natural environments. However, it is crucial to recognize that prolonged captivity can lead to diminished abilities of organisms over generations. Factors linked to the impact of phenotypic plasticity during development, such as restricted movement, may affect organism performance during ex situ conservation efforts, potentially making reintroduction into the wild unfeasible. Consequently, it is imperative to analyze physiological differences between captive‐bred and wild individuals. Therefore, this study investigates how captivity influences locomotor performance, morphology, and metabolic capacities of adults and juveniles of the threatened treefrog Ololygon alcatraz, in comparison to natural populations. We obtained proportional measurements of individuals and assessed their locomotor performance through jumping exercise. We also measured the metabolic capacities of the frogs by examining the activity of enzymes involved in energetic metabolic pathways in their skeletal muscle fibers. We found that wild adult frogs had larger limbs, greater jumping abilities, and a more glycolytic profile, while captive adult frogs had smaller limbs and increased aerobic enzyme activity compared to their wild counterparts. These differences probably arise from phenotypic plasticity in ontogenetic development that differs between captive and natural environments, as juveniles do not show such differences. These results highlight the need for innovative strategies in managing captive O. alcatraz populations, which will aid in their successful translocation to the wild and strengthen ex situ conservation efforts. [ABSTRACT FROM AUTHOR]

Sexual communication often takes place in networks with multiple competing signalers being simultaneously assessed by mate choosers. Altered sensory conditions, such as noise and light pollution, can affect communication by altering signal production and perception. While evidence of sensory pollution affecting sexual signaling is widespread, few studies assess impacts on sexual signaling during rival interactions as well as mate choice, let alone whether urban and non-urban populations have diverged in their response. Here, we investigate the effects of urban sensory conditions on sexual communication in urban and forest túngara frogs (Engystomops pustulosus). We recorded dyadic vocal rival interactions and assessed mate choice with and without noise and light pollution in the lab. We show that urban sensory conditions can directly impact the intensity of rival interactions, differences between rivals, and mate choice, though changes were often in opposite directions for frogs of urban and forest origins. Moreover, we demonstrate that urban-induced changes in rival interactions can also indirectly affect how females choose between potential mates. Our study reveals origin-dependent direct and indirect effects of noise and light pollution and suggests local adaptation of sexual communication in urban populations. [ABSTRACT FROM AUTHOR]

Frogs have a highly conserved body plan, yet they employ a diverse array of locomotor modes, making them ideal organisms for investigating the relationships between morphology and locomotor function, in particular whether anatomical complexity is a prerequisite for functional complexity. We use diffusible iodine contrast‐enhanced microCT (diceCT) imaging to digitally dissect the gross muscle anatomy of the pelvis and hindlimbs for 30 species of frogs representing five primary locomotor modes, including the first known detailed dissection for some of the world's smallest frogs, forming the largest digital comparative analysis of musculoskeletal structure in any vertebrate clade to date. By linking musculoskeletal dissections and phylogenetic comparative methods, we then quantify and compare relationships between anatomy and function across over 160 million years of anuran evolution. In summary, we have found that bone lengths and pelvic crest sizes are generally not reliable predictors of muscle sizes, which highlights important implications for future palaeontological studies. Our investigation also presents previously unreported differences in muscle anatomy between frogs specialising in different locomotor modes, including several of the smallest frog hindlimb muscles, which are extremely difficult to extract and measure using traditional approaches. Furthermore, we find evidence of many‐to‐one and one‐to‐many mapping of form to function across the phylogeny. Additionally, we perform the first quantitative analysis of how the degree of muscle separation can differ between frogs. We find evidence that phylogenetic history is the key contributing factor to muscle separation in the pelvis and thigh, while the separation of shank muscles is influenced more strongly by locomotor mode. Finally, our anatomical 3D reconstructions are published alongside this manuscript to contribute towards future research and serve as educational materials. [ABSTRACT FROM AUTHOR]

Exposure to contagious pathogens can result in behavioural changes, which can alter the spread of infectious diseases. Healthy individuals can express generalized social distancing or avoid the sources of infection, while infected individuals can show passive or active self-isolation. Amphibians are globally threatened by contagious diseases, yet their behavioural responses to infections are scarcely known. We studied behavioural changes in agile frog (Rana dalmatina) juveniles upon exposure to a Ranavirus (Rv) using classic choice tests. We found that both non-infected and Rv-infected focal individuals spatially avoided infected conspecifics, while there were no signs of generalized social distancing, nor self-isolation. Avoidance of infected conspecifics may effectively hinder disease transmission, protecting non-infected individuals as well as preventing secondary infections in already infected individuals. On the other hand, the absence of self-isolation by infected individuals may facilitate it. Since infection status did not affect the time spent near conspecifics, it is unlikely that the pathogen manipulated host behaviour. More research is urgently needed to understand under what circumstances behavioural responses can help amphibians cope with infections, and how that affects disease dynamics in natural populations. [ABSTRACT FROM AUTHOR]

