One-third of known amphibian populations have become extinct, with habitat loss and degradation being the leading causes in the United States. Site occupancy has been suggested as one of the most effective state variables in describing population declines. The objectives of this study were to determine occupancy estimates of five southwestern desert anurans, accounting for imperfect detection, and to determine the main factors impacting detection. We conducted call and visual surveys on three consecutive nights after rain events at 21 breeding sites for Mexican Spadefoot (Spea multiplicata), Plains Spadefoot (Spea bombifrons), Couch's Spadefoot (Scaphiopus couchii), Great Plains Toad (Anaxyrus cognatus), and Green Toad (Anaxyrus debilis). We used occupancy modeling to estimate the proportion of sites occupied for all species detected during the sampling period. Spea multiplicata and A. debilis were most prevalent, followed by A. cognatus, Sp. bombifrons, and Sc. couchii, respectively. In addition to the inclusion of repeated site surveys to decrease bias, incorporating visual surveys greatly improved occupancy estimates for southwestern desert anurans. Detection was highest on survey night one for Sp. multiplicata, Sp. bombifrons, Sc. couchii, and A. debilis (72.2–100%); warmer air temperature improved detection of A. cognatus. Sky conditions did not significantly influence desert anuran detectability. Immediate survey after rain events and the combination of call and visual surveys are critical to increase accuracy when studying desert anurans.

Many high-elevation regions in the western USA are protected public lands that remain relatively undisturbed by human impact. Over the last century, however, nonnative trout and cattle have been introduced to subalpine wetland habitats used by sensitive amphibian species. Our study compares the relative importance of cattle and trout impact on amphibian assemblages, abundance, and occupancy within a broader context of high-elevation environmental variables. We evaluated amphibian species richness and abundance across 89 subalpine wet meadow sites in the Klamath Mountains of Northern California, USA. At each wet meadow we also measured environmental characteristics including wilderness designation, elevation, meadow size, number of pools, distance to nearest lake, presence of nonnative trout, and impact of cattle. Cluster analysis found amphibian assemblages fell into three distinct groups, and ordination suggested the number of pools, elevation, and presence of nonnative trout are significant site variables associated with species groups in wet meadows. Individual species differed in population response to environmental characteristics. Regression trees and occupancy models indicated that the most-important variables associated with the population size and site occupancy of individual amphibian species are nonnative trout, wilderness area designation, the number of pools, and the distance to the nearest lake. While nonnative trout exhibited a strongly negative correlation with amphibian assemblages, abundance, and occupancy, cattle impact was only weakly associated with occupancy and abundance of some species.

The social behavior of turtles during the nesting season can be attributed to a series of functions such as reducing predation, increasing hatchling survivorship, and information exchange between nesting females. However, the mechanism(s) used to remain in a group during the different phases of nesting behavior has yet to be explained. The objective of this study is to document the sounds produced by Giant South American River Turtle, Podocnemis expansa, during the nesting period, and identify how acoustic mechanisms might facilitate social behavior and group aggregation during this period. From September 2009 to October 2011, the sound repertoire of P. expansa was identified during the nesting period, which begins with the migration of the turtles from the flooded forests to the nesting beaches and terminates when the hatchlings emerge and the females migrate with the hatchlings to the flooded forests. Sounds were recorded when the turtles were active in different behavioral patterns (1) migrating; (2) aggregating in front of the nesting beaches before basking; (3) nesting at night; (4) waiting in the water without nesting or after they have nested; and (5) waiting for the arrival of the hatchlings. We observed six types of sound in the recordings of turtles made during the nesting period. These data indicate that this species is social, and that sound plays an important role in the synchronization of the activities of groups during the nesting season.

Animal color signals evolve in response to selection by visual systems that perceive them, ambient light spectra that illuminate them, and features of the background against which they are juxtaposed. In Anolis lizards, males use a colorful dewlap, together with head-bobbing displays, to deter conspecific rivals and to attract females. As most anoles are both arboreal and sympatric with one or more congeners, selection should favor dewlap colors that contrast sufficiently with the visual background of foliage to be detectable, and that differ reliably from dewlaps of sympatric congeners to be discriminable. We used spectroradiometry and computational visual modeling for five species of closely related Jamaican anoles to calculate the detection probability of each species' dewlap in each of the species' light habitats. Despite substantial interspecific differences in dewlap colors, as well as moderate differences in habitat light spectra, results of our analyses did not support the prediction that a given species' dewlap should be more detectable in its “own” light habitat than in those of sympatric congeners. Rather, dewlaps tended to perform similarly across most light environments. Our results resemble those reported for Puerto Rican anoles, and we discuss potential reasons why Anolis dewlap color design does not appear to be optimized for specific light habitats.

Habitat loss and fragmentation threaten Timber Rattlesnake (Crotalus horridus) populations in contiguous, mature forests of eastern North America, yet information regarding the life history of C. horridus in fragmented habitats is sparse. In this study, we used mark–recapture data on body size and rattle morphology to compare the size at birth and per ecdysis growth rates of C. horridus from a fragmented habitat in west-central Missouri (MO) with those from a closed-canopy forest in northwest Arkansas (AR). The MO population is typically exposed to a shorter frost-free period than the AR population, so individuals may have less time to acquire prey. At birth, snakes in the MO population were significantly shorter than those from AR, but MO snakes increased in length more rapidly than AR snakes through their first eight ecdyses. Sexual size dimorphism was apparent in the MO population when males and females diverged in size between the fifth and sixth ecdyses, whereas growth trajectories of AR males and females remained indistinguishable through the first eight ecdyses. Crotalus horridus in the agriculturally fragmented habitat may have grown faster than their forest-dwelling counterparts because fields and edges provide prey with stable food sources, unlike the boom and bust production typical of acorn mast crops. Although previous studies have demonstrated that C. horridus growth rates vary along latitudinal and elevational gradients due to climatic constraints on foraging, our study suggests that prey abundance may be just as important in shaping variation in life history both within and among populations.

