Dendropsophus nekronastes is a poorly known species of the D. leucophyllatus group endemic to the Atlantic Forest of southern Bahia, Brazil. We describe the external morphology of the tadpole of D. nekronastes and compare it with other known tadpoles of the D. leucophyllatus group. The tadpole of D. nekronastes generally resembles most species of the D. leucophyllatus group; however, a dark longitudinal stripe bordered by a yellow stripe on the dorsum differentiates it from all previously described tadpoles of species in the D. leucophyllatus group.

Dendropsophus nekronastes é uma espécie pouco conhecida do grupo D. leucophyllatus, endêmica da Mata Atlântica do sul da Bahia, Brasil. Descrevemos a morfologia externa do girino de D. nekronastes e comparamos com outros girinos conhecidos do grupo D. leucophyllatus. O girino de D. nekronastes se assemelha em geral à maioria das espécies do grupo D. leucophyllatus. No entanto, a faixa longitudinal escura do dorso margeada por uma faixa amarela difere de todos os girinos descritos das espécies do grupo D. leucophyllatus.

Sexual dichromatism, where males and females of the same species differ in coloration, is best studied in diurnal animals. Nocturnal animals such as frogs do not seem good candidates for widespread sexual dichromatism, or for the use of visual signals in social communication in general. Yet, up to 25% of treefrog species (Anura: Hylidae) show some degree of sexual difference in their dorsal coloration. The ventral side of frogs is hidden during rest, but the throat region becomes visible in active individuals, especially in calling males. We compiled a database of 249 treefrog species that include members of all seven subfamilies of the Family Hylidae. We document that the throat region of male frogs is frequently colorful and of a different color than the abdomen (ventral dichromatism), that there is interspecific variation in throat coloration, and that males and females differ in throat coloration (sexual dichromatism). We also examined intraspecific variation in throat coloration, using Eastern Gray Treefrogs, Dryophytes versicolor (Hyla versicolor) as the focal species. Here, we document throat color is sexually dimorphic, that it varies among males, is associated with better body condition, and on average is darker in mated compared to unmated males. Our study finds that throat color dichromatism is the most prevalent type of sexual dichromatism in treefrogs, and that throat coloration may have sexual signal function.

Ophidiomycosis (snake fungal disease; SFD) is a disease of conservation concern caused by the fungus Ophidiomyces ophidiicola that threatens the health of snake populations worldwide. Gaps exist in our knowledge about the prevalence of this disease across landscapes. In our study, we compared the prevalence of ophidiomycosis between a low-impacted forest site (n = 93) and a highly disturbed remediated landfill (n = 53) in Anderson County, Tennessee, USA. Free-ranging snakes were examined for the presence of skin lesions that are consistent with ophidiomycosis and were swabbed to detect O. ophidiicola DNA using quantitative PCR (qPCR). Apparent ophidiomycosis (qPCR-positive and skin lesions present) was diagnosed at both sites, but there was no significant difference in prevalence between the two sites (24.7% at the forest site; 22.6% at the landfill site). Apparent ophidiomycosis was most prevalent in Racers (38%; Coluber constrictor) and Ring-Necked Snakes (26%; Diadophis punctatus). There was no difference in ophidiomycosis status between sites for the most-sampled species: Racers, Black Rat Snakes (Pantherophis obsoletus), and Ring-necked Snakes (Diadophis punctatus). Our study represents the first report of ophidiomycosis at focal sites in Tennessee. The findings suggest that O. ophidiicola may be ubiquitous across the landscape and point to the need for further study of diverse habitat types for the prevalence of O. ophidiicola.

Alligator Snapping Turtles (Macrochelys temminckii) possess unique head morphology that suggests strong natural selection for bite performance, which likely influences foraging and prey selection, as well as the outcomes of intrasexual aggressive encounters, mating, and defense against predators. Therefore, bite performance has the potential to directly and indirectly impact fitness. In this study, we assessed the effects of captivity on bite force by comparing the performance of captive and reintroduced M. temminckii. On average, free-ranging M. temminckii bite with greater force than do individuals residing in captivity, and captive individuals housed under seminatural conditions in outdoor ponds outperformed those housed indoors. Further, we found that free-ranging M. temminckii released into different river systems performed comparably and required less provocation than captives to display gaping and biting behavior. It remains to be determined whether the observed performance differences were more strongly influenced by physiological limitations on muscle performance or by behavioral variation in motivation to bite with maximum force.

