Thermal Biology of Zoo-Housed Chelonoidis chilensis: Determining the Activity Pattern and Estimating Selected and Critical Maximum Temperature

Ectothermic animals depend on environmental temperature to regulate their body temperature. The Chaco Tortoise (Chelonoidis chilensis) is widespread in South America; however, populations are threatened mainly because of the pet trade. We described the activity pattern of C. chilensis relative to environmental temperature under semi-natural conditions in a zoo enclosure. We also estimated thermal parameters under controlled laboratory conditions: selected temperature (Tsel) and critical maximum temperature (CTmax) between sex and size indicators. In the enclosure, 81% of the observations were from inactive tortoises and 19% from active tortoises. Tortoises were active over a wide thermal range (12.0°?38.0° C) and Tsel was 34.4° ± 0.3° C (mean ± standard error), with no significant differences among sizes or between sexes. Heavier tortoises spent significantly more time at the lowest temperature than lighter ones. The range of CTmax was 36.3°?42.0° C and this parameter was inversely related to tortoise length but did not differ between sexes. The results suggest a wide thermal range in C. chilensis, dependence of thermal behavior on body size but not on sex, and a wider range of body temperatures in smaller individuals than in larger ones. Knowing the parameters that influence thermoregulation contributes to the improvement of management strategies under semi-natural conditions, which, in turn, can be extrapolated to wild populations.Fil: Buteler, Candela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Centro de Zoología Aplicada; ArgentinaFil: Lábaque, María Carla. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Ciencias y Tecnología de los Alimentos; ArgentinaFil: Leynaud, Gerardo Cristhian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Centro de Zoología Aplicada; Argentin

Thermal Biology of Zoo-Housed Chelonoidis chilensis: Determining the Activity Pattern and Estimating Selected and Critical Maximum Temperature

Ectothermic animals depend on environmental temperature to regulate their body temperature. The Chaco Tortoise (Chelonoidis chilensis) is widespread in South America; however, populations are threatened mainly because of the pet trade. We described the activity pattern of C. chilensis relative to environmental temperature under semi-natural conditions in a zoo enclosure. We also estimated thermal parameters under controlled laboratory conditions: selected temperature (Tsel) and critical maximum temperature (CTmax) between sex and size indicators. In the enclosure, 81% of the observations were from inactive tortoises and 19% from active tortoises. Tortoises were active over a wide thermal range (12.0°?38.0° C) and Tsel was 34.4° ± 0.3° C (mean ± standard error), with no significant differences among sizes or between sexes. Heavier tortoises spent significantly more time at the lowest temperature than lighter ones. The range of CTmax was 36.3°?42.0° C and this parameter was inversely related to tortoise length but did not differ between sexes. The results suggest a wide thermal range in C. chilensis, dependence of thermal behavior on body size but not on sex, and a wider range of body temperatures in smaller individuals than in larger ones. Knowing the parameters that influence thermoregulation contributes to the improvement of management strategies under semi-natural conditions, which, in turn, can be extrapolated to wild populations.Fil: Buteler, Candela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Centro de Zoología Aplicada; ArgentinaFil: Lábaque, María Carla. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Ciencias y Tecnología de los Alimentos; ArgentinaFil: Leynaud, Gerardo Cristhian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Centro de Zoología Aplicada; Argentin

Functional traits reveal environmental constraints on amphibian community assembly in a subtropical dry forest

