Rivulus Poey.

It comprises at least two valid species of nonannual fishes (max. 50 mm SL) distributed in freshwater systems of Cuba (Ponce de León et al., 2014). The genus is distinguished from other non-annual rivulines by the following synapomorphies: all hypurals fused (single plate); neural prezygapophysis of caudal vertebrae rudimentary; fourth ceratobranchial teeth absent; about 50% of anterior half of caudal fin covered by scales; four neuromasts on the anterior supraorbital series; and black round spot with white margin on the dorsoposterior portion of caudal peduncle in females (Costa, 2011a).

“ Rivulus ”. This taxon is composed by a single non-annual species endemic of the Hispaniola Island, “ Rivulus roloffi ” Roloff, which according to Hrbek et al. (2004) would be the sister species of all rivulines except Rivulus sensu stricto .