A recent systematic revision pointed out that the name Boana polytaenia has been applied to a nonmonophyletic assemblage because populations identified as B. polytaenia from the northern Mantiqueira and southern Espinhaço mountain ranges are not closely related with the species' nominal clade. In this sense, specimens from these two biogeographic regions were recovered within two clades named Boana sp. 3 and Boana sp. 4, respectively. Here we characterized and compared external morphologies, calls, and DNA of specimens of the clade of B. polytaenia and from the two candidate species (Boana sp. 3 and Boana sp. 4). From these comparisons we herein describe a new cryptic species. Boana guarinimirim sp. nov. differs from its closely related species by the presence of a supracloacal crest, calcar appendage, and conspicuous discs on toes. Nevertheless, the new species could not be completely discriminated from its distantly related taxon B. polytaenia. We applied the new name to the clade distributed throughout the northern Mantiqueira range (Boana sp. 3), but the new name could also be applied to the clade from southern Espinhaço range (Boana sp. 4). Additional sampling efforts and new sources of evidence, such as larvae morphology and chromosomal features, should evaluate whether the lineages are conspecifics.

Exposure to predators during early life stages can alter behavioral and physical traits during ontogeny. This is important for biphasic amphibian species because juvenile movement behavior can be shaped by carry-over effects of the larval environment and direct effects of abiotic conditions in terrestrial habitats. We explored the interaction of aquatic predator cue exposure, juvenile morphology, and abiotic terrestrial conditions on the movement behavior of postmetamorphic Northern Red-legged Frogs (Rana aurora). We quantified carry-over effects of aquatic predator cues and direct effects of substrate conditions on individual movement behavior using a combination of seminatural enclosed runways and powder tracking assays. We found a latent effect of aquatic condition, such that crayfish-exposed individuals had greater relative body condition at metamorphosis, and all predator-exposed individuals had larger body lengths relative to controls. Terrestrial conditions were the dominant factor shaping movement behavior. During runway movement assays, individual conditional movement displacement was likely greater in dry soil and low humidity conditions than in moist conditions with high humidity. For nocturnal powder tracking assays, individuals were more likely to have greater path distances during warmer temperatures, whereas paths were less meandering in cooler, dry conditions. Morphologically larger individuals moved greater distances only during the powder tracking assays. We observed latent effects of aquatic predator exposure on juvenile morphology; however, the relationship between these changes and the relative importance of direct environmental conditions in shaping movement behavior is unclear. Our results demonstrate the interconnected nature of aquatic and terrestrial environments in shaping the movement of juvenile amphibians.

The competitive effects among tadpoles make the bullfrog a possible agent of native amphibian population declines at its introduction sites. Our aim was to analyze the dietary composition of an invasive population of Lithobates catesbeianus tadpoles and to evaluate the degree of dietary changes among activity months. We hypothesized that bullfrog tadpoles would exhibit temporal changes in diet, consistent with the variation of tadpole size and availability of resources. We collected 94 bullfrog tadpoles and identified 50 taxa in their digestive tracts. The items most frequently consumed were microalgae of the genera Navicula (frequency of occurrence [Fo] = 19) and Cymbella (Fo = 17). The trophic niche breadth was 8.13, which is considered moderate-high. The trophic habits of L. catesbeianus larvae changed seasonally, with the diets during October and December being numerically similar (Morisita's quantitative index = 0.86). The composition of the diet had a similarity of 63% (Jaccard's qualitative index) between August and October. The larvae of L. catesbeianus collected during the different months showed significant differences in their stages of development and body mass. On average, individuals were larger and more developed in the month of December, which was to be expected given that the abundance of prey items is greatest during the summer season. Our results show that L. catesbeianus tadpoles have a wide trophic niche with a diet that is not strongly selective; thus, the aquatic life-history stages play an important role in the structuring of invaded anuran larval communities.

