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URI permanente para esta coleçãohttps://bdc.icmbio.gov.br/handle/cecav/1481
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Item Nesting of Phrynops geoffroanus (Testudines: Chelidae) on sandy beaches along the Upper Xingu River, Brazil.(Zoologia, 2011-10) Ferreira Júnior, Paulo D.; Balestra, Rafael A. M.; Moreira, José R.; Freitas, Fábio de O.; Lustosa, Ana P. G.; Jorge, Rafael F.; Rosa, Artur J. de M.; Sampaio, Antônio A.; Gomes, Aline S.This work presents the first data on incubation temperature of Phrynops geoffroanus (Schweigger, 1812) in a natural environment, and provides information on nest predation, hatching success and size of offspring born in the nests on sandy beaches along the Upper Xingu River. Thirty-one P. geoffroanus nests were found, of which eleven were completely predated, mainly by Cerdocyon thous (Linnaeus, 1766). Incubation was completed in nine out of the 17 nests protected by netting. The nests presented an average of 13.1 eggs and were distributed over the various geomor phological sectors of the nine sampled beaches. The size and weight of the hatchlings varied significantly between nests, and the incubation period in protected nests lasted for 76.5 days, less than reported for controlled incubation in the laboratory. Daily variation in incubation temperature in the three nests monitored for temperature was lower in those situated in fine sand sediments. Incubation temperature varied from 22 to 39 C and may have affected hatching success, which reached 60.8% in protected nests. Nest distribution in different geomorphological sectors indicated the plasticity of P. geoffroanus in terms of variation in nesting environment, which partly explains the species’ broad geoographical distribution.Item The trophic niche of Mesoclemmys vanderhaegei (Testudines: Chelidae): evidence from stable isotopes.(Zoologia, 2017-08-22) Marques, Thiago S.; Brito, Elizângela S.; Lara, Neliton R.F.; Beloto, Luciana M.; Valadão, Rafael M.; de Camargo, Plínio B.; Verdade, Luciano M.Ecological niche is the multidimensional space comprising the resources used by an organism. Intraspecific variation in resource exploitation is common in reptile populations to maximize coexistence of individuals. The use of stable isotope analysis is an effective tool when there are variations in resource exploitation, since it can provide quantitative information about food consumption and habitat use. Mesoclemmys vanderhaegei (Bour, 1973) is a medium-sized turtle with a limited distribution in south central Brazil and Paraguay. In spite of that, little is known about its ecology. In this study we used stable isotope analysis to understand the intraspecific trophic niche variation in M. vanderhaegei at Serra das Araras Ecological Station, state of Mato Grosso, Brazil. The isotopic ratios of δ15N and δ13C were determined in claw samples collected from 14 males and 14 females. Isotopic niche width values were not statistically different between the sexes, there was a high degree of overlap between sexual niches and there were no relationships between isotopic compositions and body size. These results suggest that individuals of both sexes and throughout their ontogenetic development exploit food resources with the same isotopic baseline.