Cynodonichthys fuscolineatus (Bussing, 1980) .

Arenal Rivulus; Olomina, Alumina, Olomina Saltona, Killi, Saltón, Olomina del Arenal, Killi del Arenal.

Distribution: Global: Middle America; northwestern Costa Rica, Atlantic and Pacific drainages; Costa Rica: RF, SC (Atlantic) and Be (Pacific), 525– 731 m.a.s.l., Sec, Pot.

Occurrence and conservation status: End, EN.

References: Bussing (1980: 336, as Rivulus fuscolineatus —synonym; detailed description, including illustrations, information on distribution and ecology), Bussing (1987: 119, as R. fuscolineatus —synonym; 1998: 171, as R. fuscolineatus —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).