Genotoxic risk assessment of solar UV radiation in tadpoles from Brazilian wetlands.

Solar ultraviolet (UV) radiation is an environmental genotoxic factor linked to amphibian decline. Here we assessed the genotoxic risk of UVB and UVA exposure for tadpoles from open ponds in southern Brazil, a mid-latitude region influenced by stratospheric ozone depletion. Daily UV doses were measured on the surface of a pond in Taim Ecological Station (TAIM; 32°49'24''S; 52°38'31''W) on a cloudless summer day to predict the worst-case scenario for UV-induced DNA damage. Pond descriptors were related to the use of microhabitats by Boana pulchella tadpoles in two ponds over the climate seasons of 2013 and 2014. Our results indicate that shaded microhabitats were more frequent than unshaded ones in autumn, winter, and spring but not in summer. Hence, the penetration of UV radiation into the water of unshaded microhabitats was evaluated through laboratory experiments with artificial UV sources and pond water samples. Physical and biological sensors were applied in the experiments to measure the incident UV radiation and its genotoxic action. By integrating field and laboratory data, we demonstrate that low doses of biologically effective UV radiation reached the tadpoles in autumn, winter, spring, and early summer due to a high proportion of shaded microhabitats and a high concentration of solids in unshaded microhabitats. However, the relative reduction of shaded microhabitats jointly with a declining water level in late summer may have exposed tadpoles to high UV doses. Our experiments also indicate that solar UVB radiation, but not UVA, is primarily responsible for the induction of DNA pyrimidine dimers in organisms living under the surface of aquatic ecosystems. The present work highlights the determinant role of wetland descriptors for minimizing the genotoxic potential of UV radiation and its consequences for amphibians.

Pet distribution modelling: Untangling the invasive potential of Trachemys dorbigni (Emydidae) in the Americas.

Human activities have been changing the global biogeographic patterns by the introductions of invasive species. For reptiles, the invasion rate increase of non-native species is remarkably related to the pet trade, especially for freshwater turtles. Here we estimated the invasive potential of the South American turtle Trachemys dorbigni in the Americas using a combination of climatic and human activity variables. We built species distribution models based on data from the native and invasive ranges, using the ensemble model from five different algorithms (GAM, MAXENT, BRT, RF and GBM). We compared the two models' performance and predictions, one calibrated with only climatic variables (climate-driven), and the second also included a descriptive variable of human activity (climate plus human-driven). Suitable areas for T. dorbigni covered occurrence areas of its congeners and highly diversified ecoregions, such as the eastern USA, the islands of Central America, and the south eastern and eastern Brazilian coast. Our results indicate that human activities allow T. dorbigni to establish populations outside of its original climatic niche. Including human activity variables proved fundamental to refining the results to identify more susceptible areas to invasion and to allow the efficient targeting of prevention measures. Finally, we suggested a set of actions to prevent T. dorbigni becoming a highly impacting species in the areas identified as more prone to its invasion.

Reproductive biology of the sword snake tomodon dorsatus (Serpentes: Dipsadidae) in south Brazil: comparisons within the tribe Tachymenini

We described the reproductive cycle, size-fecundity relationships, reproductive effort, and sexual maturity of Tomodon dorsatus in South Brazil. We examined 87 individuals (25 males and 62 females) from herpetological collections. The description of the reproductive cycle was based on the morpho-anatomical and histological changes in male testes, ductus deferens, and kidney and in female ovary and oviduct. The age at the onset of sexual maturity was estimated by skeletochronology of the caudal vertebra. The reproduction is seasonal semi-synchronous with most of the individuals showing a reproductive peak in the spring. Males and females have developed sperm storage strategies, increasing the reproductive success. Males store sperm in the ductus deferens during the autumn and winter, while females storage takes place in the utero-vaginal junction furrows during the autumn and early winter. Larger females produce a higher number of larger follicles and eggs. Females invest more in growth before reaching sexual maturity than males. Females reach sexual maturity earlier (4 years old) than males (5 years old) and have larger bodies but lower longevity. Reproductive strategies of Tachymenini specie are highly conserved.

