Temperature is a key abiotic factor influencing the development and survival of ectothermic animals. Amphibians, especially those from tropical regions, are considered highly vulnerable to climate change due to their limited acclimation capacity. In this study, we evaluated the effects of thermal acclimation on the development, morphology, and survival of Pithecopus gonzagai, an anuran species endemic to the Caatinga, a tropical semiarid biome in northeastern Brazil. Tadpoles were reared under three temperature regimes: control (28.6 ± 0.7 °C), intermediate (30.8 ± 0.7 °C), and high (33.0 ± 0.9 °C), simulating present and projected future climatic conditions. Thermal acclimation significantly affected survival and metamorphic success, with the highest mortality observed at 33 °C, where no individuals completed metamorphosis. Morphological effects were transient with no clear pattern and there was no change on time to metamorphosis. Behavioral parameters, including swimming speed, mobility rate, and exploration rate, were not affected by temperature. Our findings highlight the sensitivity of early developmental stages of tropical amphibians to increased temperatures and emphasize the potential threats posed by climate change to species inhabiting already thermally challenging environments such as the Caatinga.

Ecoacoustics tools reveal effects of human-caused wildfires on anuran communities of the Yungas Andean Forest.

Abstract Amphibians play an important role in linking aquatic and terrestrial ecosystems through nutrient cycling, energy flow, and bioturbation. In this study, we investigated the isotopic niches of three tropical frog species (Polypedates megacephalus, Microhyla mukhlesuri, and Microhyla ninhthuanensis) inhabiting temporary ponds in southern Vietnam, constructing an ontogenetic snapshot using stable isotope analysis of carbon (δ13C) and nitrogen (δ15N). We examined ontogenetic changes in isotopic signatures and dietary sources across species, comparing tadpoles and adult frogs. Our results revealed distinct isotopic niche partitioning among syntopic tadpole species within a shared pond. Microhyla ninhthuanensis (neustonic feeder) occupied the most specialized niche, whereas P. megacephalus (opportunistic omnivore) and M. mukhlesuri (nektonic suspension feeder) exhibited broader, more variable isotopic niches. Notably, M. ninhthuanensis tadpoles exhibited the closest isotopic match to conspecific adults, suggesting dependence on terrestrially derived carbon sources throughout ontogeny. Distinct isotopic niches were identified for M. mukhlesuri, both in different ponds and among various cohorts within the same pond. The observed trophic differentiation among tadpoles of the three species with different feeding modes appears to facilitate their stable coexistence in shared pond habitats by minimizing resource competition.

Changes in phenological patterns in breeding behavior are useful for determining the effect of climate change on amphibian communities, many of which are declining and at risk of extinction. Most climate change research focuses on long-term warming trends with less consideration for the increasing frequency of extreme weather events. The calling probability of four early spring-breeding anurans, including the boreal chorus frog (Pseudacris maculata), spring peeper (Pseudacris crucifer), wood frog (Boreorana sylvatica), and American toad (Anaxyrus americanus), was determined using autonomous recording units from 2022 to 2025. An unusually warm March in 2024 ("false spring") followed by freezing temperatures allowed us to assess the impact of a weather event on the calling probability of the four anuran species. Coinciding with the warmer temperatures in March, the first date of calling was advanced by 11-18 days in 2024 compared to 2022. However, the probability of calling was reduced in 2024 for all species except the spring peeper, which had the highest probability of calling in that year. The probability of calling in boreal chorus frogs decreased from 69% in years with average weather to 49% in 2024, which may lead to negative fitness consequences for this declining species. This study exemplifies the species-specific response of spring-breeding anurans to seasonal and environmental variables, highlighting the potential impact of weather events on calling behavior. Phenological shifts can create mismatches between the timing of reproduction and the availability of resources important for the survival of offspring, thus negatively impacting recruitment and persistence of local anuran populations.

