Toe pad morphology and adhesion in the miniaturized gecko, Chatogekko amazonicus (Gekkota: Sphaerodactylidae).

Chatogekko amazonicus is a miniaturized gecko from northern South America and is among the smallest of toe pad bearing lizards. The toe pads of C. amazonicus are miniscule, between 18% and 27% of the plantar surface area. We aimed to investigate the relationship between adhesive toe pad morphology, body size, and adhesive capabilities. Using scanning electron microscopy, we determine that the adhesive pads of C. amazonicus exhibit branched setae similar to those of other geckos, but that are generally much smaller. When compared with other gecko taxa, we show that C. amazonicus setae occupy a similar range of seta length: snout-vent length ratio and aspect ratio as other gekkonoid species (i.e. Gekkonidae, Phyllodactylidae, and Sphaerodactylidae). We demonstrate that C. amazonicus-even with its relatively small toe pads-is capable of climbing a smooth glass surface at a nearly vertical angle. We suggest that sphaerodactylids like C. amazonicus offer an excellent system for studying toe pad morphology and function in relation to miniaturization.

Genetic structure and landscape effects on gene flow in the Neotropical lizard Norops brasiliensis (Squamata: Dactyloidae).

One key research goal of evolutionary biology is to understand the origin and maintenance of genetic variation. In the Cerrado, the South American savanna located primarily in the Central Brazilian Plateau, many hypotheses have been proposed to explain how landscape features (e.g., geographic distance, river barriers, topographic compartmentalization, and historical climatic fluctuations) have promoted genetic structure by mediating gene flow. Here, we asked whether these landscape features have influenced the genetic structure and differentiation in the lizard species Norops brasiliensis (Squamata: Dactyloidae). To achieve our goal, we used a genetic clustering analysis and estimate an effective migration surface to assess genetic structure in the focal species. Optimized isolation-by-resistance models and a simulation-based approach combined with machine learning (convolutional neural network; CNN) were then used to infer current and historical effects on population genetic structure through 12 unique landscape models. We recovered five geographically distributed populations that are separated by regions of lower-than-expected gene flow. The results of the CNN showed that geographic distance is the sole predictor of genetic variation in N. brasiliensis, and that slope, rivers, and historical climate had no discernible influence on gene flow. Our novel CNN approach was accurate (89.5%) in differentiating each landscape model. CNN and other machine learning approaches are still largely unexplored in landscape genetics studies, representing promising avenues for future research with increasingly accessible genomic datasets.

The role of environmental gradients and microclimates in structuring communities and functional groups of lizards in a rainforest-savanna transition area.

Environmental heterogeneity poses a significant influence on the functional characteristics of species and communities at local scales. Environmental transition zones, such as at the savanna-forest borders, can act as regions of ecological tension when subjected to sharp variations in the microclimate. For ectothermic organisms, such as lizards, environmental temperatures directly influence physiological capabilities, and some species use different thermoregulation strategies that produce varied responses to local climatic conditions, which in turn affect species occurrence and community dynamics. In the context of global warming, these various strategies confer different types of vulnerability as well as risks of extinction. To assess the vulnerability of a species and understand the relationships between environmental variations, thermal tolerance of a species and community structure, lizard communities in forest-savanna transition areas of two national parks in the southwestern Amazon were sampled and their thermal functional traits were characterized. Then, we investigated how community structure and functional thermal variation were shaped by two environmental predictors (i.e., microclimates estimated locally and vegetation structure estimated from remote sensing). It was found that the community structure was more strongly predicted by the canopy surface reflectance values obtained via remote sensing than by microclimate variables. Environmental temperatures were not the most important factor affecting the occurrence of species, and the variations in ecothermal traits demonstrated a pattern within the taxonomic hierarchy at the family level. This pattern may indicate a tendency for evolutionary history to indirectly influence these functional features. Considering the estimates of the thermal tolerance range and warming tolerance, thermoconformer lizards are likely to be more vulnerable and at greater risk of extinction due to global warming than thermoregulators. The latter, more associated with open environments, seem to take advantage of their lower vulnerability and occur in both habitat types across the transition, potentially out-competing and further increasing the risk of extinction and vulnerability of forest-adapted thermoconformer lizards in these transitional areas.

