Crenicichla dandara, new species, is endemic to the rio Xingu above the Belo Monte narrows, and its major left bank tributary the rio Iriri. The new species is distinguished from all congeners by the following combination of characters: body uniformly black (live fishes) or dark brown (preserved specimens) in adults and 74–86 scales in the E1 row. Crenicichla dandara is considered herein to be the tenth species of the C. lugubris group, but its allies within the group are not clear. Among members of this group, C. dandara is most similar in general body shape, snout characteristics and squamation to C. lugubris and C. adspersa, but lacks a caudal-fin blotch as does C. johanna and C. monicae, a condition rare within the Crenicichla-Teleocichla clade. The overall black coloration in Crenicichla dandara is shared with the syntopic, but not closely related, Teleocichla preta. Both species inhabit clear water rapids where they hide among the shadows of large rocks, suggesting that the dark coloration is for camouflage and ambush predation. Based on a preliminary assessment of its conservation status following the criteria and categories of IUCN classification, Crenicichla dandara is considered as a species of least concern (LC).