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| Registros recuperados: 1.204 | |
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| Quagio-Grassiotto,Irani; Gameiro,Maria Carolina; Schneider,Tatiana; Malabarba,Luiz Roberto; Oliveira,Claudio. |
| Spermiogenesis in the curimatid species, Steindachnerina insculpta, Cyphocharax gillii, C. modestus, C. spilotus, and Potamorhina altamazonica, is characterized by lateral development of the flagellum, nuclear rotation, eccentric nuclear fossa formation, and chromatin compacted into thick fibers. These spermatozoa exhibit a spherical head containing a nucleus with the chromatin highly condensed into thick fibers with small electron-lucent areas, and no acrosome. The nuclear fossa is of the moderate type and eccentric and penetrated by the centriolar complex. The midpiece is small, has many elongate vesicles, and a short cytoplasmic channel. Mitochondria may be elongate, branched or C-shaped, and are separated from the initial segment of the axoneme by the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Fish; Spermatid; Sperm; Ultrastructure. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252003000100004 |
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| Lima,Flávio C. T.; Moreira,Cristiano R.. |
| Three new species of Hyphessobrycon (Characiformes: Characidae) are described from the upper rio Araguaia basin. Hyphessobrycon langeanii n. sp. is distinguished from all congeners by the presence of a well-defined, round humeral spot, a reticulate color pattern, a broad, horizontally-elongate caudal-peduncle blotch, and a relatively wide, faint midlateral dark stripe. Hyphessobrycon eilyos n. sp. is distinguished from all congeners by the absence of humeral and caudal spots; by the presence of numerous dark chromatophores on the lateral surface of the body, intensely concentrated on the ventral region from the pelvic-fin origin to the end of the caudal-fin base, dorsal, adipose, and caudal fins with carmine red pigmentation in life; and the presence of... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Endemism; Neotropical; Ostariophysi. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252003000100003 |
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| Castro,Ricardo M. C.; Ribeiro,Alexandre C.; Benine,Ricardo C.; Melo,Alex L. A.. |
| A new genus and species of glandulocaudine, Lophiobrycon weitzmani, is described based on specimens collected in headwater tributary streams of the rio Grande, upper rio Paraná system, State of Minas Gerais, southeastern Brazil. The inclusion of the new species in the phylogeny of the subfamily Glandulocaudinae proposed by Weitzman & Menezes (1998), reveals a sister group relationship between the new genus and the monophyletic group composed of Glandulocauda and Mimagoniates that currently form the tribe Glandulocaudini. The new species can be readily distinguished from all other species of the tribe by the autapomorphic presence in adult male individuals (with more than 23.9 mm standard length) of an adipose-fin whose base extends for almost the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Glandulocaudinae; Phylogeny; Mimagoniates; Glandulocauda. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252003000100002 |
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| Pompeu,Paulo dos Santos; Alves,Carlos Bernardo Mascarenhas. |
| Lagoa Santa is a shallow permanent lake, located in Belo Horizonte metropolitan region, Brazil. In this study, the loss in fish diversity of the lake over the past 150 years is evaluated. Local extinction of almost 70% of the original fish fauna is described. Probably, the main causes of this richness loss were: obstruction of natural communication with rio das Velhas, non-native species introduction, change in the water level, organic pollution, and elimination of littoral and submerged vegetation. |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Rio das Velhas; Lagoa Santa; Urbanization; Habitat destruction; Species introduction; Historical diversity loss. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252003000200008 |
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| Akama,Alberto; Ferraris, Jr.,Carl J.. |
| A new species of auchenipterid catfish, Entomocorus melaphareus, is described. The new species is readily distinguished from its two congeners, Entomocorus benjamini Eigenmann, 1917, and E. gameroi Mago Leccia, 1983, by having darkly pigmented, rather than hyaline, pectoral and pelvic fins. Entomocorus melaphareus is known from the margins of the lower and middle rio Amazonas, and is the only species of the genus known from the main channel of that river. |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Auchenipteridae; Neotropical; Entomocorus benjamini; Entomocorus gameroi. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252003000200001 |
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| Britto,Marcelo R.; Lima,Flávio C.T.. |
| A new Corydoras species from the rio Tiquié, upper rio Negro system, Amazonas, Brazil, is described. This taxon was previously referred to as "Corydoras species 'Asher'", "Corydoras cf. reynoldsi", and "Corydoras aff. reynoldsi" in the aquarist literature. The new taxon can be distinguished from all its congeners, except Corydoras reynoldsi and C. weitzmani, by its color pattern, consisting of three large, dark blotches, the first one ("mask") on the head, across the eye; the second one on the trunk at the level of dorsal fin; and the third one on the trunk at the level of the adipose fin. It can be distinguished from Corydoras reynoldsi mainly by the development of trunk blotches; and from C. weitzmani by the presence of a dusky saddle between the dorsal... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Corydoras reynoldsi; Corydoras weitzmani; Neotropical; Amazon. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252003000200002 |
