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According to Richards’ hypothesis, the presence of a nonpigmented unicellular alga in the intestinal tract of tadpoles is believed to be the inhibitory factor that affects their growth. It is proposed that thecanimals eat their fecal material containing these algal cells, which are then reintroduced into their systems when the alga is shed with the feces and dropped to the bottom. In this study, we aimed to investigate the plasticity of metamorphic traits in the Asiatic toad (Bufo gargarizans) under different combinations of fecal material and food levels. Our findings revealed that B. gargarizans tadpoles reared at high food levels exhibited accelerated larval periods but had smaller metamorphic sizes compared to those reared at low food levels. This suggests that the tadpoles prioritize rapid development at the expense of body mass during metamorphosis. Furthermore, our study discovered evidence supporting the positive effect of fecal material on tadpole growth, as indicated by the investigation of growth rate. Importantly, the presence of feces did not result in smaller body mass on average for Asiatic toad tadpoles compared to those raised in the absence of fecal material. The difference in body mass between fecal material treatments tended to be smaller at low food levels, implying that feces does not inhibit growth in B. gargarizans tadpoles. Therefore, our results contradict Richards’ hypothesis and provide support for a novel mechanism that is selected for in areas where coprophagy is likely to be advantageous, particularly in times of food scarcity. [ABSTRACT FROM AUTHOR]

ABSTRACT Recent genomic analyses have provided new insights into the process of interspecific introgression and its consequences on species evolution. Most recent studies, however, focused on hybridization between recently radiated species, with few examining the genomic outcomes of ancient hybridization across deeply diverged species. Using whole genome data of moustache toads (Leptobrachium), we identified signals of three hybridization events among nine species that diverged at the Eocene. An ancient introgression from L. leishanense to the ancestral branch (C1) of L. liui introduced adaptive variants. The highly introgressed regions include genes with important functions in odorant detection and immune responses. These genes are preserved in all three descendent populations of L. liui_C1, and these regions likely have been positively selected over a long filtering process. A recent introgression occurred from L. huashen to L. tengchongense, with the introgressed regions being mostly neutral. Furthermore, one F1 hybrid individual was detected between sympatric L. ailaonicum and L. promustache. The signals of introgression largely disappeared after removing the hybrid individual, indicating an occasional hybridization but minimal introgression. Further examination of highly divergent but low introgressed genomic regions revealed both pre‐mating isolation and genetic incompatibility as potential mechanisms of resisting introgression and maintaining species boundaries. Additionally, no large X‐effect was found in these introgression events. Hybridization between deeply diverged amphibian species may be common, but detectable introgressions are likely less so, with recent introgression being mostly neutral and the rare ancient one potentially adaptive. Our findings complement recent genomic work, and together they provide a better understanding of the genomic characteristics of interspecific introgression and its significance in species adaptation and evolution. [ABSTRACT FROM AUTHOR]

Copyright of Forensic Science & Technology is the property of Institute of Forensic Science, Ministry of Public Security and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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]

Discoveries of new species can greatly impact our understanding of the biogeography of a region. For example, groups of amphibian lineages restricted to the Afrotemperate forests of Tanzania and Ethiopia are indicative of a shared biogeographical history of this highly discontinuous ecosystem. Curiously, many of these lineages are absent from the geographically intermediate Kenyan highlands. This phylogeographical interval is generally considered to be attributable to the younger, volcanic origins of much of the Kenyan highlands, and thus an amphibian fauna that is derived largely from recent colonization events rather than comprising older relicts. Contrasting with this view, here we report on the discovery of a single specimen of Bufonidae (true toad) from Mount Kenya. The specimen belongs to a species new to science and deserves recognition at the generic level owing to its notable molecular phylogenetic and morphological divergences from other described taxa. It is most closely related to the Tanzanian genera Churamiti and Nectophrynoides. The discovery of this new toad and its association with Afrotemperate species is significant because it links Kenya to the biogeographically more ancient Tanzanian mountains and supports the potential longevity of the Afrotemperate forests in Kenya. Broadly, it highlights that we are still adding major branches to the phylogeny of anurans. [ABSTRACT FROM AUTHOR]

Elaborate visual signals play a crucial role in communication between many breeding animals, often evolving through female mate choice and male-male competition. Neotropical Yellow Toads (Incilius luetkenii) exhibit a temporary elaborate visual trait during their brief annual mating events, transitioning from a drab, female-like brown coloration to a vibrant lemon-yellow. They engage in scramble competition, where males physically compete with both lone and amplectant males for access to females. Previous studies suggest that male color may serve as a sex identification signal in the toads' large breeding aggregations, and that females do not appear to choose males based on color. In this study we investigated whether variation in male coloration functions as an intrasexual signal during male-male interactions. Using realistic robotic model toads in a two-choice arena, we addressed two questions. First, do male Yellow Toads respond differently to a lone male versus a male in amplexus with a female when both males are the same color? Secondly, do male Yellow Toads respond differently to two amplectant males varying in the brightness of their yellow coloration? Males approached the amplectant pair nearly twice as often as the lone male, although this pattern was not statistically significant. Males did not exhibit a differential reaction to bright amplectant males versus dull amplectant males. Therefore, variation in male yellow color and the presence of a female do not appear to influence male-male competitive behavior. Overall, this study contributes to our understanding of temporary color change in vibrantly colored anuran species. [ABSTRACT FROM AUTHOR]

We present genome assemblies for 18 snake species representing 18 families (Serpentes: Caenophidia): Acrochordus granulatus , Aparallactus werneri , Boaedon fuliginosus , Calamaria suluensis , Cerberus rynchops , Grayia smithii , Imantodes cenchoa , Mimophis mahfalensis , Oxyrhabdium leporinum , Pareas carinatus , Psammodynastes pulverulentus , Pseudoxenodon macrops , Pseudoxyrhopus heterurus , Sibynophis collaris , Stegonotus admiraltiensis , Toxicocalamus goodenoughensis , Trimeresurus albolabris , and Tropidonophis doriae. From these new genome assemblies, we extracted thousands of loci commonly used in systematic and phylogenomic studies on snakes, including target-capture datasets composed of ultraconserved elements (UCEs) and anchored hybrid enriched loci (AHEs), as well as traditional Sanger loci. Phylogenies inferred from the two target-capture loci datasets were identical with each other and strongly congruent with previously published snake phylogenies. To show the additional utility of these non-model genomes for investigative evolutionary research, we mined the genome assemblies of two New Guinea island endemics in our dataset (S. admiraltiensis and T. doriae) for the ATP1a3 gene, a thoroughly researched indicator of resistance to toad toxin ingestion by squamates. We find that both these snakes possess the genotype for toad toxin resistance despite their endemism to New Guinea, a region absent of any toads until the human-mediated introduction of Cane Toads in the 1930s. These species possess identical substitutions that suggest the same bufotoxin resistance as their Australian congenerics (Stegonotus australis and Tropidonophis mairii) which forage on invasive Cane Toads. Herein, we show the utility of short-read high-coverage genomes, as well as improving the deficit of available squamate genomes with associated voucher specimens. [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]

