The objective of this study was to describe and compare the reproductive cycle of Pleurodema tucumanum in dry and rainy years in a portion of the Chaco Serrano in western Argentina. We captured 141 males and 93 females during their months of activity between 2011 and 2015. Adults were sexed and their body size and weight were determined. We weighed fat bodies and calculated testis volume in males and fecundity in females. Fecundity was based on the number of mature oocytes present in the ovary, the ovarian complement. Like many species of the family Leptodactylidae, this species presents sexual dimorphism, with females being larger than males. The reproductive variables showed no significant differences between dry and rainy years. Linear regression analyses between abiotic factors (maximum temperature, minimum temperature, and accumulated rainfall) and reproductive variables showed significant positive relationships. Both in dry and rainy years, we recorded the presence of atretic follicles and developing and maturing oviducts. In rainy years, mature oocytes were observed from November through April, and from October to March in dry years (local summer). Only in dry years were significant variations observed in fat body weight during the reproductive season. Annual cycles of rainy periods do not affect the reproductive activity of this species, which appears to be a strategy for its permanence in this Chacoan region.

Trophic subsidy is an ecological process consisting in the transference of nutrients between adjacent habitats, allowing the occupancy of less productive habitats by several species. We tested for the existence of trophic subsidy provided by aquatic plants of temporary ponds in maintaining individuals of the sand dune lizard Liolaemus occipitalis in southern Brazil. This lizard is a sit-and-wait predator restricted to coastal sand dunes. As these sand dunes occur in a mosaic of temporary ponds, we hypothesized the existence of a nutritional/energetic dependence of lizards from adjacent aquatic habitats. Our evaluation was based on carbon and nitrogen stable isotope analysis in association with gut content analysis of lizards sampled along an entire inundation cycle. Stomach contents revealed no seasonal variation in consumed prey item composition. Nevertheless, we detected changes in prey group composition. The volumetric contribution of Diptera increased over inundation classes (increase = 5%; peak = 61%). Carbon and nitrogen stable isotope ratios indicated that the L. occipitalis trophic web is mainly maintained by terrestrial sources. Isotope ratios also indicated the existence of aquatic contributions to tissue formation, but, despite its tendency to increase over the inundation process (10.7–13.3%), this trend lacks statistical support. We conclude that the studied population of L. occipitalis partially depends on trophic subsidy from aquatic sources and that any conservation plan for this endangered lizard species should take into account the preservation of non-habitats like temporary ponds.

The sandy coastal plains of Brazil are one of the most threatened ecosystems of the Atlantic Forest domain, due primarily to habitat suppression and fragmentation. Glaucomastix littoralis is a threatened endemic lizard that was found to have a declining population in a previous study. Our principal hypothesis in the present study is that altered habitats are less likely to be occupied by G. littoralis due to the elimination of conditions favorable to this species. We tested this hypothesis by analyzing which habitat variables determine abundance, occurrence, and detectability of G. littoralis, comparing populations from six different sites representing different levels of conservation in sandy coastal habitats (restinga) in northern Rio de Janeiro state. We used Royle–Nichols occupancy models to estimate the abundance of G. littoralis and single-species multi-scale occupancy models to estimate its detectability and spatial distribution. The location of the transect was the covariate that best explained the abundance of G. littoralis. The estimated population size for the whole area was 265 individuals, and the estimated mean abundance per transect was = 18 ± 3. Occupancy by G. littoralis was higher in transects with regenerating vegetation. We found a positive relationship between large-scale occupancy rates and the distance of the transect from the nearest human settlement. Detectability was affected by air temperature and was higher at sites with deeper leaf litter and in sandy microhabitats. Site occupancy by G. littoralis was also higher at sites with deeper leaf litter. Our findings indicate that the modification of Brazilian restinga habitats could drive G. littoralis to extinction.

The fossil record of the genus Bothrops is still sparse in South America. Most records belong to extant species recovered in strata not older than the late Pleistocene. The genus was also tentatively reported from the early Pliocene and early–middle Pleistocene of Buenos Aires province, Argentina, based on fragmentary specimens. The aim of the present contribution is to report the partial vertebral column of a viperid snake discovered in the lower Pliocene layers of Farola de Monte Hermoso locality, southern Buenos Aires province. The specimen can be referred to the extant genus Bothrops, representing the oldest occurrence for this taxon. This finding supports the hypothesis sustained by previous authors that indicate a “stasis” in the evolution of the South American herpetofauna since the late Neogene, at least.

