30 resultados para Geochelone carbonaria


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A chorioallantoic membrane artery in embryos of the red-footed tortoise, Chelonoidis carbonaria was occlusively cannulated for measurement of blood pressure and injection of drugs. Two age groups of embryos in the final 10 % of incubation were categorized by the ratio of embryonic body to yolk mass. All embryos first received cholinergic and β-adrenergic blockade. This revealed that β-adrenergic control was established in both groups whereas cholinergic control was only established in the older group immediately prior to hatching. The study then progressed as two series. Series one was conducted in a subset of embryos treated with histamine before or after injection of ranitidine, the antagonist of H2 receptors. Injection of histamine caused an initial phasic hypertension which recovered, followed by a longer lasting hypertensive response accompanied by a tachycardia. Injection of the H2 receptor antagonist ranitidine itself caused a hypotensive tachycardia with subsequent recovery of heart rate. Ranitidine also abolished the cardiac effects of histamine injection while leaving the initial hypertensive response intact. In series, two embryos were injected with histamine after injection of diphenhydramine, the antagonist to H1 receptors. This abolished the whole of the pressor response to histamine injection but left the tachycardic response intact. These data indicate that histamine acts as a non-adrenergic, non-cholinergic factor, regulating the cardiovascular system of developing reptilian embryos and that its overall effects are mediated via both H1 and H2 receptor types. © 2013 Springer-Verlag Berlin Heidelberg.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Pós-graduação em Genética - IBILCE

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From September 2008 to March 2010, 397 ticks (315 larvae, 33 nymphs, 23 females, and 26 males) were collected from captive and free-living wildlife species in northeastern Brazil. Six tick species were identified, including Amblyomma auricularium (Conil) on Tamandua tetradactyla (L.),Amblyomma dubitalum Neumann on Hydrochaeris hydrochaeris (L.), Nectomys rattus (Pelzen) and T. tetradactyla, Amblyomma parvim A ragao on T. tatradactyla, Amblyomma rotundatum Koch on Boa constrictor L., Chelonoidis carbonaria (Spix), Kinosternon scorpioides (L.) and Rhinella jimi (Stevaux), Amblyomma cerium Koch on Bradypus variegatus Schinz, and Rhipicephalus sanguineus (Latreille) on Lycalopex vetulus (Lund). Nectomys rattus and T. tetradactyla are new hosts for A. dubitatum This study extends the known distribution of A. dubitatum in South America and provides evidence that its geographical range has been underestimated because of the lack of research. Four (A. dubitatum, A. parvum, A. rotundatum, and R. sanguineus) of six tick species identified in this study have previously been found on humans in South America, some of them being potentially involved in the transmission of pathogens of zoonotic concern.

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A radiation of five species of giant tortoises (Cylindraspis ) existed in the southwest Indian Ocean, on the Mascarene islands, and another (of Aldabrachelys ) has been postulated on small islands north of Madagascar, from where at least eight nominal species have been named and up to five have been recently recognized. Of 37 specimens of Madagascan and small-island Aldabrachelys investigated by us, 23 yielded significant portions of a 428-base-pair (bp) fragment of mitochondrial (cytochrome b and tRNA-Glu), including type material of seven nominal species (A. arnoldi, A. dussumieri, A. hololissa, A. daudinii, A. sumierei, A. ponderosa and A. gouffei ). These and nearly all the remaining specimens, including 15 additional captive individuals sequenced previously, show little variation. Thirty-three exhibit no differences and the remainder diverge by only 1-4 bp (0.23-0.93%). This contrasts with more widely accepted tortoise species which show much greater inter- and intraspecific differences. The non-Madagascan material examined may therefore only represent a single species and all specimens may come from Aldabra where the common haplotype is known to occur. The present study provides no evidence against the Madagascan origin for Aldabra tortoises suggested by a previous molecular phylogenetic analysis, the direction of marine currents and phylogeography of other reptiles in the area. Ancient mitochondrial DNA from the extinct subfossil A. grandidieri of Madagascar differs at 25 sites (5.8%) from all other Aldabrachelys samples examined here.