Costa Rica is considered a hot spot for biodiversity and wildlife conservation in Central America, and sea turtles are a good example of this. Largely distributed along both the Caribbean and Pacific coast, adult females of five of the seven extant sea turtle species select beaches on both coasts as their breeding sites. Although Green Sea Turtles (Chelonia mydas), Leatherback Sea Turtles (Dermochelys coriacea), Hawksbill Sea Turtles (Eretmochelys imbricata), and Olive Ridley Sea Turtles (Lepidochelys olivacea) have been extensively studied in Costa Rica, little information regarding Loggerhead Sea Turtles (Caretta caretta) is available. Thus, we present an exhaustive data record of every Loggerhead encountered at Tortuguero beach (northeastern Caribbean coast of Costa Rica) over the past 60 yr. We collected Loggerhead nesting data between 1957 and 2021 through daytime and nocturnal monitoring activities. We documented 14 Loggerhead Sea Turtle nesting attempts between 1957 and 2021 at Tortuguero. Among them, seven nested successfully, four did not lay eggs, and one's fate is unknown. Additionally, two turtles were killed by jaguars. Mean minimum curve carapace length (CCLmin) measurements for Loggerheads was 98.2 ± 3.7 cm (range, 90.0–101.4 cm). Finally, we found that every encounter occurred between April and July, which coincides with the Loggerhead nesting season in the Northwest Atlantic. Our study is the first assessment of Loggerhead Sea Turtles nesting in Costa Rica, bringing to light new records for this species in the Caribbean Sea.

Having an accurate estimate of population size and density is imperative to the conservation of chelonian species and a central objective of many monitoring programs. Capture–recapture and related methods are widely used to obtain information about population size of chelonians. However, classical capture–recapture methods have strict spatial sampling requirements and do not account for lack of geographic closure caused by movement of individuals in and out of the surveyed landscape. Newly developed spatial capture–recapture (SCR) models address these limitations by specification of explicit models for spatial sampling as well as the spatial distribution of individuals in the population. Spatial capture–recapture models have not yet been applied to the study of chelonian populations. Here we demonstrate their application to a population of box turtles in Maryland that has been studied for 75 yr. Results support dramatic declines in population size of box turtles since the 1940s.

Raillietiella orientalis, an invasive pentastome parasite, inhabits the lungs of snakes as adults and is rapidly spreading in Florida and Australia. The species that serve as intermediate hosts are currently unknown. We conducted laboratory infection experiments with insects (Blaberus discoidalis), lizards (Anolis sagrei), and anurans (Anaxyrus terrestris, Lithobates sphenocephalus, Osteopilus septentrionalis) to develop an understanding of which species may serve as intermediate hosts and to determine the fitness consequences of infection by R. orientalis. Lizards and insects, but not anurans, were readily infected by consuming food that was contaminated with pentastome eggs. Anolis sagrei and L. sphenocephalus were both infected after eating a single roach that was infected with R. orientalis larvae. Comparison with uninfected control animals revealed that pentastome infection did not significantly affect survival or growth in roaches, lizards, or anurans. The life cycle of R. orientalis in Florida is likely to involve a sequence of three hosts, with eggs hatching in coprophagous insects that infect lizards and anurans that infect the definitive host (snakes) after they are consumed. Our results indicate that the native species that serve as intermediate hosts are unlikely to experience major negative consequences from R. orientalis, unlike the native snake species that serve as the definitive hosts. The diversity of species that can serve as intermediate hosts and the potential for vehicular rafting by infected roaches and anoles indicate that the rapid geographic range expansion of R. orientalis will probably continue.

Northern Red-Bellied Cooters (Pseudemys rubriventris) have a disjunct distribution with a relictual population in southeastern Massachusetts and a larger range across the mid-Atlantic United States. The relictual population is currently listed with protections under the U.S. Endangered Species Act but the status of the population in the remainder of the species' range has not been assessed, and there is concern that it may be at risk of extinction without protection. The U.S. Fish and Wildlife Service requires scientific information of the species' status to inform conservation decisions. There is little empirical information available from P. rubriventris populations and, furthermore, the majority of what exists comes from the disjunct northern subpopulation. To fill data gaps in the species' life history and reduce geographic bias, we supplement available data from P. rubriventris with demographic rate estimates from other Pseudemys species to parameterize an age-structured population projection model. Our estimate of mean population growth rate was 0.987 (0.92–1.04), indicating that P. rubriventris populations may be in decline. However, there was considerable uncertainty in our results, with 35% of projections resulting in stable or increasing populations. Additional uncertainty about parameter values, geographic variation, and current threats limit the assessment. We discuss the merits and limitations of our population projection modeling (PPM) approach where other analytical methods are precluded by lack of available data.