The relationships between functional traits and environmental gradients are useful to identify different community assembly processes. In this work, we used an approach based on functional traits to analyse if changes in hydroperiod and tree covers of ponds are relevant for local amphibian community assembly processes. Ephemeral ponds with low vegetation cover are expected to impose constraints on different species with particular trait combinations and, therefore, to exhibit communities with lower functional diversity than more stable ponds with greater tree cover. Sampling was conducted in 39 temporary ponds located along vegetation and hydroperiod gradients in the most arid portion of the Chaco ecoregion. Seven functional traits were measured in each species present in the regional pool. Associations between these traits and environmental gradients were detected using multivariate ordination techniques and permutation test (RLQ and fourth-corner analyses respectively). Functional diversity indices were then calculated and related to variations in the environmental gradients. The results obtained allowed us to identify different sets of traits associated with hydroperiod and tree cover, suggesting that these environmental variables are relevant for structuring amphibian communities according to interspecific variations in functional traits from both, larval and adult stages. Contrary to our expectations, communities associated with more stable ponds and with greater tree cover exhibited lower functional diversity than expected by chance (and were the ponds with highest species richness). This result indicates that the reduction in relative importance of environmental restrictions imposed by a very short hydroperiod and the lack of tree cover, favours different species of the regional pool that are similar in several functional traits. Accordingly, communities associated with stable ponds with high tree cover exhibited high functional redundancy.Fil: Lescano, Julián Norberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Miloch, Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Leynaud, Gerardo Cristhian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentin

Evaluating behavior and enclosure use of Zoo-housed broadsnouted Caiman (Caiman latirostris): A case study in the Zoo of Córdoba (Argentina)

Los zoológicos son ambientes que permiten avanzar en la investigación de diversas especies, particularmente aquellas difíciles de observar en vida silvestre. Los estudios de comportamiento en estos ambientes proveen información importante acerca del estado de bienestar de los animales. Aquí describimos los comportamientos de una población de siete Yacarés Overos (Caiman latirostris) compuesta por machos y hembras de distintas edades. Evaluamos la asociación de las frecuencias de comportamientos con atributos individuales (sexo y clase etaria) y con variables ambientales (temporada, hora del día y temperatura ambiente media). Calculamos el Índice de Dispersión de la Participación para estimar el uso del espacio en relación a atributos individuales y variablesambientales. Adicionalmente, evaluamos la adecuación del habitáculo y medidas de manejo mediante el análisis de las Cinco Libertades. Los resultados mostraron mayor frecuencia de comportamientos acuáticos en adultos que en subadultos, lo cual podría reflejar un cambio ontogenético comportamental o bien ser una consecuencia de la jerarquía de dominancia. Hubo pocas diferencias comportamentales entre sexos. Los comportamientos acuáticos estuvieron asociados a temperaturas bajas, pudiendo atribuirse al comportamiento de termorregulación. Los resultados también mostraron un movimiento diario desde el agua a la mañana hacia la tierra al mediodía y tarde. Registramos una alta tasa de comportamientos agonistas y se discutieron las posibles causas e implicancias. El uso del espacio fue reducido, con zonas escasamente utilizadas o no utilizadas, y marcada variabilidad entre individuos. Finalmente, un 53% de las recomendaciones de manejo para esta especie se cumplieron en la población en estudioLos zoológicos son ambientes que permiten avanzar en la investigación de diversas especies, particularmente aquellas difíciles de observar en vida silvestre. Los estudios de comportamiento en estos ambientes proveen información importante acerca del estado de bienestar de los animales. Aquí describimos los comportamientos de una población de siete Yacarés Overos (Caiman latirostris) compuesta por machos y hembras de distintas edades. Evaluamos la asociación de las frecuencias de comportamientos con atributos individuales (sexo y clase etaria) y con variables ambientales (temporada, hora del día y temperatura ambiente media). Calculamos el Índice de Dispersión de la Participación para estimar el uso del espacio en relación a atributos individuales y variables ambientales. Adicionalmente, evaluamos la adecuación del habitáculo y medidas de manejo mediante el análisis de las Cinco Libertades. Los resultados mostraron mayor frecuencia de comportamientos acuáticos en adultos que en subadultos, lo cual podría reflejar un cambio ontogenético comportamental o bien ser una consecuencia de la jerarquía de dominancia. Hubo pocas diferencias comportamentales entre sexos. Los comportamientos acuáticos estuvieron asociados a temperaturas bajas, pudiendo atribuirse al comportamiento de termorregulación. Los resultados también mostraron un movimiento diario desde el agua a la mañana hacia la tierra al mediodía y tarde. Registramos una alta tasa de comportamientos agonistas y se discutieron las posibles causas e implicancias. El uso del espacio fue reducido, con zonas escasamente utilizadas o no utilizadas, y marcada variabilidad entre individuos. Finalmente, un 53% de las recomendaciones de manejo para esta especie se cumplieron en la población en estudio.Fil: Prystupczuk, Lilen. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Leynaud, Gerardo Cristhian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Lábaque, María Carla. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; Argentin

