Relicts in the mist: Two new frog families, genera and species highlight the role of Pantepui as a biodiversity museum throughout the Cenozoic.

The iconic mountains of the Pantepui biogeographical region host many early-diverging endemic animal and plant lineages, concurring with Conan Doyle's novel about an ancient "Lost World". While this is the case of several frog lineages, others appear to have more recent origins, adding to the controversy around the diversification processes in this region. Due to its remoteness, Pantepui is challenging for biological surveys, and only a glimpse of its biodiversity has been described, which hampers comprehensive evolutionary studies in many groups. During a recent expedition to the Neblina massif on the Brazil-Venezuela border, we sampled two new frog species that could not be assigned to any known genus. Here, we perform phylogenetic analyses of mitogenomic and nuclear loci to infer the evolutionary relationships of the new taxa and support their description. We find that both species represent single lineages deeply nested within Brachycephaloidea, a major Neotropical clade of direct-developing frogs. Both species diverged >45 Ma from their closest relatives: the first is sister to all other Brachycephaloidea except for Ceuthomantis, another Pantepui endemic, and the second is sister to Brachycephalidae, endemic to the Brazilian Atlantic Forest. In addition to these considerable phylogenetic and biogeographic divergences, external morphology and osteological features support the proposition of two new family and genus-level taxa to accommodate these new branches of the amphibian tree of life. These findings add to other recently described ancient vertebrate lineages from the Neblina massif, providing a bewildering reminder that our perception of the Pantepui's biodiversity remains vastly incomplete. It also provides insights into how these mountains acted as "museums" during the diversification of Brachycephaloidea and of Neotropical biotas more broadly, in line with the influential "Plateau theory". Finally, these discoveries point at the yet unknown branches of the tree of life that may go extinct, due to global climate change and zoonotic diseases, before we even learn about their existence, amphibians living at higher elevations being particularly at risk.

Diversification of the terrestrial frog genus Anomaloglossus (Anura, Aromobatidae) in the Guiana Shield proceeded from highlands to lowlands, with successive loss and reacquisition of endotrophy.

Two main landscapes emerge from the Guiana Shield: the highlands to the west called the Pantepui region and the Amazonian lowlands to the east, both harbouring numerous endemic species. With 32 currently recognized species, the genus Anomaloglossus stands out among Neotropical frogs as one that diversified only within the Guiana Shield both in the highlands and the lowlands. We present a time-calibrated phylogeny obtained by using combined mitogenomic and nuclear DNA, which suggests that the genus originates from Pantepui where extant lineages started diversifying around 21 Ma, and subsequently (ca. 17 Ma) dispersed during the Miocene Climatic Optimum to the lowlands of the eastern Guiana Shield where the ability to produce endotrophic tadpoles evolved. Further diversification within the lowlands in the A. stepheni group notably led to an evolutionary reversal toward exotrophy in one species group during the late Miocene, followed by reacquisition of endotrophy during the Pleistocene. These successive shifts of reproductive mode seem to have accompanied climatic oscillations. Long dry periods might have triggered evolution of exotrophy, whereas wetter climates favoured endotrophic forms, enabling colonization of terrestrial habitats distant from water. Acquisition, loss, and reacquisition of endotrophy makes Anomaloglossus unique among frogs and may largely explain the current species diversity. The micro evolutionary processes involved in these rapid shifts of reproductive mode remain to be revealed.

Testing assertions of widespread introgressive hybridization in a clade of neotropical toads with low mate selectivity (Rhinella granulosa species group).

Discordance between different genomic regions, often identified through multilocus sequencing of selected markers, presents particular difficulties in identifying historical processes which drive species diversity and boundaries. Mechanisms causing discordance, such as incomplete lineage sorting or introgression due to interspecific hybridization, are better identified based on population-level genomic datasets. In the toads of the Rhinella granulosa species group, patterns of mito-nuclear discordance and potential hybridization have been reported by several studies. However, these patterns were proposed based on few loci, such that alternative mechanisms behind gene-tree heterogeneity cannot be ruled out. Using genome-wide ddRADseq loci from a subset of species within this clade, we found only partial concordance between currently recognized species-level taxon boundaries and patterns of genetic structure. While most taxa within the R. granulosa group correspond to clades, genetic clustering analyses sometimes grouped distinct taxonomic units into a single cluster. Moreover, levels of admixture between inferred clusters were limited and restricted to a single taxon pair which is best explained by incomplete lineage sorting as opposed to introgressive hybridization, according to D-statistics results. These findings contradict previous assertions of widespread cryptic diversity and gene flow within the R. granulosa clade. Lastly, our analyses suggest that diversification events within the Rhinella granulosa group mostly dated back to the early Pliocene, being generally younger than species divergences in other closely related clades that present high levels of cross-species gene flow. This finding uniquely contradicts common assertions that this young clade of toads exhibits interspecific hybridization.