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Vários pesquisadores têm avaliado impactos de estradas. Estes podem envolver aspectos paisagísticos, degradação do solo, poluição do ar e impactos sobre a fauna, como atropelamentos. Na estrada Raimundo Mascarenhas, que atravessa a Floresta Nacional de Carajás (ca. 400 mil hectares), há intenso tráfego de veículos automotores. O objetivo deste trabalho foi testar se há diferenças entre trechos da estrada, em três escalas espaciais; se há alteração ao longo dos anos; se alguns táxons são mais freqüentemente atropelados, e se a freqüência de atropelamentos aumenta com a precipitação mensal. Analisamos a freqüência de atropelamentos de vertebrados de abril/2003 até outubro/2006 ao longo dos 25 km iniciais da estrada. Registramos 155 atropelamentos. O número de atropelamentos diminui ao longo dos anos (P=0,01), e com a distância do início da estrada (P=0,0002). Serpentes (Ophidia) e gambás Didelphis marsupialis foram mais atropelados (7,5/ano), seguidos de aves, raposas Cerdocyon thous, quatis Nasua nasua, roedores (Rodentia), e não identificados (4,9/ano); cuíca Marmosops sp., tapeti Sylvilagus brasiliensis, guariba Alouatta sp., irara Eira barbara, jabuti Geochelone sp., lagartos (Lacertilia) e macaco prego Cebus apella (1/ano). Não houve relação significativa entre o número mensal de atropelamentos e a precipitação mensal.

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According to most studies on seed dispersal in tropical forests, mammals and birds are considered the main dispersal agents and the role played by other animal groups remains poorly explored. We investigate qualitative and quantitative components of the role played by the tortoise Chelonoidis denticulata in seed dispersal in southeastern Amazon, and the influence of seasonal variation in tortoise movement patterns on resulting seed shadows. Seed shadows produced by this tortoise were estimated by combining information on seed passage times through their digestive tract, which varied from 3 to 17 days, with a robust dataset on movements obtained from 18 adult C. denticulata monitored with radio transmitters and spoon-and-line tracking devices. A total of 4,206 seeds were found in 94 collected feces, belonging to 50 seed morphotypes of, at least, 25 plant genera. Very low rates of damage to the external structure of the ingested seeds were observed. Additionally, results of germination trials suggested that passage of seeds through C. denticulata`s digestive tract does not seem to negatively affect seed germination. The estimated seed shadows are likely to contribute significantly to the dispersal of seeds away from parent plants. During the dry season seeds were dispersed, on average, 174.1 m away from the location of fruit ingestion; during the rainy season, this mean dispersal distance increased to 276.7 m. Our results suggest that C. denticulata plays an important role in seed dispersal in Amazonian forests and highlight the influence of seasonal changes in movements on the resulting seed shadows.

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We developed and optimized a simple, efficient and inexpensive method for in vitro culture of peripheral blood lymphocytes from the Brazilian tortoise Chelonoidis carbonaria (Testudinidae), testing various parameters, including culture medium, mitogen concentration, mitotic index, culture volume, incubation time, and mitotic arrest. Peripheral blood samples were obtained from the costal vein of four couples. The conditions that gave a good mitotic index were lymphocytes cultured at 37°C in minimum essential medium (7.5 mL), with phytohemagglutinin as a mitogen (0.375 mL), plus streptomycin/penicillin (0.1 mL), and an incubation period of 72 h. Mitotic arrest was induced by 2-h exposure to colchicine (0.1 mL), 70 h after establishing the culture. After mitotic arrest, the cells were hypotonized with 0.075 M KCl for 2 h and fixed with methanol/acetic acid (3:1). The non-banded mitotic chromosomes were visualized by Giemsa staining. The diploid chromosome number of C. carbonaria was found to be 52 in females and males, and sex chromosomes were not observed. We were able to culture peripheral blood lymphocytes of a Brazilian tortoise in vitro, for the preparation of mitotic chromosomes.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The following new species are described - Cerambycinae, Sydacini: Sydax flechtmanni sp. nov. from Brazil (São Paulo); Eburiini: Ebrodacrys biffipradorum sp. nov. from Brazil (Roraima); - Lamiinae, Pteropliini: Ataxia piauiensis sp. nov. from Brazil (Piuaí); Calliini: Amucallia carbonaria sp. nov. from French Guiana; A. citrina sp. nov. from Guiana. Also in Lamiinae, two new genera of Onciderini are proposed. Ubytyra gen. nov., type species U. tuberosa sp. nov. from Peru (Junin) e Japi gen. nov., type species J. duartei sp. nov., from Brazil (São Paulo); Ubytyra gen. nov. can be distinguished by the sides of prothorax with long central spine rounded at apex, and this new feature among Onciderini is discussed. Japi gen. nov., is characterized by a fringe of long hairs on the inner side of antennomere III, present only in species from North and Central America, and gender comparison of these species is done and discussed. In Hemilophini, Pseudotacocha gen. nov., type species P. magnifica sp. nov. from Peru (Cuzco), are described. The new genera can be distinguished by eyes well developed, elytra with two carinae and the apices outer with short spine; a comparison with related genera is done.