Breeding-site selection by red-belly toads, Melanophryniscus stelzneri (Anura: Bufonidae), in Sierras de Córdoba, Argentina

Differences among wetlands can have important consequences on reproductive success of amphibians; thereforehabitat selection is expected to be of particular importance for anurans inhabiting heterogeneous environments. To investigateif the red-belly toad (Melanophryniscus stelzneri; Anura: Bufonidae) uses available habitats differentially and to determine themain factors influencing the use of certain water bodies as breeding habitat, we surveyed 30 spawning sites used by red-bellytoads, and 30 adjacent unused sites, in an area of the Sierras of Córdoba, Argentina. We evaluated the relative importanceof morphological and biotic features of ponds, and the presence of other organisms within the water body on the use ofponds as breeding sites by red-belly toads. Eight habitat variables related to important water body features were recorded andwere used to fit a habitat selection model with GLM. Red-belly toads presented a positive selection to mallines, a wetlandcharacteristic of the Sierras of Córdoba. They were associated with small, shallow ephemeral ponds with muddy banks and ahigh percent of vegetation cover. In general, the ponds used did not host other anuran species or potential predators. Breedingsite selection by red-belly toads is largely consistent with records for other species of the genus in other parts of Argentina.Fil: Pereyra, Laura Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del NOA. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Museo de Ciencias Naturales. Instituto de Bio y Geociencias del NOA; ArgentinaFil: Lescano, Julián Norberto. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Zoología Aplicada; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Leynaud, Gerardo Cristhian. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Zoología Aplicada; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

First description of courtship and copulation in Pristidactylus casuhatiensis (Squamata, Leiosauridae)

Background: Reproductive behaviour under natural conditions is hard to record, especially in rare and cryptic species, such as the Casuhatien anole (Pristidactylus casuhatiensis). This medium size lizard is endemic to the Sierras Australes Bonaerenses, a rocky outcrop in the Southern Pampas of Argentina. Methods: During spring and summer from 2018 to 2022, we surveyed five hills at above 600 m altitude, where specimens were known to occur. Every time we detected a courtship or copulation event, we took photographs of the specimens for their individual identification, and recorded the body temperature of the participating individuals as well as air temperature, wind speed and relative humidity. We recorded the duration in minutes of each phase of the event (immobilization, juxtaposition of the cloacae followed by copulation, and finally, restraint and separation) and described the main habitat features of the site where it happened. Results: We detected 12 reproductive events; all of them occurred in October and November, on Funke, Puntudo and Tres Picos hills, mostly between 1300 and 1700 h. The mean duration of each copulation phase was 6 min (95% CI = ± 1.4, n = 10), 4.3 min (95% CI = ± 1.8, n = 10) and 3.8 min (95% CI = ± 3.42, n = 10), respectively. Conclusion: The reproductive activity of the Casuhatien anole is concentrated in the spring, particularly in the early afternoon, following the patterns described for other species of lizards. During these events, the greatest exposure of individuals could make them more vulnerable. This, together with other features related to their reproductive behaviour revealed in this paper may contribute to the planning of conservation actions.Fil: Luján Ogeda, Daniela Belén. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Areco, A.. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Leynaud, Gerardo Cristhian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Zalba, Sergio Martín. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentin

Morphology, phylogeny and taxonomy of South American bothropoid pitvipers (Serpentes, Viperidae)

