This paper presents a new record for a heterotypic synonym of Pithophora roettleri (P. oedogonia)for the São Franscisco River basin. Pithophora are green filamentous algae, branched, with intercallary akinetes of variable (P. roettleri) or invariable (P. oedogonia) forms in the same individual. The species was found in a temporary pond, which has high electrical conductivity and temperature, and is localized in a semiarid area (Caatinga biome). The soil has median natural fertility and high concentration of dissolved salts. A short diagnosis with illustrations and two models of the potential geographic distribution for the species are included.