Environmental sympatry through time: spatio-temporal distribution and conservation status of two sympatric anuran species (Leptodactylidae) in South America / Simpatría ambiental a través del tiempo: distribución espacio-temporal y estado de conservación de dos especies de anuros simpátricos (Leptodactylidae) en América del Sur

Abstract Introduction: Leptodactylus latinasus and Physalaemus cuqui are sympatric anuran species with similar environmental requirements and contrasting reproductive modes. Climatic configuration determines distribution patterns and promotes sympatry of environmental niches, but specificity/selectivity determines the success of reproductive modes. Species distribution models (SDM) are a valuable tool to predict spatio-temporal distributions based on the extrapolation of environmental predictors. Objectives: To determine the spatio-temporal distribution of environmental niches and assess whether the protected areas of the World Database of Protected Areas (WDPA) allow the conservation of these species in the current scenario and future. Methods: We applied different algorithms to predict the distribution and spatio-temporal overlap of environmental niches of L. latinasus and P. cuqui within South America in the last glacial maximum (LGM), middle-Holocene, current and future scenarios. We assess the conservation status of both species with the WDPA conservation units. Results: All applied algorithms showed high performance for both species (TSS = 0.87, AUC = 0.95). The L. latinasus predictions showed wide environmental niches from LGM to the current scenario (49 % stable niches, 37 % gained niches, and 13 % lost niches), suggesting historical fidelity to stable climatic-environmental regions. In the current-future transition, L. latinasus would increase the number of stable (70 %) and lost (20 %) niches, suggesting fidelity to lowland regions and a possible trend toward microendemism. P. cuqui loses environmental niches from the LGM to the current scenario (25 %) and in the current-future transition (63 %), increasing the environmental sympathy between both species; 31 % spatial overlap in the current scenario and 70 % in the future. Conclusion: Extreme drought events and rainfall variations, derived from climate change, suggest the loss of environmental niches for these species that are not currently threatened but are not adequately protected by conservation units. The loss of environmental niches increases spatial sympatry which represents a new challenge for anurans and the conservation of their populations.

Resumen Introducción: Leptodactylus latinasus y Physalaemus cuqui son especies de anuros simpátricos con requerimientos ambientales similares y modos reproductivos contrastantes. La configuración climática determina los patrones de distribución y promueve la simpatría de los nichos ambientales, pero la especificidad/selectividad determina el éxito de los modos reproductivos. Los modelos de distribución de especies (MDE) son una herramienta valiosa para predecir distribuciones espacio-temporales basadas en la extrapolación de predictores ambientales. Objetivos: Determinar la distribución espacio-temporal de los nichos ambientales y evaluar si las áreas protegidas de la base de Datos Mundial de Áreas Protegidas (DMAP) permiten la conservación de estas especies en el escenario actual y futuro. Métodos: Aplicamos diferentes algoritmos para predecir la distribución y superposición espacio-temporal de nichos ambientales de L. latinasus y P. cuqui dentro de América del Sur en el último máximo glacial (UGM), Holoceno medio, actual y futuro. Evaluamos el estado de conservación de ambas especies con las unidades de conservación de la DMAP. Resultados: Todos los algoritmos aplicados mostraron un alto rendimiento para ambas especies (TSS = 0.87, AUC = 0.95). Las predicciones de L. latinasus mostraron amplios nichos ambientales desde LGM hasta el escenario actual (49 % de nichos estables, 37 % de nichos ganados y 13 % de nichos perdidos), sugiriendo fidelidad histórica por regiones climático-ambientales estables. En la transición actual-futura L. latinasus incrementaría la cantidad de nichos estables (70 %) y perdidos (20 %), sugiriendo fidelidad por regiones de tierras bajas y la posible tendencia hacia el microendemismo. P. cuqui pierde nichos ambientales desde el LGM al escenario actual (25 %) y en la transición actual-futura (63 %), incrementando la simpatría ambiental entre ambas especies; 31 % de superposición espacial en el escenario actual y 70 % en el futuro. Conclusión: Los eventos de sequía extrema y las variaciones de precipitaciones, derivados del cambio climático, sugieren la pérdida de nichos ambientales para estas especies, actualmente no se encuentran amenazadas, pero no están adecuadamente protegidas por las unidades de conservación. La pérdida de nichos ambientales aumenta la simpatría espacial que representa un nuevo desafío para estos anuros y la conservación de sus poblaciones.

