Navegando por Assunto "Rio Orinoco (Bacia do Amazonas)"

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Acesso aberto (Open Access)
Revisão taxonômica de Gymnorhamphichthys (Gymnotiformes, Rhamphichthyidae) com descrição de duas novas espécies
(Universidade Federal do Pará, 2010) RAMOS, Cristiane do Socorro; WOSIACKI, Wolmar Benjamin; http://lattes.cnpq.br/0040413891328104
A taxonomic revision of the genus Gymnorhamphichthys is presented, a diagnosis for the genus is modified and expanded, five nominal species are recognized, and two new species are described: Gymnorhamphichthys sp. n. 1, from rivers of Paraguay basin, is diagnosed by thin bars on the dorsal region of its body, bars long slender reaching or exceeding below the lateral line, number of bars 6-19, and by the low number of anal rays (141-177), among other characters; Gymnorhamphichthys sp. n. 2, from Amazon basin, is diagnosed by the presence of a dark mask on the head, wide rectangular-shaped bars, and by the high number of anal rays (185-260), among other characters. A dichotomous key to species is provided.
Acesso aberto (Open Access)
Revisão taxonômica do gênero Polycentrus Müller & Troschel, 1848 (Perciformes; Polycentridae) com a descrição de três novas espécies
(Universidade Federal do Pará, 2010) COUTINHO, Daniel Pires; WOSIACKI, Wolmar Benjamin; http://lattes.cnpq.br/0040413891328104
The genus Polycentrus Müller & Troschel is revised. Four species are recognized, P. schomburgkii is redescribed and three species are described as new. The genus diagnosis is enlarged based in meristic, morfology and colour pattern. Polycentrus n. sp. “Caxiuanã”, from Lowlands Amazon Bansin, is diagnosed by the totaly serrated interopercular edge vs. smooth or partialy serrated on the congeners. Polycentrus sp. n. “Rio Negro” from midle rio Negro, is diagnosed by the smooth lacrhymal bone vs. serrated in congeners plus a combination of non-exclusive characters. Polycentrus n. sp. “Flechal” is diagnosed by a dark opercular vertical bar vs. vertical opercular bar absent plus a combination of non-exclusive characters. A dichotomic key to species and remarks about exclusive characters is provided.