Nicolás Pelegrin

Herpetofauna of protected areas in the Caatinga II: Serra da Capivara National Park, Piauí, Brazil

We provide a list of amphibians, lizards, chelonians, and snakes collected during a 30-day expedition to the Serra da Capivara National Park, Piaui State, Brazil. Thirty-seven pitfall trap arrays composed of 4 buckets each, along with glue traps, funnel traps, and haphazard searches, were used to sample the herpetofaunal diversity. We recorded 17 species of lizards, 1 caecilian, 1 chelonian, 7 frogs, and 11 snakes. Rarefaction curves suggest that local biodiversity is still underestimated. An atypical drought during the period of study may have contributed to lower captures of certain groups, especially amphibians and snakes. The presence of water-dependent and forest-dependent species within local canyons (“Boqueiroes”) suggests that these areas harbor faunas associated with relictual rainforest fragments and need to be better studied and managed accordingly.

Toward a Periodic Table of Niches, or Exploring the Lizard Niche Hypervolume

Widespread niche convergence suggests that species can be organized according to functional trait combinations to create a framework analogous to a periodic table. We compiled ecological data for lizards to examine patterns of global and regional niche diversification, and we used multivariate statistical approaches to develop the beginnings for a periodic table of niches. Data (50+ variables) for five major niche dimensions (habitat, diet, life history, metabolism, defense) were compiled for 134 species of lizards representing 24 of the 38 extant families. Principal coordinates analyses were performed on niche dimensional data sets, and species scores for the first three axes were used as input for a principal components analysis to ordinate species in continuous niche space and for a regression tree analysis to separate species into discrete niche categories. Three-dimensional models facilitate exploration of species positions in relation to major gradients within the niche hypervolume. The first gradient loads on body size, foraging mode, and clutch size. The second was influenced by metabolism and terrestrial versus arboreal microhabitat. The third was influenced by activity time, life history, and diet. Natural dichotomies are activity time, foraging mode, parity mode, and habitat. Regression tree analysis identified 103 cases of extreme niche conservatism within clades and 100 convergences between clades. Extending this approach to other taxa should lead to a wider understanding of niche evolution.

Natural History of Bothrops itapetiningae Boulenger, 1907 (Serpentes: Viperidae: Crotalinae), an Endemic Species of the Brazilian Cerrado

Abstract We present data on habitat use, activity, sexual dimorphism, reproduction, and diet of Bothrops itapetiningae, a species endemic to the Brazilian Cerrado. Habitat use was studied through active search techniques in several areas from July 1997 to July 2000. Diet, reproduction, activity, and sexual dimorphism were studied through the analysis of specimens deposited in Brazilian museums. Annual activity was inferred from collection records grouped by month and season. The specimens were sexed by direct observation of gonads and sexual dimorphism was assessed using morphological data. The reproductive cycle of the species was studied by analyzing the number of vitellogenic and nonvitellogenic follicles, ova, and embryos by month. The diet was determined by analyzing stomach and digestive tract contents. The species is a habitat specialist, associated with open cerrado grasslands, and is active more frequently during the rainy season (October to March). Males have longer tails whereas females have longer heads. The reproductive cycle is seasonal and probably biennial, with births (5.8 ± 2.9 embryos) occurring during the rainy season. Diet is of a generalist, but mammals are important items for both sexes and all age classes. Bothrops itapetiningae is among the smaller Brazilian pit vipers. Its low fecundity, high habitat specialization, and sensitivity to human disturbances, along with the high level of threat to its natural grassland habitat in the Brazilian Cerrado, makes this a potentially threatened snake. Knowledge of its biology is fundamental to conserving and managing this species. Resumo Apresentamos informações sobre uso de habitat, atividade, dimorfismo sexual, reprodução e dieta da cotiarinha (Bothrops itapetiningae), espécie endêmica do Cerrado Brasileiro. O uso de habitat foi estudado com base em diversas técnicas de buscas ativas ao longo de várias áreas de Cerrado, de julho de 1997 a julho de 2000. A atividade, reprodução, dimorfismo sexual e dieta foram estudadas através da análise de espécimes depositados em diversos museus brasileiros. O padrão anual de atividades de foi inferido a partir dos registros de coleta agrupados por mês e por estação. Os espécimes foram sexados pela observação direta das gônadas, dados morfológicos foram registrados para analisar o dimorfismo sexual. O ciclo reprodutivo da espécie foi estudado através da análise do número de folículos vitelogênicos e não vitelogênicos, óvulos e embriões por mês. Informações sobre dieta foi obtida por dissecção do estômago e trato digestivo. A espécie é especialista em habitat, associada a campos abertos de planalto e é ativa mais frequentemente durante a estação chuvosa (outubro a março). Os machos têm caudas mais longas, enquanto que as fêmeas têm cabeças maiores. O ciclo reprodutivo é sazonal com nascimentos (5,8 ± 2,9 embriões) ocorrendo durante a estação chuvosa. A dieta é generalista, mas mamíferos são itens importantes na dieta de ambos os sexos e classes etárias. Bothrops itapetiningae possui baixa fecundidade, alta especialização habitat e alta sensibilidade a distúrbios humanos. Juntamente com o alto nível de ameaça de seus habitats naturais, torna-se uma prioridade conhecer melhor sua biologia para o seu manejo e conservação.