Uso y selección de microhábitat en un ensamble de anuros del Chaco Serrano de Argentina / Microhabitat use and selection by an anuran assemblage from the Chaco Serrano of Argentina

Introducción: El estudio de las estrategias de uso y partición del recurso espacial resulta importante para entender los mecanismos de coexistencia de especies de anfibios simpátricas, más aún cuando existen variaciones temporales en la disponibilidad de hábitats. Objetivo: Conocer los patrones de uso de microhábitat, sus variaciones estacionales y la posible influencia de la filogenia en un ensamble de anuros del Chaco Serrano de Argentina. Métodos: Los muestreos se realizaron en el área protegida Parque Natural Valle Fértil, Departamento Valle Fértil, San Juan, entre el 2012 y 2017. En campo, se registró el microhábitat donde se encontró cada ejemplar y se midieron variables del sitio. Además, se determinó la disponibilidad de microhábitats. Los datos se analizaron mediante el índice de selectividad de Manly. Para evaluar variaciones temporales en el uso de microhábitats se utilizaron modelos lineales generalizados (GLM). Resultados: Las especies evaluadas fueron: Rhinella arenarum arenarum, Leptodactylus latrans, Pleurodema tucumanum y Odontophrynus occidentalis. Todas las especies mostraron diferencias en las frecuencias de uso: R. a. arenarum mostró preferencias hacia los sitios rocosos y acuáticos, P. tucumanum exhibió preferencias hacia los sitios con suelo desnudo y rocas, L. latrans y O. occidentalis presentaron mayores preferencias hacia los sitios rocosos y acuáticos. Todas las especies excepto Odontophrynus exhibieron variaciones estacionales en la selección y uso de los microhábitats. Odontophrynus occidentalis presentó diferencias en las proporciones de uso entre microhábitats. Conclusiones: Este estudio muestra la plasticidad en el uso de microhábitats como un determinante importante en la distribución espacial de anuros, sin restricciones aparentes impuestas por la competencia, el espacio ni la filogenia. Cuando la actividad de las especies es coincidente, el recurso espacial puede distribuirse de manera que se reduzca el solapamiento entre especies.

Introduction: Research on spatial resource usage and partition strategies is important to understand the mechanisms of coexistence in sympatric amphibian species, even more when there are temporal variations in habitat availability. Objective: To learn about the patterns of microhabitat use, its seasonal variations and the possible influence of phylogeny on an anuran assembly of the Chaco Serrano in Argentina. Methods: Samplings were carried out in the Valle Fértil Natural Park protected area, Valle Fértil Department, San Juan, between 2012 and 2017. In the field, we recorded the microhabitat where each specimen was found, and we also measured site variables. In addition, microhabitats availability was determined. Data were analyzed using Manly's selectivity index. Generalized linear models (GLM) were used to assess temporal variations in microhabitat use. Results: The species evaluated were: Rhinella arenarum arenarum, Leptodactylus latrans, Pleurodema tucumanum and Odontophrynus occidentalis. All species showed differences in usage frequencies: R. a. arenarum showed preferences for rocky and aquatic sites, P. tucumanum showed preferences towards bare soil and rocky sites, L. latrans and O. occidentalis showed greater preferences for rocky and aquatic sites. All species but Odontophrynus exhibited seasonal variations in microhabitat selection and usage. Odontophrynusoccidentalis showed differences in usage proportions among microhabitats. Conclusions: This study shows plasticity in microhabitat usage as an important determinant of anuran spatial distribution, without apparent restrictions imposed by space competition or phylogeny. When species activity is coincident, the space resource may be distributed in a way that species overlap is reduced.

Choledocystus elegans (Digenea: Plagiorchiidae) of Leptodactylus paraensis (Amphibia: Leptodactylidae) from the Brazilian Amazon / Choledocystus elegans (Digenea: Plagiorchiidae) de Leptodactylus paraensis (Amphibia: Leptodactylidae) da Amazônia brasileira

Abstract The trematodes are parasites of the several vertebrates including amphibians, however the knowledge about of the taxonomy these parasites is still confuse. The trematode Choledocystus elegans was found in the small intestine of the Leptodactylus paraensis in eastern Amazon and presents the following characteristics: several pointed tegumentary spines, papillae on the outer and inner edges of the oral and ventral suckers, a round, well-developed cirrus sac, a well-developed cirrus, oblique testicles, a ovary right side, uterine loops extending between the testicles, follicular vitellaria distributed throughout the body, starting at the genital pore region and caeca close the end of the body. For the first time, this study identified C. elegans parasitizing L. paraensis and describes morphological aspects never characterized using light and scanning electron microscopy.