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.

Integrative species delimitation uncovers hidden diversity within the Pithecopus hypochondrialis species complex (Hylidae, Phyllomedusinae) and its phylogeography reveals Plio-Pleistocene connectivity among Neotropical savannas.

Despite their limited vagility and pronounced habitat heterogeneity in the tropics, many anuran species have unexpectedly extensive geographic ranges. One prominent example of this phenomenon is Pithecopus hypochondrialis, which is found in the Cerrado, Guianan savanna, and Llanos domains, as well as isolated tracts of savanna and open habitat within the Amazon Forest. The present study employs an integrative species delimitation approach to test the hypothesis that P. hypochondrialis is in fact a species complex. We also reconstruct the relationships among the lineages delimited here and other Pithecopus species. In this study, we employ Ecological Niche Modelling (ENM) and spatiotemporal phylogeographic reconstruction approaches to evaluate a multitude of scenarios of connectivity across the Neotropical savannas. We identified three divergent lineages, two of which have been described previously. The lineages were allocated to a lowland Pithecopus clade, although the relationships among these lineages are weakly supported. Both the ENM and the phylogeographic reconstruction highlight the occurrence of periods of connectivity among the Neotropical savannas over the course of the Pliocene and Pleistocene epochs. These processes extended from eastern Amazonia to the northern coast of Brazil. The findings of the present study highlight the presence of hidden diversity within P. hypochondrialis, and reinforce the need for a comprehensive taxonomic review. These findings also indicate intricate and highly dynamic patterns of connectivity across the Neotropical savannas that date back to the Pliocene.

Seasonal flooding decreases fruit-feeding butterfly species dominance and increases spatial turnover in floodplain forests of central Amazonia.

The seasonal flood pulse in Amazonia can be considered a primary driver of community structure in floodplain environments. Although this natural periodic disturbance is part of the landscape dynamics, the seasonal inundation presents a considerable challenge to organisms that inhabit floodplain forests. The present study investigated the effect of seasonal flooding on fruit-feeding butterfly assemblages in different forest types and strata in central Amazonia. We sampled fruit-feeding butterflies in the canopy and the understory using baited traps in adjacent upland (unflooded forests-terra firme), white and blackwater floodplain forests (várzea and igapó, respectively) during the low- and high-water seasons. Butterfly abundance decreased in the high-water season, especially of dominant species in várzea, but the number of species was similar between seasons in the three forest types. Species composition differed between strata in all forest types. However, the flood pulse only affected butterfly assemblages in várzea forest. The ß-diversity components also differed only in várzea. Species replacement (turnover) dominated the spatial ß-diversity in igapó and terra firme in both seasons and várzea in the high-water season. Nonetheless, nestedness was relatively higher in várzea forests during the low-water season, mainly due to the effect of dominant species. These results emphasize the importance of seasonal flooding to structure butterfly assemblages in floodplain forests and reveal the idiosyncrasy of butterfly community responses to flooding in different forest types. Our results also suggest that any major and rapid changes to the hydrological regime could severely affect floodplain communities adapted to this natural seasonal hydrological cycle, threatening the existence of these unique environments.

Two new species of geckos of the genus Phyllopezus Peters, 1878 (Squamata: Gekkota: Phyllodactylidae) from northeastern Brazil.

We describe two new species of Brazilian geckos of the genus Phyllopezus based on morphological and molecular data. The first species is currently known from a relictual Cerrado enclavecampos rupestres, in the mountains of the Serra do Espinhao in the state of Bahia. The second species is known from northeastern Atlantic Forest and transitional areas with Caatinga biome in the state of Alagoas. The two new species are sister taxa and together are the sister clade to the remaining species in the Phyllopezus pollicaris species complex. These new species can be morphologically distinguished from their congeners by meristic and morphometric characters, in addition to color pattern and genetic differentiation.

Diversity, biogeography, and reproductive evolution in the genus Pipa (Amphibia: Anura: Pipidae).