Understanding species' geographic distributions is important for informing their conservation; however, an accurate understanding of where species occur is often precluded by a paucity of species records. For taxa that are difficult to visually distinguish at the species level, this problem can be compounded by misidentification of existing records. Citizen science has emerged as a potentially powerful tool to increase species observation data, but whether it can meaningfully add to our understanding of the distributions of species that are typically difficult to identify is contentious. We evaluated the volume, spread, and species identification accuracy of 3 yr of data from an acoustics-based citizen science dataset with a national aggregate of species observations collected over more than 140 yr (i.e., unvouchered human observations, photo-vouchered citizen science observations, and preserved specimens) to demonstrate the boundaries of five small, morphologically conserved frog species in eastern Australia. The national aggregate contained the most species records; however, the annual rate of record collection was much greater in the acoustic citizen science dataset. A high proportion of likely misidentified records were detected in the national aggregate dataset. Spatial bias differed between datasets, with acoustic citizen science data more biased toward highly populated areas. We demonstrate that citizen science can collect large volumes of spatially and taxonomically valid data which, especially when used in combination with more traditionally collected species records, can inform the detailed delineation of ranges in historically confusing groups of frog species.

The Common Mudpuppy (Necturus maculosus (Rafinesque, 1818)) is found in many watersheds from eastern Canada to the southeastern United States. Although its range is large, recent observations suggest its population is dwindling in the Great Lakes region. A lack of understanding about its distribution at a finer scale or whether diet and body condition exhibit seasonal patterns limits our ability to develop a conservation management plan. This study investigated seasonal changes in Common Mudpuppy diets and body condition across western New York (USA) over a 2-yr period by using rock turning (RT) and trapping (TR) collection methods. Common Mudpuppies were found in all four major watersheds of the region in both lentic and lotic habitats. RT was more efficient than TR in streams, whereas TR was a better option in lakes. Male-to-female sex ratios and four of five measured morphological features did not differ between collection methods, although the largest and smallest Common Mudpuppies were captured by RT, suggesting some size selectivity in TR. Body girth was significantly smaller for Common Mudpuppies collected by RT, and this was attributed to seasonal differences in activity. Stomach contents were varied and differed by season, with 41 unique prey types recovered, including several forms of microplastics. In summer and fall, Common Mudpuppies fed on invertebrates exclusively, but during winter and spring, fish were incorporated into the diet. Body condition reflected the change in diet, with a higher body condition when fish were present in the diet. These findings suggest seasonal data are necessary to fully understand Common Mudpuppy conservation needs.

Middle-American knob scaled lizards of the genus Xenosaurus are viviparous lizards characterized by flattened bodies, peculiar knob-like scales, and extreme specialization to a crevice-dwelling ecology. Species within this rarely seen and enigmatic genus are distributed throughout much of Mexico and Guatemala. Xenosaurus is the sole surviving genus of the ancient family Xenosauridae and little is known about the origins and biogeographic history of members of the group. To address this deficit, we estimated divergence times across Xenosaurus under the fossilized birth–death model, including published ddRADseq data, morphological data for six extant and three fossil relatives to genus Xenosaurus, and fossil occurrence data for the three fossil relatives. Crown Xenosaurus was estimated to be 35 million years old, considerably younger than the stem age of the family, implying high rates of extinction. The distribution of Xenosaurus populations across Mexico and the location of the three fossil relatives in western North America suggest a Nearctic origin with a north to southeast direction of range evolution in Xenosaurus. To test this hypothesis, we performed a Bayesian biogeographic analysis under the Dispersal Extinction Cladogenesis (DEC) model, in order to estimate the historical ranges and patterns of dispersal across the genus. The results of the biogeographic analysis supported this historical north to southeast movement. In conjunction with our diversification estimates, our DEC results suggest that climatic events such as cooling during the Miocene and Pliocene may have shaped the divergence and current distributions in Xenosaurus.