Resumo Os trematodas são parasitas de vários grupos de vertebrados incluindo os anfíbios, contudo o que se conhece sobre a taxonomia destes parasitas ainda é confusa. O trematoda Choledocystus elegans foi encontrado no intestino delgado de Leptodactylus paraensis na Amazônia oriental e apresenta as seguintes características: vários espinhos pontiagudos no tegumento, papilas nas bordas externa e interna das ventosas orais e ventrais, bolsa do cirro bem desenvolvida contendo um cirro desenvolvido, testículos oblíquos, ovário destro, alças uterinas que se estendem entre os testículos, folículos vitelínicos distribuída por toda a lateral do corpo, começando ao nível do poro genital e cecos intestinais chegando até a região posterior do corpo do helminto. Pela primeira vez, este estudo identificou C. elegans parasitando L. paraensis e descreve aspectos morfológicos nunca caracterizados usando microscopia de luz comum e eletrônica de varredura.

Helminth fauna of Leptodactylus syphax (Anura: Leptodactylidae) from Caatinga biome, northeastern Brazil / Helmintofauna de Leptodactylus syphax (Anura: Leptodactylidae) do bioma da Caatinga, Nordeste do Brasil

Abstract Leptodactylus syphax is distributed in central, southeastern and northeastern Brazil, eastern Bolivia and southern Paraguay, occupying open areas and rock outcrops, in rock cavities and termite burrows. We collected 21 frogs from the Caatinga region of the state of Ceará, northeastern Brazil, and 7,021 helminths were recovered from 18 of these hosts (overall prevalence = 85.7%). Six helminth taxa were recovered, as follows: Aplectana membranosa (n = 3,756); Schrankiana formosula (n = 3,176); larvae of Physaloptera sp. (n = 43); unidentified nematode larvae (n = 7); digenean metacercariae of Lophosicyadiplostomum sp. (n = 2); and cystacanths of Acanthocephala (n = 37). The similarity of helminth composition between L. syphax from the Caatinga and other species of the L. fuscus group showed that some anurans were clustered according to parasite species and others according to geographic locality. This study presents new helminth records for the Neotropical region, thus helping in understanding the pattern of species distribution, and it increases the knowledge of parasites associated with amphibians.

Resumo Leptodactylus syphax está distribuída na região central, Sudeste e Nordeste do Brasil, Leste da Bolívia e Sul do Paraguai, ocupando áreas abertas e afloramentos rochosos, cavidades rochosas ou de cupins. Foram coletadas 21 rãs oriundas da região de Caatinga do Ceará, nordeste brasileiro, e 7.021 helmintos foram recuperados em 18 hospedeiros (prevalência geral = 85,7%). Seis taxa de helmintos foram recuperados, como segue: Aplectana membranosa (n = 3.756), Schrankiana formosula (n = 3.176), larvas de Physaloptera sp. (n = 43), larvas de nematódeos não identificado (n = 7), metacercárias de Lophosicyadiplostomum sp. (n = 2), e cistacantos de Acantocéfalos (n = 37). A similaridade da composição de helmintos entre L. syphax da Caatinga e outras espécies do grupo L. fuscus mostrou que alguns anuros foram agrupados de acordo com a espécie do parasita e outros de acordo com a localidade geográfica. Este estudo apresenta novos registros de helmintos para a região Neotropical, ajudando na compreensão do padrão de distribuição das espécies e aumenta o conhecimento sobre os parasitas associados a anfíbios.

Ocellatin peptides from the skin secretion of the South American frog Leptodactylus labyrinthicus (Leptodactylidae): characterization, antimicrobial activities and membrane interactions

Background The availability of antimicrobial peptides from several different natural sources has opened an avenue for the discovery of new biologically active molecules. To the best of our knowledge, only two peptides isolated from the frog Leptodactylus labyrinthicus, namely pentadactylin and ocellatin-F1, have shown antimicrobial activities. Therefore, in order to explore the antimicrobial potential of this species, we have investigated the biological activities and membrane interactions of three peptides isolated from the anuran skin secretion. Methods Three peptide primary structures were determined by automated Edman degradation. These sequences were prepared by solid-phase synthesis and submitted to activity assays against gram-positive and gram-negative bacteria and against two fungal strains. The hemolytic properties of the peptides were also investigated in assays with rabbit blood erythrocytes. The conformational preferences of the peptides and their membrane interactions have been investigated by circular dichroism spectroscopy and liposome dye release assays. Results The amino acid compositions of three ocellatins were determined and the sequences exhibit 100% homology for the first 22 residues (ocellatin-LB1 sequence). Ocellatin-LB2 carries an extra Asn residue and ocellatin-F1 extra Asn-Lys-Leu residues at C-terminus. Ocellatin-F1 presents a stronger antibiotic potential and a broader spectrum of activities compared to the other peptides. The membrane interactions and pore formation capacities of the peptides correlate directly with their antimicrobial activities, i.e., ocellatin-F1 > ocellatin-LB1 > ocellatin-LB2. All peptides acquire high helical contents in membrane environments. However, ocellatin-F1 shows in average stronger helical propensities. Conclusions The obtained results indicate that the three extra amino acid residues at the ocellatin-F1 C-terminus play an important role in promoting stronger peptide-membrane interactions and antimicrobial properties. The extra Asn-23 residue present in ocellatin-LB2 sequence seems to decrease its antimicrobial potential and the strength of the peptide-membrane interactions.(AU)

