995 resultados para Grimm, Jacob, 1785-1863.
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In populational studies, the weight/width carapace relationship analysis, can furnish indications about the individual physiological variations as a function of the environment, and it can indicate sexual dimorphism. The goal of this research is to find the mathematical expressions of weight/width carapace relationship in the crab Hepatus pudibundus. This study was accomplished by analysing the crabs that were sampled monthly with a shrimp fishing boat equipped with 2 otter-trawl nets, during the period from november/1988 to october/1989. A total of 624 specimens were obtained composed of 244 males and 380 females. In each group the sex, the weight (PE) and the carapace width (LC) were determined. The obtained values agree with the studied range, showing variations during male and female development, represented by the potential function of the equation Y = aX(b). Such variations are probably related to reproductive strategies.
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This paper appraises the influence of chelipeds on sexual and maturation phasis of the crab Hepatus pudibundus (Herbst, 1785), collected in Ubatuba (SP) region. The allometric constants obtained from the regression (carapace width X cheliped weight) adjusted to a power function (Y=aX(b)) were analysed. It was verified that males show larger chelipeds than females. The mean percentage of the chelipeds weight differs in sex and maturation.
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The objective of the present study was to characterize the fecundity of Callinectes ornatus from the northern coast of São Paulo, Brazil. To study the fecundity and its relationships to size, brood weight, and egg size, the ovigerous females were collected at 2-month intervals for two consecutive years (January, 1991 to November, 1992) in the Ubatuba region using a fishing boat equipped with an otter-trawl type of net. After collecting, the animals were screened, bagged, labeled, and stored frozen. Only data from 38 females carrying early stage eggs were considered. In the laboratory, the specimens were thawed at room temperature, the pleopod structure with the egg mass was removed and the eggs were carefully removed from the pleopods. The samples were then fixed in 10% formalin and stored in 70% ethanol, until the time for processing. Processing followed the method of Hines (1982, 1988). Following the frequency determination of carapace width and fecundity, mean egg number, mean volume and mean dry weight of brooded egg mass were determined for each class obtained. Data were analyzed by regressions of log-log transformations for allometric plots (Y = aX(b)) of reproductive variables versus carapace width. Carapace width was one of the main factors for the determination of fecundity, which ranged 171 570 +/- 94 634 eggs, with females of the same size class presenting a wide amplitude of variation. This supports the hypothesis that portunid females present staggered spawning, possibly presenting more than one period of reproduction within one year. The present species showed lower fecundity than the remaining portunids studied, but they did show a rapid and efficient embryonic development, presumably capable of assuring reproductive success.
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The locomotory and feeding activity rhythms of Callinectes ornatus Ordway, 1863 and Callinectes danae Smith, 1869 were examined under laboratory conditions. Light significantly influenced the activity of these organisms. However, activity in both species was affected by the presence of food, independently of photoperiod regime.
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Population structure and reproductive season of the portunid crab Callinectes ornatus were studied in animals collected from the Ubatuba bays, Sao Paulo, Brazil (23°20' to 23°35' S and 44°50' to 45°14' W). The samples were taken in three trawls performed every other month from January 1991 to May 1993. A total of 3,829 specimens of C. ornatus were obtained. Their size ranged from 9.3 to 84.6 mm (carapace width). Their median size based on their cephalothoracic width and their size frequency were determined as well. Their reproduction was continuous, with variable proportions of ovigerous females. The highest incidence of ovigerous females occurred in January 1991, 1992 and 1993 and March and November 1992. The oscillations of the environmental factors between the seasons are not so intense in subtropical regions, therefore allowing the continuity of the physiological process of growth and reproduction throughout the year.
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The feeding activity along the day cycle and the time consumed for extracellular digestion were evaluated in the portunids C. ornatus and C. danae. Swimming crabs were obtained from trawling in Ubatuba bay, São Paulo, Brazil, during both the rainy and dry seasons. In each season, daily scheduled samples were taken at dawn (±6 h), noon (±12 h), dusk (±18 h) and midnight (±24 h). All individuals were dissected and the degree of stomach replenishment was recorded. In order to estimate the time elapsed for extracellular digestion, crabs were fed, and groups were dissected at 30 min intervals to check the conditions of their stomachs. In general, both species show a higher feeding activity during periods of lower light intensity, as evidenced by an increased percentage of full stomachs in dusk and midnight samples. The obtained results support higher feeding activity at night in these species and indicate short time for extracellular digestion, not exceeding 8 h. Nevertheless, full stomachs were recorded in all sampling schedules. In this case, it should be considered that elimination of certain food items such as fish bones, mollusk shells and carapace fragments of crustaceans could take more time than other items. Additionally, some crab species could require a cycle of cell replacement in the midgut gland epithelium until they can take their next meal.
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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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Stalked barnacles Octolasmis lowei Darwin, 1851 are frequently found attached to decapod crustaceans. Their epibiotic association depends on many factors, which are mainly related to characteristics of the host's biology. This study evaluated the infestation and distribution of stalked barnacles in the branchial chambers of crabs, and analyzed the data with respect to the host's sex, maturity stage, molt cycle and size. The crab species Arenaeus cribrarius Lamarck, 1818, Callinectes danae Smith, 1869, Callinectes ornatus Ordway, 1863, Hepatus pudibundus Herbst, 1785, Libinia ferreirae Brito Capello, 1871, and Persephona punctata Linnaeus, 1758 were sampled and found to be infested by O. lowei. No juvenile crabs were infested. The prevalence of infestation by O. lowei was significantly different among C. danae, C. ornatus, and H. pudibundus males and females. All infested hosts were in the intermolt period. The mean size of infested crabs was larger than that observed for non-infested individuals. Internally, stalked barnacles were concentrated on the central gills or walls and floor of branchial chambers, suggesting that these gills provide more favorable conditions for the settlement and development of these epibionts. These results highlight the relationship between epibiont infestation and host biology, as well as the role of decapod crustaceans as a suitable substrate for the development of stalked barnacle O. lowei. © 2013 Sociedade Brasileira de Zoologia All rights reserved.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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O presente trabalho trata de um estudo detalhado sobre a biologia reprodutiva e alimentar de Liophis reginae semilineatus e Liophis taeniogaster, de populações restritas a Amazônia Oriental, através da análise de dimorfismo sexual, maturidade sexual, ciclo reprodutivo, fecundidade, composição da dieta e relações presa-predador. As duas espécies são simpátricas, porém não foram realizadas comparações entre ambas, devido a distância filogenética (Moura-Leite, 2001), por apresentarem diferenças quanto aos recursos alimentares e microhábitats freqüentados (Cunha & Nascimento, 1993), sendo apresentadas em dois capítulos distintos, o primeiro tratando da biologia reprodutiva e alimentar de Liophis reginae semilineatus e o segundo capítulo tratando da biologia reprodutiva e alimentar de Liophis taeniogaster.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)