9 resultados para Identity

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


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The identification of the lebranche mullet in the western south Atlantic has long been problematical. In most recent works either Mugil liza Valenciennes and M. platanus Gunther, 1880 or M. liza and M. cephalus Linnaeus, 1758 were recognized from the region and more rarely the occurrence of only one species has been proposed but without sufficient morphological, biochemical or molecular data to allow the designation of the taxonomically appropriate name. Analysis of meristic and morphometric data taken from samples collected from Venezuela to Argentina, clearly indicates that there is only one species of lebranche mullet in the Caribbean Sea region and the Atlantic coast of South America and that Mugil liza is the appropriate name. The comparison of the combined data from all the samples of M. liza with the data taken from one sample of M. cephalus that originated in the Mediterranean, the possible locality from which type specimens were collected (Eschmeyer and Fricke, 2009), revealed significant differences indicating that they are different species. It is also suggested that individuals from the western north Atlantic identified as M. cephalus might represent a population of M. liza in this region.

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The generic identity of Odontophrynus moratoi is controversial since the original description due to the presence of intermediate morphological features between the genera Odontophrynus and Proceratophrys. Herein we performed molecular analyses of three genes (16S, cyt b and Rag-1) and recovered O. moratoi deeply imbedded inside a clade containing only Proceratophrys species, appearing as the sister group of Proceratophrys concavitympanum. Therefore, this study formally transfers the species O. moratoi to the genus Proceratophrys [Proceratophrys moratoi (Jim & Caramaschi 1980) comb. nov].

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Cycloramphus jordanensis was described based on a single preserved specimen from Campos do Jordao (22 degrees 44` S ,45 degrees 35` W), State of Sao Paulo, Brazil. While examining the holotype; we noticed the presence of toe and tarsal fringes. Because these characters are absent in Cycloramphus, we suspected that the species was mistakenly placed in the genus. X-ray images of the holotype revealed T-shaped terminal phalanges and fang-like teeth. Together with the presence of toe and tarsal fringes, these characters squarely place the specimen in the genus Megaelasia. Considering the striking niche differences between Cycloramphus and Megaclosia, we expect the new combination will facilitate location of new individuals of this rare frog.

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The present work focuses on 12 taxa of the genus Centropyxis Stein, 1857 to explore the conflict between traditional and contemporary taxonomic practices. We examined the morphology, biometry, and ecology of 2,120 Centropyxis individuals collected from Tiete River, Sao Paulo, Brazil; with these new data we studied the consistency of previously described species, varieties, and forms. We encountered transitional forms of test morphology that undermine specific and varietal distinctions for three species and nine varieties. Biometrical analyses made comparing the organisms at the species level suggest a lack of separation between Centropyxis aculeata and Centropyxis discoides, and a possible distinction for Centropyxis ecornis based on spine characteristics. However, incongruence between recent and previous surveys makes taking any taxonomic-nomenclatural actions inadvisable, as they would only add to the confusion. We suggest an explicit and objective taxonomic practice in order to enhance our taxonomic and species concepts for microbial eukaryotes. This will allow more precise inferences of taxon identity for studies in other areas.

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Individual fitness and the structure of marine communities are strongly affected by spatial competition. Among the most common space holders are the colonial ascidians, which have the ability to monopolize large areas of hard substrate, overgrowing most other competitors. The effects of competition on colony growth and on gonad production of the ascidian Didemnum perlucidum were studied in southeastern Brazil by experimentally removing surrounding competitors. Colonies of D, perlucidum competing for space exhibited a growth rate 9 times less than that of colonies that were competitor free. Among the colonies subject to competition, growth rates were unrelated to the percentage of colony border that was free of competitors. However, the identity of the competitor was important in the outcome of border contacts. At the beginning of the experiment, most border encounters of D. perlucidum were with solitary organisms, which in most cases were overgrown. These were progressively replaced by colonial ascidians and bryozoans, resulting mostly in stand-off interactions. Besides reducing asexual growth, spatial competition also affected female gonad production. Colonies free of competitors had a significantly higher proportion of zooids with ovaries. Thus, our findings show that spatial competition reduces both ascidian colony size and gonad production.

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We describe Kochiana new genus to accommodate a small Brazilian theraphosine species described originally as Mygale brunnipes by Koch (1842), resulting in Kochiana brunnipes new combination. Recently, specimens were rediscovered in northeastern Brazilian Atlantic rainforest. A preliminary cladistic analysis using equal weights parsimony and implied weights, was carried out to examine its phylogenetic placement. Kochiana new genus was monophyletic in all trees regardless of weighting scheme or concavity used. There is preliminary evidence for Kochiana new genus monophyly and weak evidence for its placement as sister group of Plesiopelma. Kochiana new genus can be characterized by the presence of a hornshaped spermatheca in females and males with a palpal bulb having prolateral accessory keels and a well developed medial crest on the embolus apex.

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The geographic variation and hemipenial morphology of Siagonodon brasiliensis are described based on a comprehensive sample, allowing the reappraisal of its generic identity, and the proposal of a new nomenclatural combination. We suggest that the presence of two supralabials, as mentioned in the original description of S. brasiliensis, is not a common feature for this species, occurring at low frequencies throughout its geographic distribution. Based on a diagnosis presented in a recently published paper, as well as on additional external traits and on hemipenial characters, we recognize Siagonodon brasiliensis as a species of the genus Tricheilostoma. In addition, a new species of worm snake of the genus Siagonodon is described from the savannas of the state of Tocantins, Brazil. The new species differs from other congeners by having a slightly acuminate snout in lateral and ventral views, subcircular rostral in dorsal view, and 12 scale rows around middle of tail. The diagnosis of the genus Siagonodon is revised and expanded based on direct observation of morphological characters.

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Lactation is an energy-demanding process characterized by massive food and water consumption, cessation of the reproductive cycle and induction of maternal behavior. During lactation, melanin-concentrating hormone (MCH) mRNA and peptide expression are increased in the medial preoptic area (MPO) and in the anterior paraventricular nucleus of the hypothalamus. Here we show that MCH neurons in the MPO coexpress the GABA synthesizing enzyme GAD-67 mRNA. We also show that MCH neurons in the MPO of female rats are innervated by neuropeptides that control energy homeostasis including agouti-related protein (AgRP), alpha-melanocyte stimulating hormone (alpha MSH) and cocaine- and amphetamine-regulated transcript (CART). Most of these inputs originate from the arcuate nucleus neurons. Additionally, using injections of retrograde tracers we found that CART neurons in the ventral premammillary nucleus also innervate the MPO. We then assessed the projections of the female MPO using injections of anterograde tracers. The MPO densely innervates hypothalamic nuclei related to reproductive control including the anteroventral periventricular nucleus, the ventrolateral subdivision of the ventromedial nucleus (VMHvl) and the ventral premammillary nucleus (PMV). We found that the density of MCH-ir fibers is increased in the VMHvl and PMV during lactation. Our findings suggest that the expression of MCH in the MPO may be induced by changing levels of neuropeptides involved in metabolic control. These MCH/GABA neurons may, in turn, participate in the suppression of cyclic reproductive function and/or sexual behavior during lactation through projections to reproductive control sites. (C) 2009 Elsevier B.V. All rights reserved.

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We analyze the consistency of the recently proposed regularization of an identity based solution in open bosonic string field theory. We show that the equation of motion is satisfied when it is contracted with the regularized solution itself. Additionally, we propose a similar regularization of an identity based solution in the modified cubic superstring field theory.