Abstract A new species of Platydoras is described from the rio Xingu Basin, Brazil. Platydoras birindellii is distinguished from congeners by having gas bladder simple (vs. with posterior secondary chamber) and dorsal and caudal fins uniformly dusky (vs. with distinct marks composed of dark broad band or blotch on central portion of dorsal fin and pair of dark broad stripes on caudal fin, one central to each lobe). Platydoras birindellii shares a simple gas bladder with the sister taxon to Platydoras, Centrochir crocodili, a monotypic genus endemic to the Magdalena Basin. With respect to the caudal skeleton, the parhypural is incompletely fused to hypurals 1+2 in P. birindellii, a condition that is intermediate between those of Centrochir (parhypural typically separated from hypurals 1+2 by distinct suture) and Platydoras (parhypural typically fully fused to hypurals 1+2). Platydoras birindellii is commonly found in rocky clearwater rapids and apparently endemic to the middle and upper portions of the Xingu draining the Brazilian Shield.

中文翻译：

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Platydoras birindellii，巴西新谷盆地条纹鲶鱼（鲶形目：剑鱼科）的新种

摘要 在巴西里约兴谷盆地描述了一种新的侧柏属植物。Platydoras birindellii 与同类的区别在于具有简单的气囊（与后次室相比）和背鳍和尾鳍均匀暗淡（与背鳍中央部分由深色宽带或斑点组成的明显标记和一对深色宽尾鳍上有条纹，每个叶中央有一条）。Platydoras birindellii 与 Platydoras 的姊妹类群 Centrochir crocodili 共享一个简单的气囊，Centrochir crocodili 是马格达莱纳盆地特有的单型属。关于尾骨骨骼，在 P. birindellii 中，parhypural 与 hypurals 1+2 不完全融合，介于 Centrochir（侧部通常与 hypurals 1+2 通过不同的缝合线分开）和 Platydoras（侧部通常与 hypurals 1+2 完全融合）之间的情况。Platydoras birindellii 常见于岩石清澈的急流中，显然是引流巴西地盾的新古河中部和上部的特有种。