Apex predators play critical ecological roles, making their conservation a high priority. In tropical Australia, some populations of freshwater crocodiles (Crocodylus johnstoni) have plummeted by greater than 70% due to lethal ingestion of toxic invasive cane toads (Rhinella marina). Laboratory-based research has identified conditioned taste aversion (CTA) as a way to discourage consumption of toads. To translate those ideas into landscape-scale management, we deployed 2395 baits (toad carcasses with toxin removed and containing a nausea-inducing chemical) across four gorge systems in north-western Australia and monitored bait uptake with remote cameras. Crocodile abundance was quantified with surveys. Free-ranging crocodiles rapidly learned to avoid toad baits but continued to consume control (chicken) baits. Toad invasion at our sites was followed by high rates of crocodile mortality (especially for small individuals) at a control site but not at nearby treatment sites. In areas with high connectivity to other waterbodies, repeated baiting over successive years had continuing positive impacts on crocodile survival. In summary, we succeeded in buffering the often-catastrophic impact of invasive cane toads on apex predators. [ABSTRACT FROM AUTHOR]

Persistent individual variation in behaviour, or 'personality', is a widespread phenomenon in animals, and understanding the evolution of animal personality is a key task of current biology. Natural selection has been proposed to promote the integration of personality with animal 'intrinsic states', such as metabolic or endocrine traits, and this integration varies with ecological conditions. However, these external ecological modulatory effects have rarely been examined. Here, we investigate the effects of thermal acclimation on between-individual covariations between physiology and behaviour in Asiatic toads (Bufo gargarizans) along an altitudinal gradient. Our results reveal that the thermal modulatory effects on the covariations depend on the altitudinal population. Specifically, at low altitudes, between-individual covariations are highly plastic, with risk-taking behaviour covarying with baseline glucocorticoids (GCs) under warm acclimation, but risk-taking and exploration behaviour covarying with resting metabolic rate (RMR) under cold acclimation. In contrast, between-individual covariations are relatively fixed at high altitudes, with risk-taking behaviour consistently covarying with baseline GCs. Furthermore, at low altitudes, changes in covariations between RMR and personality are associated with adjustment of energy management models. Evidently, animal physiological states that determine or covary with personality can adapt according to the seasonal thermal environment and the thermal evolutionary background of populations. Our findings highlight the importance of a multi-system physiological approach to understand the evolution of animal personality. [ABSTRACT FROM AUTHOR]

Environmental temperature strongly influences the adaptation dynamics of amphibians, whose limited regulation capabilities render them susceptible to thermal oscillations. A central element of the adaptive strategies is the transcription factors (TFs), which act as master regulators that orchestrate stress responses, enabling species to navigate the fluctuations of their environment skillfully. Our study delves into the intricate relationship between TF expression and thermal adaptation mechanisms in the Rhinella spinulosa populations. We sought to elucidate the dynamic modulations of TF expression in prometamorphic and metamorphic tadpoles that inhabit two thermally contrasting environments (Catarpe and El Tatio Geyser, Chile) and which were exposed to two thermal treatments (25 °C vs. 20 °C). Our findings unravel an intriguing dichotomy in response strategies between these populations. First, results evidence the expression of 1374 transcription factors. Regarding the temperature shift, the Catarpe tadpoles show a multifaceted approach by up-regulating crucial TFs, including fosB, atf7, and the androgen receptor. These dynamic regulatory responses likely underpin the population's ability to navigate thermal fluctuations effectively. In stark contrast, the El Tatio tadpoles exhibit a more targeted response, primarily up-regulating foxc1. This differential expression suggests a distinct focus on specific TFs to mitigate the effects of temperature variations. Our study contributes to understanding the molecular mechanisms governing thermal adaptation responses and highlights the resilience and adaptability of amphibians in the face of ever-changing environmental conditions. [ABSTRACT FROM AUTHOR]

Boulenophrys sangzhiensis and Boulenophrys tuberogranulata, two narrow‐distributed toad species within the Megophryidae family in southern China, are experiencing population declines due to habitat loss and degradation. Despite their critical conservation status, the two species remain largely overlooked in public and scientific spheres. This study presented the first sequencing, assembly, and annotation of the complete mitogenomes of both species using next‐generation sequencing. The mitogenome of B. sangzhiensis was 16,950 bp, while that of B. tuberogranulata was 16,841 bp, each comprising 13 protein‐coding genes (PCGs), 22 transfer RNA genes (tRNAs), two ribosomal RNA genes (rRNAs), and a noncoding control region (D‐loop). The gene content, nucleotide composition, and evolutionary rates of each mitogenome were analyzed. Both mitogenomes exhibited negative AT skew and GC skew with high A + T content. ATP8 exhibited the highest evolutionary rate, while COI had the lowest. A phylogenetic analysis based on 28 mitogenomes revealed two major clades of Megophryidae, supporting the classification of two subfamilies, Megophryinae and Leptobrachiinae. Within the subfamily Megophryinae, the genus Boulenophrys was divided into two species groups. Intriguingly, despite coexisting in Zhangjiajie City, B. sangzhiensis and B. tuberogranulata exhibited distinct origins from the two different species groups, underscoring the unique role of the coexisting area Zhangjiajie in driving their speciation and preserving their current populations. A parallel pattern was also identified in the Leptobrachiinae genus Leptobrachium within the same region. This study provided valuable data references and enhanced our understanding of the molecular characteristics of these threatened amphibian species. [ABSTRACT FROM AUTHOR]

During the last decades several miniaturized frogs have been described from different parts of the world. Those frogs, measuring less than 25 mm, show similar miniaturization features as the loss of phalanges in both the anterior and posterior limbs and the reduction of bone elements. However, there seems to be a limit regarding the minimum size of frogs and here we wanted to find an answer to the question: which is the smallest amphibian in the world? In 2019, an endemic species of toad known only from two localities in southern Bahia, Brazil, was studied. When we compared the size of adult representatives of this species with those of other species discovered in various parts of the world in the last decade, we observed that individuals of Brachycephalus pulex are the amphibians with the smallest total length recorded, thus qualifying them to bear the title of the tiniest anuran amphibian, and also tiniest vertebrate in the world. [ABSTRACT FROM AUTHOR]

