Adriana Malvasio

Avaliação da predação de Podocnemis expansa e Podocnemis unifilis (Testudines, Podocnemididae) no rio Javaés, Tocantins

Podocnemis expansa and P. unifilis long lived with late sexual maturation, which influences a low replacement rate of individuals. Their populations are characterized by low adults mortality, but high mortality of embryos and hatchlings. The natural nest predation is an important factor for hatchling success. In Javaes River, the eggs and hatchlings can be predated by a large number of animals such as birds, vultures (Coragyps atratus and Cathartes aura), carcara (Polyborus plancus), jabiru (Jabiru mycteria); lizards (Tupinambis teguixin) and small mammals, coati (Nasua nasua) and crab-eating-fox (Cerdocyon thous). About 65,98% of nests of P. unifilis are predated (41,68% totally and 24,30% partially). Only 5,31% of P. expansa nests are partially predated. There are many aquatic predators, like carnivorous fish, mainly piranhas (Serrasalmus nattereri) and caimans (Melanosuchus niger e Caimam crocodilus). The predators of P. unifilis females are: black caiman (Melanosuchus niger), jaguar (Panthera onca) and puma (Puma concolor), and of P. expansa females is the P. onca. In average 3,93% of P. unifilis females are predated annually while that to P. expansa the average is 5,66%.

Reproductive Allometry of Podocnemis expansa (Testudines: Podocnemididae) in Southern Brazilian Amazon

Abstract Podocnemis expansa is the largest freshwater turtle in South America and exhibits a complex reproductive behavior. Females lay eggs in sandy banks formed during the dry season. Nesting habitat can influence hatching success and sex determination. In some turtle species, female body size is crucial to determine reproductive parameters such as clutch size and shape. In this study, we investigate allometric relationships between female body size and their tracks, and clutch characteristics and nest shape in sandy beaches along the Javaés River, southern Brazilian Amazon. Our results indicate that female body size can be estimated based on tracks. Larger females leave larger foot tracks in the sand and have larger clutch sizes with larger clutch mass than smaller females. Female carapace width and body mass can be considered reliable variables to estimate clutch size and total clutch mass for the species. Larger females should be protected because they can be responsible for most annual clutch production. Resumo Podocnemis expansa é o maior quelônio de água doce da América do Sul, apresentando um comportamento reprodutivo complexo. Essa espécie nidifica em bancos arenosos formados durante as vazantes dos rios da Amazônia. As características do ambiente de nidificação podem influenciar o sucesso reprodutivo e o sexo dos filhotes. Alguns trabalhos já demonstraram que o tamanho corporal da fêmea é determinante para as condições da ninhada (quantidade e tamanho dos ovos) e nas dimensões dos ninhos (profundidade e diâmetro) em algumas espécies de quelônios. O presente estudo investigou as relações alométricas entre o tamanho corpóreo da fêmea, seus rastros, as variáveis da ninhada e a forma dos ninhos em ambiente natural em uma praia do rio Javaés, na Amazônia Brasileira. Foi observado que o tamanho corpóreo da fêmea de P. expansa pode ser estimado em função do seu rastro. Fêmeas maiores deixam rastros maiores na areia, além de produzirem mais ovos (tamanho da ninhada) e com maior massa (massa da ninhada) do que fêmeas menores. A largura da carapaça e a massa da fêmea podem ser consideradas variáveis confiáveis para estimar o tamanho e a massa da ninhada dessa espécie. A proteção de fêmeas de maior tamanho deveria ser priorizada, já que podem ser responsáveis por grande parte da produção anual de ovos.

Ontogeny of the Shell Bones of Embryos of Podocnemis unifilis (Troschel, 1848) (Testudines, Podocnemididae)

The aim of the present study was to investigate the sequence of shell bone formation in the embryos of the Pleurodira, Podocnemis unifilis. Their bones and cartilage were collected and cleared before staining. The shell was also examined by obtaining a series of histological slices. All the bony elements of the plastron have independent ossification centers, which subsequently join together and retain two fontanelles until the period of hatching. This turtle has a mesoplastra, which is characteristic of the Podocnemididae. The carapace begins to form concurrently with the ossification of the ribs at the beginning of stage 20. All the plates, except the suprapygal, initiate ossification during the embryonic period. The main purpose of the histological investigation was to highlight the relationship between the formation of the carapace and ribs with that of the neural plates. The costal and neural plates were found not to independent ossification centers, but to be closely related to components of the endoskeleton, originating as expansions of the perichondral collar of the ribs and the neural arches, respectively. Considering the ribs as an endoskeletal element of the carapace, the carapace and plastron begin ossification at the same stage in P. unifilis. This pattern reveals similarities with other Pleurodira, as well as evident variations, such as the presence of the seven neural bones and the presence of only one ossification center in the nuchal plate. Anat Rec, 2011.

Brazil's Podocnemis expansa Conservation Program: Retrospective and Future Directions

Abstract Between 1975 and 2004 the giant South American river turtle (Podocnemis expansa) as well as Podocnemis unifilis and Podocnemis sextuberculata had part of their nesting beaches protected. This resulted in the release of approximately 46 million hatchlings and the apparent recovery of these species in some areas; however, this ranching program faces operational and bureaucratic difficulties. In addition, harvesting wild populations is banned by Brazilian law, thereby excluding local villagers from using this natural resource.

