A new specie of the Liolaemus genus is described in the present work, it was collected in the north-west of Santa Cruz Province, Argentina, at 1485 m. This new lizard belongs to the silvanae group, previously described as Vilcunia genus, characterized by the absence of precloacal pores in males, the presence of dorsal tridentate scales, lateral keeled nuchal scales overlap and postfemoral scales subimbricated. This Patagonian specie has a small size, with a squat look and shows a dorsal coloration pattern with outstanding dorsal-lateral bands, these bands can be of different colors, such as yellow, orange, brown or grey. The individuals of this specie are melanics in the ventral part of the body. This new specie lives in a place with extreme climatic conditions, low temperatures and with a cloudy sky most of the time. These are insectivorous and viviparous lizards, whose phylogenetic relationship with other members of the group are still unknown.

Among 21 species for which information is available (out of ca. 100 extant species), three diploglossines, five gerrhonotines, and six anguines attend their eggs during incubation, implying that parental behavior might be synapomorphic for the more inclusive clade Anguidae. A captive Gerrhonotus infernalis attended her clutch for 62 days, occasionally left it to feed and defecate, and did not pursue prey in the presence of her neonates. Viviparous Barisia imbricata, Elgaria coerulea, and Mesaspis moreleti consume extraembryonic debris and sometimes assist with birth; viviparous M. monticolus and Diploglossus fasciatus (mode of reproduction unknown) likely attend their neonates; and parental behavior is perhaps absent in viviparous Anguis fragilis and Ophiodes. Meager circumstantial evidence suggests that chemical cues influence those activities in anguids, and that thermoregulation, defense of eggs and/or young, and hygienic removal of spoiled eggs or birth debris are among the ecological advantages of their parental behavior. Viviparity has evolved at least four times within Anguidae, consistent with theoretical expectations that live birth is favored in egg-guarding taxa. These diverse lizards thus show much promise for studies of specialized parental investment in ectothermic vertebrates.

The family Pipidae includes five genera and two subfamilies, Pipinae and Dactylethrinae. Pipinae is restricted to Central and South America, occurring in the Amazon and Atlantic forest. We analyzed sexual dimorphism, female fertility, and diet of Pipa arrabali from their range's southernmost portion in Serra do Cachimbo, Pará, Brazil, and compared it to previous studies on populations near Manaus. We found no sexual dimorphism in shape, but females are significantly larger than males. Nineteen of 31 females had tadpoles embedded under the skin. Females harbored more and smaller tadpoles than previously reported for other populations. Diet of P. arrabali at the end of the dry season consisted mainly of dipteran pupae, contrasting to Manaus populations, where tadpoles were the main item, therefore underscoring the importance of prey availability on frog diet composition.

We assessed the conservation status of 61 species from a central Brazilian snake assemblage by ranking species according to their vulnerability to ten threat factors that are thought to influence the survival of snake populations. The anomalepidid snake Liotyphlops ternetzii whereas the species with the lowest risk and the colubrid Drymoluber brazili was the most threatened. Less than 15% of the Distrito Federal snake fauna was considered free from any threat. The natural-history of the species, its geographic distribution, and human attitudes were important factors in determining the levels of threat for central Brazilian snakes. Principal Component and Cluster analyses were used to classify species into vulnerability groups that were based on sharing similar threat factors. Thirteen groups were identified which classified species in categories ranging from no risk to threatened. Within Brazil, status assessments of additional snake assemblages in other biomes would be useful in generating a comprehensive conservation plan for the country.

There is currently little information on the biology of anurans of the genus Crossodactylus (Leptodactylidae, Hylodinae), which comprise small diurnal frogs that live associated with streams in areas of Atlantic Rainforest. In this study, we analyzed some aspects of the natural history of Crossodactylus aeneus in an area of Atlantic forest in the state of Rio de Janeiro, southeastern Brazil. A total of 37 individuals of C. aeneus were collected during the study, all of them associated with streams inside the forest. Most of the individuals (60%) were found on rocks. Most of the animals were collected during the day, although some were active at night. The diet of C. aeneus was composed of various arthropods, with beetles, ants, dipterans and insect larvae being the predominant items. Of the 21 collected females, eleven contained 70–127 unpigmented vitelogenic eggs.