Documenting changes in the distribution and abundance of a given taxon requires historical data. In the absence of long-term monitoring data collected throughout the range of a taxon, conservation biologists often rely on preserved museum specimens to determine the past or present, putative geographic distribution. Distributional data for the Houston Toad (Anaxyrus houstonensis) has consistently been confounded by similarities with a sympatric congener, the Dwarf American Toad (A. americanus charlesmithi), both in monitoring data derived from chorusing surveys, and in historical data via museum specimens. In this case, misidentification can have unintended impacts on conservation efforts, where the Houston Toad is federally endangered, and the Dwarf American Toad is of least concern. Previously published reports have compared these two taxon on the basis of their male advertisement call and morphological appearance, often with the goal of using these characters to substantiate their taxonomic status prior to the advent of DNA sequencing technology. However, numerous studies report findings that contradict one another, and no consensus on the true differences or similarities can be drawn. Here, we use contemporary recordings of wild populations of each taxon to test for quantifiable differences in male advertisement call. Additionally, we quantitatively examine a subset of vouchered museum specimens representing each taxon to test previously reported differentiating morphometric characters used to distinguish among other Bufonids of East-Central Texas, USA. Finally, we assemble and qualitatively evaluate a database of photographs representing catalogued museum vouchers for each taxon to determine if their previously documented historic ranges may be larger than are currently accepted. Our findings reveal quantifiable differences between two allopatric congeners with respect to their male advertisement call, whereas we found similarities among their detailed morphology. Additionally, we report on the existence of additional, historically overlooked, museum records for the Houston Toad in the context of its putative historic range, and discuss errors associated with the curation of these specimens whose identity and nomenclature have not been consistent through time. These results bookend decades of disagreement regarding the morphology, voice, and historic distribution of these taxa, and alert practitioners of conservation efforts for the Houston Toad to previously unreported locations of occurrence. [ABSTRACT FROM AUTHOR]

Copyright of Ege Journal of Fisheries & Aquatic Sciences (EgeJFAS) / Su Ürünleri Dergisi is the property of Ege Journal of Fisheries & Aquatic Sciences (EgeJFAS) / Su Urunleri Dergisi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Understanding how age and body size vary across elevations can provide insights into the evolution of life‐history traits in animals. In the present study, we compared the demographic (using skeletochronology) and morphological traits of the Tibetan toad (Bufo tibetanus) between two populations from different elevational habitats (2650 vs. 3930 m). We found that (1) the mean age and body size of females were significantly greater than those of males in both populations; (2) both sexes of toads from the higher elevation tended to be significantly older in age and larger in body size; (3) there was a significant positive relationship between age and body size within each sex of the toad at both elevations; and (4) growth rates varied between the two populations, with the higher rate observed in the lower‐elevation population. Our results suggested that factors other than age, such as elevation‐associated temperature, influence the observed differences in body size between the two populations. Future research at a broader range of elevations should focus on these factors and evaluate their influence on animal growth patterns. [ABSTRACT FROM AUTHOR]

Herpetofauna are globally declining but often overlooked in conservation efforts. Since many herpetofauna are susceptible to localized road mortality, we develop the first North American herpetofauna roadkill models to inform conservation planning. The iNaturalist Roadkills of Texas database is employed to develop and compare ensembles of feature-selected MaxEnt species distribution models (SDMs) and kernel density estimate models (KDEMs) of roadkill, including broad-taxa models (btSDMs and btKDEMs) of combined Texas herpetofauna, and single-species models for the state threatened Texas Horned Lizard (Phrynosoma cornutum) and common generalist Gulf Coast Toad (Incilius nebulifer). We also novelly evaluate cross-taxa roadkill models (ctSDMs; ctKDEMs) using both broad-taxa (bctSDMs; bctKDEMs) and single-species (sctSDMs; sctKDEMs) models, assessing how well models for one taxa project sympatric roadkill of individual species, including two rare herpetofauna with insufficient data for modeling: the state threatened Texas Tortoise (Gopherus berlandieri) and federally endangered Houston Toad (Anaxyrus houstonensis). Texas herpetofauna MaxEnt roadkill btSDMs and Texas Horned Lizard roadkill SDMs both outperformed corresponding poor accuracy KDEMs. Gulf Coast Toad MaxEnt roadkill SDMs and KDEMs had poor accuracy, but KDEMs had lower complexity. Texas herpetofauna roadkill bctSDMs had excellent and significantly highest accuracy in projecting cross-taxa roadkill for the Texas Horned Lizard and Texas Tortoise. Texas herpetofauna roadkill bctSDMs also best projected Houston Toad roadkill. Important MaxEnt SDM variables included distance to residential roads, human population density, percent cover developed open space, and live herpetofauna KDE. Texas herpetofauna bctSDMs can guide further roadkill surveys needed to improve models and develop mitigation plans for herpetofauna conservation. [ABSTRACT FROM AUTHOR]

Sartre's character Roquentin seeing his hand as a crab is analogous in some ways to Nietzsche dreaming a toad on his transparent hand. Examining both of these envisioned animals as metaphors reveals that each represents some sort of physical or psychological disease or pestilence, that each profoundly disturbs the status quo, and that each point in a different way toward suicide, but at the same time that each signifies or symbolizes a deepening of self-knowledge. Both Nietzsche and Roquentin rejected suicide, but for different reasons: the former because he wished to remain in control of his life by consciously accepting his fate, no matter how repulsive it might be; the latter because he was too apathetic and despondent to care whether he lived or died. The purpose of this article is to suggest why depressed, suicidal people might reject suicide. [ABSTRACT FROM AUTHOR]

The Rio Pescado stubfoot toad (Atelopus balios) is a critically endangered member of the struggling Atelopus genus which has been ravaged by the fungal pathogen Batrachochytridium dendrobatidis. Captive management of this species is crucial to improve survival outcomes in their native range in Ecuador. Here, we talk about reproductive successes with A. balios at The Dallas World Aquarium, which represents the first successful reproduction of this species outside of Ecuador. We document five clutches of eggs that were deposited in the adult breeding tank and the developmental rates of the offspring. We also provide observations on husbandry regimes that support the recovery of the females' postdeposition along with observed time between reproductive events for females. We also document the habitat requirements of the adults of the species and the offspring with notes on feeding practices once toadlets emerge from the water. Documentation on the reproduction of Atelopus species is critical to understanding habitat preferences and cues needed to influence reproduction in the wild and thus give insights into the path of captive propagation in the conservation of the focal species. [ABSTRACT FROM AUTHOR]