Apple is a significant economic crop in China, and leaf diseases represent a major challenge to its growth and yield. To enhance the efficiency of disease detection, this paper proposes an Adaptive Cross-layer Integration Method for apple leaf disease detection. This approach, built upon the YOLOv8s architecture, incorporates three novel modules specifically designed to improve detection accuracy and mitigate the impact of environmental factors. Furthermore, the proposed method addresses challenges arising from large feature discrepancies and similar disease characteristics, ultimately improving the model's overall detection performance. Experimental results show that the proposed method achieves a mean Average Precision (mAP) of 85.1% for apple leaf disease detection, outperforming the latest state-of-the-art YOLOv10s model by 2.2%. Compared to the baseline, the method yields a 2.8% increase in mAP, with improvements of 5.1%, 3.3%, and 2% in Average Precision, Recall, and mAP50-95, respectively. This method demonstrates superiority over other classic detection algorithms. Notably, the model exhibits optimal performance in detecting Alternaria leaf spot, frog eye leaf spot, gray spot, powdery mildew, and rust, achieving mAPs of 84.3%, 90.4%, 80.8%, 75.7%, and 92.0%, respectively. These results highlight the model's ability to significantly reduce false negatives and false positives, thereby enhancing both detection and localization of diseases. This research offers a new theoretical foundation and direction for future advancements in apple leaf disease detection. [ABSTRACT FROM AUTHOR]

Chemical pollutants include the harmful effects of various substances on soils, water bodies, and biodiversity. Amphibians are one of the most endangered groups of vertebrates and are impacted by chemical pollutants in various ways due to their complex life cycles. Since trace pollutant concentrations vary across environments, different frog ecomorphs (classified by their microhabitat use) may have different exposures. We aimed to determine the association between frog ecomorphs and the occurrence of histopathological hepatic lesions (HHLs) as an indicator of contaminant exposure. We focused on small forest streams near a large urban region in Brazil, heavily polluted in the 1980s. We examined 104 frog specimens from various families. All specimens exhibited HHLs, with melanomacrophages being the most common (n = 99). Arboreal frogs exhibited more vascular congestion, while terrestrial frogs showed structural hepatic damage. Higher cobalt levels were linked to increased liver necrosis in arboreal frogs and structural issues in both arboreal and terrestrial frogs. Cadmium was associated with hepatitis in terrestrial frogs. Although metal levels had no significant effects on rheophilic frogs, the prevalence of hepatitis and necrosis indicated complex exposure pathways. Iron and aluminum were linked to fewer lesions in rheophilic frogs, suggesting resilience. The high prevalence of HHLs signals an ongoing issue, with variations among ecomorphs suggesting differential exposure to pollutants and posing a complex challenge for community conservation. [ABSTRACT FROM AUTHOR]

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]

Amphibians have the least studied life histories among vertebrates, although they have unique and the most diverse life histories within this group. We compiled a new dataset on adult body mass and 16 other life history traits of 2069 amphibian species across three orders (1796 frogs, 236 salamanders, 37 caecilians). These traits characterise fecundity, offspring development from egg deposition to metamorphosis and adult life. We established allometric models on traits for all amphibians and each of the three orders to assess a potential scaling of traits to body mass and then checked whether allometric slopes were consistent with two different metabolic scaling exponents. Further, we examined a possible fast‐slow continuum in all amphibians, as well as in each of the two orders frogs and salamanders by applying principal component analysis (PCA) to five traits. Our allometric models indicated a positive scaling to body mass for 11 traits across all amphibians, 12 in frogs, and 10 in salamanders, and for five out of eight traits analysed in caecilians. Allometric slopes on most traits characterising offspring development were not significant. All slopes did not support a three‐quarter metabolic scaling exponent, whereas slopes on age at maturity and maximum longevity were consistent with an amphibian metabolic scaling exponent of 0.88. As in fishes, reptiles, birds, and mammals, the first axes of our PCAs indicated a body mass‐dependent fast‐slow continuum in amphibians. Amphibian species of slow life histories have larger body masses, later sexual maturities and longer lifespans and lay more and larger eggs than species of fast life histories, a pattern also known from reptiles. The second axes indicated a trade‐off between egg size and number. As this trade‐off was nearly independent of body mass, we hypothesise that amphibians have occupied a broad range of ecological niches without evolutionary changes in body mass. [ABSTRACT FROM AUTHOR]

