966 resultados para terrestrial crabs


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Distribution patterns of most of the 20 Neotropical freshwater turtles belonging to the family Chelidae are usually based on few locality records. We here report on vouchered records of three species of the chelid genus Mesoclemmys in the Brazilian state of Mato Grosso. Presence of M. vanderhaegei is confirmed for the Amazon River Basin, and M. gibba and M. raniceps are recorded in Mato Grosso for the first time. © 2012 Check List and Authors.

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Fiddler crabs are deposit feeders, and use the setae on their mouth appendages to manipulate sediment particles to extract food. The number of spoon-tipped setae on the second maxilliped is frequently related to the distribution of fiddler crabs on estuarine sediments, but no study has compared the morphological diversity of these setae among multiple fiddler crab species. Here, we describe and classify the setae of the second maxillipeds of the nine Uca spp. known from the Brazilian coast. The second maxilliped of each species was examined by scanning electron microscopy. Six types of setae (five papposerrate, and one pappose) were described on the meropodite of the second maxilliped. Among the papposerrate setae, one type had a spoon-like tip, and the morphology of this type, especially the degree of curvature, differed between species. Members of Uca leptodactylus, U. uruguayensis, and U. maracoani had highly concave spoon-tipped setae. In U. rapax and U. cumulanta, the setal tip was moderately curved, while in U. thayeri, U. burgersi, and U. mordax, this curvature was slight. At the other extreme, the meropodite of the second maxilliped of U. vocator lacked setae altogether. This is the first study that describes differences in the degree of curvature of spoon-tipped setae in fiddler crabs. This trait may be strongly related to the distribution of these fiddler crabs on different estuarine substrates. © 2012, The American Microscopical Society, Inc.

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The main goals of this investigation were to describe the community structure of anomuran and brachyuran crabs inhabiting reefs constituted by colonies of Schizoporella unicornis, and to provide a species importance ranking for this community. Collections were carried out on S. unicornis reefs at two-month intervals from May 2003 to May 2004, in the rocky sublittoral of the southeastern Brazilian coast. Relative abundance and occurrence were used to rank these species in the hierarchy importance. A total of 2,018 individuals were obtained, in 11 families, 22 genera and 31 species. Porcellanidae and Pilumnidae were the most abundant families, comprising respectively almost 60% and 15% of individuals sampled. The species ranking indicated four main groups A, B, C and D, with group A subdivided. Subgroup A1 contained 9 species, including the species of greatest ecological importance for community regarding abundance and occurrence. The great abundance of crabs associated with S. unicornis seems to be the result of its recognized importance during the crab developmental cycle, and as shelter and food for some Decapod species. These observations reveal the importance of conserving the areas occupied by these reef colonies, which appear to be an important environment for maintaining local biodiversity.

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One of the most intriguing questions in ecology is how to identify which and how many species will be able to inhabit human-modified landscapes. Large-bodied mammals structure plant communities by trampling, herbivory, seed dispersal and predation, and their local extinction may have pervasive consequences in plant communities due to the breakdown of key interactions. Although much attention has been given to understanding the effects of defaunation on plant communities, information on the potential impacts on plant functional groups (seed dispersal, seed size and seedling leaves defense) inhabiting continuous forests after defaunation is scarce. We conducted mammal surveys (line transects and camera trapping) to determine the defaunation status of a continuous Atlantic forest in Brazil. Then, we evaluated the effects of defaunation on seedling diversity, richness and abundance of functional groups using 15 plot-pairs (each pair with one open and one exclusion plot) monitored over 36. months. We found that the studied area is partially defaunated because it exhibits high abundance of primates, while terrestrial mammals, such as large rodents and ungulates, are rare. We found no significant changes in either seedling richness and diversity or in the seedling composition of plant functional groups in response to mammal exclosure. Seedling mortality and recruitment were similar between plot types. Our findings suggest that at semi-defaunated areas, where arboreal species are still present, terrestrial mammals have low impacts on the plant community reassembly. © 2013 Elsevier Ltd.