With the global population on the rise, an escalating interest exists in environmentally sustainable and friendly protein sources. Insects have emerged as multifaceted resources, viewed not only as potential food items, but also as sources of traditional medicines and proteins. This study utilized response surface methodology (RSM) to ascertain the optimal extraction conditions for proteins from Musca domestica used in toad feeding, denoted as MDPs-T. The yield of MDPs-T was elevated to 18.3% ± 0.2% under these optimized conditions. Subsequently, the particle size, ζ-potentials, and structures of MDPs-T were analyzed and compared with the proteins derived from Musca domestica fed on a normal diet (MDPs-ND). This comparative analysis utilized a range of advanced techniques, involving UV spectroscopy, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), high-performance gel permeation chromatography (HPGPC), and scanning electron microscopy (SEM). The outcomes have revealed a marginal disparity in the physical and chemical properties between MDPs-T and MDPs-ND. Derosination led to a reduction in the particle size of the MDPs by 10.98% to 62.81%. MDPs-T exhibited a higher proportion of low-molecular-weight components relative to MDPs-ND. Additionally, in a comparative analysis of amino acids, MDPs-T displayed a greater abundance of essential and total amino acids relative to MDPs-ND. Consequently, MDPs-T holds potential as a valuable food supplement for human consumption or as a nutrient-rich feed supplement for animals. [ABSTRACT FROM AUTHOR]

Understanding why some small populations succeed while others fail to establish in novel environments has major implications in applied fields such as in situ species conservation and reintroductions. Species introductions outside their native range provide excellent opportunities to address such topic, since invasions usually start with small populations. We studied the life-history strategy of a population of the fire-bellied toad (Bombina bombina) introduced in France, outside the natural range of the species, to estimate its population demographic potential. The introduced population showed a fast life history strategy, with early sexual maturation at 2 years of age, a relatively short life-span (3.1 years in females and 2.3 in males, with a maximum age of 5 years), and survival rates similar to those of populations from its native range. The population presents the characteristics for becoming invasive and might pose a threat to the native yellow-bellied toad (B. variegata) populations nearby through hybridization, competition and as potential vector of pathogens and parasites. Its spread should be closely monitored and additional introductions avoided to limit its potential negative impact. [ABSTRACT FROM AUTHOR]

Individual recognition during fieldwork is necessary when estimating the size of a population for conservation or management purposes. We used a non-invasive method of individual photo identification based on dorsal color patterns. Our study aimed to estimate the size of two green toad Bufotes viridis populations in an urban habitat to provide input for conservation activities. The study was conducted in the two largest known breeding sites of the species in Poznań, Western Poland: Cytadela Park (PC) and Rataje Park (PR). We collected animals within each site's breeding habitat twice during the mating season. Dorsal pattern photographs and morphometric measurements were taken, after which the animals were released immediately. We analyzed the pictures by single-eye matching to estimate the population size using the Chapman estimator. Most individuals caught were males, and no females were recaptured. Therefore, we used only data for males and then estimated the total population size based on a calculation using the sex ratio known from the literature. The number of captured toads was higher at the PC site than at the PR site. Toads from the PC population were noticeably larger and had higher condition value indices than those from the PR population. This result is consistent with the management and history of both sites. We observed habitat transition and potential mortality due to park construction the year before our study at the PR site. In contrast, the PC site is a mature green area with more than 50 years of stable management. Despite some limitations, photo-identification may be an essential first step in estimating population size in community-based conservation initiatives for the green toad, enabling conservationists to enter the public discussion about urban conservation, providing a reference for the conservation value of urban breeding sites, and as a consequently, providing input for active conservation and habitat management (e.g., fish removal and mowing regime modifications). [ABSTRACT FROM AUTHOR]

A new species of the genus Boulenophrys is described from the coastal hills of eastern Fujian Province, China. The new taxon can be distinguished from all recognized congeners by a combination of discrete morphological character state differences and genetic divergences in the combined mitochondrial 16S + CO1 genes. We also provide a map showing the distribution pattern of Boulenophrys species in Fujian and a provincial-specific key, which will aid their conservation by helping the local authorities accurately identify species during field identifications and data collection efforts. [ABSTRACT FROM AUTHOR]

Background Skin secretions of toads are widely used in medicine all over the world for their antiviral, anti-infective, and cardiotonic properties. Because these secretions are mostly employed to combat blood parasite infection, it is important to understand their potential toxic effects on human erythrocytes. Therefore, the objective of the current investigation was to elucidate the effects of Duttaphrynus melanostictus (Schneider) skin extracts on the physiology of human erythrocytes. Methods Toads captured from their natural habitat were separated into three groups according to their body size. Hydroalcoholic extracts of toad skin were prepared by reflux heating. These extracts were then evaluated for their hemolytic and hemoglobin denaturation potential. The effects of the extracts on cytosolic and membrane-bound enzymes of human erythrocytes were assessed. Results The hemolysis and hemoglobin denaturation caused by these extracts correlated positively with the respective toad sizes. Extracts from medium and large toads led to increased osmotic fragility even at near iso-osmotic concentrations. Biochemical analysis of hemolysate showed that the treatment induced a shift of metabolic flux toward the glutathione pathway. Analysis of membrane-bound enzymes revealed a significant decrease in the activity of Na+/K+ ATPase and acetylcholinesterase. SDS-PAGE analysis of the erythrocyte membrane did not show the band of tropomodulin for the cells treated with 1000 휇g/ml extract from large toads. Conclusions In conclusion, the present study demonstrates that the toxicity of toad skin secretions aggravates with the size of the animal and interferes with the physiology of human erythrocytes, leading to their membrane disruption and rapid lysis. [ABSTRACT FROM AUTHOR]

The Arizona Toad (Anaxyrus microscaphus) is restricted to riverine corridors and adjacent uplands in the arid southwestern United States. As with numerous amphibians worldwide, populations are declining and face various known or suspected threats, from disease to habitat modification resulting from climate change. The Arizona Toad has been petitioned to be listed under the U.S. Endangered Species Act and was considered "warranted but precluded" citing the need for additional information – particularly regarding natural history (e.g., connectivity and dispersal ability). The objectives of this study were to characterize population structure and genetic diversity across the species' range. We used reduced-representation genomic sequencing to genotype 3,601 single nucleotide polymorphisms in 99 Arizona Toads from ten drainages across its range. Multiple analytical methods revealed two distinct genetic groups bisected by the Colorado River; one in the northwestern portion of the range in southwestern Utah and eastern Nevada and the other in the southeastern portion of the range in central and eastern Arizona and New Mexico. We also found subtle substructure within both groups, particularly in central Arizona where toads at lower elevations were less connected than those at higher elevations. The northern and southern parts of the Arizona Toad range are not well connected genetically and could be managed as separate units. Further, these data could be used to identify source populations for assisted migration or translocations to support small or potentially declining populations. [ABSTRACT FROM AUTHOR]