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| Hoeinghaus,David J.; Layman,Craig A.; Arrington,D. Albrey; Winemiller,Kirk O.. |
| In their native habitats of black- and clear-water Neotropical rivers, large predatory cichlids of the genus Cichla are an important food and recreational resource. Understanding patterns of movement for these species is necessary for effective management and conservation; however, no information is available on movement in natural fluvial populations. Therefore, we initiated a cooperative mark-recapture program with local sport-fishing groups to evaluate movement of Cichla in the Cinaruco River, Venezuela and to promote conservation awareness. Between January 1999 and May 2003, we tagged 2,224 individuals of three species of Cichla (C. temensis, C. orinocensis, and C. intermedia) with uniquely numbered floy tags. Over 52 months, 2.8% of the tagged fishes... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Cinaruco River; Conservation; Mark-recapture; Pavón; Tucunaré. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252003000200006 |
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| Oliveira,Claudio; Nirchio,Mauro; Granado,Ángel; Levy,Sara. |
| Fish of the family Prochilodontidae are considered one of the most important components of commercial and subsistence fishery in freshwater environments in South America. This family consists of 21 species and three genera. In the present study, the karyotypes of Prochilodus mariae, Semaprochilodus kneri, and S. laticeps from Caicara del Orinoco, Bolivar State, Venezuela were studied. The species P. mariae, S. kneri and S. laticeps exhibited 2n=54 chromosomes (40 metacentric and 14 submetacentric), a single chromosome pair with nucleolus organizer regions, and a large amount of heterochromatin found at centromeric and pericentromeric positions in almost all chromosomes. The P. mariae specimens studied displayed 0 to 3 supernumerary microchromosomes. The... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Karyotype; C-band; NOR banding; Chromossome evolution; Characiformes. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252003000100005 |
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| Albrecht,Miriam P.; Pellegrini-Caramaschi,Erica. |
| The feeding ecology of Leporinus taeniofasciatus in the upper rio Tocantins was characterized before (river phase) and after (reservoir phase) its impoundment by the Serra da Mesa Hydroelectric Dam. The importance of each food item was given by the Alimentary Index (IAi), which combines the frequency of occurrence and volumetric methods. A significant difference in the diet of L. taeniofasciatus between seasons in the river phase, detected by a multivariate analysis of variance, was not kept when the reservoir was formed. Its feeding activity, verified through the percentage of stomachs with different degrees of fullness, was not affected by the impoundment. Leporinus taeniofasciatus was able to incorporate terrestrial food items to its diet when they... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Diet; Fish; Neotropical; Reservoir. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252003000100006 |
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| Dufech,Ana Paula S.; Azevedo,Marco A.; Fialho,Clarice B.. |
| The diet of two populations of Mimagoniates rheocharis, from two freshwater streams of the rio Tramandaí, northeastern Rio Grande do Sul, Brazil, are described and compared. The specimens were collected monthly from January 1998 to March 1999, with dip nets and seine nets and preserved in 10% formalin. In laboratory, the standard length of each specimen was measured. The stomachs were removed and dissected for identification of the alimentary items. The data were analyzed using the frequency of occurrence, percent composition and index of alimentary importance methods, being the last two compared among different classes of standard length. Three methods of analysis showed the highest values for allochthonous insects, regardless the locality of collection... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Feeding; Allochthonous insects; Rio Maquiné; Diet; Neotropical. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252003000100008 |
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| Thomé-Souza,Mario J. F.; Chao,Ning Labbish. |
| Spatial and temporal variation in the benthic fish composition, species richness, density and biomass were studied in the lower rio Branco and its confluence with the rio Negro during the 1997-98 dry season (September to February). Samples were taken with a 5.28 m (16-ft) otter trawl in three expeditions and at two depth strata (<7m and >7m). Five to seven trawl hauls were made randomly in each sample site per expedition. A total of 58 trawls yielded 134 species, 5,657 individuals and 22 kg total biomass. Fishes were distributed in 25 families and seven orders. Siluriformes was the most specious with 59 species, followed by Gymnotiformes (30), Characiformes (30), Perciformes (9), Clupeiformes (4), Pleuronectiformes (1) and Tetraodontiformes (1). The... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Main channel river; Otter trawl; Rio Branco; El-Niño phenomenon. |
| Ano: 2004 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252004000300004 |
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| Registros recuperados: 1.204 | |
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