Cynodonichthys isthmensis (Garman, 1895) .

Isthmian Rivulus; Olomina, Alumina, Olomina Saltona, Killi, Saltón, Killi del Istmo.

Distribution: Global: Middle America; from central Nicaragua to eastern Costa Rica, Atlantic and Pacific drainages; Costa Rica: LN, RF, SJ, SC, Sa, To, Pa, Ma, Si (Atlantic), Be and Ta (Pacific), 0–1500 m.a.s.l., Sec, Pot.

Occurrence and conservation status: Nat, LC.

References: Bussing (1966: 237, as Rivulus isthmensis —synonym; listed, information on distribution), Bussing (1987: 123, as R. isthmensis isthmensis —synonym; 1998: 176, as R. isthmensis isthmensis —synonym; brief description, including illustrations and an identification key, information on distribution, with a map, and ecology) and Angulo et al. (2013: 995; listed, including taxonomic information and distributional data).