Consumption of the whole or part of a reptile's own shed skin or that of a conspecific (keratophagy) has been documented in 248 species of lizards in 16 families and 19 snakes in four families. There are no authentic cases in turtles or crocodilians. An earlier review based primarily on zoo records noted keratophagy in 160 species of lizards, of which 16 were from literature sources designating field observations or stomach contents. We added an additional 16 captive observations for lizards and brought the total to 89 species for which this behavior has been documented in nature. Eating shed skins of conspecifics has been observed in 23 lizard species in five families. All of the 19 snake species known to have eaten their shed skins, except one, a Clelia clelia, were in captivity. We reviewed six hypotheses that may explain the occurrence and evolution of keratophagy. These are the Nutritional Hypothesis, Skin sensitivity hypothesis, Artificial Behavior Hypothesis in Snakes, Accidental Hypothesis, Predator Avoidance Hypothesis, and the Reduced Parasite Load Hypothesis. The Nutritional and Artificial hypotheses provide the least explanatory power for this behavior. The remaining four hypotheses have varying levels of predictability but each may function within different contexts. We provide recommendations for elucidation of these hypotheses in our discussions of them. Finally, our attempts at electronic searches were hindered because of the variation in the terminology used for this behavior, and because most authors did not include an appropriate term in their list of keywords or in the abstract. We recommend standardization of the term “keratophagy,” and that authors of diet and behavioral studies in which consumption of shed skin was observed include this term in abstracts and key words.

The tadpole of Aparasphenodon brunoi is described and illustrated for the first time (external morphology and internal oral features) from Maricá, State of Rio de Janeiro, Brazil. Characters of this tadpole include: body representing 30% of total length; eyes lateral; spiracle single, sinistral, with opening directed upward and backward; anal tube median; dorsal fin originating at the mid-third of body; caudal tip extended into a flagellum; oral disc anteroventral; and labial tooth row formula 2(2)/6(1). In general, body and tail brown. Tail with transverse dark brown stripes. Morphological comparisons were made with tadpoles of eight other pond and stream-dwelling casque-headed treefrog species of the genera Argenteohyla, Osteocephalus, and Trachycephalus. The tadpoles of the subspecies of Argenteohyla possess characteristics that may indicate full specific rank of these taxa, so that the taxonomic status of these subspecies should be revaluated. Considering that high number of tooth rows is usually associated with stream dwellers, the presence of this characteristic in A. brunoi tadpoles (a pond-dweller) may represent retention of an ancestral lotic pattern. Furthermore, the number of tooth rows in the posterior labium of A. brunoi corroborates the putative morphological synapomorphy of the tribe Lophiohylini (presence of at least four posterior labial tooth rows in the larval oral disc).

We describe the lizard assemblage from an Amazonian savanna in the region of Monte Alegre, Pará, Brazil, using ecological, morphological, and life history data, and examining the role of history in the assemblage. The lizard assemblage in Monte Alegre contained seven species. Microhabitat niche breadth was low for all species in the assemblage and niche overlap varied from none to almost complete. The least overlap in microhabitat occurred among more distantly related species and the greatest overlap occurred among teiids. Lizards were active between 9:00 and 17:00 h. Active foragers tended to be active during the hottest hours of day, whereas sit and wait foragers were more commonly observed later in the day, when temperatures were lower. Analysis of body temperatures identified two statistically homogeneous groups, one with teiids and another with the remaining species. Dietary overlap was highest among teiids. Pseudocommunity analyses showed that neither mean dietary overlap nor mean microhabitat overlap differed statistically from random, indicating lack of structure. Factor scores of morphological variables per species revealed clusters corresponding to lizard families. An examination of ecological traits mapped onto a tree depicting phylogenetic relationships among species and comparisons with related species from other biomes clearly indicated the role of history in the Monte Alegre lizard assemblage. This result was corroborated by Canonical Phylogenetic Ordination analysis.

Selection should favor individuals that can assess the quality of their future offspring′s habitat in terms of its physical features and the presence of competitors or predators. Studies have shown that the presence of tadpoles at a site may deter adults from ovipositing there as the tadpoles may become competitors for resources or predators on the smaller conspecifics. Here I investigate whether tadpole size influences oviposition site selection in the leptodactylid Pleurodema borellii. The study took place at a location in northwestern Argentina, where this species naturally occurs, during five consecutive years. Six identically-sized pools were placed near an artificial pond allowing the frogs to breed without interference. Number of adults present at each pool and number of foam nests were recorded. Tadpoles were divided into three size categories (small, medium, and large) and were sampled twice a week. Adult P. borellii significantly chose two out of six of the pools to lay their eggs when small tadpoles were present, whereas they significantly avoided all the pools when medium and large tadpoles were present. The results suggest that an important factor in oviposition site selection in P. borellii is tadpole size. Females accepted a location with small tadpoles, possibly an indicator of a suitable breeding site, but they avoided locations with medium and large tadpoles that could become potential competitors as well as predators on the new progeny.

The external morphology and internal buccal characteristics of Leptodactylus elenae tadpoles are described and compared with other Leptodactylus species. The external morphology and anatomy of the buccal cavity of L. elenae are similar to other Leptodactylus in the fuscus group and suggest a pond-larval diet. The most variable features among Leptodactylus species are the lingual papillae number and the lateral ridge papillae. The latter are small and lack terminal branches in tadpoles of L. elenae. Leptodactylus tadpoles exhibit variable morphology, sometimes convergent with other genera in the family. However, it seems that both external larval morphology and internal buccal features support the current groups of Leptodactylus.