Jenynsia tucumana Aguilera & Mirande 2005

This species differs from all its congeners by having a row of dark markings ranging from dots to small vertical stripes, on the lateral surface, from the tip of the adpressed pectoral fin to the margin of hypural. It can be further diagnosed by the combination of the following characters: two, occasionally three, rows of dorsoventrally elongate markings on the lateral surface of body; a mandibular canal pore W, a wide prootic bridge, and a symmetric fifth anal-fin ray of the tubular gonopodium; 15-16 predorsal scales; absence of a swelling between the urogenital opening and the anterior base of the anal fin in females; absence of a rounded spot on dorsal pectoral-fin base; absence of a large dorsal convex expansion at subdistal segments of right half of sixth anal-fin ray of adult males; and absence of a long posterodorsal process of the lachrymal and a shorter fourth anal-fin ray in the gonopodium (Ref. 56908).

Dorsal soft rays (total): 7 - 8; Analsoft rays: 10; Vertebrae: 31 - 32

Occurs mainly in moderate to slow flowing streams with rocky bottom and algae on the substrate, where it is sympatric with Jenynsia multidentata (Ref. 56908).

Occurs mainly in moderate to slow flowing streams with rocky bottom and algae on the substrate, where it is sympatric with Jenynsia multidentata (Ref. 56908).