A role of asynchrony of seasons in explaining genetic differentiation in a Neotropical toad.

The process of diversification can be studied at the phylogeographic level by attempting to identify the environmental features that promote and maintain population divergence. Here we investigate diversification in Rhinella granulosa, a Neotropical toad from northeastern Brazil, by testing a range of hypotheses that encompass different putative mechanisms reducing gene flow among populations. We sequenced single nucleotide polymorphisms and examined individual predictions related to the role of geographic barriers (rivers), ecological gradients, historical habitat stability, and spatial variation in climate seasonality, also known as the asynchrony of seasons hypothesis. This hypothesis postulates that temporal asynchrony of wet and dry seasons over short distances causes parapatric populations to become isolated by time. After determining genetic structure, inferring past distributions, ranking demographic models, and estimating the power of monthly climatic variables, our results identified two populations that are not associated with geographic barriers, biome gradients, or historical refugia. Instead, they are predicted by spatial variation in monthly rainfall and minimum temperature, consistent with the asynchrony of seasons hypothesis, supported also by our comparative framework using multiple matrix regression and linear mixed effects modeling. Due to the toad's life history, climate likely mediates gene flow directly, with genetic differentiation being provoked by neutral mechanisms related to climate driven population isolation, and/or by natural selection against migrants from populations with different breeding times. The asynchrony of seasons hypothesis is seldom considered in phylogeographic studies, but our results indicate that it should be tested in systems where breeding is tightly coupled with climate.

Effects of climate and geography on spatial patterns of genetic structure in tropical skinks.

Knowledge of how contemporary and historical factors drive patterns of genetic structure across geographic space can shed light on the processes underlying diversification. This approach is especially fruitful in studies of widespread species or species clades that occur across multiple environmental conditions and biomes. In the Neotropics, specifically, molecular data from widespread vertebrate species have revealed high levels of lineage diversity and spatial genetic structure - yet studies that explore the possible correlates of local structure patterns are lacking. We investigate the distribution of lineage diversity within two widespread South American skink species complexes of the genus Mabuya. We characterize genetic structure and diversity in these widely ranged lizards, and identify potential geographic and environmental correlates, to shed light on the processes that promote lineage diversification across the heterogeneous landscapes which they occupy. In both groups, we found mitochondrial lineages to be spatially structured along the coastal forests and the savannas of Brazil. These mtDNA patterns are, however, not shared with those inferred from nuclear DNA markers. The geographic location of major mitochondrial genetic breaks is consistent with those of other taxa, suggesting common responses to former landscape change in eastern South America, particularly along geological faults. Genetic differentiation is correlated with environmental turnover and geographic separation in one, but not in the other, group of skinks. Compared to other studies of similarly widely distributed organisms, the link between spatial environmental gradients and genetic differentiation is not as strong or consistent, suggesting a more complex history underlying current phylogeographic patterns. Our genetic data indicate the existence of yet undescribed diversity in wide-ranging lizards, and the value of phylogenetic and phylogeographic studies of similarly understudied species.

A dune with a view: the eyes of a neotropical fossorial lizard.

