Uruguay River Sprat

Belly sharply keeled. No distinct silver stripe along the flank and the first (anterior) supra-maxilla minute or absent (cf. Platanichthys platana). Distinguished from very similar R. arcuata of coastal waters by having fewer dorsal and pectoral fin rays and fewer gill rakers total; from small Sardinella and Harengula by the evenly rounded hind margin of the gill opening.

Dorsal spines (total): 0; Dorsal soft rays (total): 15 - 16; Analspines: 0; Analsoft rays: 12 - 23

Apparently confined to freshwater at mouths of rivers and their lower reaches. Presumably schooling.

fisheries: subsistence fisheries