Lizard Assemblages from Natural Cerrado Enclaves in Southwestern Amazonia: The Role of Stochastic Extinctions and Isolation1

Diversity patterns of lizard assemblages from a protected habitat mosaic in the Brazilian Cerrado savanna

Differences in habitat complexity and structure can directly influence the composition, diversity, and structure of species assemblages. Measurements of functional and phylogenetic diversity complement the commonly used measurements of taxonomic diversity, elucidating the relationships between species, their traits, and their evolutionary history. In this study, we evaluated how the mosaic of open and forested formations in a federal conservation unit in the western portion of the Brazilian Cerrado savanna influences the taxonomic, functional, and phylogenetic structure of lizard assemblages. Lizards were sampled for 15 months using pitfall traps set in open and forested formations. We recorded 292 lizards distributed among 16 species from eight families, with species composition differing among the formations. Richness was greater in the assemblages from open formations, while functional diversity and phylogenetic variability were greater in those of forested formations. Lizard assemblages in open formations were functionally and phylogenetically clustered, probably as a result of environmental filters acting on species, while the assemblages from forested formations were randomly structured. Different environmental and historical mechanisms have apparently shaped the current diversity of lizards in the region. This study shows that Cerrado vegetation mosaics can promote wide variation in different aspects of the taxonomic, functional, and phylogenetic structure from the lizard assemblages.

Taxonomic revision of the genus Xenopholis Peters, 1869 (Serpentes: Dipsadidae): Integrating morphology with ecological niche

A reliable identification and delimitation of species is an essential pre-requisite for many fields of science and conservation. The Neotropical herpetofauna is the world's most diverse, including many taxa of uncertain or debated taxonomy. Here we tackle one such species complex, by evaluating the taxonomic status of species currently allocated in the snake genus Xenopholis (X. scalaris, X. undulatus, and X. werdingorum). We base our conclusions on concordance between quantitative (meristic and morphometric) and qualitative (color pattern, hemipenes and skull features) analyses of morphological characters, in combination with ecological niche modeling. We recognize all three taxa as valid species and improve their respective diagnosis, including new data on color in life, pholidosis, bony morphology, and male genitalia. We find low overlap among the niches of each species, corroborating the independent source of phenotypic evidence. Even though all three species occur in the leaf litter of distinct forested habitats, Xenopholis undulatus is found in the elevated areas of the Brazilian Shield (Caatinga, Cerrado and Chaco), whereas X. scalaris occurs in the Amazon and Atlantic rainforests, and X. werdingorum in the Chiquitanos forest and Pantanal wetlands. We discuss the disjunct distribution between Amazonian and Atlantic Forest snake species in the light of available natural history and ecological aspects. This study shows the advantages of combining multiple data sources for reliable identification and circumscription of ecologically similar species.

A brief history of research in campo rupestre: identifying research priorities and revisiting the geographical distribution of an ancient, widespread Neotropical biome

Few ecologists and evolutionary biologists are familiar with the ecology and evolution of the campo rupestre, an ancient azonal peinobiome characterized by a fire-prone, nutrient-impoverished, montane vegetation mosaic, home to thousands of endemics and climate refugia. With the goal of providing a synthetic view of the campo rupestre, we provide a brief historical account of the biological research, revisit its geographical distribution and identify knowledge gaps. The azonal campo rupestre is distributed as isolated and naturally fragmented sky islands, mostly in Central and Eastern Brazil and in the Guyana Shield, with significant areas across the Amazon, Cerrado, Atlantic Forest, Caatinga and Pantanal. Our proposal to elevate campo rupestre to the level of biome is expected to improve communication among scientists and consolidate the use of the term campo rupestre in the ecological and evolutionary literature, as is the case for analogous ecosystems, such as kwongan, fynbos, páramos and tepuis. Based on the identification of knowledge gaps, we propose a research programme comprising ten key topics that can foster our understanding of the ecology and evolution of campo rupestre and, potentially, support conservation strategies.