A fisherman’s tale: activity, habitat use and the first evidence of lingual lure behavior in a South American snake

Literature data suggests that Thamnodynastes strigatus (Serpentes, Dipsadidae) is a snake that actively forages for anurans near waterbodies, using several microhabitats for this activity (e.g., shrubs, soil, and water). However, herein we present dissonant data previously known to the species, both concerning type of prey and foraging strategy. A total of 72 observations were performed exclusively at night, when snakes were in vegetation near streams in 93% of the cases. Among these observations, 41 were active snakes, and most of them (97%) were in an ambush position on the vegetation, peering at fishes. On two occasions, the snakes used a lingual lure behavior in order to attract fishes. This is only the sixth species in which this behavior has been observed, and the first in South America. Therefore, we provide additional data on T. strigatus habitat activity and habitat use, as well as unpublished data on ambush and lingual lure behavior for the Neotropical genus Thamnodynastes

A fisherman’s tale: activity, habitat use and the first evidence of lingual lure behavior in a South American snake

Literature data suggests that Thamnodynastes strigatus (Serpentes, Dipsadidae) is a snake that actively forages for anurans near waterbodies, using several microhabitats for this activity (e.g., shrubs, soil, and water). However, herein we present dissonant data previously known to the species, both concerning type of prey and foraging strategy. A total of 72 observations were performed exclusively at night, when snakes were in vegetation near streams in 93% of the cases. Among these observations, 41 were active snakes, and most of them (97%) were in an ambush position on the vegetation, peering at fishes. On two occasions, the snakes used a lingual lure behavior in order to attract fishes. This is only the sixth species in which this behavior has been observed, and the first in South America. Therefore, we provide additional data on T. strigatus habitat activity and habitat use, as well as unpublished data on ambush and lingual lure behavior for the Neotropical genus Thamnodynastes

Morphological variation and sexual dimorphism in two sympatric dipsadine snakes from Southern Brazil

Snakes have high morphological variation, including between sexes. Most of these variations are evidenced only by linear measurements, which are generally restricted to size traits. Using traditional and geometric morphometrics methods we analyze how body size attributes and head size and shape varies between sexes and species of two sympatric Tachymenini snakes, Thamnodynastes strigatus and Tomodon dorsatum. We took body size measurements from 87 specimens of T. strigatus and 83 specimens of T. dorsatum. We also extracted head shape and size of 146 specimens of T. strigatus and 156 specimens of T. dorsatum. Our results showed sexual differences in some body size attributes and in head shape and size. Females of both species had larger SVL, BM, HW, BW and heads than in males. But, T. strigatus is not sexually dimorphic in head size. Females of the T. strigatus also exhibited an enlargement of the parietal region compared to the males, while T. dorsatum females exhibited a wider snout than males. These sexual differences could be a result of fecundity selection and may also indicate that females consume larger preys than conspecific males. At the species level, T. strigatus is larger in body and head size than T. dorsatum. The head shape of T. strigatus is characterized by a more elongated head with larger frontal and prefrontal scales and slender snout compared to T. dorsatum. Shape differences between these two snakes probably evolved in association with divergences in habitat use e.g. terrestrial and arboreal and diet specialization e.g. piscivory, and malacophagy.

Morphological variation and sexual dimorphism in two sympatric dipsadine snakes from Southern Brazil

Snakes have high morphological variation, including between sexes. Most of these variations are evidenced only by linear measurements, which are generally restricted to size traits. Using traditional and geometric morphometrics methods we analyze how body size attributes and head size and shape varies between sexes and species of two sympatric Tachymenini snakes, Thamnodynastes strigatus and Tomodon dorsatum. We took body size measurements from 87 specimens of T. strigatus and 83 specimens of T. dorsatum. We also extracted head shape and size of 146 specimens of T. strigatus and 156 specimens of T. dorsatum. Our results showed sexual differences in some body size attributes and in head shape and size. Females of both species had larger SVL, BM, HW, BW and heads than in males. But, T. strigatus is not sexually dimorphic in head size. Females of the T. strigatus also exhibited an enlargement of the parietal region compared to the males, while T. dorsatum females exhibited a wider snout than males. These sexual differences could be a result of fecundity selection and may also indicate that females consume larger preys than conspecific males. At the species level, T. strigatus is larger in body and head size than T. dorsatum. The head shape of T. strigatus is characterized by a more elongated head with larger frontal and prefrontal scales and slender snout compared to T. dorsatum. Shape differences between these two snakes probably evolved in association with divergences in habitat use (e.g. terrestrial and arboreal) and diet specialization (e.g. piscivory, and malacophagy).