The genus Pipa is a species-poor clade of Neotropical frogs and one of the most bizarre-looking due to many highly derived anatomical traits related to their fully aquatic lifestyle. With their African relatives, they form the Pipidae family, which has attracted much attention, especially regarding its anatomy, reproductive biology, paleontology and biogeography. However, the actual diversity and phylogenetic relationships within Pipa remain poorly understood, and thus so do their historical biogeography and the evolution of striking features, such as the absence of teeth and endotrophy in some species. Using short mtDNA sequences across the distribution of the genus, we identified 15 main lineages (Operational Taxonomic Units - OTUs). This more than doubles the number of the currently seven valid nominal species. Several closely related OTUs do not share nuDNA alleles, confirming species divergence. Time-calibrated phylogenies obtained from mitogenomes and from 10 nuclear loci provide highly similar topologies but strikingly distinct node ages for Pipa. High dN/dS ratios and the variation of substitution rates across the trees suggest a strong effect of saturation on fast evolving positions of mtDNA, producing a substantially shorter stem branch of Pipa. Focusing on the nuDNA topology, we inferred an early Neogene Amazonian origin of the diversification of Pipa, with an initial split between the Guiana-Brazilian Shields and Western Amazonia, a pattern observed in many other co-distributed groups. All the western species are edentate, suggesting a single loss in the genus. Each of these groups diversified further out of Amazonia, toward the Atlantic Forest and toward trans-Andean forests, respectively. These events are concomitant with paleogeographic changes and match patterns observed in other co-distributed taxonomic groups. The two Amazonian lineages have probably independently acquired endotrophic larval development.

Gender, Race and Parenthood Impact Academic Productivity During the COVID-19 Pandemic: From Survey to Action.

The coronavirus disease 2019 (COVID-19) pandemic is altering dynamics in academia, and people juggling remote work and domestic demands - including childcare - have felt impacts on their productivity. Female authors have faced a decrease in paper submission rates since the beginning of the pandemic period. The reasons for this decline in women's productivity need to be further investigated. Here, we analyzed the influence of gender, parenthood and race on academic productivity during the pandemic period based on a survey answered by 3,345 Brazilian academics from various knowledge areas and research institutions. Productivity was assessed by the ability to submit papers as planned and to meet deadlines during the initial period of social isolation in Brazil. The findings revealed that male academics - especially those without children - are the least affected group, whereas Black women and mothers are the most impacted groups. These impacts are likely a consequence of the well-known unequal division of domestic labor between men and women, which has been exacerbated during the pandemic. Additionally, our results highlight that racism strongly persists in academia, especially against Black women. The pandemic will have long-term effects on the career progression of the most affected groups. The results presented here are crucial for the development of actions and policies that aim to avoid further deepening the gender gap in academia.

Phylogeographic model selection using convolutional neural networks.

The discipline of phylogeography has evolved rapidly in terms of the analytical toolkit used to analyse large genomic data sets. Despite substantial advances, analytical tools that could potentially address the challenges posed by increased model complexity have not been fully explored. For example, deep learning techniques are underutilized for phylogeographic model selection. In non-model organisms, the lack of information about their ecology and evolution can lead to uncertainty about which demographic models are appropriate. Here, we assess the utility of convolutional neural networks (CNNs) for assessing demographic models in South American lizards in the genus Norops. Three demographic scenarios (constant, expansion, and bottleneck) were considered for each of four inferred population-level lineages, and we found that the overall model accuracy was higher than 98% for all lineages. We then evaluated a set of 26 models that accounted for evolutionary relationships, gene flow, and changes in effective population size among the four lineages, identifying a single model with an estimated overall accuracy of 87% when using CNNs. The inferred demography of the lizard system suggests that gene flow between non-sister populations and changes in effective population sizes through time, probably in response to Pleistocene climatic oscillations, have shaped genetic diversity in this system. Approximate Bayesian computation (ABC) was applied to provide a comparison to the performance of CNNs. ABC was unable to identify a single model among the larger set of 26 models in the subsequent analysis. Our results demonstrate that CNNs can be easily and usefully incorporated into the phylogeographer's toolkit.