Kin recognition has been selected by natural selection because it can enhance the chances of cooperation among close relatives, but it could also be an accidental consequence of other life-history processes. In this study, we carried out experiments by using Asiatic toad tadpoles (Bufo gargarizans) to evaluate the hypothesis that: (1) individuals can use waterborne chemical cues or combine other possible cues to communicate kinship identity when exposed to kin during early ontogeny; (2) unfamiliar siblings (or familiar non-siblings) should have similar growth with unfamiliar non-siblings because the former is not able to identify their relatives (or may not consider familiar non-siblings as kin); (3) the familiar siblings may obtain a more equal resource share in populations of siblings, thus size variation is weak. The first and second predictions were partially better supported: kinship had a positive effect on tadpole growth, obtained larger mass at metamorphosis, and increased survival, but development time was longer than that of unfamiliar non-siblings. Further, the growth of unfamiliar siblings and familiar non-siblings was different from that of familiar siblings, suggesting that Asiatic toad tadpoles lose kin-recognition ability when isolated across the embryonic stage or may not be considered as siblings when exposed to water from non-sibling groups during early embryonic development. Thus, besides chemical cues, Asiatic toad tadpoles need to combine other possible modalities to communicate kinship identity. The third prediction was supported weakly. Therefore, our results suggest that exposure to kin during early embryonic development is essential for altering kin-recognition ability. More importantly, familiar sibling groups can be expected to develop slower and spend more time in the water, allowing more time for feeding and growth, which is consistent with kin selection theory, suggesting that natural selection should drive the evolution of mechanisms that minimize the competitive intensity between sibling groups. [ABSTRACT FROM AUTHOR]

Research on amphibian parasites has been on the increase because of the noticeable decline of amphibians. Studies on these parasites have been limited to their prevalence and infection patterns, and there is still a dearth of knowledge on the phenotypic variations. To characterise and investigate the genetic variability and relatedness of amphibian nematode parasites, two nematode parasites–suspected Cosmocerca sp. and suspected Rhabdias sp.–of the toad Schlerophrys regularis were investigated. One hundred and sixty-eight S. regularis were collected from three study areas: Ikorodu, Ojota and Badagry. Intestines were dissected to obtain the enteric parasites, and lungs were washed in saline solution. Parasites were labelled according to the location of collection (Badagry 5A-5I, Ikorodu 5J–5O, Ojota 5P and 5S) and were then preserved for further identification. Eighteen parasites were identified morphologically using standard keys and by amplification of the 18S small subunit (SSU) ribosomal DNA sequence. Phylogenetic analysis was done using the Neighbour-Joining method. From the sequence homology and phylogenetic analysis, the suspected Cosmocerca sp. shared the closest genetic relatedness with Aplectana chamaeleonis isolate AC3 with 100% similarities while the suspected Rhabdias sp. shared the closest genetic relatedness with Rhabditoides regina isolate DF5012 with 100% similarities. Based on location, four Aplectana chamaeleonis (5E, 5F, 5G, 5H) and five Rhabditoides regina (5A, 5B, 5C, 5D, 5I) were from Badagry, four Aplectana chamaeleonis (5J, 5M, 5N, 5O) and two Rhabditoides regina (5K, 5L) from Ikorodu, one Aplectana chamaeleonis (5S) and two Rhabditoides regina (5P, 5Q) from Ojota. We report that Rhabditoides regina, a parasite known to be associated with insects, was recovered in the lungs of toads. Further investigations to resolve the complexities of superfamily Cosmocercoidea are recommended. Relatedness was not influenced by collection location as parasites were not unique to a specific environment. [ABSTRACT FROM AUTHOR]

We present the first record of interspecific amplexus between Rhinella horribilis and Incilius coniferus in the surroundings of a natural water pond in the Mamoní Valley Preserve Center, Chepo District, Eastern Region of Panama. [ABSTRACT FROM AUTHOR]

Many organisms facultatively produce different phenotypes depending on their environment, yet relatively little is known about the genetic bases of such plasticity in natural populations. In this study, we describe the genetic variation underlying an extreme form of plasticity––resource polyphenism––in Mexican spadefoot toad tadpoles, Spea multiplicata. Depending on their environment, these tadpoles develop into one of two drastically different forms: a carnivore morph or an omnivore morph. We collected both morphs from two ponds that differed in which morph had an adaptive advantage and performed genome-wide association studies of phenotype (carnivore vs. omnivore) and adaptive plasticity (adaptive vs. maladaptive environmental assessment). We identified four quantitative trait loci associated with phenotype and nine with adaptive plasticity, two of which exhibited signatures of minor allele dominance and two of which (one phenotype locus and one adaptive plasticity locus) did not occur as minor allele homozygotes. Investigations into the genetics of plastic traits in natural populations promise to provide novel insights into how such complex, adaptive traits arise and evolve. [ABSTRACT FROM AUTHOR]

Even after research identifies new approaches for wildlife management, translating those methods for delivery can be logistically challenging. In tropical Australia, invasive cane toads (Rhinella marina) fatally poison many anuran‐eating native predators. Small‐scale trials show that vulnerable predators exposed to small (nonlethal) toads can learn to delete toads from their diets, increasing survival of those predators after toads invade. We deployed this method in the remote Kimberley region of tropical Australia, with >200,000 eggs, tadpoles, or metamorph toads released in advance of the expanding toad invasion front. Remote camera surveys before and after "teacher toad" deployment showed that large monitor lizards (Varanus panoptes) were almost extirpated from control plots but remained abundant in treatment plots, indicating broad‐scale success of this novel intervention. [ABSTRACT FROM AUTHOR]

Disease monitoring of amphibian assurance populations is an important buffer against ongoing global extinctions. This study documents a high incidence of neoplasia in a zoo-managed assurance population of Puerto Rican crested toads (Peltophryne lemur ; PRCTs). Over 5 years, neoplasia was diagnosed in 17/49 (35%) submitted adult PRCTs and was the cause of death or euthanasia in 13/17 (72%). Most toads were male (16/17; 94%) and 6 to 11-years-old (average 8.1 years). Notably, seven toads (41%) had multiple neoplasms. Of the 29 neoplasms identified, 17 (59%) were cutaneous or subcutaneous. The most common neoplasms included mast cell tumors (MCTs; 8/29; 28%), histiocytic sarcomas (6/29; 21%), lymphoma/leukemia (4/29; 14%), and squamous cell carcinomas (3/29; 10%). Distant metastases were documented in 6/8 (75%) toads with MCTs. Causes for neoplasia in this population were not determined though may include genetic or environmental factors. Continued investigations of managed endangered amphibians will help elucidate mechanisms of carcinogenesis. [ABSTRACT FROM AUTHOR]

