Fishes from the Tirimbina Biological Reserve, La Virgen de Sarapiquí, Heredia, Costa Rica Author Angulo, Arturo Author Naranjo-Elizondo, Beatriz Author Rojas, Emmanuel Author Ley-López, Juan Manuel text Check List 2017 2017-10-27 13 5 683 702 http://dx.doi.org/10.15560/13.5.683 journal article 10.15560/13.5.683 1809-127X (10) Alfaro cultratus ( Regan 1908: 458 ) ; Knife live- bearer (En), Olomina (sp) Figure 3E Body elongate, moderately deep and deeply compressed; lateral line reduced to a series of individual pits along side of body; fins without spines; a single dorsal fin; males with anal fin modified into a short gonopodium not extending beyond the dorsal fin insertion; ventral margin of the caudal peduncle sharp and compressed, scales forming a sheathed keel; caudal fin rounded; gen- eral coloration yellowish gray or pale yellow (almost transparent in some specimens) with metallic blue/green flashes in the abdomen and a thin dark line running along the entire length of the body; fins transparent or yellow; maximum body length ca 65 mm SL.