Phylogenetic relationships of the poorly known treefrog Boana hobbsi (Cochran amp; Goin, 1970) (Anura: Hylidae), systematic implications and remarks on morphological variations and geographic distribution.

Boana hobbsi is a poorly known hylid frog currently placed within the Boana punctata group. Yet, morphological, ecological and bioacoustic traits do not support this placement, with no molecular data being available to date to test this hypothesis. Based on newly collected mitochondrial DNA sequences, morphological data review and field observations, we provide new insight into the phylogenetic relationships, morphological variations and geographic distribution of B. hobbsi. Our findings reveal that B. hobbsi is nested (with strong support) within the Boana benitezi group, recovering once more a polyphyletic Boana punctata group. Supported by this new genetic, morphological and ecological evidence, we propose a new taxonomic arrangement which includes B. hobbsi as a member of the Boana benitezi group. Furthermore, we emphasize the importance of conducting biological inventories in remote Amazonian areas, where many taxonomic and geographic knowledge gaps persist with regards to Amphibian diversity.

Diversification history of clown tree frogs in Neotropical rainforests (Anura, Hylidae, Dendropsophus leucophyllatus group).

General consensus emphasizes that no single biological process can explain the patterns of species' distributions and diversification in the Neotropics. Instead, the interplay of several processes across space and time must be taken into account. Here we investigated the phylogenetic relationships and biogeographic history of tree frogs in the Dendropsophus leucophyllatus species group (Amphibia: Hylidae), which is distributed across Amazonia and the Atlantic rainforests. Using Next Generation Sequencing (NGS) and double digest restriction-site associated DNA (ddRADseq), we inferred phylogenetic relationships, species limits, and temporal and geographic patterns of diversification relative to the history of these biomes. Our results indicate that the D. leucophyllatus species group includes at least 14 independent lineages, which are currently arranged into ten described species. Therefore, a significant portion of species in the group are still unnamed. Different processes were associated to the group diversification history. For instance, the Andes uplift likely caused allopatric speciation for Cis-Andean species, whereas it may also be responsible for changes in the Amazonian landscape triggering parapatric speciation by local adaptation to ecological factors. Meanwhile, Atlantic Forest ancestors unable to cross the dry diagonal biomes after rainforest's retraction, evolved in isolation into different species. Diversification in the group began in the early Miocene, when connections between Atlantic Forest and the Andes (Pacific Dominion) by way of a south corridor were possible. The historical scenario in Amazonia, characterized by several speciation events and habitat heterogeneity, helped promoting diversification, resulting in the highest species diversity for the group. This marked species diversification did not happen in Atlantic Forest, where speciation is very recent (late Pliocene and Pleistocene), despite its remarkable climatic heterogeneity.

Pleistocene expansion and connectivity of mesic forests inside the South American Dry Diagonal supported by the phylogeography of a small lizard.

Traditionally focused on Amazonian and Atlantic rainforests, studies on the origins of high Neotropical biodiversity have recently shifted to also investigate biodiversity processes in the South American dry diagonal, encompassing Chaco, Cerrado savannas, and Caatinga seasonally dry tropical forests. The plateau/depression hypothesis states that riparian forests in the Brazilian Shield in central Brazil are inhabited by Pleistocene lineages, with shallow divergences and signatures of population expansion. Moreover, riparian forests may have acted as a vegetation network in the Pleistocene, allowing gene/species flow across the South American dry diagonal. We tested these hypotheses using Colobosaura modesta, a small gymnophthalmid lizard from forested habitats in the Cerrado savannas and montane/submontane forests in the Caatinga. We conducted phylogeographic analyses using a multi-locus dataset, tested alternative demographic scenarios with Approximate Bayesian Computation, and also employed species delimitation tests. We recovered a history of recent colonization and expansion along riparian forests, associated with Pleistocene climate shifts, and the existence of a new species of Colobosaura restricted to the Serra do Cachimbo region. We also present evidence that riparian forests have provided an interconnected network for forest organisms within the South American dry diagonal and that Pleistocene events played an important role in their evolutionary history.