Eight in one: morphological and molecular analyses reveal cryptic diversity in Amazonian alopoglossid lizards (Squamata: Gymnophthalmoidea)

Among the currently recognized species of Alopoglossus, the Amazonian Alopoglossus angulatus has the widest distribution. We here analyse variation in scutellation and morphometrics of A. angulatus by examining 785 specimens of Alopoglossus. We also analyse intra- and interspecific genetic structure and differentiation using two mitochondrial (Cytb and ND4) and two nuclear (SNCAIP and PRLR) genes from 97 samples. Both morphological and molecular analyses are based on specimens and samples from Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru and Suriname. Our results reveal A. angulatus as a monophyletic group composed of eight independently evolved lineages: A. angulatus s.s. plus three revalidated species plus two newly described species plus two putative species. We provide descriptions of all taxa, except for the putative species, including the first description of the neotype of A. angulatus and redescriptions of resurrected junior synonyms. Illustrations, diagnoses and geographical distribution maps are provided. Gene and species trees are also provided. The two new taxa recognized in this paper, along with the revalidation of three taxa, increase the total number of known species of Alopoglossus from nine to 14.

Comparative phylogeography of mainland and insular species of Neotropical molossid bats (Molossus)

Historical events, habitat preferences, and geographic barriers might result in distinct genetic patterns in insular versus mainland populations. Comparison between these two biogeographic systems provides an opportunity to investigate the relative role of isolation in phylogeographic patterns and to elucidate the importance of evolution and demographic history in population structure. Herein, we use a genotype-by-sequencing approach (GBS) to explore population structure within three species of mastiff bats (Molossus molossus, M. coibensis, and M. milleri), which represent different ecological histories and geographical distributions in the genus. We tested the hypotheses that oceanic straits serve as barriers to dispersal in Caribbean bats and that isolated island populations are more likely to experience genetic drift and bottlenecks in comparison with highly connected ones, thus leading to different phylogeographic patterns. We show that population structures vary according to general habitat preferences, levels of population isolation, and historical fluctuations in climate. In our dataset, mainland geographic barriers played only a small role in isolation of lineages. However, oceanic straits posed a partial barrier to the dispersal for some populations within some species (M. milleri), but do not seem to disrupt gene flow in others (M. molossus). Lineages on distant islands undergo genetic bottlenecks more frequently than island lineages closer to the mainland, which have a greater exchange of haplotypes.

Dietary niche variation and its relationship to lizard population density

Insular species are predicted to broaden their niches, in response to having fewer competitors. They can thus exploit a greater proportion of the resource spectrum. In turn, broader niches are hypothesized to facilitate (or be a consequence of) increased population densities. We tested whether insular lizards have broader dietary niches than mainland species, how it relates to competitor and predator richness, and the nature of the relationship between population density and dietary niche breadth. We collected population density and dietary niche breadth data for 36 insular and 59 mainland lizard species, and estimated competitor and predator richness at the localities where diet data were collected. We estimated dietary niche shift by comparing island species to their mainland relatives. We controlled for phylogenetic relatedness, body mass and the size of the plots over which densities were estimated. We found that island and mainland species had similar niche breadths. Dietary niche breadth was unrelated to competitor and predator richness, on both islands and the mainland. Population density was unrelated to dietary niche breadth across island and mainland populations. Our results indicate that dietary generalism is not an effective way of increasing population density nor is it result of lower competitive pressure. A lower variety of resources on islands may prevent insular animals from increasing their niche breadths even in the face of few competitors.

Null models for understanding fairy shrimp habitats

The Chilean fairy shrimp species are represented by the Branchinecta genus, which are poorly described, and mainly occur in shallow ephemeral pools in the Atacama Desert of northern Chile and the Southern Chilean Patagonian plains. The aim of the present study was to perform an initial ecological characterization of Branchinecta habitats and its associated communities in the Chilean Southern Patagonian plains (45-53°S) using null models (co-occurrence, niche sharing and size overlap). The results of the co-occurrence analysis revealed that the species’ associations are structured, meaning that at different kinds of Branchinecta habitats, the associated species are different. I did not find niche sharing, which means interspecific competition is absent. Finally the size overlap analysis revealed structured patterns, which are probably due to environmental homogeneity or colonization extinction processes. The habitats studied are shallow ephemeral pools, with extreme environmental conditions, where continuous local colonization and extinction processes probably occur, which would explain the marked Branchinecta species endemism.