Ocellatin peptides from the skin secretion of the South American frog Leptodactylus labyrinthicus (Leptodactylidae): characterization, antimicrobial activities and membrane interactions

Abstract Background The availability of antimicrobial peptides from several different natural sources has opened an avenue for the discovery of new biologically active molecules. To the best of our knowledge, only two peptides isolated from the frog Leptodactylus labyrinthicus, namely pentadactylin and ocellatin-F1, have shown antimicrobial activities. Therefore, in order to explore the antimicrobial potential of this species, we have investigated the biological activities and membrane interactions of three peptides isolated from the anuran skin secretion. Methods Three peptide primary structures were determined by automated Edman degradation. These sequences were prepared by solid-phase synthesis and submitted to activity assays against gram-positive and gram-negative bacteria and against two fungal strains. The hemolytic properties of the peptides were also investigated in assays with rabbit blood erythrocytes. The conformational preferences of the peptides and their membrane interactions have been investigated by circular dichroism spectroscopy and liposome dye release assays. Results The amino acid compositions of three ocellatins were determined and the sequences exhibit 100% homology for the first 22 residues (ocellatin-LB1 sequence). Ocellatin-LB2 carries an extra Asn residue and ocellatin-F1 extra Asn-Lys-Leu residues at C-terminus. Ocellatin-F1 presents a stronger antibiotic potential and a broader spectrum of activities compared to the other peptides. The membrane interactions and pore formation capacities of the peptides correlate directly with their antimicrobial activities, i.e., ocellatin-F1 > ocellatin-LB1 > ocellatin-LB2. All peptides acquire high helical contents in membrane environments. However, ocellatin-F1 shows in average stronger helical propensities. Conclusions The obtained results indicate that the three extra amino acid residues at the ocellatin-F1 C-terminus play an important role in promoting stronger peptide-membrane interactions and antimicrobial properties. The extra Asn-23 residue present in ocellatin-LB2 sequence seems to decrease its antimicrobial potential and the strength of the peptide-membrane interactions.

Synergic effects between ocellatin-F1 and bufotenine on the inhibition of BHK-21 cellular infection by the rabies virus

Background Rabies is an incurable neglected zoonosis with worldwide distribution characterized as a lethal progressive acute encephalitis caused by a lyssavirus. Animal venoms and secretions have long been studied as new bioactive molecular sources, presenting a wide spectrum of biological effects, including new antiviral agents. Bufotenine, for instance, is an alkaloid isolated from the skin secretion of the anuran Rhinella jimi that inhibits cellular penetration by the rabies virus. Antimicrobial peptides, such as ocellatin-P1 and ocellatin-F1, are present in the skin secretion of anurans from the genus Leptodactylus and provide chemical defense against predators and microorganisms. Methods Skin secretion from captive Leptodactylus labyrinthicus was collected by mechanical stimulation, analyzed by liquid chromatography and mass spectrometry, and assayed for antiviral and cytotoxic activities. Synthetic peptides were obtained using solid phase peptide synthesis, purified by liquid chromatography and structurally characterized by mass spectrometry, and assayed in the same models. Cytotoxicity assays based on changes in cellular morphology were performed using baby hamster kidney (BHK-21) cells. Fixed Rabies virus (Pasteur Virus - PV) strain was used for virological assays based on rapid fluorescent focus inhibition test. Results Herein, we describe a synergic effect between ocellatin-F1 and bufotenine. This synergism was observed when screening the L. labyrinthicus skin secretion for antiviral activities. The active fraction major component was the antimicrobial peptide ocellatin-F1. Nevertheless, when the pure synthetic peptide was assayed, little antiviral activity was detectable. In-depth analyses of the active fraction revealed the presence of residual alkaloids together with ocellatin-F1. By adding sub-effective doses (e.g. < IC50) of pure bufotenine to synthetic ocellatin-F1, the antiviral effect was regained. Moreover, a tetrapetide derived from ocellatin-F1, based on alignment with the virus's glycoprotein region inferred as a possible cell ligand, was able to maintain the synergic antiviral activity displayed by the full peptide. Conclusions This novel antiviral synergic effect between a peptide and an alkaloid may present an innovative lead for the study of new antiviral drugs.(AU)