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An indirect method for the georeferencing of 3D point clouds obtained with terrestrial laser scanning (TLS) data using control lines is presented. This technique could be used for rapid data acquisition where resources do not permit the use of expensive navigation sensors or the placement of pre-signalised targets. The most important characteristic is the development of a mathematical model based on the principle that the direction vector of the TLS straight line is coplanar with the plane defined by the origin of the TLS system, one endpoint of a control line and the direction vector of the control line in the ground reference coordinate system. The transformation parameters are estimated by minimising the distance between the control lines and their corresponding TLS straight lines. The proposed method was tested using both simulated and real data, and the advantages of this new approach are compared with conventional surveying methods. © 2013 This article is a U.S. Government work and is in the public domain in the USA.

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É registrada pela primeira vez a ocorrência de Fredius reflexifrons (Ortmann, 1897), um caranguejo da família Pseudothelphusidae de ampla distribuição na Amazônia e nas Guianas, no estado do Ceará, Nordeste do Brazil. São feitos registros adicionais de dessa espécie e de Fredius denticulatus (H. Milne-Edwards, 1853) para a região amazônica. É feita uma discussão sobre os limites orientais da distribuição da família Pseudothelphusidae no Brasil.

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This study evaluated the bioaccumulation of tributyltin (TBT) by the blue crab (Callinectes sapidus). Animals were fed with contaminated food containing 30 µg g-1 of TBT expressed as Sn. The analytes were determined in the gills, hepatopancreas and muscle. Acid digestion was used in the total Sn determination, and a solid-phase extraction technique was used for the selective determination of TBT. Limits of detection of 44.6 and 4.46 ng g-1 were found for HG-ICP OES (hydride generation-inductively coupled plasma optical emission spectroscopy) and ICP-MS (ICP-mass spectrometry), respectively. The results for non-contaminated animals were below 50 ng g-1, while the animals subjected to the contaminated food showed higher tissue concentrations of Sn (until 6229 ng g-1) and TBT (until 3357 ng g-1) related to the number of exposure days. According to the results, Sn is bioaccumulated by the blue crab in higher concentrations in the hepatopancreas. For most of these animals, the results suggest that Sn is bioaccumulated as TBT.

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

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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

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Insects of the suborder Heteroptera are known for their odor, for being pests, or for being disease carriers. To gain better insight into the cytogenetic characteristics of heteropterans, 18 species of terrestrial Heteroptera belonging to eight families were studied. The presence of heteropycnotic corpuscles during prophase I, terminal or interstitial chiasmas, telomeric associations between chromosomes, ring disposals of autosomes during metaphase, and late migrations of the sex chromosomes during anaphase were analyzed. These features showed identical patterns to other species of Heteroptera previously described in the literature. Another studied characteristic was chromosome complements. The male chromosome complements observed were 2n = 12 chromosomes [10A + XY, Galgupha sidae (Amyot & Serville) (Corimelaenidae) and Pachycoris torridus (Scopoli) (Scutelleridae)]; 2n = 13 [10A + 2m + X0, Harmostes serratus (Fabricius), Harmostes apicatus (Stål), Jadera haematoloma (Herrich-Schaeffer), Jadera sanguinolenta (Fabricius), Jadera sp. (Rhopalidae)], and Neomegalotomus parvus (Westwood) (Alydidae); 2n = 13 [12A + X0, Stenocoris furcifera (Westwood) (Alydidae); 2n = 14 [12A + XY, Dictyla monotropidia (Stål) (Tingidae)]; 2n = 19 [18A + X0, Acanonicus hahni (Stål) (Coreidae)]; 2n = 21 [18A + 2m + X0, Acanthocephala sp. (Dallas) (Coreidae)]; 2n = 27 [24A + 2m + X0, Anisoscelis foliacea marginella (Dallas) (Coreidae)]; 2n = 18 [16A + XY, Oncopeltus fasciatus (Dallas) (Lygaeidae)]; 2n = 17 [14A + X1X2Y, Oxycarenus hyalinipennis (Costa) (Lygaeidae)]; 2n = 16 [12A + 2m + XY, Pachybrachius bilobatus (Say) (Lygaeidae)]; 2n = 26 [24A + XY, Atopozelus opsinus (Elkins) (Reduviidae)]; and 2n = 27 [24A + X1X2Y, Doldina carinulata (Stål) (Reduviidae)]. The diversity of the cytogenetic characteristics of Heteroptera was reflected in the 18 studied species. Thus, this study extends the knowledge of these characteristics, such as the variations related to chromosome complements, sex chromosome systems, and meiotic behavior.

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