Sunlight-induced genotoxicity and damage in keratin structures decrease tadpole performance.

The increased incidence of solar ultraviolet (UV) radiation, an environmental genotoxic agent, due to ozone depletion or deforestation may help to explain the enigmatic decline of amphibian populations in specific localities. In this work, we evaluated the importance of DNA repair performed by photolyases to maintain the performance of treefrog tadpoles after acute and chronic treatments with environmental-simulated doses of solar UVB and UVA radiation. Immediately after UV treatments, tadpoles were exposed to a visible light source to activate photolyases or kept in dark containers. The biological effects of UV treatments were evaluated through morphological, histological, locomotor and survival analyzes of Boana pulchella tadpoles (Anura: Hylidae). The results indicate that tadpole body weight suffered influence after both UVB and UVA treatments, although the body length was bit affected. The locomotor performance of UVB-exposed tadpoles was significantly reduced. In addition, UVB radiation induced a severe impact on tadpole skin, as well as on keratinized structures of mouth (tooth rows and jaw), indicating that these should be important effects of solar UV radiation in the reduction of tadpole performance. Furthermore, photolyases activation was fundamental for the maintenance of tadpole performance after chronic UVB exposures, but it was relatively inefficient after acute exposures to UVB, but not to UVA radiation. Therefore, this work demonstrates how the UV-induced genotoxicity and structural alterations in the skin and oral apparatus affect tadpole performance and survival.

Reproductive biology of Philodryas patagoniensis (Snakes: Dipsadidae) in south Brazil: female reproductive cycle

In this study, we describe the female reproductive cycle of Philodryas patagoniensis in south Brazil, which was described through morpho-anatomical and histological analyses. The peak of secondary vitellogenesis occurred during winter-spring (July-December), ovulation in spring (October-December), mating and fertilization in spring-summer (October-February), oviposition in spring-autumn (October-May) and births from late spring to autumn (December-July). The diameter of vitellogenic follicles/eggs was larger in winter-spring than in other seasons. The diameter of the shell glands was also larger in winter-spring. In spite of the clear reproductive peak, gonads only showed reduced activity in the autumn. Therefore, at the individual level, females have a discontinuous cyclical reproduction; in the populational level, the reproductive cycle is seasonal semisynchronous. We support the hypothesis that P.patagoniensis have the ability to produce multiple clutches with long-term stored sperm. Sexual dimorphism in body size was evident, and females are significantly larger and heavier than males. Larger females were able to produce follicles and eggs in larger amount and size. The maternal body size was positively related to the reproductive effort and fecundity. To conclude, we deliberated about the proximal and distal causes that influence the reproductive traits and patterns of P.patagoniensis.

Reproductive biology of Philodryas patagoniensis (Snakes: Dipsadidae) in south Brazil: female reproductive cycle

In this study, we describe the female reproductive cycle of Philodryas patagoniensis in south Brazil, which was described through morpho-anatomical and histological analyses. The peak of secondary vitellogenesis occurred during winter-spring (July-December), ovulation in spring (October-December), mating and fertilization in spring-summer (October-February), oviposition in spring-autumn (October-May) and births from late spring to autumn (December-July). The diameter of vitellogenic follicles/eggs was larger in winter-spring than in other seasons. The diameter of the shell glands was also larger in winter-spring. In spite of the clear reproductive peak, gonads only showed reduced activity in the autumn. Therefore, at the individual level, females have a discontinuous cyclical reproduction; in the populational level, the reproductive cycle is seasonal semisynchronous. We support the hypothesis that P.patagoniensis have the ability to produce multiple clutches with long-term stored sperm. Sexual dimorphism in body size was evident, and females are significantly larger and heavier than males. Larger females were able to produce follicles and eggs in larger amount and size. The maternal body size was positively related to the reproductive effort and fecundity. To conclude, we deliberated about the proximal and distal causes that influence the reproductive traits and patterns of P.patagoniensis.