Recent phylogenetic studies in Himalayan lazy toads of the genus Scutiger Theobald, 1868 revealed the presence of genetically deeply divergent lineages. The taxonomy of S. nepalensis sensu lato was re-assessed based on museum material considering molecular and morphological data. The results strongly support the recognition of a new species, S. kanjiroba sp. nov. distributed along the Nepalese Kanjiroba massif. It is further shown that S. sikimmensis has an apparently much more restricted distribution range than previously thought. The frequent misidentification of Scutiger across large areas of the Himalaya-Tibet area highlights the significance of careful taxonomic evaluation of collection material and the need for the direct morphological comparison of closely related species when describing new species. [ABSTRACT FROM AUTHOR]

A key component of amphibian antipredator strategies is the chemical defenses that make them toxic and/or distasteful, like the cardiotoxic bufadienolides synthesized by the true toads and stored in granular skin glands. The morphology of adult toad glands is well-described, but the ontogenetic timing and distribution of glands during larval stages are poorly understood. A comparative understanding of granular gland development is needed to elucidate the mechanisms underlying the diversification of toad chemical defenses and their ecological roles across lineages and ontogeny. Herein, we analyzed gland morphology before and after metamorphosis of Rhinella horribilis, Incilius melanochlorus, and I. luetkenii. We hypothesized that granular gland development would begin earlier and progress faster in relatively more toxic Rhinella species. Our results showed that the timeline of skin development, the relative dimensions and quantity of structures, and the appearance of protein and mucin content in granular and mucous glands did not vary among Rhinella and Incilius. Furthermore, epidermal mucus and/or giant cells in larval toads may act as sources of chemical defenses prior to gland development. Our findings suggest that gland development is well-conserved among these genera; it is possible that reported differences in toxin profiles are not due to divergent morphogenesis during larval or metamorphic stages, but rather to differences in molecular function or structural differentiation in juveniles or adults. Therefore, complementary studies using integrative techniques such as immunohistochemistry and comparative transcriptomics are needed to uncover the mechanisms responsible for the diversity of chemical defenses found in bufonid toads across development. [ABSTRACT FROM AUTHOR]

Vocal communication plays an important role in survival, reproduction, and animal social association. Birds and mammals produce complex vocal sequence to convey context-dependent information. Vocalizations are conspicuous features of the behavior of most anuran species (frogs and toads), and males usually alter their calling strategies according to ecological context to improve the attractiveness/competitiveness. However, very few studies have focused on the variation of vocal sequence in anurans. In the present study, we used both conventional method and network analysis to investigate the context-dependent vocal repertoire, vocal sequence, and call network structure in serrate-legged small treefrogs Kurixalus odontotarsus. We found that male K. odontotarsus modified their vocal sequence by switching to different call types and increasing repertoire size in the presence of a competitive rival. Specifically, compared with before and after the playback of advertisement calls, males emitted fewer advertisement calls, but more aggressive calls, encounter calls, and compound calls during the playback period. Network analysis revealed that the mean degree, mean closeness, and mean betweenness of the call networks significantly decreased during the playback period, which resulted in lower connectivity. In addition, the increased proportion of one-way motifs and average path length also indicated that the connectivity of the call network decreased in competitive context. However, the vocal sequence of K. odontotarsus did not display a clear small-world network structure, regardless of context. Our study presents a paradigm to apply network analysis to vocal sequence in anurans and has important implications for understanding the evolution and function of sequence patterns. [ABSTRACT FROM AUTHOR]

We studied the effect of antibiotic gentamicin at concentrations of 0.05, 0.1, 0.2, 0.4, and 1 mg/ml on the maintenance of sperm motility of the common toad Bufo bufo during cold storage of spermic urine samples at 4°C. Parameters of sperm motility during storage of samples with gentamicin at concentrations of 0.05-0.4 mg/ml did not differ significantly, but were higher (p<0.0001) than in the control (storage without antibiotic). Gentamicin at a concentration of 1 mg/ml had a negative effect on sperm motility. After 2 weeks of storage of toad spermic urine samples with gentamicin, the largest number of sperm was preserved when using antibiotic at a concentration of 0.4 mg/ml. [ABSTRACT FROM AUTHOR]

Agrochemicals cause diverse effects on aquatic communities, and amphibian species are particularly threatened due the high susceptibility to contamination. Present study evaluates the toxicity of a widely used fungicide tebuconazole (Trigal®) by the assessment of mortality and developmental alterations at acute, subchronic, and chronic exposure during the embryo‐larval development of the South American toad Rhinella arenarum. Also, the sensitivity of the different embryonic stages was evaluated with 24‐h pulse exposure treatments. The results demonstrated that larvae were more sensitive than embryos at acute exposure (LC50‐24 and 96 h = 74.62, 31.92 mg/L and 24.27, 16.81 mg/L for embryos and larvae, respectively). Nevertheless, embryos toxicity increased significantly achieving a sensitivity very similar to larvae at chronic exposure (LC50‐168 and 504 h = 13.31, 4.35 mg/L and 14.47, 6.83 mg/L for embryos and larvae, respectively). Embryos exhibited several sublethal effects from 5 mg/L at 96 h onwards, such as delayed development, reduce body size, edemas, tail/axial flexures, weakness, and absence of movements. The teratogenic index at 96 h was 10.13, indicating the severe teratogenic potential of the fungicide. 24‐h pulse exposure treatments showed an increased sensitivity in intermediate stages as S.11, S.18, S20, and S.23 (NOEC‐96 h = 100, 200, 75, and 20 mg/L, respectively), while stage S.25 was the most sensitive to the fungicide (NOEC‐96 h = 5 mg/L). About metamorphic process, tebuconazole caused an acceleration of metamorphosis at the lowest concentration (0.001 mg/L), but also an increase in mortality and in addition, significant differences in the weight in all treatments. The results obtained throughout this work indicate that tebuconazole cause several adverse effects in Rhinella arenarum embryo‐larval development. [ABSTRACT FROM AUTHOR]