Frogs belonging to the genus Nyctibatrachus are endemic to the Western Ghats biodiversity hotspot. They are the second most speciose frogs in the Western Ghats, with 70% of the species having narrow distribution ranges. They are also highly cryptic in nature. In this study, we describe a new species of Nyctibatrachus frog from the central Western Ghats of India. Nyctibatrachus kali sp. nov. is described from the Kali River basin of North Karnataka. The new species is distinguishable from all 34 currently recognised Nyctibatrachus species by a combination of morphological, acoustic and phylogenetic analyses. Molecular phylogeny based on two mitochondrial genes (16S rRNA and ND1) reveals that it belongs to the N. sanctipalustris clade. Based on the analysis of 16S rRNA, Nyctibatrachus kali sp. nov. shows genetic divergence >5% with its congeners, and based on the analysis of ND1, Nyctibatrachus kali sp. nov. shows genetic divergence >10% with its congeners. The bioacoustics analyses indicated that the new species differed from their closest congeners based on the dominant frequency of the advertisement calls and the number of notes in each call. For the first time, we observed two distinct advertisement call categories–call notes with low and high dominant frequency in Nyctibatrachus kali sp. nov. and its congeners. Our study adds to the rich diversity of frogs from the Western Ghats of India.

Amphibians thrive in a wide variety of habitats and are determined by factors like metamorphic life cycle, reproductive activity and modes. The primary objective of the study is to provide baseline information in reviewing the biogeographic range of included species and provide information regarding the microhabitat preferences of amphibians in Mt. Sumagaya Range. Opportunistic sampling was conducted to record anurans which took place during the day (0900–1400 hours) and at night (1900–2300 hours) using standard illuminating device along the established Biodiversity Monitoring Sites (BMS) trail, streams, and rivers. A total of 19 anuran species were observed, providing 12 additional species records in the study site where eight (32%) species were only observed in arboreal microhabitats. Eight (32%) species were only observed in arboreal microhabitat and the five (20%) species solely preferred aquatic microhabitat types. Invasive species such as Rhinella marina and Kaloula pulchra were recorded during the survey. Given the high level of endemism in Misamis Oriental, the presence of these invasive alien species highlights the urgent need to strengthen conservation and protection efforts in the region.

The oral eukaryotic microbiome of amphibians remains largely unexplored, despite its potential importance for host health and resistance to fungal pathogens such as Batrachochytrium dendrobatidis (Bd). Melanophryniscus admirabilis, a critically endangered red-belly toad species endemic to Brazil and restricted to a 700-m stretch of the Forqueta River, offers unique insights into host-microbiome interactions within highly specialized and threatened neotropical environments. While its narrow distribution limits broader applications, the genus Melanophryniscus is widely distributed across South America, potentially serving as a broader model for comparative microbiome research across varied ecological contexts. We analyzed the oral eukaryotic microbiota of ten wild M. admirabilis using 18S rRNA gene amplicon sequencing, with the Illumina MiSeq platform. Taxonomic assignments were performed at the phylum, class, and genus levels. Microbial community structure was assessed via hierarchical clustering and non-metric multidimensional scaling (NMDS) method based on Bray-Curtis dissimilarity. In addition, functional profiles were inferred from taxonomic data using PICRUSt2 to explore the potential ecological roles of the detected taxa. Excluding host-derived reads, the predominant fungal phyla identified were Ascomycota and Basidiomycota. Among them, the genus Malassezia was present across all samples, suggesting a potentially host-adapted association. Given its known adaptation to mucosal environments and consistent abundance in our dataset, we hypothesize that Malassezia may compete with the fungal pathogen Bd, potentially acting as a natural microbial protector. Other fungal genera, including Phlebia, Microdochium, Fusarium, and Rhodotorula, were detected at lower abundance and may reflect a mixture of commensal, environmental, or opportunistic fungi. Functional prediction analyses revealed signatures of saprotrophic activity and suggested potential metabolic contributions to host-associated niches. The high proportion of unclassified and multi-affiliated sequences highlights the current limitations of reference databases for amphibian-associated eukaryotes, and underscores the value of this study in providing a novel community-level description of oral fungi in a neotropical anuran species. This study provides the first characterization of the oral eukaryotic microbiome of M. admirabilis, revealing a diverse and structured fungal community dominated by Malassezia, with predicted functions related to environmental adaptation and fungal competition. These findings suggest that the oral cavity of amphibians harbors functionally active microbial communities that may play a role in pathogen resistance and host-microbe symbiosis.