Injured Salvator merianae (Teiidae) regenerates six tails in central Argentina

Lizards have the ability of regenerate many tissues like nerve cells, part of the mandible, parts of the limb, and most of them can regenerate the tail. Tail autotomy followed by tail regeneration is a strategy widely used in lizards to escape from predators. In some cases tail breaks but it does not detaches completely from the body, leading to a regenerated tail with multiple tips. Here we report the finding of a young individual of Salvator merianae from central Argentina which regenerated six tails after being injured.

Is There Evidence for Population Regulation in Amphibians and Reptiles

Abstract From the 1950s to the present, many researchers have tested time series data for density dependence. All kinds of organisms have been studied, from microorganisms to insects and vertebrates to plants. A variety of techniques and population growth models were developed, and the conceptual framework to study populations has been improved. We searched for long time series data on amphibians and reptiles in the literature. From 102 population time series, and after filtering the dataset, we tested for density dependence in time series data for 69 populations (52 species) of amphibians (anurans and caudatans), serpents, lacertilians, chelonians, rhynchocephalians, and crocodilians. We used the exponential growth state-space model and the Ornstein-Uhlembeck state-space model as proxy models for density-independent and density-dependent population growth models, selecting between them with the parametric bootstrap likelihood ratio test. The hypothesis of density independence was rejected for 2 amphibians, 11 serpents, 3 chelonians, 1 rhynchocephalian, and 2 crocodilian populations. Detailed data for serpents and chelonians allowed identification of external factors such as changing food supplies and habitats as drivers of observed changes in population densities. We highlight the need of both long-term and experimental studies on reptile and amphibian populations in semipristine or preserved areas. Resumen Desde los años 50s hasta nuestros días, diversos investigadores han puesto a prueba denso-dependencia en series temporales de datos. Todo tipo de organismos han sido estudiados, desde microorganismos a insectos, vertebrados y aves. Una variedad de técnicas y de modelos de crecimiento poblacional se han desarrollado, e incluso el marco conceptual de estudios poblacionales fue mejorado. Realizamos búsquedas de datos en series temporales largas para reptiles y anfibios en la literatura. De las 102 poblaciones encontradas y luego de filtrar la base de datos, analizamos 69 poblaciones (52 especies) de anfibios (anura y caudata), serpientes, lagartos, tortugas, tuatara, alligators y caimanes. Utilizamos exponential growth state-space y Ornstein-Uhlembeck state-space como aproximación a los modelos de crecimiento poblacional denso-independiente y denso-dependiente, seleccionando entre ellos por medio del parametric bootstrap likelihood ratio test. La hipótesis de denso-independencia fue rechazada para poblaciones de 2 anfibios, 11 serpientes, 3 tortugas, 1 tuatara, 1 alligator y 1 caimán. Información detallada disponible para las poblaciones de serpientes y tortugas permitieron identificar factores externos (como cambios en el alimento disponible y en el hábitat) como responsables de los cambios observados en las densidades poblacionales. Resaltamos la necesidad tanto de estudios a largo plazo o experimentales, en poblaciones de anfibios y reptiles en áreas semiprístinas o preservadas.

