Abstract
A new Hypoptopomatinae is described from the upper rio Jequitinhonha basin. The new species is distinguished from all congeners by having the ventral laminar expansions of cleithrum and coracoid bearing only 1–30 odontodes, restricted to the area near the pectoral-fin insertion; the anterior plates of mid-ventral lateral series reduced, not ventrally elongated, the first or the second markedly round; pectoral-fin unbranched ray distinctly divided distally, with 7–15 ossified segments, reaching almost half of its length; and accessory process on first epibranchial present. Microlepidogaster discus is further distinguished from its congeners by several other osteological features. The problems concerning the taxonomy of Microlepidogaster, as well as the pattern of distribution of the genus, are discussed.