Prorivulus, Costa, Wilson J. E. M., 2004

Costa, Wilson J. E. M., 2004, A new killifish genus and species from the coastal plains of northeastern Brazil (Teleostei: Cyprinodontiformes: Rivulidae), Zootaxa 642, pp. 1-10 : 3

Prorivulus new genus

Type species: Prorivulus auriferus Costa, Lima & Suzart , new species.

Diagnosis: A non­annual fish genus, similar to Rivulus and Kryptolebias , and distinguished from the remaining rivulid genera by having anal­fin rays soft in both sexes (vs. hardened in females), urogenital papilla minute in males (vs. prominent and tubular), and absence of a dark bar on iris (vs. presence). Similar to Kryptolebias and distinguished from Rivulus by possessing frontal E­scales overlapped (vs. not overlapped), third epibranchial with distinct uncinate process (vs. short indistinct process), distal cartilage of the first hypobranchial restricted to articulation with first ceratobranchial (vs. cartilage expanded anteriorly), ventral process of angulo­articular broad (vs. narrow), and posterior flange of cleithrum absent (vs. present). Similar to Rivulus and distinguished from Kryptolebias by having unossified interhyal (vs. ossified) and by the absence of the distal process of second epibranchial (vs. presence). Differs from other rivulids, except the two species of Stenolebias and Rivulus romeri Costa , by having five branchiostegal rays (vs. six).

Included taxa: Only the type species.

Etymology: From the Latin pro (a prefix meaning priority in space or time) and rivulus (stream, and also a nominal rivulid genus), referring to the basal position of the genus regarding Rivulus and all the annual fish rivulid genera. Gender masculine.