Ceratophryid frogs inhabit the lowlands of South America and exhibit greater diversity in the semiarid Gran Chaco. The presence of Ceratophryidae dates back to the late Miocene on the eastern slopes of the Andes in Argentina. Herein, we describe the remains of Ceratophrys from late Miocene of Palo Pintado Formation (Salta, Argentina). Fragmentary bones were recovered from the base of the unit in beds dated between 8 and 7.7 million years ago. The specimen IBIGEO-P141 exhibits the fusion of dentary and mentomeckelian bones forming a fang, a sharp-edged lower jaw, and sculptured bones as Ceratophryidae. The granular pattern of sculpturation, differences between pars facialis and pars dentalis of maxillary, and the shape of lower jaw, support its assignment to the genus Ceratophrys. Combined bioclimatic data and geographic distribution of living Ceratophrys indicate a strong influence of precipitation variables in the distribution of these frogs with adaptations to survive long dry periods. These facts suggest a seasonal rainfall with a well-defined dry season during the deposition of lower levels of Palo Pintado Formation. The palaeoclimatic conditions resemble those occurring in the actual semiarid Chaco, and reveal that the historical geographic distribution of Ceratophryidae was retracted eastward due to the Andean uplift. [ABSTRACT FROM AUTHOR]

Salinity can be an environmental stressor for anurans, as their highly permeable skin makes them prone to osmotic stress when exposed to saline conditions. However, certain anuran species have colonized areas near saltwater habitats, suggesting an ability to acclimate to saline conditions. Here, we evaluated physiological and behavioral responses to saline conditions in adult Cuban treefrogs (Osteopilus septentrionalis), an invasive anuran found throughout Florida. To examine their response to salinity, adult frogs were maintained in two treatments simulating a freshwater (0.5 ppt) or brackish (8.0 ppt) environment for 6 weeks. To assess their physiological response to this potential stressor, all frogs were submerged in a brackish solution to quantify individual weight change every 2 weeks. We found that frogs maintained in brackish solution lost more weight at Weeks 2 and 6 when compared to Week 0, suggesting that salinity may be an environmental stressor for Cuban treefrogs. Yet, the weight change at Week 4 was similar to the pre‐exposure period, which may indicate that constant exposure to salinity may alter their physiological response to saline conditions. To supplement the physiological analyses, we investigated avoidance behavior toward saline conditions by offering individuals a choice between freshwater or brackish environments. Our results showed that Cuban treefrogs chose freshwater environments more frequently and may thus avoid saline ones. This study reveals that salinity may induce plastic and avoidance responses in Cuban treefrogs, potentially allowing them to expand their range into areas typically stressful for most anurans. Research Highlights: Salinity has dehydrating effects on adult Cuban treefrogs, which can elicit physiological and avoidance responses.Prolonged exposure to saline conditions can modulate physiological responses to salinity. [ABSTRACT FROM AUTHOR]

The ways in which animals sense the world changes throughout development. For example, young of many species have limited visual capabilities, but still make social decisions, likely based on information gathered through other sensory modalities. Poison frog tadpoles display complex social behaviors that have been suggested to rely on vision despite a century of research indicating tadpoles have poorly-developed visual systems relative to adults. Alternatively, other sensory modalities, such as the lateral line system, are functional at hatching in frogs and may guide social decisions while other sensory systems mature. Here, we examined development of the mechanosensory lateral line and visual systems in tadpoles of the mimic poison frog (Ranitomeya imitator) that use vibrational begging displays to stimulate egg feeding from their mothers. We found that tadpoles hatch with a fully developed lateral line system. While begging behavior increases with development, ablating the lateral line system inhibited begging in pre-metamorphic tadpoles, but not in metamorphic tadpoles. We also found that the increase in begging and decrease in reliance on the lateral line co-occurs with increased retinal neural activity and gene expression associated with eye development. Using the neural tracer neurobiotin, we found that axonal innervations from the eye to the brain proliferate during metamorphosis, with few retinotectal connections in recently-hatched tadpoles. We then tested visual function in a phototaxis assay and found tadpoles prefer darker environments. The strength of this preference increased with developmental stage, but eyes were not required for this behavior, possibly indicating a role for the pineal gland. Together, these data suggest that tadpoles rely on different sensory modalities for social interactions across development and that the development of sensory systems in socially complex poison frog tadpoles is similar to that of other frog species. [Display omitted] • Ranitomeya imitator tadpoles hatch with fully developed lateral line systems. • Use of mechanosensory stimuli for begging is dependent on developmental stage. • The visual system of R. imitator tadpoles continues to develop through metamorphosis. • When visual capabilities are poor, tadpoles rely more on mechanosensory inputs. [ABSTRACT FROM AUTHOR]

