23 research outputs found

    Dimorfismo sexual em Siluriformes e Gymnotiformes (Ostariophysi) da Amazônia

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    Harttia merevari, a new species of catfish (Siluriformes: Loricariidae) from Venezuela

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    Harttia merevari, a new species of loricariid catfish, is described from eight specimens captured in the upper Caura River, Orinoco River basin, Venezuela. The new species is recognized by the following combination of characters: abdomen naked; two or three preanal plates; a bony plate before each branchial opening; seven lateral plates between the pectoral and pelvic fins; maxillary barbel short and attached to the oral disk by a fleshy fold; head dorsal surface and anterior portion of the body light or dark yellow with numerous, round black spots; posterior region of the body light or dark yellow with five black transverse bands, dorsal central area of the two anterior bands diffused. The discovery of this new species extends the distribution of the genus northwest to include the Orinoco River basin on the northern slope of the Guyana shield

    Taxonomy of Ixinandria Isbr\ufccker & Nijssen (Loricariidae: Loricariinae) based on morphological and molecular data

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    The genus Ixinandria was described in 1979 to include I. steinbachi from the upper río Juramento in northern Argentina and I. montebelloi from the upper río Bermejo in southern Bolivia. We used a multivariate morphometric analysis (Principal Components Analysis) and a molecular comparison of the Cytochrome Oxidase I gene to investigate variation among distinct populations from the known distribution range of both species. We conclude that the populations are not significantly distinct and do not deserve separate species recognition, and we place I. montebelloi in the synonymy of I. steinbachi.O gênero Ixinandria foi descrito em 1979 para incluir I. steinbachi do alto rio Juramento no norte da Argentina e I. montebelloi do alto rio Bermejo no sul da Bolívia. Utilizamos análise morfométrica multivarida (Análise de Componentes Principais) e uma comparação molecular do gene Citocromo Oxidase I para investigar a variação entre populações distintas da área de distribuição de ambas as espécies. Concluímos que as populações não são significativamente distintas e não merecem reconhecimento como espécies separadas, e colocamos Ixinandria montebelloi na sinonímia de I. steinbachi
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