Synergic effects between ocellatin-F1 and bufotenine on the inhibition of BHK-21 cellular infection by the rabies virus

Background Rabies is an incurable neglected zoonosis with worldwide distribution characterized as a lethal progressive acute encephalitis caused by a lyssavirus. Animal venoms and secretions have long been studied as new bioactive molecular sources, presenting a wide spectrum of biological effects, including new antiviral agents. Bufotenine, for instance, is an alkaloid isolated from the skin secretion of the anuran Rhinella jimi that inhibits cellular penetration by the rabies virus. Antimicrobial peptides, such as ocellatin-P1 and ocellatin-F1, are present in the skin secretion of anurans from the genus Leptodactylus and provide chemical defense against predators and microorganisms. Methods Skin secretion from captive Leptodactylus labyrinthicus was collected by mechanical stimulation, analyzed by liquid chromatography and mass spectrometry, and assayed for antiviral and cytotoxic activities. Synthetic peptides were obtained using solid phase peptide synthesis, purified by liquid chromatography and structurally characterized by mass spectrometry, and assayed in the same models. Cytotoxicity assays based on changes in cellular morphology were performed using baby hamster kidney (BHK-21) cells. Fixed Rabies virus (Pasteur Virus PV) strain was used for virological assays based on rapid fluorescent focus inhibition test. Results Herein, we describe a synergic effect between ocellatin-F1 and bufotenine. This synergism was observed when screening the L. labyrinthicus skin secretion for antiviral activities. The active fraction major component was the antimicrobial peptide ocellatin-F1. Nevertheless, when the pure synthetic peptide was assayed, little antiviral activity was detectable. In-depth analyses of the active fraction revealed the presence of residual alkaloids together with ocellatin-F1. By adding sub-effective doses (e.g. IC50) of pure bufotenine to synthetic ocellatin-F1, the antiviral effect was regained. Moreover, a tetrapetide derived from ocellatin-F1, based on alignment with the viruss glycoprotein region inferred as a possible cell ligand, was able to maintain the synergic antiviral activity displayed by the full peptide. Conclusions This novel antiviral synergic effect between a peptide and an alkaloid may present an innovative lead for the study of new antiviral drugs.

Novos registros na distribuição geográfica de anuros na floresta com araucária e considerações sobre suas vocalizações / New records in the geographic distribution range of the anurans of the araucaria forest and considerations on their vocalizations

Estudos envolvendo análises bioacústicas têm possibilitado a identificação de espécies pertencentes a grupos complexos, bem como a descrição e diferenciação de espécies crípticas. Recorrendo a esta ferramenta e com o objetivo de aumentar o conhecimento sobre a composição de espécies de anfíbios em áreas de Floresta com Araucária, foram amostradas 11 áreas nos estados do Paraná e Santa Catarina. Os resultados ampliaram significativamente o conhecimento da distribuição geográfica de oito espécies de anfíbios anuros: Ischnocnema henselii, Dendropsophus anceps, atualmente classificada como criticamente ameaçada no Estado do Paraná, D. nahdereri, Scinax granulatus, Trachycephalus dibernardoi, Pseudis cardosoi, Leptodactylus araucaria e L. nanus. Alguns destes registros representam correções em identificações anteriores: Ischnocnema henselii é uma espécie críptica e algumas populações até o momento eram confundidas no Paraná com I. guentheri; Trachycephalus dibernardoi era identificada como T. imitatrix e Leptodactylus nanus como L. marmoratus. A caracterização e descrição dos cantos destas espécies também são apresentadas.

Studies involving bioacoustics analysis turned possible the identification of complex species groups, as well as the description and differentiation of cryptic species. In order to increase the knowledge on the species composition of amphibians in Araucaria Forests, we sampled eleven areas in the states of Paraná and Santa Catarina, which significantly increased the geographic distribution range of eight amphibian species: Ischnocnema henselii, Dendropsophus anceps, a currently classified as critically endangered in Paraná State, D. nahdereri, Scinax granulatus, Trachycephalus dibernardoi, Pseudis cardosoi, Leptodactylus araucaria and L. nanus. Some of the new records represent corrections of previous identifications for example: Ischnocnema henselii is a cryptic species with some populations in Paraná that have been previously mistaken to I. guentheri; Trachycephalus dibernardoi was mistaken for T. imitatrix and Leptodactylus nanus to L. marmoratus. We also characterize and describe the calls of all these species.

