Short-legged, small, robust frogs of the family Craugastoridae present a remarkable beta-diversity in the high Andes, their distributions being characterized by a very high degree of micro-endemism to specific valleys. We used dataloggers to study the temperature and humidity conditions of microhabitats of several species of the genus Microkayla at three elevation belts: below, within, and above the altitudinal range of their distribution in Bolivia. We also conducted thermal physiology experiments on a limited number of individuals of one of these species. Our aim was to infer on factors that may limit the distribution of anurans in a biological hotspot that is threatened by climate warming. We found an unexpected thermal heterogeneity within the slopes at three different Andean valleys that explained the specific distribution of species of Microkayla at each site. Species distribution was associated to elevation belts with the highest ambient relative humidity, and there was high variability in thermal preference when individuals were experimentally exposed to a thermal gradient. Critical thermal maxima compared to the temperatures that frogs confront in nature, as well as thermal performance trials, revealed that the studied species has a broad physiological tolerance to temperature. These results point to moisture, and not temperature, as the limiting climatic factor determining the occurrence of these species in high Andean slopes, but further experimental work on water balance is needed. The predicted desertification of the Andes in future climate change scenarios poses a potentially serious threat to this highly diverse group of amphibians.

We describe a new species of Macropholidus lizard from the Andean highlands of southern Ecuador and northern Peru based on recent collections. Among other characters, the new species differs from other species of Macropholidus in having a paired series of enlarged middorsal scale rows restricted to the nape, striated dorsal scales, as well as ocelli on tail, flanks, scapular region and neck. We also present a molecular phylogeny of Cercosaurinae and genetic distances as additional evidence supporting delimitation of the new species, which is sister to M. annectens from southern Ecuador. Data on Andean orogeny and age estimates of cercosaurine lizards suggest that the Huancabamba Depression, long recognized for its dual role as a biogeographic barrier and a migration corridor, has also served as a center of origin and diversification of Macropholidus lizards.

Pseudoautotomy is presumably a derived character within Lepidosauria and occurs in taxa that have lost the ability to perform autotomy. In general, species capable of employing pseudoautotomy as a defensive strategy against predators present a high frequency of damaged tails in series deposited in herpetological collections. We assessed data from three largely sympatric Echinanthera species in the Brazilian Atlantic Rainforest (E. cephalostriata, E. cyanopleura, and E. undulata) to test previous assumptions that species of Echinanthera use their tails defensively. This hypothesis derives from anecdotal observations during fieldwork and is reinforced by the number of specimens presenting tail breakage in scientific collections. In general, the frequency of damaged tails in these species resembles that of others in which pseudoautotomy has been demonstrated. Statistical analyses revealed no differences in tail breakage frequencies between sexes for the analyzed species or between the two geographical groups defined for E. cyanopleura. In contrast, we detected a significant difference between snout–vent length and sex regarding pseudoautotomy probability for E. cyanopleura, with a positive relationship between tail breakage frequency and snout–vent length.

Social structure in anurans is directly related to reproductive traits such as chorus organization, male territoriality, pair formation, breeding site choice, and temporal breeding pattern. The Neotropical treefrog Dendropsophus sanborni is an excellent model for studies on reproductive dynamics because it is a prolonged-breeder and usually occurs in high densities. Here, our goals were to better understand the factors that lead to social organization and influence seasonal reproductive dynamics of males of the species. We addressed the hypotheses that (1) the seasonal dynamics of D. sanborni is locally delimited by climatic conditions throughout its breeding season and (2) territorial males are structured spatially and temporally based on body size. We carried out monthly field sampling between October 2015 and September 2016 in an ecotone region of Brazil that originally comprised Semideciduous Seasonal Forest and Cerrado (savannah vegetation). We specifically analyzed environmental conditions, population abundance, size of calling males, and microhabitat use. Our results showed that environmental conditions drive the seasonal reproductive pattern and social structure of calling males is not organized by size. We did not find significant variation in male size among months of the breeding season or among perch heights and types. Our findings suggest a prolonged seasonal reproductive pattern associated with climatic factors without a social structure based on body size.