South American bothropoids comprise a monophyletic and greatly diverse group of pitvipers that were initially included in the genus Bothrops and later assigned to five genera. Until recently, most phylogenetic analyses of bothropoids used exclusively mitochondrial DNA sequences, whereas few of them have included morphological traits. Moreover, the systematic affinities of some species remain unclear. In this study, we performed a parsimony analysis of morphological data obtained from the examination of 111 characters related to lepidosis, colour pattern, osteology, and hemipenial morphology of 35 of the 48 species that compose the bothropoid group. The morphological data analysed contain novel information about several species, including the incertae sedis. Morphology was analysed separately and combined with 2393 molecular characters obtained from published sequences of four mitochondrial genes. Five characters of the ecology were also included. A sensitivity analysis was performed using different weighting criteria for the characters. The congruence among different sources of evidence was evaluated through partitioned and total evidence analyses, the analyses of reduced datasets and the use of incongruence length difference test. With few exceptions, results showed groups of species similar to those obtained in previous studies; however, incongruences between morphological and molecular characters, and within the molecular partition, were revealed. This conflict affects the relationship between particular groups of species, leading to alternative phylogenetic hypotheses for bothropoids: hierarchical radiation or two major lineages within the group. The results also showed that Bothrops sensu stricto is paraphyletic. We discuss previous taxonomic approaches and, considering both phylogenetic hypotheses, we propose an arrangement that rectifies the paraphyly of Bothrops: maintaining Bothrocophias, assigning Bothrops andianus to this genus; and recognising the sister clade as Bothrops, synonymising Bothriopsis, Bothropoides and Rhinocerophis.Fil: Carrasco, Paola Andrea. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Zoología Aplicada; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Mattoni, Camilo Ivan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Cátedra de Diversidad Animal I; ArgentinaFil: Leynaud, Gerardo Cristhian. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Zoología Aplicada; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Scrocchi Manfrini, Gustavo Jose. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Zoología Aplicada; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentin

A new species of pitviper of the genus Bothrops (Serpentes: Viperidae: Crotalinae) from the Central Andes of South America

We describe a new species of montane pitviper of the genus Bothrops from the Cordillera Oriental of the Central Andes, distributed from southern Peru to central Bolivia. The new species can be distinguished from its congeners by the characteristic combination of a dorsal body color pattern consisting of triangular or subtriangular dark brown dorsal blotches, paired dark brown parallel occipital stripes, a conspicuous dark brown postocular stripe, the presence of canthorostrals in some specimens, prelacunal fused or partially fused with second supralabial, one scale usually separating internasals, rostral trapezoidal, two canthals oval to rounded, similar size or slightly larger than internasals, three or four medial intercanthals, eight to twelve intersupraoculars, intercanthals and intersupraoculars keeled and frequently slightly keeled, supraoculars oval, one to three suboculars, two to three postoculars, loreal subtriangular, two to six prefoveals, subfoveals absent, two or none postfoveals, one or two scales between suboculars and fourth supralabial, seven or eight supralabials, nine or eleven infralabials, 23-25 middorsal scales, 189-195 ventrals in females and 182-190 in males, 48-58 subcaudals in females and 54-63 in males, exceptionally undivided. The new species is apparently restricted to areas within Andean montane forests that are less humid and devoid of large trees.Fil: Timms, J.. Museo Nacional de Ciencias Naturales; EspañaFil: Chaparro Auza, Juan C.. Museo de Biodiversidad del Perú; PerúFil: Venegas, Pablo J.. Centro de Ornitología y Biodiversidad; PerúFil: Salazar Valenzuela, David. Universidad Tecnológica Indoamérica; EcuadorFil: Scrocchi Manfrini, Gustavo Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; ArgentinaFil: Cuevas, Jairo. Universidad Complutense de Madrid; EspañaFil: Leynaud, Gerardo Cristhian. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Zoología Aplicada; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Carrasco, Paola Andrea. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Zoología Aplicada; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentin

A new species of Bothrops (Serpentes: Viperidae: Crotalinae) from Pampas del Heath, southeastern Peru, with comments on the systematics of the Bothrops neuwiedi species group

We describe a new species of pitviper of the genus Bothrops from the Peruvian Pampas del Heath, in the Bahuaja-Sonene National Park. Pampas del Heath is an area of seasonally flooded savannas and a northwestern extension of the Gran Chaco Boliviano-Paraguayo. The new species is easily distinguished from its congeners by the exclusive combination of dorsal color pattern of body consisting of small C-shaped blotches, postocular stripe originating posteriorly to the eye, covering posterior supralabials, dorsum of the head with paired markings arranged symmetrically, venter cream heavily speckled with brown, prelacunal scale discrete in contact with second supralabial, three to five prefoveals, subfoveal single usually present, postfoveals absent to two, canthals two, seven intersupraoculars, one or two suboculars, two or three postoculars, seven or eight supralabials, nine to eleven infralabials, 26-27 interrictals, 23-25 middorsal scales, 172 ventrals in the female and 169-173 in males, 45 subcaudals in the female and 50 in males. We performed separate and combined phylogenetic analyses based on morphology and five mitochondrial genes and recovered the new species as a member of the Bothrops neuwiedi species group. All lineages of this clade inhabit the South American dry diagonal. This novel species of pitviper increases the known diversity of the genus Bothrops and adds to the number of described taxa from the unique and scarcely known ecosystem of Pampas del Heath.Fil: Carrasco, Paola Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Grazziotin, Felipe G.. Governo do Estado de Sao Paulo. Secretaria da Saude. Instituto Butantan; BrasilFil: Farfan, Roy Santa Cruz. Museo de Historia Natural de la Universidad Nacional de; PerúFil: Koch, Claudia. Zoologisches Forschungsmuseum Alexander Koenig; AlemaniaFil: Ochoa, José A.. Museo de Biodiversidad del Perú; PerúFil: Scrocchi Manfrini, Gustavo Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; ArgentinaFil: Leynaud, Gerardo Cristhian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Chaparro, Juan C.. Museo de Biodiversidad del Perú; Per

Thermoconformity strategy in the freshwater turtle Hydromedusa tectifera (Testudines, Chelidae) in its southern distribution area

Ectotherm species are not capable of generating metabolic heat; therefore, they present different strategies for regulating their body temperatures, ranging from a precise degree of thermoregulation to a passive thermoconformity with ambient temperatures. In reptiles, aerial basking is the most common mechanism for gaining heat. However, among aquatic reptiles, such as freshwater turtles, aquatic basking is also frequent. Hydromedusa tectifera is a turtle of exclusively aquatic and nocturnal habits widely distributed in South America. We studied the relationship between body temperature (Tb) of H. tectifera and its habitat, and explored the effects of sex, life stage and body size and mass on Tb. Fieldwork was conducted in two streams of a mountain area of central Argentina. We recorded cloacal temperature, size and mass of 84 turtles. We also determined individuals’ sex and life stage (adult/juvenile). Regarding ambient temperatures, we measured water temperature on the surface (Tsurf) and at depth of turtle capture (Tdepth) and air temperature. Mean Tb was 18.58 °C (Min = 10.20 °C; Max = 25.70 °C). Tsurf and Tdepth were highly correlated. Multi-model analysis using Akaike criterion indicated that Tb was strongly associated with water temperature, whereas air temperature and body size and mass did not show a significant effect. There was also no effect of turtle sex or life stage on Tb. Our results indicate that H. tectifera is a thermoconformer and eurythermal species. A nocturnal pattern of activity and a fully aquatic lifestyle are suggested as determinant factors.Fil: Molina, Francisco Joaquín. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Zoología Aplicada; ArgentinaFil: Leynaud, Gerardo Cristhian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentin