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We report new locality records for Rhinella kumanday Caicedo-Martínez et al., 2024, a recently described toad species known only from the department of Caldas in the Cordillera Central of Colombia. Based on fieldwork and a review of museum specimens, we document this species’ presence at two localities in the department of Quindío, extending the species’ known distribution approximately 75–80 km south of its type locality. Specimens were found in Andean secondary forests at elevations of 2440–2460 m.

Anuran species are threatened by a range of anthropogenically induced disturbances, highlighting the need for robust and reliable monitoring programs to detect trends in species occupancy. Anuran species experience not only differences in seasonal distributions of breeding activity, but also interannual variations in habitat occupancy which are dependent on stochastic environmental processes. Acoustic calling surveys are a widely used and reportedly reliable technique for detecting a range of anuran species in Southern Ontario. Short-term applications of this technique may be challenged to detect species which are temporarily absent from suitable habitats due to natural extirpation processes. In this paper, I analyzed anuran occupancy data from 67 long-term acoustic monitoring sites across Southern Ontario to determine the relationship between accumulated species occupancy and number of monitoring years. Data was taken from Birds Canada’s Marsh Monitoring Protocol database for amphibians and filtered to extract sites which were monitored for at least 8 years and recorded at least 4 anuran species. Species accumulation curves were created using EstimateS. Results suggest that there may be detectability issues for some species such as the pickerel frog, wood frog, and western chorus frog. Interannual detection rates and species accumulation curves point to the need for long-term (> 5 years) monitoring programs to reliably detect on average more than 90% of anuran species occupying a monitoring site. They also reflect well-documented reports of high species turnover in anuran metapopulations, suggesting that extirpation-recolonization processes are widespread and frequent. Monitoring programs should address this issue by lengthening monitoring programs, particularly those that aim to document changes to species occupancy before and after major habitat disturbances.

Phasmahyla cruzi is an endemic treefrog species from the Brazilian Atlantic Forest for which basic natural history information is still lacking. In this study, we monitored two populations over a 12-month period in Ubatuba, São Paulo, Brazil, to investigate the species’ ecology, home range, and reproductive patterns. We used non-invasive photographic identification combined with minimum convex polygon (MCP) analysis to estimate home ranges. Based on the monthly sampling, we assessed the influence of abiotic factors (temperature and humidity) on activity patterns. We recorded 1,054 adult, 2,142 tadpole, and 22 egg clutch encounters. Males vocalized from September to April and showed territorial behaviour. Reproduction occurred through axillary amplexus, with oviposition on folded leaves suspended over streams. Mean P. cruzi estimated home range was 460 m2, with individuals in higher elevations using significantly larger areas. A positive relationship was found between humidity and both individual abundance and clutch frequency. This study presents the first detailed data on habitat use, reproduction, and spatial ecology of P. cruzi, providing essential information for conservation efforts targeting this poorly known species endemic to the Atlantic Rainforest.

The selection of breeding habitat has broadscale implications for species distributions and community structure and smaller-scale ramifications for offspring survival and parental fitness. In anurans, offspring deposition is a decisionmaking process that involves the assessment of multiple factors at a breeding site, including the presence of predators and competitors. Evolutionary theory predicts that adult anurans should seek to minimize the risk of predation to offspring, reduce the pressure of competition, and maximize offspring survival. Many experimental studies have demonstrated the ability of anurans to assess deposition sites for predation and competition and to choose accordingly, but our understanding of the various ecological factors involved in site choice and the broader consequences of choice is still limited. Here, we review and synthesize the literature on the influence of predators and competitors on anuran deposition behavior. We highlight current gaps in our understanding of this topic and outline future avenues of research.

Amphibian skin is a mucosal surface in direct and continuous contact with a microbially diverse and laden aquatic and/or terrestrial environment. As such, frog skin is an important innate immune organ and first line of defence against pathogens in the environment. Critical to the innate immune functions of frog skin are the maintenance of physical, chemical, cellular, and microbiological barriers and the complex network of interactions that occur across all the barriers. Despite the global decline in amphibian populations, largely as a result of emerging infectious diseases, we understand little regarding the cellular and molecular mechanisms that underlie the innate immune function of amphibian skin and defence against pathogens. In this review, we discuss the structure, cell composition and cellular junctions that contribute to the skin physical barrier, the antimicrobial peptide arsenal that, in part, comprises the chemical barrier, the pattern recognition receptors involved in recognizing pathogens and initiating innate immune responses in the skin, and the contribution of commensal microbes on the skin to pathogen defence. We briefly discuss the influence of environmental abiotic factors (natural and anthropogenic) and pathogens on the immunocompetency of frog skin defences. Although some aspects of frog innate immunity, such as antimicrobial peptides are well-studied; other components and how they contribute to the skin innate immune barrier, are lacking. Elucidating the complex network of interactions occurring at the interface of the frog's external and internal environments will yield insight into the crucial role amphibian skin plays in host defence and the environmental factors leading to compromised barrier integrity, disease, and host mortality.

Although most of the unique ways that frogs reproduce were described in the 1800s and 1900s, additional modes are still being discovered in the 21st Century. The concept of reproductive mode has evolved from descriptive natural history to an integration of developmental biology, genetics, systematics, evolution, ecology, behavior, and physiology that frames our thinking about the transition of vertebrates from water to land and about anuran reproductive adaptations to diverse environments today. We have classified reproductive modes, examined quantitative parameters, searched for geographical and ecological patterns, and described variability. We have speculated about selective pressures guiding the evolution of terrestrial reproduction and argued about the usefulness of reproductive mode as a character to construct phylogenies. In the past, researchers assumed that the reproductive modes exhibited by living frogs represented stages in an incomplete, linear sequence of steps toward greater independence from open water, with direct development at the end of the spectrum. Newly proposed phylogenies based on molecular data allow us to re-think the evolution of anuran reproductive modes. On another level, we are increasingly realizing the value of incorporating life history information (aquatic larvae or terrestrial development) in setting priorities to formulate more effective and ecologically relevant conservation strategies. The next decade is certain to witness significant advances in our understanding of anuran reproductive modes.

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

In bioacoustic recognition approaches, a “flat” classifier is usually trained to recognize several species of anurans, where the number of classes is equal to the number of species. Consequently, the complexity of the classification function increases proportionally with the number of species. To avoid this issue, we propose a “hierarchical” approach that decomposes the problem into three taxonomic levels: the family, the genus, and the species. To accomplish this, we transform the original single-labelled problem into a multi-output problem (multi-label and multi-class) considering the biological taxonomy of the species. We then develop a top-down method using a set of classifiers organized as a hierarchical tree. We test and compare two hierarchical methods, using (1) one classifier per parent node and (2) one classifier per level, against a flat approach. Thus, we conclude that it is possible to predict the same set of species as a flat classifier, and additionally obtain new information about the samples and their taxonomic relationship. This helps us to better understand the problem and achieve additional conclusions by the inspection of the confusion matrices at the three classification levels. In addition, we propose a soft decision rule based on the joint probabilities of hierarchy pathways. With this we are able to identify and reject confusing cases. We carry out our experiments using cross-validation performed by individuals. This form of CV avoids mixing syllables that belong to the same specimens in the testing and training sets, preventing an overestimate of the accuracy and generalizing the predictive capabilities of the system. We tested our methods in a dataset with sixty individual frogs, from ten different species, eight genera, and four families, achieving a final Macro-Fscore of 80 and 70% with and without applying the rejection rule, respectively.

Efforts to draw inferences about species occurrence frequently account for false negatives, the common situation when individuals of a species are not detected even when a site is occupied. However, recent studies suggest the need to also deal with false positives, which occur when species are misidentified so that a species is recorded as detected when a site is unoccupied. Bias in estimators of occupancy, colonization, and extinction can be severe when false positives occur. Accordingly, we propose models that simultaneously account for both types of error. Our approach can be used to improve estimates of occupancy for study designs where a subset of detections is of a type or method for which false positives can be assumed to not occur. We illustrate properties of the estimators with simulations and data for three species of frogs. We show that models that account for possible misidentification have greater support (lower AIC for two species) and can yield substantially different occupancy estimates than those that do not. When the potential for misidentification exists, researchers should consider analytical techniques that can account for this source of error, such as those presented here.