Effect of fragmentation on the Costa Rican dry forest avifauna

Deforestation and changes in land use have reduced the tropical dry forest to isolated forest patches in northwestern Costa Rica. We examined the effect of patch area and length of the dry season on nestedness of the entire avian community, forest fragment assemblages, and species occupancy across fragments for the entire native avifauna, and for a subset of forest dependent species. Species richness was independent of both fragment area and distance between fragments. Similarity in bird community composition between patches was related to habitat structure; fragments with similar forest structure have more similar avian assemblages. Size of forest patches influenced nestedness of the bird community and species occupancy, but not nestedness of assemblages across patches in northwestern Costa Rican avifauna. Forest dependent species (species that require large tracts of mature forest) and assemblages of these species were nested within patches ordered by a gradient of seasonality, and only occupancy of species was nested by area of patches. Thus, forest patches with a shorter dry season include more forest dependent species.

Lizard assemblage from a sand dune habitat from southeastern Brazil: a niche overlap analysis

ABSTRACT Communities are structured by interactions of historical and ecological factors, which influence the use of different resources in time and space. We acquired data on time of activity, microhabitat use and diet of a lizard assemblage from a sand dune habitat in a coastal area, southeastern Brazil (Restinga de Jurubatiba). We analyzed the data of niche overlap among species in these three axes (temporal, spatial and trophic) using null models. We found a significant overlap within the trophic niche, whereas the overlap for the other axes did not differ from the expected. Based on this result, we discuss the factors acting on the structure of the local lizard community.

Conserving Biogeography: Habitat Loss and Vicariant Patterns in Endemic Squamates of the Cerrado Hotspot

Little is known about the threat levels and impacts of habitat loss over the Cerrado Squamate fauna. The region is under severe habitat loss due to mechanized agriculture, accelerated by changes in the Brazilian National Forest Code. The Squamate fauna of the Cerrado is rich in endemics and is intrinsically associated with its surrounding microhabitats, which make up a mosaic of phitophysiognomies throughout the region. Herein we evaluate current conservation status of Squamate biogeographic patterns in the Brazilian Cerrado, the single savanna among global biodiversity hotspots. To do so, we first updated point locality data on 49 endemic Squamates pertaining to seven non-random clusters of species ranges in the Cerrado. Each cluster was assumed to be representative of different biogeographic regions, holding its own set of species, herein mapped according to their extent of occurrence (EOO). We then contrasted these data in four different scenarios, according to the presence or absence of habitat loss and the presence or absence of the current protected area (PA) cover. We searched for non-random patterns of habitat loss and PA coverage among these biogeographic regions throughout the Cerrado. Finally, with the species EOO as biodiversity layers, we used Zonation to discuss contemporary PA distribution, as well as to highlight current priority areas for conservation within the Cerrado. We ran Zonation under all four conservation scenarios mentioned above. We observed that habitat loss and PA coverage significantly differed between biogeographic regions. The southernmost biogeographic region is the least protected and the most impacted, with priority areas highly scattered in small, disjunct fragments. The northernmost biogeographic region (Tocantins-Serra Geral) is the most protected and least impacted, showing extensive priority areas in all Zonation scenarios. Therefore, current and past deforestation trends are severely threatening biogeographic patterns in the Cerrado. Moreover, PA distribution is spatially biased, and does not represent biogeographic divisions of the Cerrado. Consequently, we show that biogeographic patterns and processes are being erased at an accelerated pace, reinforcing the urgent need to create new reserves and to avoid the loss of the last remaining fragments of once continuous biogeographic regions. These actions are fundamental and urgent for conserving biogeographic and evolutionary information in this highly imperiled savanna hotspot.

