Rivulus Poey. It

Loureiro, Marcelo, Sá, Rafael de, Serra, Sebastián W., Alonso, Felipe, Lanés, Luis Esteban Krause, Volcan, Matheus Vieira, Calviño, Pablo, Nielsen, Dalton, Duarte, Alejandro & Garcia, Graciela, 2018, Review of the family Rivulidae (Cyprinodontiformes, Aplocheiloidei) and a molecular and morphological phylogeny of the annual fish genus Austrolebias Costa 1998, Neotropical Ichthyology 16 (3), pp. 1-20 : 6

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).