Hematophagous Flies Attracted to Frog Calls in a Preserved Seasonal Forest of the Austral Neotropics, with a Description of a New Species of Corethrella (Diptera: Corethrellidae).

The signaler-eavesdropper interaction has been investigated for a wide range of organisms, and although many flies feed on calling frogs, this dynamic has been addressed only poorly in the austral Neotropics. We investigated this interaction in southern Brazil using pairs of suction traps (acoustic + silent) broadcasting frog calls or an artificial white noise in ponds and streams. From 139 sessions, flies of the genera Corethrella (Corethrellidae), Forcipomyia (Ceratopogonidae) and Uranotaenia (Culicidae) were collected, including five Corethrella species, the most abundant of which was previously unknown and is formally described here. Additionally, we present the southernmost records of Corethrella lopesi, C. alticola and C. atricornis. Numbers of Forcipomyia midges and Uranotaenia mosquitoes did not differ between silent traps and traps broadcasting frog calls, and did not differ between white noise traps and adjacent silent traps. However, the number of female Corethrella was significantly higher in traps broadcasting calls of the pond-breeding frog P. aff. gracilis compared to adjacent silent traps; calls of this frog attracted the five Corethrella species and also collected significantly more female Corethrella than the white noise. By evaluating different taxa of flies and broadcasting different sounds, we demonstrated that Corethrella midges were attracted only to the acoustic cue of P. aff. gracilis calls, while Forcipomyia and Uranotaenia were captured in traps by chance. Our results suggest that female Corethrella feed on males of the common pond-breeding frog P. aff. gracilis in southern Brazil, and highlight the utility of frog call traps in revealing the diversity of Corethrella in the austral Neotropics.

Extension of the geographical distribution of two anuran species for Rio Grande do Sul State, Brazil, with comments on natural history / Extensão da distribuição geográfica de duas espécies de anuros para o Estado do Rio Grande do Sul, Brasil, com comentários sobre história natural

We record for the first time Crossodactylus schmidti (Anura: Hylodidae) and Proceratophrys avelinoi (Anura: Cycloramphidae) from Rio Grande do Sul State, Brazil, based on individuals captured in an area of Mesophytic Semideciduous Forest, the Parque Estadual do Turvo, located in the northwest region of the state. These records extend the geographical range for both species in about 60 km from the nearest known locality, the Municipality of San Vicente, Misiones, Argentina. We provide a characterization of the calling site used by males of Crossodactylus schmidti, and we also determined the niche breadth of P. avelinoi regarding to the use of water bodies.

Reportamos o primeiro registro de Crossodactylus schmidti (Anura: Hylodidae) e Proceratophrys avelinoi (Anura: Cycloramphidae) para o Estado do Rio Grande do Sul, Brasil, com base em indivíduos coletados em área de Floresta Estacional Semidecidual, Parque Estadual do Turvo, região noroeste do estado. Estes registros ampliam a área de distribuição das duas espécies em aproximadamente 60 km a partir da localidade mais próxima conhecida, o Município de San Vicente, Misiones, Argentina. Fornecemos, ainda, uma caracterização do sítio de vocalização de C. schmidti e determinamos a amplitude de nicho de P. avelinoi quanto ao uso de corpos d'água.