Cellular organization of the testes in Hylidae and Leptodactylidae, in the Pantanal (Mato Grosso do Sul State, Brazil) - DOI: 10.4025/actascibiolsci.v31i4.3332 / Organização celular dos testículos em Hylidae e Leptodactylidae, no Pantanal (Estado do Mato Grosso do Sul, Brasil) - DOI: 10.4025/actascibiolsci.v31i4.3332

The objective of this work was to make a comparative analysis of germ cell organization at different stages of cellular differentiation in adult males of Dendropsophus nanus (Boulenger, 1889), Pseudis limellum (Cope, 1862), P. paradoxa (Linnaeus, 1758), and Scinax acuminatus (Cope, 1862), belonging to the family Hylidae; and Leptodactylus chaquensis (Cei, 1950) and L. podicipinus (Cope, 1862), belonging to the family Leptodactylidae, collected in the Pantanal and in Serra da Bodoquena, Mato Grosso do Sul State, Brazil. The testes were removed and fixed, dehydrated in a graded series of ethanol, and embedded in methacrylate glycol resin (Historesin Leica®). The sections were stained by 1% toluidine blue and observed under light microscope. It was detected that all individual of the Hylidae family show, throughout the year, the presence of all germ cell types of spermatogenesis. However, all Leptodactylidae family individuals only show the presence of all germ cell types during the rainy season. The variations of characteristics in seminiferous epithelium organization, as well as the evident difference in the amount of spermatozoa inside the tubules, are evidence that the anurans in this work show different forms of spermatogenesis development throughout the year: the cycle is continuous for the Hylidae family, and discontinuous with explosive release of spermatozoa for the Lept

O objetivo deste trabalho foi analisar e comparar a organização das células germinativas em diferentes estádios de diferenciação celular nos machos adultos de Dendropsophus nanus (Boulenger, 1889), Pseudis limellum (Cope, 1862), Pseudis paradoxa (Linnaeus, 1758) e Scinax acuminatus (Cope, 1862), pertencentes à família Hylidae, e de Leptodactylus chaquensis (Cei, 1950) e L. podicipinus (Cope, 1862), pertencentes à família Leptodactylidae, coletados no Pantanal e na serra da Bodoquena, no Estado do Mato Grosso do Sul, Brasil. Os testículos foram retirados, fixados, desidratados em uma série alcoólica e incluídos em resina plástica do tipo methacrilato glicol (Historesin Leica®); cortados a 3 µm, corados com azul de toluidina 1% e observados no microscópio de luz. Constatou-se que os indivíduos da família Hylidae apresentam, em todas as épocas do ano, presença de todas as células de linhagem germinativa da espermatogênese. Já os indivíduos da família Leptodactylidae apresentam todas as células da linhagem germinativa somente no período chuvoso. As variações das características na organização dos epitélios seminíferos, assim como da evidente diferença na quantidade de espermatozoides no interior dos túbulos, demonstram que os anuros estudados apresentam diferentes formas de desenvolvimento da espermatogênese ao longo do ano: de forma cíclica para os da família Hylidae e acíclica, c

História natural de Leptodactylus mystacinus e Leptodactylus fuscus (Anura: Leptodactylidae) no Cerrado do Brasil Central / Natural history of Leptodactylus mystacinus and Leptodactylus fuscus (Anura: Leptodactylidae) in the Cerrado of Central Brazil

Aspectos da ecologia de Leptodactylus mystacinus e Leptodactylus fuscus foram investigados em uma área de Cerrado do Brasil Central. O estudo incluiu o uso do microhábitat, padrões de atividade, dieta e morfometria. As observações foram conduzidas entre abril de 2006 a fevereiro de 2007. As espécies são sexualmente dimórficas - fêmeas maiores que os machos - e o tamanho do corpo em L. mystacinus é maior do que o de L. fuscus. Ambas as espécies preferiram a superfície do solo (microhábitat) de hábitats brejosos com vegetação herbácea próximos a corpos lênticos de água. Leptodactylus mystacinus foi mais observado em Outubro e Novembro (20:00-20:59 e 23:00-23:59 horas) e L. fuscus em Novembro e Outubro das 19:00 às 20:59 horas. A dieta destas populações foi baseada em Arthropoda, primariamente Coleoptera, a qual foi a mais importante ordem (IVI). Diferenças nas proporções volumétricas das categorias de presas utilizadas, e nos períodos em que são mais observadas, provavelmente sejam os fatores que mais contribuem para a coexistência das duas espécies na área. Diferenças intersexuais na dieta foram observadas para estas espécies. Estas diferenças estão provavelmente associadas à alocação diferencial de recursos para a produção de gametas ou diferenças ocasionais no uso do espaço pelos dois sexos.

