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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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| Fukakusa,Clayton Kunio; Mazzoni,Talita Sarah; Malabarba,Luiz Roberto. |
| Abstract Most teleosts are externally fertilizing, with internal fertilization occurring as a relatively rare event. Until now, Euteleosteomorpha is the only teleost cohort known to undergo internal fertilization. In the teleost cohort Otomorpha, it has been recorded the presence of sperm in the ovaries of some species of Characiformes and Siluriformes, but no fertilized eggs have been found so far in the female reproductive tract. It has been presumed that oocytes can be released into the water with associated spermatozoa and only there becomes fertilized, and the term insemination has been used to characterize the strategy adopted by these fish. Here, we present the discovery of the first case of internal fertilization in the teleost cohort Otomorpha, in... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Characiformes; Insemination; Ostariophysi; Reproduction; Spawning. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252020000100209 |
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| Lucena,Zilda Margarete Seixas de; Malabarba,Luiz Roberto. |
| Nine new species of Phenacogaster Eigenmann, 1907 are described: Phenacogaster capitulatus sp. nov. from the Neshuya River system, Ucayali River basin; Phenacogaster maculoblongus sp. nov. from the upper Cuyuni River, and tributaries of the lower Orinoco River; Phenacogaster napoatilis sp. nov. from the Napo River system, upper Amazon River basin; Phenacogaster ojitatus sp. nov. from the Xingu River system; Phenacogaster prolatus sp. nov. from the Orinoco River, canal Casiquiare and upper and middle Negro River; Phenacogaster retropinnus sp. nov. from the Negro, Madeira and Xingu river systems; Phenacogaster simulatus sp. nov. from the Potaro River, Essequibo drainage; Phenacogaster wayampi sp. nov. from the Oiapoque River, and Phenacogaster wayana sp.... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Biodiversity; Neotropical fish; Taxonomy. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1984-46702010000200014 |
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| Ricken,Cláudio; Malabarba,Luiz Roberto. |
| The analysis of the material obtained in the rescue of archaeological sites in the area surrounding the Hydroelectric Plant of Machadinho, Rio Grande do Sul, revealed that a considerable amount of bones and fish scales incorporated in the alimentary remains. Using an osteological collection as reference, we identified remains of Salminus brasiliensis (Cuvier, 1816) (Characidae), Brycon orbignyanus (Valenciennes, 1849) (Characidae), Pogonopoma obscurum Quevedo & Reis, 2002 (Loricariidae), Hemiancistrus fuliginosus Cardoso & Malabarba, 1999, Prochilodus lineatus (Valenciennes, 1836) (Prochilodontidae), Schizodon sp. (Anostomidae), Leporinus sp. (Anostomidae), Hoplias sp. (Erythrinidae), Hypostomus sp. (Loricariidae) and Crenicichla sp.... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Alimentary remains; Archaeology; Ichthology; Paleoenviroment; Zooarcheology. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1984-46702009000300011 |
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| Flores-Lopes,Fábio; Cetra,Mauricio; Malabarba,Luiz Roberto. |
| Este trabalho utiliza índices ecológicos em taxocenoses de peixes (constância de ocorrência, diversidade de espécies, riqueza, equitabilidade, índice de qualidade integrado (IQ)) como instrumento de avaliação da degradação ambiental. As amostragens foram padronizadas e realizadas sazonalmente durante dois anos, com rede de arrasto do tipo picaré, em onze pontos da bacia hidrográfica do lago Guaíba. Os pontos que apresentaram maior regularidade sazonal nos índices coincidem com locais de melhor qualidade ambiental indicados por outros fatores (frequência de anomalias, DBO5, temperatura, coliformes totais, oxigênio dissolvido). O cálculo do índice de qualidade integrado (IQ), entretanto, foi extremamente influenciado pela abundância e riqueza de espécies,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Impacto ambiental; Índice de qualidade; Lago Guaíba. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1676-06032010000400024 |
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