Mamíferos do campus da Universidade Federal de Santa Maria, Rio Grande do Sul, Brasil / Mammals of the campus of the Universidade Federal de Santa Maria, Rio Grande do Sul, Brazil

O estudo foi desenvolvido no Campus da Universidade Federal de Santa Maria (UFSM), localizado na Depressão Central do Rio Grande do Sul, no bioma Pampa. Aqui uma listagem de mamíferos é apresentada e são discutidas a ocupação espacial e estratégias de conservação da mastofauna local. Entre novembro de 2001 e outubro de 2002 foram registradas 26 espécies nativas e duas espécies exóticas (Lepus europaeus e Mus musculus) de mamíferos, distribuídas em 14 famílias. A maioria das espécies registradas apresenta ampla distribuição, é comumente associada a áreas abertas e apresenta tolerância a distúrbios antrópicos. Entretanto, também foram registradas espécies consideradas raras ou ameaçadas no Estado do Rio Grande do Sul (Lontra longicaudis, Monodelphis dimidiata e Nyctinomops laticaudatus), para as quais são sugeridas estratégias de conservação. A baixa diversidade de espécies registrada no Campus pode estar relacionada à forte pressão de modificações antrópicas, à pequena extensão da área estudada ou a fatores históricos, já que a área de estudo é originalmente campestre (Pampa), tipo de ambiente que abriga menor diversidade de mamíferos que áreas de florestas nativas.

The study was conducted in the Campus of the Universidade Federal de Santa Maria (UFSM), which is located in the Central Depression of Rio Grande do Sul State, in the Pampa biome. Here, a mammal list is presented and spatial occupation and conservation strategies of local mammals are discussed. Between November 2001 and October 2002, 26 native species and two exotic species of mammals (Lepus europaeus and Mus musculus) were recorded, representing 14 families. Most recorded species presents wide distribution, is likely associated to open environments and is tolerant to human disturbances. However, we also recorded three species that are considered rare or threatened in the State of Rio Grande do Sul (Lontra longicaudis, Monodelphis dimidiata and Nyctinomops laticaudatus), for which conservation strategies are recommended. The low species richness recorded in the Campus can be related to the strong pressure of human disturbances, to the small extension of the studied area or to historical factors, as the studied area is originally a grassland (Pampa), a type of environment containing a lower mammalian diversity than native forests.

Répteis do campus da Universidade Federal de Santa Maria, RS, Brasil / x

Este trabalho apresenta um inventário das espécies de répteis que ocorrem no campus da Universidade Federal de Santa Maria (UFSM) e arredores. A listagem está baseada em expedições mensais de campo entre novembro de 2001 e outubro de 2002 e exame do material da Coleção Herpetológica do Departamento de Biologia da UFSM. Das 36 espécies listadas, 20 foram registradas no campo e 16 foram registradas pelo exame da coleção.

This work presents an inventory of reptile species occuring in the campus of Universidade Federal de Santa Maria (UFSM) and surroundings. It is based on monthly field expeditions between November 2001 and October 2002 and examination of material in the Coleção Herpetológica do Departamento de Biologia da UFSM. Of the 36 species listed, 20 were recorded in the field whereas 16 were recorded in the collection.

Contenção farmacológica de ouriços-cacheiros (Sphiggurus spp) pela associação de xilazina e cetamina / Chemical restraint of porcupines (Sphiggurus spp) with the association of xylazine and ketamine

Onze ouriços-cacheiros (Sphiggurus spp.) foram contidos farmacologicamente para realização de exames médicos e procedimentos de manejo. Utilizaram-se, para tal finalidade, xilazina (dose média de 2,32 mg/kg) e cetamina (dose média de 29,66 mg/kg), combinadas na mesma seringa, administradas no terço final da cauda. Observou-se reação à administração dos fármacos provavelmente por dor, indução em um tempo médio de 8,20 minutos e 24,63 minutos de contenção farmacológica. Tanto a indução quanto a recuperação foram suaves e livres de efeitos excitatórios. A freqüência respiratória permaneceu inalterada, mas houve redução na freqüência cardíaca e na temperatura retal com o decorrer do tempo. A associação de xilazina e cetamina, nas doses utilizadas, foi eficiente na contenção farmacológica de ouriço-cacheiro (Sphiggurus spp.) para a realização de manejo ou procedimentos médicos menos invasivos.