BACKGROUND: Lizards are excellent models to study the adaptations of the visual system to different scenarios, and surface-dwelling representatives have been relatively well studied. In contrast, very little is known about the functional anatomy of the eyes of fossorial lineages, and properties such as the light transmission by the ocular media have never been characterised in any fossorial species. Some lizards in the family Gymnophthalmidae endemic to the sand dunes of North Eastern Brazil have evolved sand-burrowing habits and nocturnal activity. Lizards in the sister group to Gymnophthalmidae, the family Teiidae, have decidedly diurnal and epigeal lifestyles, yet they are equally poorly known in terms of visual systems. We focussed on the eye anatomy, photoreceptor morphology and light transmittance properties of the ocular media and oil droplets in the gymnophthalmid Calyptommatus nicterus and the teiid Ameivula ocellifera. RESULTS: The general organisation of the eyes of the fossorial nocturnal C. nicterus and the epigeal diurnal A. ocellifera is remarkably similar. The lenses are highly transmissive to light well into the ultraviolet part of the spectrum. The photoreceptors have the typical cone morphology, with narrow short outer segments and oil droplets. The main difference between the two species is that C. nicterus has only colourless oil droplets, whereas A. ocellifera has colourless as well as green-yellow and pale-orange droplets. CONCLUSIONS: Our results challenge the assumption that fossorial lizards undergo loss of visual function, a claim that is usually guided by the reduced size and external morphology of their eyes. In the case of C. nicterus, the visual system is well suited for vision in bright light and shows specialisations that improve sensitivity in dim light, suggesting that they might perform some visually-guided behaviour above the surface at the beginning or the end of their daily activity period, when light levels are relatively high in their open dunes habitat. This work highlights how studies on the functional anatomy of sensory systems can provide insights into the habits of secretive species.

Measuring behavioral thermal tolerance to address hot topics in ecology, evolution, and conservation.

Understanding the impacts of anthropogenic climate change requires knowing how animals avoid heat stress, and the consequences of failing to do so. Animals primarily use behavior to avoid overheating, but biologists' means for measuring and interpreting behavioral signs of stress require more development. Herein, we develop the measurement of behavioral thermal tolerance using four species of lizards. First, we adapt the voluntary thermal maximum concept (VTM) to facilitate its measurement, interpretation, and comparison across species. Second, we evaluate the sensitivity of the VTM to diverse measurement options (warming rate, time of day, etc) across four species with highly different life histories. Finally, we clarify the interpretation of VTM in two ways. First, we show the effects of exposure to the VTM on panting behavior, mass loss, and locomotor function loss of two species. Second, we compared the VTM with the preferred body temperatures (PBT) and critical thermal maximum (CTMAX) intraspecifically. We found that the VTM can be consistently estimated through different methods and methodological options, only very slow warming rates affected its estimates in one species. Exposure to the VTM caused panting between 5 and 50 min and induced exceptionally high mass loss rates. Loss of locomotion function started after 205 min. Further, the VTM did not show intraspecific correlations with the PBT and CTMAX. Our study suggests the VTM is a robust and flexible measure of thermal tolerance and highlights the need for multispecies evaluations of thermal indices. The lack of correlation between the VTM, the PBT and CTMAX suggests the VTM may evolve relatively free between the other parameters. We make reccommendations for understanding and using the VTM in studies of ecology, evolution, and conservation.

Biogeographic links between southern Atlantic Forest and western South America: Rediscovery, re-description, and phylogenetic relationships of two rare montane anole lizards from Brazil.

Data on species ranges and phylogenetic relationships are key in historical biogeographical inference. In South America, our understanding of the evolutionary processes that underlie biodiversity patterns varies greatly across regions. Little is known, for instance, about the drivers of high endemism in the southern montane region of the Atlantic Rainforest. In this region, former biogeographic connections with other South American ecosystems have been invoked to explain the phylogenetic affinities of a number of endemic taxa. This may also be the case of the montane anole lizards Anolis nasofrontalis and A. pseudotigrinus, known from few specimens collected more than 40years ago. We combine new genetic data with published sequences of species in the Dactyloa clade of Anolis to investigate the phylogenetic relationships of A. nasofrontalis and A. pseudotigrinus, as well as estimate divergence times from their closest relatives. Based on newly sampled and previously overlooked specimens, we provide a taxonomic re-description of those two taxa. Our phylogenetic analysis recovered six main clades within Dactyloa, five of which were previously referred to as species series (aequatorialis, heterodermus, latifrons, punctatus, roquet). A sixth clade clustered A. nasofrontalis and A. pseudotigrinus with A. dissimilis from western Amazonia, A. calimae from the Andes, A. neblininus from the Guiana Shield, and two undescribed Andean taxa. We therefore define a sixth species series within Dactyloa: the neblininus series. Close phylogenetic relationships between highly disjunct, narrowly-distributed anoles suggest that patches of suitable habitat connected the southern Atlantic Forest to western South America during the Miocene, in agreement with the age of former connections between the central Andes and the Brazilian Shield as a result of Andean orogeny. The data also support the view of recurrent evolution (or loss) of a twig anole-like phenotype in mainland anoles, in apparent association with the occurrence in montane settings. Our findings stress the value of complementary genetic sampling efforts across South American countries to advance studies of mainland anole taxonomy and evolution.