Species richness and evidence of random patterns in assemblages of South American Titanosauria during the Late Cretaceous (Campanian-Maastrichtian)

The Titanosauria were much diversified during the Late Cretaceous, but paleobiological information concerning these sauropods continues to be scarce and no studies have been conducted utilizing modern methods of community analysis to infer possible structural patterns of extinct assemblages. The present study sought to estimate species richness and to investigate the existence of structures in assemblages of the South American Titanosauria during the Late Cretaceous. Estimates of species richness were made utilizing a nonparametric estimator and null models of species co-occurrences and overlapping body sizes were applied to determine the occurrence of structuring in this assemblages. The high estimate of species richness (n = 57) may have been influenced by ecological processes associated with extinction events of sauropod groups and with the structures of the habitats that provided abundant support to the maintenance of large numbers of species. The pseudocommunity analysis did not differ from that expected by chance, indicating the lack of structure in these assemblages. It is possible that these processes originated from phylogenetic inertia, associated with the occurrence of stabilized selection. Additionally, stochastic extinction events and historical factors may also have influenced the formation of the titanosaurian assemblages, in detriment to ecological factors during the Late Cretaceous. However, diagenetic and biostratinomic processes, influenced by the nature of the sedimentary paleoenvironment, could have rendered a random arrangement that would make assemblage structure undetectable.

Cercosaura ocellata Wagler, 1830 (Lacertilia, Gymnophthalmidae): distribution extension of Northeastern Brazil

The lizard, Cercosaura ocellata, with its type-locality suggested as being South America's Northeast, is widely distributed in the North and Midwest regions of Brazil, with scarcity of records for the states in the Northeast Region. This work aims to enlarge the geographical distribution of this species. An individual of C. ocellata was registered in a fragment of Atlantic Rain Forest, Mata de Tejipió (08° 05′ 45.59″ S, 34° 57′ 04.91″ W). This register expands its distribution 585 km north and 770 km south, respectively from its closest locations, Bahia and Ceará, filling a gap of disjunct distribution of approximately 900 km in the northeast region of the country.

Biogeography of the lizard genus Tropidurus Wied-Neuwied, 1825 (Squamata: Tropiduridae): distribution, endemism, and area relationships in South America

Based on comprehensive distributional records of the 23 species currently assigned to the lizard genus Tropidurus, we investigated patterns of endemism and area relationships in South America. Two biogeographic methods were applied, Parsimony Analysis of Endemicity (PAE) and Brooks Parsimony Analysis (BPA). Two areas of endemism were detected by PAE: the first within the domains of the semiarid Brazilian Caatinga, which includes seven endemic species, and the second in the region of the Serranía de Huanchaca, eastern Bolivia, in which three endemic species are present. The area cladograms recovered a close relationship between the Atlantic Forest and areas of the South American open corridor. The results revealed a close relationship among the provinces Caatinga (Cerrado, Parana Forest (Pantanal+Chaco)). The uplift of the Brazilian Central Plateau in the Late Pliocene-Early Pleistocene (4-2 Myr BP) has been interpreted as a major event responsible for isolation and differentiation of biotas along these areas. However, we emphasize that without the establishment of a temporal framework concerning the diversification history of Tropidurus it is premature to correlate cladogenetic events with specific time periods or putative vicariant scenarios. The limiting factors hampering the understanding of the biogeographic history of this genus include (1) the absence of temporal references in relation to the diversification of distinct clades within Tropidurus; (2) the lack of an appropriate taxonomic resolution of the species complexes currently represented by widely distributed forms; and (3) the need for a comprehensive phylogenetic hypothesis. We suggest that these three important aspects should be prioritized in future investigations.