Aspects of the ecology of Leptodactylus mystacinus and Leptodactylus fuscus were investigated in an area of the Cerrado of Central Brazil. The study included use of microhabitat, activity patterns, diet and, morphometry. Observations were conducted between April, 2006, and February, 2007. The species are sexually dimorphic - females larger than males - and body size in L. mystacinus is larger than that of L. fuscus. Both species preferred the ground surface (microhabitat) of wetland habitats with herbaceous vegetation close to lentic water bodies. Leptodactylus mystacinus was observed most often in October and November (8:00-8:59PM and 11:00-11:59 PM), and L. fuscus in November and October between 7:00 PM and 8:59 PM. The diet of both populations was based on Arthropoda, primarily Coleoptera, which was the most important order (IVI). Differences in the volumetric proportions of the categories of then preys used, and in the periods when they were most observed, are probably the factors that contribute the most to the coexistence of both species in the area. Intersexual differences in the diet were observed in both species. These differences were probably associated with the differential allocation of resources to the production of gametes or occasional differences in the use of space by the two sexes.

Further notes on the natural history of the South American pepper frog, Leptodactylus labyrinthicus (Spix, 1824) (Anura, Leptodactylidae) / Notas complementares sobre a história natural da rã-pimenta sul-americana, Leptodactylus labyrinthicus (Anura, Leptodactylidae)

Leptodactylus labyrinthicus tadpoles reach a large size in the nest through consumption of trophic eggs. We previously suggested that the trophic eggs are laid just after amplexus has finished, but our new data do not support this hypothesis. We also present further details on the natural history of the species with regard to breeding activity, spawning site, retreats and the ability of tadpoles in preying upon fully-growth heterospecific tadpoles. We also show that the tadpoles are mainly nocturnal and take diurnal refuges. We collected the data in Brazil in three localities within the Cerrado Biome. We examined burrows used by L. labyrinthicus males, verified if females still contained mature eggs just after released from amplexus, and tested the ability of tadpoles in preying fully-growth heterospecific tadpoles. Field observations and experiments were conducted on tadpole activity time, hiding behaviour and level of susceptibility to predation by the bird leaf-scrapers in four sheltering situations. Reproduction could start before the first rains; this may be advantageous by allowing the tadpoles to exploit eggs of other frogs. We found one floating nest built in a temporary pool. The nest of the species is normally circumscribed in an excavated basin beside the water body. Adult males were found during the day with their head-out of the entrance of underwater burrows, which were perforations through dense root mats beside calling/spawning sites. Probably, these burrows in permanently water-filled soil are actively excavated by males. Females released all their eggs during the amplexus, so trophic eggs are not produced by the currently-accepted mechanism. Fully-grown heterospecific tadpoles were not preyed upon by L. labyrinthicus tadpoles, which can prey only slow-moving newly hatched ones. Field tadpoles took shelter under mud/dead leaves during daylight and became exposed on the bottom at night. Free-ranging leaf-scrapers removed...