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Workers from social insect colonies use different defence strategies to combat invaders. Nevertheless, some parasitic species are able to bypass colony defences. In particular, some beetle nest invaders cannot be killed or removed by workers of social bees, thus creating the need for alternative social defence strategies to ensure colony survival. Here we show, using diagnostic radioentomology, that stingless bee workers (Trigona carbonaria) immediately mummify invading adult small hive beetles (Aethina tumida) alive by coating them with a mixture of resin, wax and mud, thereby preventing severe damage to the colony. In sharp contrast to the responses of honeybee and bumblebee colonies, the rapid live mummification strategy of T. carbonaria effectively prevents beetle advancements and removes their ability to reproduce. The convergent evolution of mummification in stingless bees and encapsulation in honeybees is another striking example of co-evolution between insect societies and their parasites.

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Perhaps the most enduring debate in reptile systematics has involved the giant Galápagos tortoises (Geochelone nigra), whose origins and systematic relationships captivated Charles Darwin and remain unresolved to this day. Here we report a phylogenetic reconstruction based on mitochondrial DNA sequences from Galápagos tortoises and Geochelone from mainland South America and Africa. The closest living relative to the Galápagos tortoise is not among the larger-bodied tortoises of South America but is the relatively small-bodied Geochelone chilensis, or Chaco tortoise. The split between G. chilensis and the Galápagos lineage probably occurred 6 to 12 million years ago, before the origin of the oldest extant Galápagos island. Our data suggest that the four named southern subspecies on the largest island, Isabela, are not distinct genetic units, whereas a genetically distinct northernmost Isabela subspecies is probably the result of a separate colonization. Most unexpectedly, the lone survivor of the abingdoni subspecies from Pinta Island (“Lonesome George”) is very closely related to tortoises from San Cristóbal and Española, the islands farthest from the island of Pinta. To rule out a possible recent transplant of Lonesome George, we sequenced DNA from three tortoises collected on Pinta in 1906. They have sequences identical to Lonesome George, consistent with his being the last survivor of his subspecies. This finding may provide guidance in finding a mate for Lonesome George, who so far has failed to reproduce.

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[ES] Se describe una nueva especie de tortuga terrestre fósil para la isla de Sal en función de cuatro restos óseos: un fémur, dos huesos del caparazón y un cráneo incluido en una matriz caliza. La nueva especie, relativamente próxima a la actual Geochelone sulcata del Sahel, se caracteriza por presentar un tamaño más pequeño que ésta (longitud del caparazón próxima a los 400 mm) y por ser mucho menos robusta.

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[ES] Una nueva especie de tortuga terrestre extinguida en el Plioceno de Gran Canana es descrita con el nombre de Geochelone vulcanica. La comparación con el material óseo similar de G. burchardi en la isla de Tenerife, demuestra las grandes diferencias existentes entre ambos taxones. Los huevos fósiles de tortugas terrestres descritos en la isla de Gran Canana se consideran pertenecientes a la nueva especie.