Batrachochytrium dendrobatidis (Bd) is a lethal fungal species that parasitizes vertebrates and is associated with the worldwide decline of amphibian populations. The development of sensitive, rapid detection methods, particularly DNA-based techniques, is critical for effective management strategies. This study evaluates the efficacy of DNA extraction and a portable PCR device in a mountable field laboratory setup for detecting Bd near the habitats of three critically endangered Atelopus toad species in Ecuador. We collected skin swabs from Atelopus balios, A. nanay, and A. bomolochos, and environmental DNA (eDNA) samples from streams in Andean and coastal regions of Ecuador. For eDNA, a comparison was made with duplicates of the samples that were processed in the field and in a standard university laboratory. Our findings revealed Bd detection in eDNA and swabs from 6 of 12 water samples and 10 of 12 amphibian swab samples. The eDNA results obtained in the field laboratory were concordant with those obtained under campus laboratory conditions. These findings highlight the potential of field DNA-based monitoring techniques for detecting Bd in amphibian populations and their aquatic habitats, particularly in remote areas. Furthermore, this research aligns with the National Action Plan for the Conservation of Ecuadorian Amphibians and contributes to the global effort to control this invasive and deadly fungus. [ABSTRACT FROM AUTHOR]

Inter-individual variation in antipredatory behaviour has long attracted curiosity among scientists. Deimatism is a complex, multi-component antipredatory strategy consisting of prey suddenly unleashing unexpected defences to startle predators and stop their attack. Deimatic species provide an appealing system to investigate the trade-offs between alternative behavioural phenotypes when faced with a threat. Yet, inter-individual variation in deimatic behaviour is almost unexplored. Here, we simulated a predator attack on 71 yellow-bellied toads, Bombina pachypus , to investigate the extent and pattern of inter-individual variation in the unken reflex behaviour, a deimatic display performed by some amphibians. Results show that deimatic displays consistently differ among B. pachypus individuals. Only about half of the individuals reacted to the simulated predation stimuli by exhibiting the display, which varied in responsiveness, duration and intensity. All the behavioural descriptors were highly repeatable. Finally, we found significant correlations between the measured parameters, defining two prevalent behavioural profiles: individuals quickly doing the unken reflex, with high intensity and long duration of the display, and individuals avoiding the unken reflex but instead escaping. This dichotomy resembles the proactive and reactive patterns in coping styles, and raises intriguing questions on the evolutionary processes shaping multiple adaptive responses to predation within populations. [ABSTRACT FROM AUTHOR]

Density dependent carry-over effects from one life history stage to another can affect the dynamics of populations. Here we study such carry-over effects from the tadpole to the postmetamorphic juvenile stage in an endangered amphibian, the natterjack toad (Epidalea calamita). We raised tadpoles in outdoor aquatic mesocosms at four densities and assessed juvenile performance after metamorphosis in terrestrial mesocosms. High larval density reduced mass at metamorphosis by 50 % and doubled the length of the larval period. Survival was reduced at the high densities. Larger metamorphs had higher survival in terrestrial mesocosms and remained larger than cohort members at the end of the 30-day experiment. Because juvenile survival drives amphibian population dynamics, density-dependent carry-over effects to the juvenile stage are likely to affect population viability. We discuss the implications of the results for amphibian conservation practice, both pond construction programs and surveys of amphibian populations. [ABSTRACT FROM AUTHOR]

Bufadienolides, naturally occurring steroids primarily found in toads, have garnered attention for their pharmacological properties and ecological significance. In this study, we isolated and identified 21 bufadienolides from the gallbladders of Bufo gargarizans, comprising four new compounds and 17 known ones. Notably, the predominance of 15 bufadienolides with a 3α-OH configuration in toad bile differs significantly from the 3β-OH bufadienolides found in venom secreted by toad glands. Moreover, our investigation into the biotransformation of 3β-OH and 3α-OH bufadienolides in the liver and kidney tissues of toads revealed an irreversible conversion from 3β-OH to 3α-OH bufadienolides, suggesting a crucial role in toad self-detoxification. These findings provide valuable insights into the structural diversity of bufadienolides and advance our understanding of their medical and ecological significance. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the acute lethality and chronic sublethal effects of lithium (Li) on Rhinella arenarum tadpoles as model organisms. First a 96 h toxicity assay was performed by exposing tadpoles to Li concentrations from 44.08 to 412.5 mg L−1 to estimate the mortality, and lethal and sublethal effects. Another bioassay was carried out by exposing tadpoles to two environmentally relevant Li concentrations (2.5 and 20 mg L−1) for one and two weeks. The sublethal effects of Li on tadpoles were evaluated by analyzing biochemical, genotoxic, and physiological biomarkers. The mortality in Li-exposed tadpoles increased over time. The median lethal concentration (LC50) ranged from 319.52 (281.21–363.05) mg L−1 at 48 h to 66.92 (52.76–84.89) mg L−1 at 96 h. Exposure to Li at 2.5 and 20 mg L−1 induced alterations in enzymes related to detoxification, antioxidant, and hepatic mechanisms, endocrine disruption of thyroid hormones, genotoxicity, and effects on the physiology of the heart and gastrointestinal systems. Tadpoles exposed to the highest concentration in the chronic bioassay (20 mg L−1 Li), which is the concentration commonly recorded in Li mining sites, showed significant mortality after one week of exposure. These results warn about the high ecotoxicological risk of Li as a contaminant of emerging concern for amphibians. [ABSTRACT FROM AUTHOR]

The genus Rhinella (Bufonidae) comprises 92 species of Neotropical toads. In Colombia, Rhinella is represented by 22 recognized species, of which nine belong to the Rhinella festae group. Over the past decade, there has been increasing evidence of cryptic diversity within this group, particularly in the context of Andean forms. Specimens of Rhinella collected in high Andean forests on both slopes of the Central Cordillera in Colombia belong to an undescribed species, Rhinella kumanday sp. nov. Genetic analyses using the mitochondrial 16S rRNA gene indicated that the individuals belong to the festae species group. However, they can be distinguished from other closely related species such as Rhinella paraguas and Rhinella tenrec by a combination of morphological traits including the presence of tarsal fold, a moderate body size, and substantial genetic divergence in the 16S rRNA gene (> 5%). Through this integrative approach, the specimens from the Central Cordillera of Colombia are considered an evolutionary divergent lineage that is sister to R. paraguas, and described as a new species. Rhinella kumanday sp. nov. is restricted to the Central Cordillera of Colombia inhabiting both slopes in the departments of Caldas and Tolima, in an elevational range between 2420 and 3758 m. With the recognition of this new species, the genus Rhinella now comprises 93 species with 23 of them found in Colombia, and ten species endemic to the country. [ABSTRACT FROM AUTHOR]