Girinos de L. labyrinthicus crescem parcialmente no ninho consumindo ovos tróficos. Sugerimos anteriormente que os ovos tróficos seriam postos logo após o amplexo, porém nossos novos dados não corroboram esta hipótese. Apresentamos também mais detalhes da história natural da espécie relacionados à estação reprodutiva, local de desova, abrigos e capacidade dos girinos em predar girinos heteroespecíficos plenamente desenvolvidos. Demonstramos ainda que os girinos são noturnos e se utilizam de refúgios diurnos. Coletamos os dados no Brasil em três locais no Bioma Cerrado. Determinamos o formato e dimensões de buracos utilizados por machos, verificamos se fêmeas liberadas do amplexo ainda portavam óvulos maduros e testamos a capacidade dos girinos em predar girinos heteroespecíficos plenamente desenvolvidos. Realizamos observações naturalísticas e experimentais com girinos para descrever o horário de atividade, comportamento de refúgio e grau de suscetibilidade à predação pela ave sabiá-poca em diferentes tipos de substratos. Desovas podiam ocorrer antes das primeiras chuvas, possibilitando aos girinos explorar ovos de outros anuros no meio da estação chuvosa. Encontramos um ninho construído na superfície da água de uma poça temporária. Os ninhos da espécie geralmente são circunscritos em bacias escavadas às margens do corpo d'água. Machos adultos foram encontrados durante o dia em buracos subaquáticos, os quais eram perfurações adjacentes aos sítios de vocalização/desova. Provavelmente, esses buracos em solos encharcados são ativamente escavados pelos machos. As fêmeas liberam todos os óvulos durante o amplexo, portanto, os ovos tróficos não são produzidos pelo mecanismo aceito presentemente. Os girinos oferecidos nos testes não foram consumidos pelos girinos de L. labyrinthicus, os quais conseguem predar apenas recém-eclodidos. No campo, os girinos se refugiavam entre o lodo ou folhas mortas durante o dia, porém ficavam expostos sobre...

Morfologia bucal interna dos girinos de Leptodactylus labyrinthicus Spix, 1824 (Amphibia: Anura: Leptodactylidae) / Internal buccal morphology of the tadpoles of Leptodactylus labyrinthicus Spix, 1824 (Amphibia: Anura: Leptodactylidae)

A microanatomia do disco oral e da cavidade bucal da larva de Leptodactylus labyrinthicus é descrita e comparada com outras espécies do gênero pertencentes ao grupo de L. pentadactylus. Trinta e cinco girinos entre os estágios 25 e 46 foram dissecados e analisados em microscopia eletrônica de varredura. A descrição da morfologia oral foi feita utilizando larvas entre os estágios 36 e 39. A morfologia oral da larva de L. labyrinthicus é similar às descritas para outros girinos com adaptação a macrofagia, com forte queratinização das coberturas das mandíbulas, redução das estruturas bucais internas e presença de uma glote descoberta, propícias às dietas carnívoras. As larvas do grupo de L. pentadactylus compartilham essa tendência à redução das estruturas de seleção e captura de partículas, apresentando redução no número de papilas da arena do assoalho e do teto bucal, redução ou ausência das papilas anteriores às bolsas bucais, apenas duas papilas pós-nasais, pequenas papilas laterais à crista mediana e zonas glandulares restritas a estreitas faixas no bordo velar. Nos girinos do gênero Leptodactylus a morfologia larvária reflete os grupos atuais propostos para o gênero.

The microanatomy of the oral disc and the buccal cavity of the tadpole of Leptodactylus labyrinthicus is described and compared with other species included in the L. pentadactylus species group. Thirty-five tadpoles between stages 25 and 46 had been dissected and analyzed in scanning electron microscopy. The oral and internal buccal morphology was analyzed in tadpoles between stages 36 and 39. The buccal morphology of the tadpole of L. labyrinthicus is similar to other tadpoles with adaptation to macrophagy, such as the strong queratinization of the jaw, reduction of the internal buccal structures and presence of one glote uncovered, propitious to carnivorous diets. The tadpole of L. pentadactylus species group share this trend to the reduction of the structures of selection and capture of particle, including reduction in the number of the buccal roof and floor arena papillae, reduction or absence of anterior papillae on the buccal pocket, only two postnarial papillae, small lateral ridge papillae and glandular zones restricted in narrow bands on the edge of velum. In the tadpoles of genera Leptodactylus the larval morphology reflects the current groups considered for this genera.

Recognition and distribution of Leptodactylus mystaceus (Anura; Leptodactylidae) in the State of São Paulo, Southeastern Brazil

Leptodactylus mystaceus, a widespread species over South America, is diagnosed based on specimens from the State of São Paulo, its southernmost geographic distribution limit. Here we present the first record of this species for Southeastern Brazil, extending its distribution for approximately 1,300 km to the southeast. We also include a description of its advertisement call, natural history data, photograph in life and morphological illustrations that make easier the identification of the species.

Leptodactylus mystaceus, uma espécie com ampla distribuição geográfica pela América do Sul, é diagnosticada com base em exemplares do Estado de São Paulo, seu limite meridional de distribuição geográfica. Apresentamos aqui o primeiro registro da espécie para o Sudeste do Brasil, ampliando sua distribuição conhecida em cerca de 1.300 km ao sudeste. Também incluímos a descrição da vocalização de anúncio, informações sobre história natural, fotografia em vida e desenhos de caracteres morfológicos que auxiliam na identificação desta espécie.