Molecular data reveal spatial and temporal patterns of diversification and a cryptic new species of lowland Stenocercus Duméril & Bibron, 1837 (Squamata: Tropiduridae).

Phylogenetic studies have uncovered biogeographic patterns and the associated diversification processes of Neotropical wet forest taxa, yet the extensive open and drier biomes have received much less attention. In the Stenocercus lizard radiation, restricted sampling and phylogenetic information have limited inferences about the timing, spatial context, and environmental drivers of diversification in the open and dry lowland settings of eastern and southern South America. Based on new DNA sequence data of previously unsampled species, we provide an updated historical biogeographic hypothesis of Stenocercus. We infer phylogenetic relationships, estimate divergence times, and track ancestral distributions, asking whether cladogenetic events within the genus correlate to reported shifts in South American landscapes during the past 30millionyears, focusing in the open and drier areas. To examine correlations between genetic and ecological divergence, we extracted environmental data from occurrence records and estimated climatic envelopes occupied by lowland taxa. Our results suggest that Stenocercus began to diversify around the South American Midwest by the late Oligocene. We recovered two main lowland and two main Andean clades within the genus; within both Andean clades, most cladogenetic events date back to the Miocene, synchronously with the most intense phase of Andean uplift. In the western clade of lowland Stenocercus, species ranges and divergence times are consistent with major landscape shifts at the upper Guaporé and Paraguay River basins as a result of Andean orogeny, suggesting vicariant speciation. By contrast, in the 'horned' lowland clade, we find evidence that dispersal and ecological differentiation have shaped species divergences and current ranges in the Brazilian Cerrado, Caatinga, Pampas and Atlantic Forest, possibly under a vanishing refuge scenario. Lastly, our phylogenetic results indicate two divergent clades within the formerly recognized taxon S. sinesaccus, and further evaluation of morphological data corroborates the existence of a distinct, new species of Stenocercus, here described. The new taxon occurs in the Chapada dos Parecis massif in the Brazilian states of Mato Grosso and Rondônia.

Phylogenetic relationships of Amazonian anole lizards (Dactyloa): taxonomic implications, new insights about phenotypic evolution and the timing of diversification.

The ecology and evolution of Caribbean anoles are well described, yet little is known about mainland anole species. Lack of phylogenetic information limits our knowledge about species boundaries, morphological evolution, and the biogeography of anoles in South America. To help fill this gap, we provide an updated molecular phylogeny of the Dactyloa (Dactyloidae), with emphasis on the punctata species group. By sampling understudied Amazonian taxa, we (i) assess the phylogenetic placement of the 'odd anole', D. dissimilis; (ii) infer the relationships of the proboscis-bearing D. phyllorhina, testing the hypothesis of independent nasal appendage evolution within the anole radiation; and (iii) examine genetic and dewlap color variation in D. punctata and D. philopunctata. Combining multiple nuclear loci with a review of the fossil record, we also (iv) estimate divergence times within the pleurodont iguanian clade of lizards, including Amazonian representatives of Dactyloa and Norops (Dactyloidae) and of Polychrus (Polychrotidae). We recover the five Dactyloa clades previously referred to as the aequatorialis, heteroderma, latifrons, punctata and roquet species groups, as well as a sixth clade composed of D. dissimilis and the non-Amazonian D. neblinina and D. calimae. We find D. phyllorhina to be nested within the punctata group, suggesting independent evolution of the anole proboscis. We consistently recover D. philopunctata nested within D. punctata, and report limited genetic divergence between distinct dewlap phenotypes. The most recent common ancestor of Dactyloa, Anolis and Norops dates back to the Eocene. Most Amazonian taxa within both Dactyloa and Norops diverged in the Miocene, but some diversification events were as old as the late Eocene and late Oligocene. Amazonian Polychrus diverged in the Pliocene. Our findings have broad implications for anole biogeography, disputing recent suggestions that modern dactyloid genera were present in the Caribbean region during the Cretaceous.