The rise of antimicrobial resistance and the global burden of cancer demand innovative therapeutic strategies. Frog skin secretions offer a rich source of bioactive peptides, some of which exhibit remarkable dual functionality-potent antimicrobial activity coupled with selective anticancer effects. This review highlights frog skin-derived peptides that bridge the gap between antimicrobial and anticancer therapeutics, emphasizing their structural diversity, mechanisms of action, and translational potential. A comprehensive literature search was conducted to identify peptides isolated from diverse anuran species, with emphasis on studies reporting structural features, activity against Gram-positive and Gram-negative bacteria, including multidrug resistant clinical isolates, anticancer effects, and underlying molecular mechanisms of cytotoxicity. Peptides such as dermaseptins, temporins, and brevinins disrupt microbial membranes while triggering apoptosis or necrosis in cancer cells. Key physicochemical characteristics, including net positive charge, amphipathicity, and α-helical conformation, contribute to their dual functionality. Recent advances in peptide engineering and delivery have improved stability, selectivity, and therapeutic efficacy, enhancing the clinical prospects of these naturally occurring bioactive molecules. Frog skin peptides represent promising candidates for the development of next-generation antimicrobial and anticancer therapeutics.

We describe Gastrotheca mittaliiti sp. nov. from the subalpine paramo of Amazonas department in the Andes of northern Peru, in the Huancabamba region, based on phylogenetic analysis of DNA sequences from three mitochondrial and two nuclear genes, genetic distances, and diagnostic morphological characters. Our phylogenetic analysis recovered the new species with high support both as part of the Gastrotheca marsupiata species group and as the sister species of G. trachyplevra. The new species can be distinguished from the rest of its congeners by the combination of the following characters: (i) moderately small size in males (SVL = 27.6–32.5 mm, n = 4); (ii) distinctly thick and elevated supratympanic fold extending from the top edge of the tympanum to the flank covered with prominent and closely packed or fused pustules; (iii) two prominent paravertebral longitudinal pustular ridges; (iv) narrow discs on fingers and toes with truncate terminal margins; (v) dorsum covered with prominent and closely packed rounded pustules; (vi) canthus rostralis thin and straight in dorsal view; and (vii) distal subarticular tubercle rounded. In addition, we report the first record of G. turnerorum in Peru and describe new morphological variation of the Peruvian populations. Our results highlight the Huancabamba region as the hotspot of Gastrotheca species richness, a result that we discuss from a biogeographic and conservation perspective.

The evolution of alkaloid sequestration and modification in poison frogs provides an opportunity to explore the emergence of complex traits, particularly the importance of intermediate phenotypes. The origin of alkaloids in lineages of frogs may, at first glance, appear to have undergone saltational evolution in amphibians. However, the recent detection of low levels of alkaloids in several species previously thought to be 'undefended' could represent an intermediate step between passive alkaloid retention and active sequestration. This study aims to address gaps in understanding the evolutionary pathway of alkaloid sequestration and modification in poison frogs. We conducted controlled alkaloid ingestion experiments in several frog species, including sequestering and putatively non-sequestering species, to assess their ability to accumulate and modify dietary alkaloids. Our results suggest that alkaloid sequestration and modification evolved gradually, with intermediate phenotypes representing transitional stages between non-sequestering species and the active sequestration and modification observed in some poison frogs. Given current understanding of alkaloid transport and metabolism, these results allow us to propose possible mechanisms that enabled the gradual adaptation of poison frogs to evolve from alkaloid resistance to active sequestration and modification.