Natural history collections have long served as the foundation for understanding our planet’s biodiversity, yet they remain a largely untapped resource for wildlife disease studies. Extended specimens include multiple data types and specimen preparations that capture the phenotype and genotype of an organism and its symbionts—but preserved tissues may not always be optimized for downstream detection of various pathogens. Frogs are infected by an array of pathogens including Batrachochytrium dendrobatidis (Bd), Ranavirus (Rv), and Amphibian Perkinsea (Pr), which provides the opportunity to study differences in detection dynamics across tissue types. We used quantitative PCR protocols to screen two tissue types commonly deposited in museum collections, toe clips and liver, from two closely related host species, Rana catesbeiana and Rana clamitans. We compared Bd, Rv, and Pr infection prevalence and intensity between species and tissue types and found no significant difference in prevalence between species, but Bd intensity was higher in R. clamitans than R. catesbeiana. Toe tissue exhibited significantly higher Bd infection loads and was more useful than liver for detecting Bd infections. In contrast, Rv was detected from more liver than toe tissues, but the difference was not statistically significant. Our results support the use of extended specimen collections in amphibian disease studies and demonstrate that broader tissue sampling at the time of specimen preparation can maximize their utility for downstream multipathogen detection. [ABSTRACT FROM AUTHOR]

We describe a new species of leaflitter frog of the genus Noblella from southern Ecuador, province of Zamora Chinchipe. The new species is diagnosed from all its congeners by having one or two tubercles on the upper eyelids; distal phalanges strongly T-shaped; phalangeal formula on hands 2-2-3-3; phalangeal formula on feet 2-2-3-4-3; heel with a small subconical tubercle; disc on all toes with papillae; dorsum brown or brown with gray, with V-shaped inverted or scattered irregular darker marks. We include a detailed description of its osteology and a study of its phylogenetic relationships. Finally, we evaluate its conservation status and discuss the threats that are currently impacting at the type locality. [ABSTRACT FROM AUTHOR]

Most citizen science research inherently separates the observer (citizen science participant) from the observation (e.g. data point), placing artificial boundaries around what matters and how it comes to matter. We apply three elements of the philosophical framework of agential realism to reveal a more complex picture of how data arise within citizen science programmes, and its meaning to both the practice of science and the citizen science participant: 'intra‐action' (all entities have agency and are entangled with one another); 'material becoming' (what comes to matter); and 'responsibility' (accountability for what comes to matter and what is excluded from mattering).We draw on a case study of FrogID—an Australia‐wide citizen science program focused on calling frogs, with over 42,000 participants and over 1 million frog records. We conducted semi‐structured interviews with 30 FrogID users, completing two rounds of thematic and relational coding.Our findings reveal that as a consequence of their recording behaviours, FrogID participants become increasingly entangled with the nocturnal environment, with sound and with their own self. Expanding and reciprocal relationships and experiences shape the nature and frequency of their recordings.Second, meaning influences what comes to matter (i.e. what is recorded and submitted) for FrogID participants. We reveal meaning related to feedback (recognition and thus reciprocity), others (social networks and participation with family and friends) and the self (physical and mental well‐being and identity formation/becoming). These different forms of meaning influenced engagement with app use.Third, participants communicated responsibilities related to their involvement in citizen science, including responsibilities to create knowledge (e.g. longitudinal data collection), to conserve (e.g. actively conserving frog, formally committing areas to conservation) and to educate self and others (e.g. skills and competencies required for environmental action).Synthesis and applications: By recognizing a more comprehensive set of intra‐actions, beyond the observer and the observation, agential realism can reveal when, why and how citizen science observations are made; what observations come to matter and why; and how people can create a more just world. Agential realism can shape how citizen science participation, retention and biodiversity data generation are founded. We propose three opportunities for citizen science programs based on these findings. Read the free Plain Language Summary for this article on the Journal blog. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

The document published in the journal "Evolutionary Ecology" discusses recent developments in the study of poison frog evolutionary ecology, focusing on coloration, behaviors, and genetic underpinnings. The research highlights the significance of color variation, dietary preferences, alkaloid synthesis, and toxin resistance in poison frogs. Additionally, the document explores the role of coloration in signaling, predator-prey interactions, and sexual dichromatism. The study also delves into the genetic basis of color patterns and mechanisms of toxin resistance in poison frogs. Overall, the document emphasizes the importance of understanding the evolutionary ecology of poison frogs and the need for further research in this field. [Extracted from the article]

The poison frog family (Anura: Dendrobatidae) consists of species with conspicuous (e.g., warning coloration and toxicity or low palatability) and cryptic (e.g., palatable, and inconspicuous coloration) traits. Previous literature suggests that conspicuous, but not cryptic, species require diet specialization in prey high in alkaloids. To test for dietary preferences of poison frog species, we identified, to the lowest possible taxonomic rank, the diets of 21 Epipedobates darwinwallacei (conspicuous) and 22 Hyloxalus awa (cryptic) frogs living in syntopy in the Otongachi Forest in northwestern Ecuador. We then tested for differences in diet assemblage composition, and diet specialization, in these putatively conspicuous and cryptic frogs. Our analyses showed significant differences in the composition of arthropod assemblages consumed by both frog species, which translated into a narrow niche breadth and nine arthropod taxa (out of a total of 18) consumed by both species. Moreover, the index of relative importance, which measures frog's diet specialization, suggested that E. darwinwallacei, and H. awa prefer specific arthropod taxa, where the former consumes preferentially springtails and mites, while the latter consumes mostly ants and Coleoptera larvae. Thus, contrary to expectations, diet specialization is not a unique characteristic of the species with conspicuous traits when living in syntopy. [ABSTRACT FROM AUTHOR]

