Atlantirivulus, a new subgenus of the killifish genus Rivulus from the eastern Brazilian coastal plains (Teleostei: Cyprinodontiformes: Rivulidae)

Abstract

Atlantirivulus, new subgenus of Rivulus POEY, is described to include a well defi ned, geographically isolated species assem- blage, endemic to eastern Brazil, formerly known as the Rivulus santensis species group. It includes eight species, all inhab- iting Atlantic forest habitats: R. santensis KÖHLER, the type species of the new subgenus, R. depressus COSTA, R. haraldsiolii BERKENKAMP, R. janeiroensis COSTA, R. lazzarotoi COSTA, R. luelingi SEEGERS, R. nudiventris COSTA & BRASIL, and R. simpli- cis COSTA. Atlantirivulus is diagnosed by a curved ventral process of angulo-articular and infraorbital neuromasts numerous, arranged in a zigzag pattern, morphological features that are unique among aplocheiloid fi shes.