Asymmetry in a bilateral organism refers to the difference in the expression of a trait between right and left sides, which may result from genetic or environmental disturbances. Using geometric morphometrics and a phylogenetic approach, we studied asymmetry in dorsal and ventral views of the skulls of anuran species, representing 22 families, 16 of which belong to the Hyloidea clade. The cranial regions with the most pronounced shape asymmetry were identified. To discern species with elevated levels of asymmetry and to hypothesize its evolutionary trends across phylogeny we implemented the asymmetry index. Significant asymmetric skull shape variation was found between right and left sides, associated with the upper area of the mandibular joint and the anterior area of the nasals in dorsal view. In ventral view, the greatest variation was in the vomers and the ala of the parasphenoid. The degree of size-related asymmetry varied among species. Character mapping results indicate that cranial asymmetry is a conserved and widespread trait in the Hyloidea clade, representing an ancestral condition across both dorsal and ventral regions of the skull. The observed asymmetries were found in traits that develop later in their ontogeny, which would imply that as they establish fewer developmental dependencies with other traits and, consequently, are less phylogenetically constrained. The asymmetries we found belong to this category and would be more prone to change during evolution.

Detecting the presence of a particular species in the environment is essential in studies aiming to assess the abundance and distribution of the species. Identifying the factors that affect the rate of species detectability is useful in designing monitoring programs and can lead to a more consistent study method. Here, we reviewed a set of factors that potentially influence the detection of frogs. We conducted an extensive literature review to identify key elements that affect frog detectability. Primarily, we focused on the environmental variables affecting frog species, with a brief consideration of the methodological aspects related to frog detection. We synthesized commonly used environmental and habitat variables, revealing recurring patterns and their connections with frog detectability. Additionally, we explored the methodological factors influencing frog detection and identified gaps in the current literature, proposing potential future research directions. Our findings highlight the significance of environmental factors such as temperature, precipitation, humidity, cloudiness, moon phase, and some habitat characteristics on frog detectability. Geographic biases in detectability studies limit our understanding, and expanding research into underexplored regions is crucial from a global perspective. In addition, incorporating specific environmental variables tailored to each species and habitat can enhance detection accuracy, improving our understanding of frog ecology and conservation. This review highlights the importance of accounting for detectability when surveying frogs and the need to consider all the factors influencing detectability.

The Moama area on the Murray River is the most southerly location in inland New South Wales, Australia and has important landscape connectivity value as part of a 70-km long riverine forest corridor that links the two largest forests of River Red Gum Eucalyptus camaldulensis in the Murray–Darling Basin. Collation of personal observations by a herpetologist living and working in the Moama area over a 6.5-year period identified six frog species and 17 reptile species. Records of another two frog species and two reptile species from secondary sources are noted. The herpetofauna community of the Moama area is predominantly Bassian with a minor Eyrean component, reflecting the nature of the Murray riverine corridor as a mesic environment extending into the surrounding semi-arid plains. Species of particular conservation concern known from the Moama area include the frogs Crinia sloanei and Pseudophryne bibronii, the lizards Pogona barbata and Varanus varius, the snakes Anilios proximus and Morelia spilota metcalfei, and the turtles Chelodina expansa and Emydura macquarii.