Serpentes do Estado de Rondônia, Brasil

Esse estudo teve como objetivo atualizar a lista de serpentes do estado de Rondônia a partir de levantamento bibliográfico, e fornecer algumas informações sobre a distribuição das espécies. São registradas para o estado de Rondônia 118 espécies de serpentes, pertencentes a oito famílias: Leptotyphlopidae (4 espécies), Typhlopidae (1), Aniliidae (1), Boidae (6), Colubridae (21), Dipsadidae (67), Elapidae (9) e Viperidae (9). Dessas, 109 foram registradas para áreas de floresta amazônica e 27 em cerrado. A menor riqueza encontrada em cerrado (27 espécies) provavelmente deve estar associada aos poucos trabalhos desenvolvidos nessas áreas e pelo fato dessa formação vegetal ocupar uma área de cerca de apenas 5% do estado. Nove espécies (Epicrates crassus, Chironius flavolineatus, Drymoluber brazili, Apostolepis striata, Oxyrhopus rhombifer, Pseudoboa nigra, Xenodon merremii, Bothrops mattogrossensis e Crotalus durissus) foram registradas exclusivamente em áreas de cerrado, sendo formas associadas a esse ambiente na Amazônia. Seis espécies (Masticophis mentovarius, Apostolepis striata, Erythrolamprus mimus, Micrurus mipartitus, Micrurus sp. e Bothrocophias microphthalmus) são conhecidas no Brasil apenas para Rondônia. Existem lacunas sobre o conhecimento das serpentes em algumas regiões de Rondônia, sendo essencial a realização de mais estudos de inventário. Tal necessidade se torna mais urgente devido à crescente destruição dos habitats ao longo do Cerrado e nas porções sul da Amazônia.

Assessing patterns of nestedness and co-occurrence in coastal pond anuran assemblages

Segregated species co-occurrence and nestedness are two ecological patterns used to measure assemblage structure. We investigated species co-occurrence and nestedness patterns in assemblages of tadpoles and adult anurans in 30 coastal ponds in southern Brazil. Ponds varied in hydroperiod and were classified as temporary or permanent. We explored whether co-occurrence or nestedness varied among ponds in each hydroperiod. Species co-occurrence patterns were analyzed using the C-score index and three null models. In order to quantify nestedness, we used the nestedness metric based on overlap and decreasing fill (NODF). We found seventeen anuran species; however, only 13 species were observed in breeding activity, and 11 species were observed as tadpoles. The co-occurrence and nestedness analyses showed that anuran assemblages exhibit non-random patterns that were generally contingent on the hydroperiod and pond area. Only species in non-breeding adult anurans assemblages showed significant segregation when randomizations were weighted by pond area and the pattern was similar among hydroperiods. Tadpole assemblages of permanent ponds showed an aggregated co-occurrence in weighted-fixed model. In temporary ponds, NODF showed that anuran assemblages were significantly nestedness in all three phases of life cycle. We obtained contrasting results depending on the hydroperiod. These results support the hypothesis that habitat nestedness, due to hydroperiod, might be an important factor structuring anuran assemblages along the different phases of their life cycle.

Taxocenose de anfíbios anuros no Cerrado do Alto Tocantins, Niquelândia, Estado de Goiás: diversidade, distribuição local e sazonalidade

O Cerrado representa um dos maiores domínios fitogeográficos da América do Sul, sendo o segundo maior domínio de vegetação no Brasil e um dos 34 hotspots de biodiversidade do planeta. No presente estudo, a diversidade e distribuição espacial e temporal de anfíbios anuros foram estudadas entre outubro de 2005 e agosto de 2006, em três áreas de Cerrado no município de Niquelândia, estado de Goiás. Foram registradas 29 espécies pertencentes a oito famílias: Bufonidae (uma espécie), Cyclorhamphidae (três espécies), Dendrobatidae (uma espécie), Hylidae (dez espécies), Leiuperidae (uma espécie), Leptodactylidae (nove espécies), Microhylidae (duas espécies) e Strabomantidae (duas espécies). As Áreas 1 e 2 apresentaram as maiores riquezas com 21 e 18 espécies, respectivamente. Todavia, maior diversidade foi encontrada na Área 2, que apresentou uma alta equitabilidade. Dentre os sítios reprodutivos, a estabilidade do corpo d'água permanente que mantém água durante todo o ano favoreceu a ocorrência de espécies com padrões de reprodução intermediário e prolongado, contribuindo para a maior riqueza de espécies nesse ambiente. A distribuição temporal das espécies foi influenciada tanto pelo regime de chuvas quanto pela temperatura, pois os machos da maioria das espécies (86%) vocalizaram na estação chuvosa. Physalaemus cuvieri utilizou seis dos 14 sítios estudados para reprodução, sendo considerada uma espécie generalista. Por outro lado, Hypsiboas lundii, Barycholos ternetzi, Leptodactylus gr. marmoratus, Leptodactylus cf. martinezi e Ameerega flavopicta apresentam limitações impostas por modos reprodutivos específicos ficando restritas a um determinado hábitat.

