The distribution area of Leporinus pachycheilus Britski, 1976 (Osteichthyes, Anostomidae), described from the Aripuanã river, is amplified to the Jamari and the Machado rivers, all tributaries of the Madeira river, and to the Uatumã, Araguari and Tocantins drainages. A complementary description of this species is given. Geographical variation on scales number was observed among diferent populations and a highly diverse color pattern at interpopulation and in-trapopulation levels. Leporinus julii n. sp., a new species close to L.pachycheilus, is decribed from Xingu and Trombetas drainage. This is a group of species restricted to the rapids of rivers draining Brazilian and Guianean shields and the uniques to present mouth completely inferior and incisiviform teeths, inserted side by side.
Pisces; Anostomidae; Taxonomy; Amazon basin