The combined role of dispersal and niche evolution in the diversification of Neotropical lizards.

Ecological requirements and environmental conditions can influence diversification across temporal and spatial scales. Understanding the role of ecological niche evolution under phylogenetic contexts provides insights on speciation mechanisms and possible responses to future climatic change. Large-scale phyloclimatic studies on the megadiverse Neotropics, where biomes with contrasting vegetation types occur in narrow contact, are rare. We integrate ecological and biogeographic data with phylogenetic comparative methods, to investigate the relative roles of biogeographic events and niche divergence and conservatism on the diversification of the lizard genus Kentropyx Spix, 1825 (Squamata: Teiidae), distributed in South American rainforests and savannas. Using five molecular markers, we estimated a dated species tree, which recovered three clades coincident with previously proposed species groups diverging during the mid-Miocene. Biogeography reconstruction indicates a role of successive dispersal events from an ancestral range in the Brazilian Shield and western Amazonia. Ancestral reconstruction of climatic tolerances and niche overlap metrics indicates a trend of conservatism during the diversification of groups from the Amazon Basin and Guiana Shield, and a strong signal of niche divergence in the Brazilian Shield savannas. Our results suggest that climatic-driven divergence at dynamic forest-savanna borders might have resulted in adaptation to new environmental niches, promoting habitat shifts and shaping speciation patterns of Neotropical lizards. Dispersal and ecological divergence could have a more important role in Neotropical diversification than previously thought.

Patterns, Mechanisms and Genetics of Speciation in Reptiles and Amphibians.

In this contribution, the aspects of reptile and amphibian speciation that emerged from research performed over the past decade are reviewed. First, this study assesses how patterns and processes of speciation depend on knowing the taxonomy of the group in question, and discuss how integrative taxonomy has contributed to speciation research in these groups. This study then reviews the research on different aspects of speciation in reptiles and amphibians, including biogeography and climatic niches, ecological speciation, the relationship between speciation rates and phenotypic traits, and genetics and genomics. Further, several case studies of speciation in reptiles and amphibians that exemplify many of these themes are discussed. These include studies of integrative taxonomy and biogeography in South American lizards, ecological speciation in European salamanders, speciation and phenotypic evolution in frogs and lizards. The final case study combines genomics and biogeography in tortoises. The field of amphibian and reptile speciation research has steadily moved forward from the assessment of geographic and ecological aspects, to incorporating other dimensions of speciation, such as genetic mechanisms and evolutionary forces. A higher degree of integration among all these dimensions emerges as a goal for future research.

Embracing heterogeneity: coalescing the Tree of Life and the future of phylogenomics.

Building the Tree of Life (ToL) is a major challenge of modern biology, requiring advances in cyberinfrastructure, data collection, theory, and more. Here, we argue that phylogenomics stands to benefit by embracing the many heterogeneous genomic signals emerging from the first decade of large-scale phylogenetic analysis spawned by high-throughput sequencing (HTS). Such signals include those most commonly encountered in phylogenomic datasets, such as incomplete lineage sorting, but also those reticulate processes emerging with greater frequency, such as recombination and introgression. Here we focus specifically on how phylogenetic methods can accommodate the heterogeneity incurred by such population genetic processes; we do not discuss phylogenetic methods that ignore such processes, such as concatenation or supermatrix approaches or supertrees. We suggest that methods of data acquisition and the types of markers used in phylogenomics will remain restricted until a posteriori methods of marker choice are made possible with routine whole-genome sequencing of taxa of interest. We discuss limitations and potential extensions of a model supporting innovation in phylogenomics today, the multispecies coalescent model (MSC). Macroevolutionary models that use phylogenies, such as character mapping, often ignore the heterogeneity on which building phylogenies increasingly rely and suggest that assimilating such heterogeneity is an important goal moving forward. Finally, we argue that an integrative cyberinfrastructure linking all steps of the process of building the ToL, from specimen acquisition in the field to publication and tracking of phylogenomic data, as well as a culture that values contributors at each step, are essential for progress.