Identifying and quantifying the main factors that are jeopardizing amphibian communities worldwide is essential for planning effective amphibian conservation. We collected data on the presence/absence of salamanders and newts (Caudata) and frogs and toads (Anura) in >3600 water points from a large region (30,000 km2) in NW Spain during a 10‐year period (2004–2013). We contrasted a large set of hypotheses explaining presence/absence as a function of anthropogenic factors across the regional elevation gradient (1–2036 m). Logistic regression modeling revealed that salamanders and newts were mainly influenced by pollution and by land use changes, and that the effect of these factors changed with elevation. However, frogs and toads were affected by a larger set of factors acting synergistically, although not including land use changes, and their effect operated at all elevation ranges, except in the case of biological factors (invasive species and wild boar abundance) with higher effects at low elevation. Changes in land use was the most common factor at any elevation and included the abandonment of rural areas, which favors shrub and tree encroachment on former open land, and loss of water points. The most resilient species at any elevation were two frogs, Pelophylax perezi and Rana parvipalmata. The least resilient species were two salamanders, Chioglossa lusitanica and Lissotriton helveticus, followed closely by two toads, Alytes obstetricans and Pelobates cultripes. Unoccupied sites had higher frequencies of biological effects and of changes in land use in the first 5 years of study and lower frequencies of direct human influence factors in the second period. Overall, our results showed that the studied amphibian metacommunity was negatively influenced both by direct and indirect anthropogenic factors, but also that many amphibian species were not only capable of occupying sites which had been altered by human action, but were even favored by land uses generating open habitat, a habitat type that is increasingly uncommon in the region, in the entire Iberian Peninsula and in Europe. [ABSTRACT FROM AUTHOR]

Abstract Most citizen science research inherently separates the observer (citizen science participant) from the observation (e.g. data point), placing artificial boundaries around what matters and how it comes to matter. We apply three elements of the philosophical framework of agential realism to reveal a more complex picture of how data arise within citizen science programmes, and its meaning to both the practice of science and the citizen science participant: ‘intra‐action’ (all entities have agency and are entangled with one another); ‘material becoming’ (what comes to matter); and ‘responsibility’ (accountability for what comes to matter and what is excluded from mattering). We draw on a case study of FrogID—an Australia‐wide citizen science program focused on calling frogs, with over 42,000 participants and over 1 million frog records. We conducted semi‐structured interviews with 30 FrogID users, completing two rounds of thematic and relational coding. Our findings reveal that as a consequence of their recording behaviours, FrogID participants become increasingly entangled with the nocturnal environment, with sound and with their own self. Expanding and reciprocal relationships and experiences shape the nature and frequency of their recordings. Second, meaning influences what comes to matter (i.e. what is recorded and submitted) for FrogID participants. We reveal meaning related to feedback (recognition and thus reciprocity), others (social networks and participation with family and friends) and the self (physical and mental well‐being and identity formation/becoming). These different forms of meaning influenced engagement with app use. Third, participants communicated responsibilities related to their involvement in citizen science, including responsibilities to create knowledge (e.g. longitudinal data collection), to conserve (e.g. actively conserving frog, formally committing areas to conservation) and to educate self and others (e.g. skills and competencies required for environmental action). Synthesis and applications: By recognizing a more comprehensive set of intra‐actions, beyond the observer and the observation, agential realism can reveal when, why and how citizen science observations are made; what observations come to matter and why; and how people can create a more just world. Agential realism can shape how citizen science participation, retention and biodiversity data generation are founded. We propose three opportunities for citizen science programs based on these findings. Read the free Plain Language Summary for this article on the Journal blog.

Anurans exhibit a diverse acoustic repertoire, and the release call is emitted when an individual is improperly clasped, often by males mistakenly grasping other males or unreceptive females during amplexus. The release call also serves as a crucial source for taxonomic resolution. However, for certain widespread hylid genera like Trachycephalus, knowledge about their release calls is limited or non-existent. Trachycephalus comprises 18 species, yet only one has its release call described. This study presents the first description of the release call of T. typhonius from a population in the Cerrado of Central-Western Brazil. Its release call is composed of a multipulsed note, distinguishing it from the only other known call in the genus (T. 'vermiculatus'). Given the differences in the release call parameters between these species, such variations could serve as diagnostic criteria for distinguishing the two lineages. Additional descriptions of release calls, including from more T. typhonius and T. 'vermiculatus' populations, are essential for species diagnosis and taxonomic classification. [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]