Reptiles y anfibios de una localidad del Chaco Húmedo en Formosa, Argentina

Presentamos aqui una lista de lagartos, serpientes, anfibios y anfisbenas registrados entre Noviembre de 2013 y Febrero de 2014 en el Chaco Humedo en La Picadita, Formosa, Argentina (26°02’16” S, 59°09’26” O). Los especimenes se capturaron con 25 trampas cerco-pozo dispuestas en dos parches de bosque tipico del Chaco Humedo y busqueda activa en areas inundables (“esteros”). Se registraron 6 especies de lagartos, 9 de serpientes, 2 de anfisbenidos y 29 de anfibios, totalizando 46 especies. Las curvas de rarefaccion sugieren que nuestro esfuerzo de muestreo fue apropiado para anfibios, pero se necesitan mas muestreos para un muestreo completo de lagartos y serpientes. Las trampas permitieron registrar a Chiasmocleis albopunctata (y al genero Chiasmocleis ) por primera vez en Argentina. El uso de trampas cerco-pozo en combinacion con busqueda activa es un metodo util para capturar anfibios elusivos y cripticos como los microhylidos.

Stable isotope ecology of a hyper-diverse community of scincid lizards from arid Australia

We assessed the utility of stable isotope analysis as a tool for understanding community ecological structure in a species-rich clade of scincid lizards from one of the worlds most diverse lizard communities. Using a phylogenetic comparative framework, we tested whether δ15N and δ13C isotopic composition from individual lizards was correlated with species-specific estimates of diet and habitat use. We find that species are highly divergent in isotopic composition with significant correlations to habitat use, but this relationship shows no phylogenetic signal. Isotopic composition corresponds to empirical observations of diet for some species but much variation remains unexplained. We demonstrate the importance of using a multianalytical approach to questions of long-term dietary preference, and suggest that the use of stable isotopes in combination with stomach content analysis and empirical data on habitat use can potentially reveal patterns in ecological traits at finer scales with important implications for community structuring.

Activity and reproductive patterns of lizards in the Chaco of Argentina

We studied the activity and breeding pattern of dominant lizard species in the Arid Chaco, the southernmost subregion of the Chaco ecoregion (Chancaní Reserve, Córdoba province, Argentina). Lizards were captured with pitfall traps over a 4-year period. In total, 1449 individuals belonging to 11 of the 12 lizard species recorded in the area were trapped. Of these, we selected six species for a detailed analysis: Teius teyou and Stenocercus doellojuradoi accounted for 63% of the captures, Tropidurus etheridgei, Liolaemus chacoensis and Homonota fasciata accounted for 32%, and 5% comprised Leiosaurus paronae and the remaining five species. All the studied species were active during the warm–rainy season (September to March). Monthly lizard captures were highly correlated with monthly mean temperature and rainfall. No captures occurred during the remaining months of the year. All reproductive tactics known for the Chaco lizards were observed in Chancaní, including single clutch in a short breeding season in summer or autumn, as well as an extended breeding season with multiple clutches. Stenocercus doellojuradoi and L. paronae showed a singular reproductive timing, suggesting the occurrence of egg retention. Compared with sub-tropical Chaco sites, the Arid Chaco only differs in the lack of winter activity, resulting from the lower temperature and rainfall regime of our study site.

First record of the genus Chiasmocleis Mèhelÿ, 1904 (Anura, Microhylidae) in Argentina

Chiasmocleis Mehely, 1904 is the most diverse genus of Microhylidae, with Chiasmocleis albopunctata (Boettger, 1885) being the species with the largest distribution. This species is typical of open habitats from State of Tocantins in Brazil to Asuncion in Paraguay, which is its southernmost previous record. Herein we report the first record of C. albopunctata in Argentina, extending its known distribution 173 km SW from Asuncion in Paraguay.