The Rhinella veraguensis group is likely a paraphyletic assemblage that contains 16 species of Andean toads. To date, descriptions are available for larval stages of only three species, all of which possess a distinct sucker in the abdominal region. In this study, we describe the tadpoles of Rhinella rumbolli, a medium-sized Salta Toad typical of forest streams in northwestern Argentina. Thirty-three larvae (Gosner Stages 32–36) were processed for studies of the external morphology, buccal cavity, and musculoskeletal system. These larvae show a mosaic of features, some typical of the genus and some others unique to the R. veraguensis group. Several character states are specific to R. rumbolli, namely the lack of an abdominal sucker, 2–4 lingual papillae, and the absence of adrostral cartilages. Some traits are frequent in other stream tadpoles such as the muscular tail, large oral disc with complete labial rows, and the wide and robust anterior neurocranium. Bufonid tadpoles exhibit an extraordinary variation in ecology, such as preferred microhabitat, and the diversity within the family is exemplified within the genus Rhinella. Further comparative morphological and developmental studies, framed in the context of phylogenetic hypotheses, are needed in order to explore the pattern variation in different clades and to discuss character evolution and form–function relationships.

We describe a new species of the Rhinella acrolopha group (previously Rhamphophryne) from mid-elevations (1800–2500 m) of the Cordillera Occidental of Colombia. It is found exclusively in cloud forest habitats and is not associated with streams or other bodies of water. The species is characterized by possessing eight presacral vertebrae, fusion of the sacrum and urostyle, and nuptial excrescences in adult males, and in lacking conspicuous cranial ornamentation and vocal slits. The most striking characteristic of this species is its middle ear, which lacks a tympanic membrane and annulus but possesses a short stapes that articulates with the palatoquadrate and squamosal in a manner similar to the middle ear of many salamanders. A population of this species in the Serranía de los Paraguas seems to be stable despite drastic declines in many sympatric species.

We describe a new species of Oreobates from Jujuy, Argentina. The new species is clearly diagnosable from other species of Oreobates by a combination of morphological characters and support by molecular evidence (genetic distance and phylogenetic analysis). We also provide taxonomic comments about O. discoidalis and O. barituensis, emphasizing the need for an exhaustive revision of these species.

We describe a new species of ranid frog from the Hylarana signata complex in Peninsular Malaysia based on morphological and genetic differentiation. The new species can be distinguished from its congeners by the following combination of characters: (1) adult males reaching 37.4–37.6 mm snout–vent length; (2) nuptial pads absent in males; (3) humeral glands in males large; (4) webbing on toes reduced, one phalanx free of web on postaxial side of Toe II and pre-axial side of Toe V; (5) dorsolateral stripe straight, continuous, red to orange in color; (6) middorsal region black, unmarked; (7) flanks black, coloration unstratified; (8) flanks, dorsal surfaces of limbs, and upper lip with large, round, yellow spots; (9) venter grayish-brown, with light spots on throat and light reticulations on ventrum. The new species is phenotypically most similar to Hylarana siberu but differs by having larger, more-dense, and more-rounded spots on the flanks and dorsal side of limbs, larger spots along the entire upper lip, and having light, distinct spots on the throat and light reticulations on the ventrum. We use mitochondrial data to estimate genealogical relationships and genetic divergences between the new species, H. siberu, a related and undescribed Sumatran population, and other members of the H. signata complex. These data unequivocally support the specific recognition of the new taxon and provide insights into its evolutionary relationships.

We describe a new species of Phrynosoma from central northeastern Guerrero, México; perform a phylogenetic analysis of mitochondrial and nuclear sequence data to estimate its phylogenetic relationships; and investigate the monophyly of Phrynosoma asio, P. braconnieri, and P. taurus. The new species can be distinguished from all of its congeners by the possession of a unique combination of morphological characteristics. The molecular genetic data include three fragments of the mitochondrial genome and six nuclear genes (2419 and 3909 base pairs in total, respectively) for 31 samples belonging to the 16 previously recognized species of Phrynosoma and the new species. The new species is strongly supported in maximum likelihood analyses of both the concatenated mitochondrial and nuclear data as a monophyletic, distinct evolutionary lineage sister to, and moderately divergent from, P. taurus, and highly divergent from all of the other species of Phrynosoma. A Bayesian species tree analysis also strongly supports the monophyly of the Brevicauda clade, and a sister relationship between P. taurus and the new species.

Se describe una especie nueva de Phrynosoma del centro-noreste de Guerrero, México; se realiza un análisis filogenético de secuencias de ADN mitocondrial y nuclear para estimar sus relaciones filogenéticas, y se investiga la monofilia de P. asio, P. braconnieri, y P. taurus. La nueva especie puede distinguirse de todos sus congéneres por la posesión de una combinación única de caracteres morfológicos. Los datos genéticos moleculares incluyen secuencias de tres fragmentos del genoma mitocondrial y seis genes nucleares (2419 y 3909 pares de bases en total, respectivamente) para 31 muestras de las 16 especies de Phrynosoma previamente reconocidas y la nueva especie. La nueva especie es fuertemente apoyada en análisis de máxima verosimilitud de los datos concatenados (tanto mitocondriales como nucleares) como un linaje evolutivo distinto y monofilético, hermano y moderadamente divergente de P. taurus y altamente divergente de todas las otras especies de Phrynosoma. Un análisis Bayesiano de árbol de las especies también apoya fuertemente la monofilia del clado Brevicauda y la relación de especies hermanas entre P. taurus y la nueva especie.