The harlequin toads (Bufonidae, Atelopus) from the Cordillera Occidental of Colombia are poorly understood, with several species being known only from few specimens and a single locality. Material from the Yotoco area, Departamento Valle del Cauca, has been addressed in previous studies and was allocated ambiguously to different available names. We here describe the Yotoco Atelopus as a species new to science as it is readily distinguished from all congenerics by a combination of morphological characters (i.e., snout profile, cranial crests, skin texture, pattern and coloration). In addition, we comment on the taxonomy of three Atelopus populations from the Cordillera Occidental and the Cordillera Central of Colombia; two of them we tentatively assign to A. nicefori and A. sonsonensis, respectively. The third one remains of unclear status. The need for further examination of the harlequin toads from the Andes of Colombia in an integrative taxonomic framework is emphasized. [ABSTRACT FROM AUTHOR]

The nuchal glands are organs of chemical defense embedded under the skin of several species of Rhabdophis and contain toxins sequestered from consumed prey. Rhabdophis subminiatus possesses nuchal glands, but not much information is available on its toxin source and prey preference, particularly based on its chemosensory response. We hypothesized that the response of R. subminiatus toward toads would be higher than other potential prey because the snake needs to sequester toxins contained in toad skin. We also examined the snake preference toward several bufonid species to test a hypothesis that the preference toward Duttaphrynus melanostictus is higher than other toad species due to its high availability in the habitat of the snake. To test the hypotheses, we conducted chemical response tests and compared the tongue-flick attack score (TFAS) of the snake toward prey chemical stimuli. The first experiment used only one toad species (D. melanostictus) and various potential prey animals for the source of chemical stimuli. The second experiment used chemical stimuli from several species of frogs and toads. In the first experiment, snakes showed the highest response toward D. melanostictus. However, in the second experiment, snakes showed the highest response toward a toad, Ingerophrynus biporcatus, followed by D. melanostictus, and a lower response toward another toad, Phrynoidis asper. These results indicate that the snake has a high preference toward toads, but its preference varies among toad species. Taken together, this study suggests that R. subminiatus discriminates different potential prey chemical cues and probably consumes toads to sequester their toxins. [ABSTRACT FROM AUTHOR]

Animals use colouration to serve diverse functions including camouflage, thermoregulation, and communication. Recent research has revealed that many anurans exhibit drastic colour changes and growing evidence supports that these changes are sexually selected signals. Male yellow toads, Incilius luetkenii , exhibit dynamic sexual dichromatism, changing from mud-brown to lemon-yellow during their brief breeding events. Toads darken when isolated in captivity, which is hypothesized to be a stress response, although the mechanisms driving this change have yet to be experimentally investigated. We confined breeding toads to small terrariums for four hours and predicted that colour and corticosterone levels would change in isolation. We found that toads darkened during isolation, but that corticosterone levels did not change with colour. Our correlational results suggest that corticosterone is not the main driver of colour change in yellow toads and highlight avenues for future research that may enhance our understanding of colour change in anurans. [ABSTRACT FROM AUTHOR]

Aim: We propose a combined approach to explore the model transferability and the effect of climate change on habitat suitability. Location: Southwest United States. Taxon: Amphibians; Anura; Bufonidae; Anaxyrus microscaphus. Methods: To assess the impacts of climate change on A. microscaphus, we obtained 3162 records from the Arizona Game and Fish Department. We classified occurrence records data into six historical groups (from 1960 to 2018) and a contemporary group (from 2019 to 2022). We investigated the ability of historical data to generate accurate predictions of the species' contemporary distribution. We used species distribution modelling to compute habitat suitability values and identified spatial clusters of high suitability values (using hotspot analyses). Results: We show that historical occurrences successfully predicted the contemporary distribution of A. microscaphus. We demonstrate that the geographical distribution of contemporary hotspots is strongly related to precipitation of the wettest quarter. This research provides evidence that climate change will likely affect the distribution of hotspots and the habitat suitability of A. microscaphus. Losses of 37%–48% contraction are expected at the margins of the range both in the north and south of the geographic limits. Main Conclusions: We show that recent past data can be used to predict contemporary species distribution accurately. We highlight that habitat suitability values of A. microscaphus are strongly related to climate, topography and distance to streams. This study provides clear evidence of the negative impacts of climate change on habitat suitability in the Southwest United States drylands. Our approach has applied utility to managers to target survey areas, monitor habitat changes, plan for conservation mitigation measures, conserve stream flows across the species' range and inform recovery if needed. Thus, managers could use previously collected data to predict contemporary species distribution when their occurrence accurately characterizes the species' ecological niche. [ABSTRACT FROM AUTHOR]

Amphibians are widely known as a prolific source of bioactive metabolites. In this work, we isolated and characterized compounds with antiparasitic activity from the oocytes of the toad Rhinella alata collected in Panama. Bio-guided isolation and structural elucidation were carried out using chromatographic and spectroscopic techniques, respectively. The organic extract was subjected to solid phase extraction followed by HPLC purification of the fraction with in vitro activity against Trypanosoma cruzi trypomastigotes. Seven steroids (1–7) of the bufadienolide family were isolated, and their structures were determined using NMR and MS analyses; of these 19-formyl-dyscinobufotalin, (3) is reported as a new natural product. Compounds 1 and 3–7 resulted in a good anti-trypanosomal activity profile. Among these, 16β-hydroxyl-hellebrigenin (1) and bufalin (7) showed significant selectivity values of >5 and 2.69, respectively, while the positive control benznidazole showed a selectivity of 18.81. Furthermore, molecular docking analysis showed compounds 1, 3 and 7 interact through H-bonds with the amino acid residues GLN-19, ASP-158, HIS-159 and TRP-177 from cruzipain at the catalytic site. Given the lack of therapeutic options to treat American trypanosomiasis, this work can serve as the basis for further studies that aim for the development of bufadienolides or their derivatives as drugs against Chagas disease. [ABSTRACT FROM AUTHOR]

This article discusses the impact of extreme rainfall on the yellow-bellied toad Bombina variegata, an endangered species found in Europe. The toad typically breeds in small ponds, but heavy rain can flush out the tadpoles and even destroy their habitats. The study conducted in southern Poland found that after a torrential downpour, tadpole numbers decreased in all the ponds surveyed, with natural ponds being the most affected. The findings highlight the potential dangers of heavy rainfall on breeding sites and suggest the need for conservation efforts to consider the location of breeding ponds in relation to stream banks and local relief. Additionally, the article emphasizes the potential impact of climate change on the toad's population, as changes in local rainfall patterns can increase the risk of flash floods and further endanger the species. [Extracted from the article]