At the time of the recent description of Beytell's bullfrog (Pyxicephalus beytelli), no information about the breeding biology of this frog was known to science. The intensive publicity in the social media that followed this description caught the eye of a USA‐based film maker who incidentally recently filmed the breeding biology of this frog in the Okavango Delta in northern Botswana. This paper is based on these observations. [ABSTRACT FROM AUTHOR]

Although neobatrachians represent about 95% of anuran diversity, their fossil record, especially during the Mesozoic, remains scarce and often limited to a few damaged specimens with uncertain affinities. In South America, fossil neobatrachians have been identified from the Cretaceous deposits in Chile, Argentina, and Brazil. Here, we describe a new species of fossil neobatrachian from the Late Cretaceous (Campanian) Bauru Basin, south-eastern Brazil, based on several well-preserved specimens. The morphology of the new species was described in detail using high-resolution micro-CT, and its taxonomic affinities were investigated through a phylogenetic analysis encompassing both living and extinct taxa. The new taxon was recovered among hyloids, more specifically as closely related to other well-ossified taxa. However, due to the lack of any synapomorphies with extant families, we were unable to assign the new species to a more specific group within Neobatrachia. The discovery of a new fossil frog in the Late Cretaceous Bauru Basin significantly enhances our understanding of neobatrachian early morphology during the Late Cretaceous of South America. [ABSTRACT FROM AUTHOR]

Examples of resilience in nature give us hope amid a growing biodiversity crisis. While resilience has many definitions across disciplines, here I discuss resilience as the ability to continue to adapt and persist. Naturally, as biologists, we seek to uncover the underlying mechanisms that can help us explain the secrets of resilience across scales, from individuals to species to ecosystems and beyond. Perhaps we also ponder what the secrets to resilience are in our own lives, in our own research practices, and academic communities. In this paper, I highlight insights gained through studies of amphibian resilience following a global disease outbreak to uncover shared patterns and processes linked to resilience across amphibian communities. I also reflect on how classical resilience heuristics could be more broadly applied to these processes and to our own academic communities. Focusing on the amphibian systems that I have worked in—the Golden Frogs of Panama (Atelopus zeteki/varius) and the Mountain Yellow-Legged Frogs of California (Rana muscosa/sierrae)—I highlight shared and unique characteristics of resilience across scales and systems and discuss how these relate to adaptive renewal cycles. Reflecting on this work and previous resilience scholarship, I also offer my own thoughts about academia and consider what lessons we could take from mapping our own adaptive trajectories and addressing threats to our own community resilience. [ABSTRACT FROM AUTHOR]

Understanding the effect of environmental factors on population characteristics of amphibians is crucial for their conservation and management. This is especially pertinent in regions vulnerable to climate change, such as the Qinghai–Tibetan Plateau (QTP). Here, we investigated the underlying environmental factors affecting the occurrence and abundance of Tibetan frogs (Nanorana pleskei) in the Three-River-Source region (TRSR) on the QTP. We found that N. pleskei is predominantly located in the headwater region of the Lancang River, with an increasing population size from northwest to southeast across the TRSR. Temperature oscillation acts as an ecological filter to determine the occurrence pattern, whereas the abundance is jointly influenced by maximum monthly temperature and precipitation and precipitation variability. Our study presents up-to-date information on the distribution and population status of N. pleskei in the hinterland of the QTP, which can assist conservation practitioners in developing effective management plans. Furthermore, our findings can contribute to the understanding of the distribution and abundance of amphibians within challenging high-elevation and plateau environments, offering insights that are valuable for the conservation and management of other amphibian species inhabiting similar high-elevation regions. [ABSTRACT FROM AUTHOR]

Retinal rods, the photoreceptors of twilight vision, are able to adapt to a wide range of illumination levels. The molecular mechanisms of light adaptation have received extensive study, though no less interesting is the question of what changes occur in the phototransduction cascade after the adaptive light stimuli terminate. Our previous studies demonstrated the phenomenon of adaptation memory in the rods of amphibians: after background illumination, photoreceptor light sensitivity was reduced for several minutes, while in the dark the current was restored in 20–30 sec. This indicates the existence of additional, as yet unknown, mechanisms regulating the phototransduction cascade and operating after the adaptive effect of light. In search of specific mechanisms capable of explaining the effect of adaptive memory, we conducted experiments recording currents from single rods in frogs to assess the basal activity of the effector enzyme of the phototransduction cascade, phosphodiesterase type 6, in the dark state and after saturating background illumination. This study showed that the post-adaptation state of rods is characterized by elevated basal phosphodiesterase activity, with gradual reduction to the dark value within tens of seconds after terminating the adapting background light. These results also suggest that the components of the phototransduction cascade in rods may undergo as yet unstudied post-adaptation changes. [ABSTRACT FROM AUTHOR]