Niche expansion and the niche variation hypothesis: does the degree of individual variation increase in depauperate assemblages?

The niche expansion and niche variation hypotheses predict that release from interspecific competition will promote niche expansion in depauperate assemblages. Niche expansion can occur by different mechanisms, including an increase in within-individual, among-individual, or bimodal variation (sexual dimorphism). Here we explore whether populations with larger niche breadth have a higher degree of diet variation. We also test whether populations from depauperate lizard assemblages differ in dietary resource use with respect to variation within and/or among individuals and sexual dimorphism. We found support for the niche expansion and niche variation hypotheses. Populations in assemblages with low phylogenetic diversity had a higher degree of individual variation, suggesting a tendency for niche expansion. We also found evidence suggesting that the mechanism causing niche expansion is an increase in variation among individuals rather than an increase in within-individual variation or an increase in bimodal variation due to sexual dimorphism.

Lagartos (Squamata: Lacertilia) em áreas de floresta e de pastagem em Espigão do Oeste, Rondônia, sudoeste da Amazônia, Brasil

O presente estudo apresenta dados sobre riqueza e freqüência de captura de lagartos em áreas de floresta e pastagem em uma localidade em Rondônia (sudoeste da Amazônia) utilizando três métodos de amostragem: armadilhas de interceptação e queda, procura noturna limitada por tempo (encontro de espécimes dormindo sobre a vegetação) e encontros ocasionais. Foram encontradas 29 espécies distribuídas em nove famílias. A maioria das espécies (28) foi encontrada em floresta, enquanto que na pastagem foram encontradas oito. A maioria das espécies foi registrada pelas armadilhas de interceptação e queda (22), seguido pelos encontros ocasionais (16) e procura noturna (9). A curva do coletor apresentando dados de todos os métodos mostra que a partir do oitavo mês de amostragem não houve mais nenhum acréscimo de nova espécie nessa comunidade, evidenciando que a mesma foi bem amostrada. O fato de algumas espécies terem sido coletadas exclusivamente em apenas um dos métodos, demonstra a importância de se usar dois ou mais métodos de amostragem em estudos sobre comunidades. Essa redução de espécies se deve a retirada da cobertura vegetal e, possivelmente, às suas conseqüências: aumento das taxa de predação e de competição, dificuldades para a termo-regulação, perda de locais para abrigos e reprodução, diminuição dos recursos alimentares e perda de serapilheira.

Ecological release in lizard assemblages of neotropical savannas

We compare lizard assemblages of Cerrado and Amazonian savannas to test the ecological release hypothesis, which predicts that niche dimensions and abundance should be greater in species inhabiting isolated habitat patches with low species richness (Amazonian savannas and isolated Cerrado patches) when compared with nonisolated areas in central Cerrado with greater species richness. We calculated microhabitat and diet niche breadths with data from 14 isolated Cerrado patches and Amazon savanna areas and six central Cerrado populations. Morphological data were compared using average Euclidean distances, and lizard abundance was estimated using the number of lizards captured in pitfall traps over an extended time period. We found no evidence of ecological release with respect to microhabitat use, suggesting that historical factors are better microhabitat predictors than ecological factors. However, data from individual stomachs indicate that ecological release occurs in these areas for one species (Tropidurus) but not others (Ameiva ameiva, Anolis, Cnemidophorus, and Micrablepharus), suggesting that evolutionary lineages respond differently to environmental pressures, with tropidurids being more affected by ecological factors than polychrotids, teiids, and gymnophthalmids. We found no evidence that ecological release occurs in these areas using morphological data. Based on abundance data, our results indicate that the ecological release (density compensation) hypothesis is not supported: lizard species are not more abundant in isolated areas than in nonisolated areas. The ecology of species is highly conservative, varying little from assemblage to assemblage. Nevertheless, increases in niche breadth for some species indicate that ecological release occurs as well.