Fieldwork in premontane and lowland Amazonian forest (385–1,075 m above sea level) in and around the Amarakaeri Communal Reserve in southeastern Peru led us to describe two new species of the genus Pristimantis. We used integrative evidence from several external morphological characters, morphometric and molecular data, geographic distributions, and multivariate analyses to support the identification of these new species. Pristimantis gagliardi sp. nov. is characterized by lacking a visible tympanic annulus and membrane on skin, having basal webbing between toes, yellow blotches in groin and hidden surfaces of shanks, W-shaped scapular mark, snout subacuminate bearing a very small papilla at tip of snout, and snout–vent length (SVL) = 17.7–21.3 mm in adult males and SVL = 26.7–29.2 mm in females. Pristimantis okmoi sp. nov. is characterized by having a visible tympanic annulus and membrane on skin, basal webbing between toes, yellow blotches in groin and hidden surfaces of shanks, W-shaped scapular mark, snout rounded with small rostral papilla, and SVL = 13.63–17.04 mm in adult males; females unknown. Both species were initially misidentified as P. carvalhoi or P. imitatrix. Additionally, we provide new morphological and phylogenetic data on adult specimens of Pristimantis imitatrix, a rare Amazonian species described based on a single subadult female.

Communication often mediates social interactions, including reproduction, defense, and competition. In anurans, vocal sacs are used in communication during interactions, and they may be controlled in a variety of ways. Hylodes heyeri is diurnal and inhabits streams in the Atlantic Forest of South America. Its vocalizations are complex, probably due to living in a noisy environment, and can involve either unilateral or bilateral inflation of their paired vocal sacs. Here, we analyze the acoustic parameters of territorial calls when the Brazilian Torrent frog inflates one or two vocal sacs in response to territorial calls from playback. Males using two vocal sacs emitted fewer notes per call, had longer note duration, and higher frequencies than males using one vocal sac. We conclude that the strategy of control of the paired vocal sacs in this genus may be related to the energy expenditure for vocalization, mainly in close interactions between individuals.

Eupsophus insularis inhabits a small island in the southeast Pacific, and its natural history is unknown. The species is listed as Critically Endangered based on its restricted distribution, i.e., an island under ongoing habitat deterioration. We assessed the distribution, habitat requirements, density, diet, and threats of the species with the aim of proposing strategies for its conservation. The species is restricted to a terrestrial strip 24–205 m above sea level associated with pristine temperate humid forests located in areas of low slope. A capture–recapture study indicated that its density was 15–66 individuals/ha of optimal habitat. Its diet is composed mainly of invertebrates of the humid forest floor. The high prevalence of chytrid fungus and habitat loss are important threats to the species. Herein, we present data to help with the management of the species on the island and that might help in designing more robust strategies to mitigate present and future threats.

Liolaemus is a species-rich genus endemic to South America with relatively little known about the biology of most of the > 200 included species. One species, L. silvai is common in the coastal Atacama Desert and is sexually dimorphic. We studied their phenotypic variation in color and body size, as well as habitat use by capturing lizards active on the surface. To assess phenotypic variation, we categorized the color morph of each lizard based on visible coloration in their ventral throat region and their ventral body from the shoulder girdle to the hips. We also sexed each lizard, measured snout–vent length and body mass, and recorded incidences of tail breakage. For habitat use we measured perch height, distance from the rock edge to nearest vegetation, and the height of the rocks on which lizards were initially sighted. We assessed habitat selection by comparing perch characteristics to features available in the habitat by pairing capture rocks with the nearest rock in a random direction from the initial perch site. Male L. silvai were significantly larger than females, but color morph and tail break frequency were independent of sex. Lizards used rocks that were significantly closer to vegetation than random rocks available in the environment independently of sex or color morph. We document the same pattern for perch height. Future studies are needed to examine the exact role of vegetation for L. silvai.