We describe three new species of direct-developing frogs of the genus Pristimantis, subgenus Huicundomantis, from the Reserva Biológica Cerro Plateado in southern Ecuador, one of the most biodiverse yet least explored regions of the Cordillera del Cóndor. Combining molecular, morphological, and bioacoustic data, we provide diagnoses and phylogenetic placements for Pristimantis verrucosus sp. nov., P. plateado sp. nov., and P. melanops sp. nov. The first two species are placed within the P. cryptomelas species group, while the third belongs to the P. phoxocephalus group. The new species can be readily distinguished from their local congeners by the following combination of traits: P. verrucosus sp. nov. exhibits a coarsely tuberculate dorsum and flanks, lacks dermal folds or ridges in the occipital/scapular region, has a distinct tympanic annulus and membrane, low cranial crests, Toe V longer than Toe III, and males possess a vocal sac and slits; P. plateado sp. nov. has a silver or light bronze iris, lacks dermal folds or ridges in the occipital/scapular region, a rounded snout in dorsal and lateral views, a distinct tympanic annulus and membrane, Toe V longer than Toe III, and males lack a vocal sac and slits; P. melanops sp. nov. is characterized by a uniquely blackish iris with a white circumpupillary ring and coarsely pustulate flanks. Additionally, we provide the first description of the advertisement call for a species in the P. cryptomelas group, thereby contributing novel bioacoustic data for a clade in which vocalizations were previously unknown. All three species are endemic to a single locality and two exhibit ecological specialization, being bromeliad specialists. Given their extremely restricted distributions and the ongoing threat of habitat degradation from illegal mining activities close to their distribution site, we recommend that all three species be listed as Critically Endangered under IUCN criteria.

This study reports trematode infection in tadpoles at early developmental stages under natural conditions. While most previous records describe infections in more advanced stages, we identified metacercariae of the diplostomid Neodiplostomum sp. in tadpoles of five anuran species at the Gosner stage between 25 and 28. A total of 207 tadpoles from eight species (Families Hylidae and Leptodactylidae) were collected from seasonal water bodies from Brazil, of which 39 were found parasitized with helminths. Within this group of infected tadpoles, 20 were specifically parasitized by trematodes, 12 of them at the earliest stages of tadpole development (Gosner stage 25). This record indicates that tadpole infection with trematodes may occur earlier than previously documented, providing new insights into the infection dynamics of larval trematodes.

Natural selection can drive the evolution of similar traits through convergent evolution. Short peptides identical to the vertebrate hormone bradykinin (BK) have been reported from the venoms and skin secretions of certain species of wasps (order Hymenoptera) and frogs (order Anura), respectively. In this study, we demonstrate that the genes encoding the BK-like peptides of hymenopteran venoms and anuran skin secretions do not share common ancestry with that of the vertebrate hormone but instead independently evolved multiple times from peptide toxin genes. These peptides serve a defensive function against vertebrate predators and their resemblance to BK was driven by selection for efficacy at the predators' receptors. Our findings highlight how natural selection can drive repeated convergent evolution of similar molecules across distantly related lineages.

Amphibians, particularly anurans, play crucial ecological roles as bioindicators of environmental health and as integral components of trophic dynamics in both aquatic and terrestrial ecosystems. Despite their ecological importance, amphibian populations are experiencing global declines largely driven by anthropogenic pressures such as habitat loss, pollution, climate change, and emerging diseases (Stuart et al., 2004; International Union for Conservation of Nature, 2023) [2, 3]. The present study provides a comprehensive account of anuran diversity in the Jamshedpur region of East Singhbhum district, Jharkhand, India, including several new distributional records. This region lies within the ecologically significant Chota Nagpur Plateau, a biogeographic zone characterized by heterogeneous landscapes and high biodiversity. The study area lies within a protected area known as Dalma Wildlife Sanctuary, which is one of the key wildlife habitats in Jharkhand. The sanctuary is largely characterized by dry deciduous forests dominated by Sal (Shorea robusta), providing suitable habitat for a diverse assemblage of herpetofauna. Systematic field surveys were conducted from June 2017 to August 2019 using the Visual Encounter Survey (VES) method (Crump & Scott, 1994) [1], supplemented by opportunistic sightings and an extensive review of available literature. Field surveys were strategically scheduled to coincide with peak amphibian activity during the monsoon season to maximize detection probability. The survey primarily aimed to assess species diversity. A total of 21 anuran species belonging to four families were recorded from the study area, comprising 19 species of frogs and two species of toads. These species were distributed across a wide range of habitats, including primary forest patches, agricultural landscapes, wetlands, streams, forest edges, and human-modified environments. Notably, higher species richness and encounter rates were observed in and around Dalma Wildlife Sanctuary, highlighting its significance as a regional hotspot for amphibian diversity in eastern India. The findings emphasize the conservation value of protected and semi-natural habitats within the Chota Nagpur Plateau for sustaining amphibian populations under increasing anthropogenic pressures.

