A New Species of Knodus (Characiformes: Characidae) from the Rio Tiquié, Upper Rio Negro System, Brazil
Knodus tiquiensis, new species, is described from Rio Tiquié, a tributary of the Rio Uaupés, upper Rio Negro system, Amazon basin, Brazil. The new species is distinguished from its congeners by the presence of thickened skin forming folds that cover the basal portion of the six anteriormost branched anal-fin rays and its interradial membrane. Also, the anteriormost six anal-fin rays are considerably thicker than remaining rays of the fin. Comparisons to Knodus tiquiensis with its congeners are presented based on an examination of type material of all species currently included in the genus.
Knodus tiquiensis, espécie nova, é descrita do Rio Tiquié, um tributário do Rio Uaupés, alto Rio Negro, Amazonas, Brasil. A nova espécie pode ser distinguida de suas congêneres pela presença de uma pele espessada entre os raios anteriores da nadadeira anal, formando dobras mais desenvolvidas na base e membranas inter-radiais dos seis primeiros raios ramificados e por possuir tais raios consideravelmente mais espessos que os demais. Comparações entre Knodus tiquiensis com seus congêneres são apresentadas, baseadas em exame do material tipo de todas as espécies atualmente incluídas no gênero Knodus.Abstract
Knodus tiquiensis, holotype, MZUSP 88059, 72.6 mm SL, Brazil, Amazonas, Rio Tiquié.
Knodus tiquiensis, paratype, MZUSP 85154, 38.6 mm SL.
(A) Upper and lower jaws, left side, lateral view. (B) Upper jaw, medial view. Scale bar = 1 mm.
Knodus tiquiensis, paratype, MZUSP 85136, 54.5 mm SL.
(A) Histological section through anterior portion of anal fin about the second branched ray (magnified 15×); connective dense tissue (ctd); caliciform cells (cc); epithelial tissue (et); scales (sc); branched rays (br). (B) Details of the caliciform cells (magnified 60×). (C) Histological section through posterior portion of anal fin about the tenth branched ray (magnified 60×) showing the presence of only connective dense tissue (ctd) and epithelial tissue (et).
Map of northwestern Brazil indicating the approximate position of the type locality of Knodus tiquiensis, Rio Tiquié basin, Upper Rio Negro system, Amazon State, Brazil.
Contributor Notes
(KMF) LABORATÓ RIO DE ICTIOLOGIA DE RIBEIRÃO PRETO (LIRP), DEPTO. DE BIOLOGIA DA UNIVERSIDADE DE SÃO PAULO, AV. BANDEIRANTES, 3900, 14040-901, RIBEIRA O PRETO, SP, BRAZIL;