Molecular phylogeny, species limits, and biogeography of the Brazilian endemic lizard genus Enyalius (Squamata: Leiosauridae): an example of the historical relationship between Atlantic Forests and Amazonia.

The endemic Brazilian Enyalius encompasses a diverse group of forest lizards with most species restricted to the Atlantic Forest (AF). Their taxonomy is problematic due to extensive variation in color pattern and external morphology. We present the first phylogenetic hypothesis for the genus based on 2102 bp of the mtDNA (cyt-b, ND4, and 16S) and nuclear (c-mos) regions, uncovering all previously admitted taxa (9 spp). Different methods of tree reconstruction were explored with Urostrophus vautieri, Anisolepis grilli and A. longicauda as outgroups. The monophyly of Enyalius and its split into two deeply divergent clades (late Oligocene and early Miocene) is strongly supported. Clade A assembles most lineages restricted to south and southeastern Brazil, and within it Enyalius brasiliensis is polyphyletic; herein full species status of E. brasiliensis and E. boulengeri is resurrected. Clade B unites the Amazonian E. leechii as sister-group to a major clade containing E. bilineatus as sister-group to all remaining species from northeastern Brazil. We detected unrecognized diversity in several populations suggesting putative species. Biogeographical analyses indicate that Enyalius keeps fidelity to shadowed forests, with few cases of dispersal into open regions. Ancient dispersal into the Amazon from an AF ancestor may have occurred through northeastern Brazil.

Does heat tolerance actually predict animals' geographic thermal limits?

The "climate extremes hypothesis" is a major assumption of geographic studies of heat tolerance and climatic vulnerability. However, this assumption remains vastly untested across taxa, and multiple factors may contribute to uncoupling heat tolerance estimates and geographic limits. Our dataset includes 1000 entries of heat tolerance data and maximum temperatures for each species' known geographic limits (hereafter, Tmax). We gathered this information across major animal taxa, including marine fish, terrestrial arthropods, amphibians, non-avian reptiles, birds, and mammals. We first tested if heat tolerance constrains the Tmax of sites where species could be observed. Secondly, we tested if the strength of such restrictions depends on how high Tmax is relative to heat tolerance. Thirdly, we correlated the different estimates of Tmax among them and across species. Restrictions are strong for amphibians, arthropods, and birds but often weak or inconsistent for reptiles and mammals. Marine fish describe a non-linear relationship that contrasts with terrestrial groups. Traditional heat tolerance measures in thermal vulnerability studies, like panting temperatures and the upper set point of preferred temperatures, do not predict Tmax or are inversely correlated to it, respectively. Heat tolerance restricts the geographic warm edges more strongly for species that reach sites with higher Tmax for their heat tolerance. These emerging patterns underline the importance of reliable species' heat tolerance indexes to identify their thermal vulnerability at their warm range edges. Besides, the tight correlations of Tmax estimates across on-land microhabitats support a view of multiple types of thermal challenges simultaneously shaping ranges' warm edges for on-land species. The heterogeneous correlation of Tmax estimates in the ocean supports the view that fish thermoregulation is generally limited, too. We propose new hypotheses to understand thermal restrictions on animal distribution.

Unexpected phylogenetic positions of the genera Rupirana and Crossodactylodes reveal insights into the biogeography and reproductive evolution of leptodactylid frogs.