ABSTRACT Artificial nesting structures were trialled to enhance reproductive habitat for endangered Mary River cod ( Maccullochella mariensis ) in Queensland, Australia. Twenty‐four hollow log structures of two designs were installed across six river sites and monitored alongside natural structures during the 2024 breeding season. Mary River cod used both designs, with one confirmed spawning event in an artificial log. While cod spawning was more frequent in natural structures, the artificial habitats supported multiple fish, reptile and frog species, potentially serving as cost‐effective, multifunctional refuges. Artificial structures can supplement lost or degraded habitat, offering a promising tool for the conservation of large threatened freshwater fauna.

Abstract Species population and distribution trends are essential inputs in the development of conservation plans. While trend estimates at broad spatial scales provide fundamental information, such estimates may mask spatial heterogeneity occurring at local levels. Local variations in occupancy trends can be particularly meaningful for taxonomic groups such as amphibians that are experiencing precipitous large‐scale declines as a result of localized and variable patterns of habitat loss/degradation, climate change and disease. Here we develop a spatial occupancy model that provides nuanced inferences on multi‐scale occupancy trends. Using volunteer‐collected, participatory science data, we apply our framework to estimate multi‐scale trends for 11 anuran species across Minnesota, USA from 1996 to 2015. We found substantial fine‐scale spatial variation in occupancy trends across all 11 species, suggesting localized drivers of anuran occupancy dynamics across the state. Spatial variation in trends was highly species‐specific, with some species having positive trends that varied in magnitude across the state (e.g. boreal chorus frog [ Pseudacris maculata ]), and others that showed both positive and negative trends across the state (e.g. northern leopard frog [ Lithobates pipiens ]). Statewide projections of occupancy trends provided fine‐scale insights on anuran distribution changes that were not possible when fitting simpler models. Our Bayesian approach allows trends to be summarized across areal units (e.g. ecological strata, management units) that are directly relevant for management and conservation planning. For example, the statewide trend for American toad ( Anaxyrus americanus ) was effectively zero, but finer scale analyses across ecological strata (used for statewide wildlife conservation planning) revealed multiple areas of both localized increases and declines. Synthesis and applications . Our spatial modelling approach allows practitioners to estimate trends across multiple spatial scales to inform local and regional management priorities, particularly when summarizing trends within key areal units used for conservation planning. Our framework can be used to identify hotspots of decline across multiple sympatric species for targeted monitoring or management actions. Further, estimation of spatially varying trends provides an improved ability to assess effects of protected areas or management actions, inform spatial prioritization and hypothesize drivers of occupancy trends.

Batrachochytrium dendrobatidis (Bd) is a fungal pathogen responsible for dramatic declines of amphibian populations around the world. Experimental exposure studies have documented differences in host susceptibility to Bd, but variation in study designs may limit our ability to compare inferences across studies. Using laboratory-maintained pathogen cultures that may lose virulence over time (i.e., pathogen attenuation) or exposing hosts to foreign or local strains are choices that could affect hosts differently. To test how these study design choices affect resulting inference, we exposed a vulnerable anuran species, the boreal toad (Anaxyrus boreas boreas), to three strains of Bd that varied in passage history and geographic origin and measured differences on host survival. We also examined strain-specific information reported in 58 publications of Bd exposure experiments to investigate the potential for reproducibility across studies. We found that boreal toads exposed to strains with many passes had higher weekly survival probabilities than those exposed to the strain with few passes, indicating likely pathogen attenuation in strains with higher passage history. We also found evidence for local adaptation of Bd to its host. Eighty-eight percent of publications summarized did not report the number of Bd passages. Our findings suggest that strains with fewer passes in culture are better suited for exposure studies seeking to understand differences in host susceptibility and that the amount of passes can dramatically affect inference gained across studies.