Are there co-occurrence patterns that structure snake communities in Central Brazil?

The main factors that structure Neotropical animal communities have been the subject of discussion in ecology communities. We used a set of null models to investigate the existence of structure in snake communities from the Cerrado in Central Brazil in relation to the co-occurrence of species and guilds concerning specific resources. We used fragments (conservation units) inside the Distrito Federal and neighbor municipalities. In spite of recent human colonization in the region from the end of the 1950’s, intense habitat modification and fragmentation has taken place. Sixty three snake species are present in the Distrito Federal. Co-occurrence analysis of species and guilds associated to snake diets and habitats suggested a lack of organization. The homogeneity of habitats in Central Brazil and the minor importance of ecological effects can lead to random arrangement.

Lagartos da Marambaia, um remanescente insular de Restinga e Floresta Atlântica no Estado do Rio de Janeiro, Brasil

Este estudo apresenta os resultados de um inventário da fauna de lagartos da Marambaia, RJ. Foram registradas 12 espécies de lagartos, distribuídas em sete famílias. Teiidae é a família mais rica (3 spp.), seguida por Gekkonidae (2), Scincidae (2), e Tropiduridae (2), Gymnophthalmidae (1), Leiosauridae (1) e Polychrotidae (1). A composição da comunidade de lagartos da Marambaia é semelhante à de outras localidades do litoral sudeste brasileiro, entretanto a área comporta espécies de distribuição restrita às restingas do Estado do Rio de Janeiro e sob ameaça de extinção, como Cnemidophorus littoralis e Liolaemus lutzae. Também protege espécies típicas de florestas, como os lagartos arborícolas Enyalius brasiliensis e Anolis cf. fuscoauratus. Floresta e restinga são contínuas na Marambaia e representam os hábitats mais ricos em lagartos, reunindo, respectivamente, nove e oito espécies. A possibilidade de perda de variabilidade genética, como resultado do isolamento geográfico, e a aparente dificuldade de recolonização em casos de perda local de diversidade, somadas à modificações das paisagens por atividade antrópica, são fatores preocupantes para a conservação da herpetofauna da Marambaia.

Composição e diversidade de répteis Squamata na região sul do Parque Nacional Grande Sertão Veredas, Brasil Central

Neste estudo são apresentados os resultados de amostragem de Squamata do Parque Nacional Grande Sertão Veredas, MG, na área nuclear do Cerrado brasileiro, através de metodologia padronizada. A riqueza, diversidade e distribuição das espécies são comentadas e comparadas com os resultados em outras regiões do Cerrado. A fauna de Squamata na região inclui pelo menos 50 espécies, dentre as quais 25 lagartos, três anfisbenas e 22 serpentes, distribuídas em 12 famílias: Polychrotidae (1), Tropiduridae (3), Scincidae (4), Teiidae (3), Gymnophthalmidae (6), Anguidae (1), Amphisbaenidae (3), Anomalepididae (1), Leptotyphlopidae (1), Boidae (2), Colubridae (16) e Viperidae (2). A riqueza registrada e estimada indica que a região pode figurar entre as mais ricas em todo o Cerrado. As espécies de Squamata parecem possuir preferências previsíveis sobre os diferentes hábitats disponíveis, e admite-se a grande influência de fatores histórico-filogenéticos na distribuição espacial das espécies. A fisionomia do carrasco destacou-se por abrigar duas espécies restritas à região, Stenocercus quinarius e Psilophthalmus sp., sendo promissora para novos estudos. Os ambientes abertos, especialmente as fisionomias savânicas típicas do Cerrado, apresentaram maior riqueza, em concordância com outros locais estudados, e com implicações diretas na conservação da diversidade biológica do Cerrado.