Liolaemus duellmani is a poorly known, microendemic lizard described from southwestern Mendoza, Argentina, representing the southernmost distribution of the Liolaemus montanus species group. We report the rediscovery of the species after 43 years, presenting the fifth voucher specimen and the second female of L. duellmani. Data on external morphology, activity, and color photographs are included, and the geographic coordinates of the type locality are discussed.

Morphology and resource use have a significant influence on lizard population dynamics. In this study, sexual dimorphism and feeding ecology were assessed in a population of Sceloporus aeneus from central Mexico. Sexual dimorphism was recorded, with males being larger than females in several morphological characteristics, such as jaw width, femur length, tibia length, and forearm length, but not snout–vent length (SVL) or jaw length, which were similar in both sexes. The stomach contents analysis indicated an insectivorous diet composed of 11 prey categories, of which females consumed 11 and males consumed 9. Low values of feeding niche breadth were found, as well as high overlap between sexes and seasons. For the whole population, adult preys of the family Formicidae and orders Coleoptera and Hemiptera showed the highest values of food importance and abundance. A higher volume of stomach contents was recorded during the dry season than the wet season in both females and males. Results showed a pattern of sexual dimorphism similar to that of other species of the genus Sceloporus, but different from those of other populations of the same species. Morphological variation in jaw length and width seems to be related to food resources use because, in spite of the high similarity in the diet between sexes, the volume of stomach contents was not correlated with SVL in females. These findings suggest a constant consumption of food that is subsequently invested in reproduction. Further studies analyzing morphology and diet and their effect on reproductive characteristics such as clutch size, eggs mass, and volume are needed among populations of this species. The results obtained in this research could help explain the differences and similarities previously reported on the morphology and reproductive characteristics for S. aeneus and other species of the S. scalaris group.

Species distribution models are increasingly important in herpetological studies of spatial ecology and conservation. In this paper, we estimate the potential distribution of an endemic and threatened Mexican lizard, Plestiodon copei. The presence of this skink was estimated using the maximum entropy algorithm, and the most relevant environmental variables for the model were identified. Additionally, the specialization of the species was evaluated, the coverage of natural protected areas throughout its distribution was estimated, and the priority areas for the conservation of this lizard were delimited. The model shows that the optimum areas of distribution extend from the southeastern state of Jalisco within the Faja Volcánica Transmexicana (FVT) to the limits of the states of Puebla and Veracruz, covering an area of approximately 12,300 km^2. The distribution of P. copei was associated with high mountains and temperate forests, ecosystems strongly affected by human activities. The model predicted previously unrecorded populations, some of which were corroborated in the field. It was also found that 53.08% of the species' distribution is within natural protected areas along the FVT. These observations emphasize the urgent need to propose conservation strategies for this endemic lizard and its habitat.

Despite the key position of reptiles in evolutionary history, reptilian immune responses have received relatively little attention. Like all jawed vertebrates, reptiles possess both an innate and adaptive immune system to recognize unknown foreign substances. Although diverse immunological mechanisms have been discovered, they seem not to be adequate to avoid the invasion of some microorganisms and stop some infections. All species of crocodilians show well-defined social behaviors, and hierarchical dominance attitudes can be observed in both males and females. This behavior generates conflicts that are expressed through aggression and combat with serious health consequences. These animals have evolved a very active immune mechanisms and components that provides a fast and effective line of defense. Science has focused on those mechanisms and components because crocodilians are an especially interesting group on which to perform evolutionary studies because they are one of the surviving archosaurs, which represents an important link within “higher” vertebrates. Based on those background, they are being observed and evaluated for their potential application in domestic and wild species. These findings will not only generate an increasing value as a therapeutic resource but also to the ecosystem, and to decode biological processes that could lead to phylogenetic (ancestral) cognition. In this review, many components of the crocodilian immune system are described that could lead to a more thorough understanding of how these animals select the most appropriate response to environmental challenges and antigen exposure and identify networks to study and interesting opportunities to the experts in the field.