We report herein the fossil record of lissamphibians unearthed from the late Eocene – early Oligocene localities of the north-western side of the Transylvanian Basin. Among the late Eocene (Priabonian) fossil vertebrate sites, the Bociu locality yielded discoglossid and pelobatid frogs, while the Treznea locality yielded a moderately diverse assemblage of discoglossid (Latonia sp.), palaeobatrachid, pelobatid and ranid (Pelophylax sp.) frogs. The assemblages derived from the early Oligocene (Rupelian) fossil localities of Suceag 1 and Cetățuia Hill, Cluj-Napoca include salamandroid newts (Mioproteus gardneri), discoglossid (Latonia sp.), palaeobatrachid (Albionbatrachus oligocenicus) and ranid frogs (Pelophylax sp.). Disparity between the contemporaneous anuran assemblages from the Transylvanian Basin and those representing the more diverse cratonic Europe is derived mainly from the persisting insular conditions of the studied area. The drop of mean annual temperature in northern Europe and the enlarging freshwater corridors may have facilitated the southeastern distribution of highly aquatic amphibian groups like the proteid salamander Mioproteus, the ranid frog Pelophylax and the palaeobatrachid frog Albionbatrachus, the latter being considered a late Eocene survivor, recorded previously from the western part of the continent. [ABSTRACT FROM AUTHOR]

We describe two new species of the microhylid frog genus Choerophryne Van Kampen, 1914 from the mountains of Papua New Guinea. The first is a scansorial species known only from foothill forest at altitudes of 440-950 m a.s.l. on the northern slopes of Papua New Guinea's Central Cordillera. It is a moderately large member of the genus (males 16.8-20.6 mm snout-urostyle length) that utters long series of short whistling calls each lasting 77-125 ms. The second species is arboreal and known only from a small area of montane forest at altitudes of 2060-2300 m a.s.l. on the southern edge of the Central Cordillera. It is also moderately large for the genus (three males with snout-urostyle lengths of 19.3-20.6 mm) and produces long series of short buzzing calls, each lasting 124-173 ms. Descriptions of these two species bring the number of recognised Choerophryne to 39, and at least 18 additional species in the genus await formal description. [ABSTRACT FROM AUTHOR]

Mutualistic and similar ecological associations between tarantulas (Mygalomorphae: Theraphosidae) and other animals are reviewed. Such associations are found to occur in at least nine theraphosid subfamilies. We present 63 new cases of theraphosid–anuran associations from 10 countries, documenting these interactions for the first time in Brazil, Chile, the Dominican Republic, and the Philippines. These findings are the first documentation of such associations for 13 theraphosid and 20 anuran taxa. Additionally, we report, for the first time, associations potentially of mutualistic nature between tarantulas and snakes, whip spiders, and harvestmen. Furthermore, we provide new reports of associations with ants and termites. While some of these interactions appear to be merely tolerated cohabitations, those involving anurans and ants seem to be more prevalent and complex, clearly offering benefits for both organisms. Additionally, based on multiple observations and field experiments, we propose a new hypothesis regarding the evolution of hirsuteness in theraphosids as a defensive strategy against predatory ants. This hypothesis supports previous findings that suggest a similar function for urticating setae incorporated into egg sacs and moulting mats. We further document a unique escape strategy against ants in New World arboreal theraphosids. Finally, the possibility of a chemical defence mechanism through specialised epidermal glands in theraphosids is briefly discussed. [ABSTRACT FROM AUTHOR]

Aim: Aposematic animals, i.e., those that are defended and warn potential predators through signals, are suggested to have resource‐gathering advantages against non‐aposematic ones. We here explore this in a biogeographic framework expecting that aposematic species are better dispersers, which translates into larger geographic range size. Location: South America. Taxon: Poison frogs (Amphibia; Aromobatidae and Dendrobatidae). Methods: We use 43 toxic and 26 non‐toxic poison frog species from the lowlands only as representatives of aposematic and non‐aposematic study organisms, respectively. Realised and potential geographic ranges are calculated using minimum convex polygon and species distribution modelling methods, respectively. Accounting for species body size and phylogeny, we test if both range and aposematism are correlated using linear mixed‐effects models. Results: Aposematic and non‐aposematic species neither differ in realised nor in potential geographic range size. There was no effect on body size. Main Conclusions: The role of aposematism is not yet as clear as suggested and determinants of poison frog range sizes are multifaceted. A more integrative approach is needed using the information on behaviour, predation risk, and reproductive biology to assess the role of aposematism on observed species distributions. Such data are not yet available for most species, neither poison frogs nor other aposematic animals. [ABSTRACT FROM AUTHOR]