Estudo do esqueleto em Trachemys dorbignyi (Duméril & Bibron) (Reptilia, Testudines, Emydidae)

The skeleton of Trachemys dorbignyi (Dumeril & Bibron, 1835), based on 16 specimens incluind young and adult of both sexes is described. Designations of some structures are proposed and discussed based on data from literature and norms published in the The World Association of Veterinary Anatomists (1994).

Prevalence and parasitemia of Haemogregarina sp. in Podocnemis expansa (Testudines: Podocnemididae) from the Brazilian Amazon

Seventy-five turtles Podocnemis expansa in the Brazilian Amazon were examined for the presence of ectoparasites and hemoparasites. Samplings were performed in three study areas in the state of Tocantins, Brazil. Twenty-five specimens were sampled per study area (a commercial breeding facility, an indigenous subsistence breeding facility and a wild population of the Javaés River). Hemoparasites of the genus Haemogregarina were found in 66% (50/75) of the turtle specimens, and the infections were restricted to the commercial breeding facility and to the wild population of the Javaés River. The mean level of parasitemia was 54/2,000 erythrocytes (2%). There was no correlation between the body condition index of the chelonians and the level of parasitemia, with no significant difference between genders. No leeches were observed during the physical exams in any of the study areas, but the specimens from the commercial breeding facility were in poor physical condition with shell deformities and the presence of a relatively high amount of skin ulcerations, most likely caused by fungi and bacteria. This was the first study to record the occurrence of hemogregarines on a population scale in P. expansa and helps to increase knowledge about hemoparasites in chelonians in Brazil.

Predação de fêmeas adultas de Podocnemis expansa Schweigger (Testudines, Podocnemididae) por Panthera onca Linnaeus (Carnivora, Felidae), no Estado do Tocantins

Podocnemis expansa (tartaruga-da-amazonia) e o maior e mais importante representante da fauna de quelonios da Amazonia devido a sua importância economica como fonte alimentar para as populacoes indigenas e ribeirinhas desta regiao. Apesar disso, os aspectos relacionados a sua biologia reprodutiva, assim como os indices de predacao natural de animais adultos em seu habitat sao pouco conhecidos. Nessa pesquisa foi averiguado o numero de femeas de P. expansa predadas por Panthera onca (onca-pintada) em um rio da Amazonia Brasileira. A onca-pintada e o unico predador das femeas adultas de P. expansa nas praias do rio Javaes, Estado do Tocantins, predando em media 3,66% das femeas em postura. A predacao se da sempre a noite, quando as femeas sobem as praias para nidificar.

Population Structure of Podocnemis expansa (Testudines: Podocnemididae) in Southern Brazilian Amazon

Detailed studies of the population structure of most species of turtles in the Amazon Basin are lacking throughout their range. We estimated sex ratio, size structure, relative abundance, and recapture index for the Giant South American River Turtle (Podocnemis expansa) in Javaés River, southern Brazilian Amazon. Field work was conducted between 2004 and 2009, and comprised a total sampling effort of 368 hours in 92 sampling days. Turtles were captured by diving and seining. A total of 645 individuals (156 adult males, 109 adult females, and 380 juveniles) were captured and marked, but only five were recaptured. Carapace length showed a unimodal pattern for males, but no clear pattern for females. The population consisted predominantly of adult males and young females, with a sex ratio of 1.4:1 (M:F). Relative abundance varied from 0–5.5 animals/h depending on the capture method employed. Most animals (73.7%) were concentrated in a single location on the river (1 km out of 40 km sampled) during the study period. Population monitoring on a long-term basis will be necessary to identify the real population structure, evaluate poaching pressure, and to support the conservation project which has been ongoing since 1985 in the area.

Avaliação de padrão irregular dos escudos do casco em Podocnemis expansa e Podocnemis unifilis (Testudines, Podocnemididae)

The shell of Podocnemis expansa (Amazonian giant River turtle) and Podocnemis unifilis (Yellow-spotted Amazon River Turtle), the largest South American turtles, is a unique structure that differentiates them from other known vertebrates; and it is associated with some of their behavioral patterns. Their scute pattern is quite uniform however variations have been described and analyzed for a great number of other species of existing families. In the Javaes River, from 1999 to 2003, we observed an occurrence of abnormalities in their scute pattern. This was in the vicinity of the Araguaia National Park and the Bananal/ Cantao Environment Protected Area, west of Tocantins state. Of the both species, P. expansa is more susceptible to shell abnormalities. Of 14.378 P. expansa hatchlings observed, 13.32 % presented scute pattern abnormalities, while of 1.329 P. unifilis hatchlings, only 4.44 %. The incidence of abnormalities occurred only in the carapace, namely, 98.64% in P. expansa, and 83.05% in P. unifilis.

Percepção ambiental dos projetos de conservação dos quelônios do Tocantins, Brasil

This study aims to contribute to the study of traditional communities the effectiveness of conservation projects of turtles and their derivatives, in particular the district of Roca coffee settlement in the municipality of Pium-TO. We used questionnaire with open and closed questions favoring the opinion of respondents. It was identified that the residents know the protection projects to turtles, their goals and who execute. Residents agree that the turtles need to be protected but not give up the consumption, should integrate traditional communities as full participants in the process of transformation of society without losing the basic cultural characteristics that compose it.