Despite major progress in deciphering the amphibian tree of life by molecular phylogenetics, we identified two questions remaining to be answered regarding relationships within Hyloidea, the clade of South American origin that comprises most extant anuran diversity. A few genera like Rupirana and Crossodactylodes have enigmatic phylogenetic positions, and relationships among major lineages within some families like Leptodactylidae remain ambiguous. To resolve these specific questions we used two approaches (1) a complete matrix approach representing >6.6 kb, including most major Hyloidea lineages (61 terminals) combining different methods of phylogenetic reconstruction and measures of node support; and (2) a supermatrix approach >11.6 kb with a focus on Leptodactylidae. Both Rupirana and Crossodactylodes are unambiguously grouped with Paratelmatobius and Scythrophrys. The clade comprising these four genera is named Crossodactylodinae and embedded within Leptodactylidae. Crossodactylodinae is moderately supported as sister group of Leptodactylinae from (1) and as the sister group of the other Leptodactylidae from (2) with low support. Genera within Crossodactylodinae are scattered along a north-south axis in the Atlantic forest and their origins are very ancient (Paleocene). Such results stress the importance of the northern Atlantic forest in terms of conservation. Moreover, the position of Pseudopaludicola, which is well supported as the sister group to all other Leiuperinae, suggests that foam-nest building may have arisen independently in Leptodactylinae and Leiuperinae. Moreover, in spite of being of similar age, foam-nest builders are more widespread than nonfoam-nest breeders and have higher species diversity. Nevertheless, the bulk of the diversity within foam-nest breeders arose some 20 Myr later than the character itself.

A new Crossodactylodes Cochran, 1938 (Anura: Leptodactylidae: Paratelmatobiinae) from the highlands of the Atlantic Forests of southern Bahia, Brazil.

A new Crossodactylodes is described from Serra das Lontras, in the highlands of the Atlantic Forests of southern Bahia. The new species can be distinguished from all other Crossodactylodes by having Finger I ending in an acute tip, a larger body size, by cranial features, and by molecular data. Like their congeners, the new species live in bromeliads but is widely geographically disjunct, being apparently restricted to the summit of a mountain range in Northeastern Brazil.

A new species of Leposoma (Squamata: Gymnophthalmidae) with four fingers from the Atlantic Forest central corridor in Bahia, Brazil.

Leposoma sinepollex sp. nov., a new species of the scincoides group, is described from a mountain region in the Atlantic Forest central corridor in state of Bahia, Brazil. The new species is characterized by elongate dorsal and lanceolate ventral scales arranged in diagonal rows, a single and smooth frontonasal, five supraoculars, absence of pollex, third toe as long as or longer than fourth, absence of striations in lower part of head, parietals longer than wide and as long as interparietal, 27-29 dorsals, 25-29 scales around body, 17-19 ventrals, 12-14 total pores in the male (absent in females), 9-10 and 9-11 subdigital lamellae respectively under IV Finger and IV Toe, and strong sexual color dichromatism with a black pigmentation in the ventral parts of males, creamy in females. The new species is morphologically similar to Leposoma nanodactylus, sharing with it among other features the synapomorphic division of the first supraocular. Phylogenetic analyses of 981 bp of combined sequences (cyt b+ ND4) recovered also a strongly supported (PP = 1,0; BP = 100) sister relationship between both species. The new species and Leposoma nanodactylus are placed sister to all the other Atlantic Forest species, with L. baturitensis being the first to diverge in this radiation. We discuss the distribution of the Atlantic Forest Leposoma, as well as possible scenarios for the origin of the new species.

A new species of lizard genus Potamites from Ecuador (Squamata, Gymnophthalmidae).

Potamitesflavogularis sp. nov. is described from the Napo and Tungurahua Provinces around 1800 m elevation in eastern Ecuador. The new species is closely related, sibling, and sympatric to Potamites cochranae to which it has been previously confused. It is characterized by the absence of isolated basal flounces of spines and presence of calcareous spinules on flounces of the hemipenis, a short (1,30-1,41 times SVL) and slightly compressed tail without tubercles, tympanum slightly recessed, subimbricate ventral scales, lateral body scales lacking conspicuous enlarged tubercles, four longitudinal rows of dorsal tubercles, 6 transverse series of ventral scales, absence of intercalated scales along sides of tail, and absence of tubercles on sides of neck and gular regions. Like their congeners, the new species was found close to vegetation surrounding streams in primary and secondary forests.

Two new species of Proceratophrys Miranda-Ribeiro, 1920 (Anura; Odontophrynidae) from the Atlantic forest, with taxonomic remarks on the genus.

We describe two new species of Proceratophrys allied to the P. appendiculata species complex by the presence of single and long palpebral appendages and a triangular rostral appendage. Proceratophrys izecksohni sp. nov. is characterized by having small to medium size (SVL 32.1-54.2 mm in males), elongated hindlimbs (thigh length plus tibia length corresponding to more than 90% of snout-vent length), a broad head (head width corresponding to 55% of the snout-vent length), and by the light brown gular region and a cream colored ventral surface with scattered brown dots. Proceratophrys belzebul sp. nov. is characterized by its medium size (SVL 40.5-51.3 mm in males), by the absence of contact between the nasals bones and between the nasals and frontoparietals, by a very reduced iliac projection, by having frontoparietal bones very depressed and broad rostrally, by the smooth surface of the squamosal and nasal, by shallow, inconspicuous ventral pits on the maxillae, and by the females presenting the gular region dark brown. The two new species were previously confused with P. appendiculata for which we provide a new diagnosis. A molecular analysis based on mitochondrial and nuclear genes recovers a monophyletic Proceratophrys with high support, and the two new species in a clade with P. appendiculata and P. tupinamba. The data also reinforce the idea that the species groups presently admitted to the genus are not monophyletic.

A new species of Bachia Gray, 1845 (Squamata: Gymnophthalmidae) from the Eastern Brazilian Cerrado, and data on its ecology, physiology and behavior.

A new species of Bachia of the bresslaui group, Bachia geralista sp. nov., is described from Planalto dos Gerais, an old and partially dissected plateau extending along the Cerrados of Bahia, Minas Gerais and Tocantins states, Brazil. The new species is morphologically similar to B. bresslaui, with which it has been confused; however head scalation resembles other species from sandy spots within the Cerrado (B. psamophila and B. oxyrhina). Like in B. psamophila and B. oxyrhina, the shovel-shaped snout of the new species is highly prominent, a typical trait of psammophilous habits in other gymnophthalmids. The examination of specimens of B. bresslaui from several populations within the Cerrado revealed great variation among localities, leading to the reidentification of a specimen from Utiariti, Mato Grosso, previously referred to in the literature as the second record of B. bresslaui, as the recently described B. didactyla, suggesting that cryptic diversity might remain still undiscovered within this genus in the Cerrado. Despite occurring in a relatively open Cerrado, thermal physiology of Bachia geralista sp. nov. restricts its occurrence to shaded microhabitats within this habitat.

Rediscovery of the earless microteiid lizard Anotosaura collaris Amaral, 1933 (Squamata: Gymnophthalmidae): a redescription complemented by osteological, hemipenial, molecular, karyological, physiological and ecological data.

More than a century after its discovery by Ernest Garbe, and almost 80 years after its original description, we obtained a series of specimens of the earless gymnophthalmid Anotosaura collaris, the type species of the genus, up to now known only by a single specimen. On the basis of the material obtained at and close to the type locality we redescribe the species, adding information about the external and hemipenial morphology, osteology and karytoype. Molecular data confirm its sister relationship with Anotosaura vanzolinia as well as the close relationship of Anotosaura with the Ecpleopodini Colobosauroides and Dryadosaura. We supplement this information with thermophysiological, ecogeographical, karyotypic and ecological data.

Dehydration alters behavioral thermoregulation and the geography of climatic vulnerability in two Amazonian lizards.

High temperatures and low water availability often strike organisms concomitantly. Observing how organisms behaviorally thermohydroregulate may help us to better understand their climatic vulnerability. This is especially important for tropical forest lizards, species that are purportedly under greater climatic risk. Here, we observed the influence of hydration level on the Voluntary Thermal Maximum (VTmax) in two small Amazonian lizard species: Loxopholis ferreirai (semiaquatic and scansorial) and Loxopholis percarinatum (leaf litter parthenogenetic dweller), accounting for several potential confounding factors (handling, body mass, starting temperature and heating rate). Next, we used two modeling approaches (simple mapping of thermal margins and NicheMapR) to compare the effects of dehydration, decrease in precipitation, ability to burrow, and tree cover availability, on geographic models of climatic vulnerability. We found that VTmax decreased with dehydration, starting temperature, and heating rates in both species. The two modeling approaches showed that dehydration may alter the expected intensity, extent, and duration of perceived thermal risk across the Amazon basin for these forest lizards. Based on our results and previous studies, we identify new evidence needed to better understand thermohydroregulation and to model the geography of climatic risk using the VTmax.