3 resultados para Freeman, Nathaniel--1766-1800

em Biblioteca Digital da Produção Intelectual da Universidade de São Paulo (BDPI/USP)


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The influence of the golden lion tamarin (Leontopithecus rosalia) as a seed disperser was studied by monitoring two groups of tamarins from December 1998 to December 2000 (871.9 hours of observations) in a forest fragment in south-east Brazil. The tamarins consumed fruits of 57 species from at least 17 families. They ingested the seeds of 39 species, and 23 of these were put to germinate in the laboratory and/or in the field. L. rosalia is a legitimate seed disperser because the seeds of all species tested germinated after ingestion, albeit some in low percentages. These primates do not show a consistent effect in final seed germination, because they benefit some species while damaging others. Feces were examined for seeds that had been preyed upon or digested.

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This study unveils histological features of the intestinal tract of juvenile striped catfish Pseudoplatystoma fasciatum (Linnaeus, 1776) in three size classes (weight, standard length): I - 36.84 +/- 10.19 g, 14.52 +/- 1.54 cm; II - 59.03 +/- 11.47 g, 17.17 +/- 1.06 cm; III - 89.72 +/- 18.70 g, 20.79 +/- 1.55 cm, respectively. Histological organization of the juvenile speckled catfish intestine bears features common to the carnivorous fish, but the organ presents some convolutions that indicate a certain degree of dietary flexibility, a surprising trend, common only to omnivorous Siluriforms. The architecture of the mucosa of the speckled catfish intestine indicates that the species concentrates digestion and absorption of nutrients in the medium intestine, a common feature among carnivorous Teleosts.

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The Alagoas Curassow Mitu mitu is considered extinct in the wild. Since 1979, two females and a male caught in the wild have bred successfully in captivity, and, in 1990, hybridizations between M. mitu and Razor-billed Mitu M. tuberosum were performed. By June 2008, there were around 130 living birds in two different aviaries. We sequenced two regions of the mitochondrial DNA of both captive stocks of Alagoas Curassows. We unequivocally identified hybrids that have haplotype typical of M. tuberosum. However, unless the original studbook can be recovered there is no confident way to discriminate ""pure"" M. mitu birds for breeding and reintroduction purposes. Allied with morphological data gathered in an independent study, we suggest that conservation actions need to focus on specimens with diagnostic phenotypic characters of M. mitu, and avoid birds with mitochondria, genetic contribution of M. tuberosum. Although we have detected low levels of genetic variability among captive birds, the steady increase of the captive population suggests that inbreeding depression and hybridization are not a reproductive hindrance. Reintroduction of some of these potential hybrid birds in the original area of occurrence of the Alagoas Curassow may be the only hope to fill in the ecological niche left vacant. An educational program involving local communities to conserve future reintroduction of curassows and their restored habitat is highly recommended. Accepted 12 November 2009.