Amphibians are not only an alternative source of vital protein for humans, but also one of the best bioindicators for ecological studies. In this study, we studied the age structure, body size, and mass of an amphibian species (Pelophylax ridibundus) by sampling from two different frog farms in Türkiye. The age ranged from 4 to 13 (mean: 7.1) years in the Adana site while the age varied from 1 to 12 (mean: 5.2) years in the İstanbul site. Body size ranged between 88.21 and 103.72 mm (mean: 94.99 ± 1.15 mm) in the Adana site and 45.96 and 103.25 mm (mean: 75.90 ± 3.01 mm) in the İstanbul site. The t-test confirmed that the average age, SVL, and weight of the Adana site were higher than those of İstanbul. Body size markedly increased with age and weight (SVL-age: r = 0.659, p < 0.01; SVL-weight: r = 0.877, p < 0.001) in the İstanbul site, while in the Adana site, body size correlated only with weight. In conclusion, our research uses skeletochronology to provide demographic characteristics of marsh frogs from two unexplored frog farms located in the west and south of Türkiye. [ABSTRACT FROM AUTHOR]

Despite amphibians having the least number of families in comparison with other vertebrate classes, the digenean parasites within these host species are largely predominant. To date, no investigation has been conducted on the digenean fauna of frogs in western Iran. The helminths occurrence and morphological description of this study were analyzed for the first time. A total of 54 Levant water frogs, Pelophylax bedriagae, (n = 53), and a long-legged wood frog, Rana macronemis, (n = 1) were examined. Frogs harbor in total four digenean parasites. Three taxa were characterized based on morphological features as Gorgodera cf. asiatica, G. varsoniensis, and Pleurogenoides sp. within P. bedriagae, while Haematoloechus sp. was only found in R. macronemis. Pleurogenoides sp. exhibited a moderate prevalence (23%) and intensity (7.3 ± 6.3). Gorgodera cf. asictica can be distinguished from congeners based on the body and sucker size, the ovary and testes shape, and in G. varsoviensis by having lobulated caeca and transversely elongated testes. In addition, Pleurogenoides sp. mainly differs from all its congeners by the form of its body, genital apparatus shape and Y-shaped excretory vesicles. With regard to helminths in amphibians, the existing body of literature is extensive and complex. To accurately determine the species boundaries, both morphological and molecular data are needed. We report two new records of these parasites from the region. [ABSTRACT FROM AUTHOR]

The Cenozoic topographic development of the Himalaya‐Tibet orogen (HTO) substantially affected the paleoenvironment and biodiversity patterns of High Asia. However, concepts on the evolution and paleoenvironmental history of the HTO differ massively in timing, elevational increase and sequence of surface uplift of the different elements of the orogen. Using target enrichment of a large set of transcriptome‐derived markers, ancestral range estimation and paleoclimatic niche modelling, we assess a recently proposed concept of a warm temperate paleo‐Tibet in Asian spiny frogs of the tribe Paini and reconstruct their historical biogeography. That concept was previously developed in invertebrates. Because of their early evolutionary origin, low dispersal capacity, high degree of local endemism, and strict dependence on temperature and humidity, the cladogenesis of spiny frogs may echo the evolution of the HTO paleoenvironment. We show that diversification of main lineages occurred during the early to Mid‐Miocene, while the evolution of alpine taxa started during the late Miocene/early Pliocene. Our distribution and niche modelling results indicate range shifts and niche stability that may explain the modern disjunct distributions of spiny frogs. They probably maintained their (sub)tropical or (warm)temperate preferences and moved out of the ancestral paleo‐Tibetan area into the Himalaya as the climate shifted, as opposed to adapting in situ. Based on ancestral range estimation, we assume the existence of low‐elevation, climatically suitable corridors across paleo‐Tibet during the Miocene along the Kunlun, Qiangtang and/or Gangdese Shan. Our results contribute to a deeper understanding of the mechanisms and processes of faunal evolution in the HTO. [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]

Generally, competition excludes pairs of phylogenetically close species across the landscape. However, habitat, food and behaviour differentiation facilitate co‐occurrence of syntopic species. The taxa of frog‐biting midges Corethrella are assumed to be specialists on calling male frogs, but little is known about how habitat gradients and frog‐species composition influence their distribution and permit their coexistence in continuous landscapes.Our aims were to understand how environmental gradients in habitat, sound frequencies and frog‐species composition influence Corethrella spp. distributions and if habitat and sound frequencies segregate their occurrence across a landscape. We also investigated if habitat selection reduces co‐occurrence of species that share similar acoustic niches. The study was conducted in 20 permanent plots in Central Amazonia using different sound attractants as baits to capture Corethrella species.Habitat gradients, sound frequencies and frog‐species composition all influenced distributions of Corethrella spp. However, these factors do little to avoid Corethrella co‐occurrence, and habitat selection did not reduce co‐occurrence of species attracted to the same sound frequencies. These results suggest that competition is unlikely to affect the distribution of adults and that other aspects, such as competition in the larval phase, may be more important to permit their coexistence.The two most abundant species showed strong negative correlations in abundances, potentially indicating competition among these species, but larval habitat specialisation is likely to be the most important cause of this pattern. [ABSTRACT FROM AUTHOR]

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]