Costa, W.J.E.M. & Lanés, L.E.K., 2009
Rivulus riograndensis, a new aplocheiloid killifish from southern Brazil (Cyprinodontiformes: Rivulidae).Rivulus riograndensis, a new species of the subgenus Atlantirivulus from the Patos lagoon basin and adjacent coastal plains, southern Brazil, is described. It is similar to R. haraldsiolii and R. luelingi, and distinguished from all other species of the subgenus, by having dark brown dots over the dorsal portion of the flank and dorsum in females. This unique color pattern suggests that R. riograndensis, R. haraldsiolii and R. luelingi form a monophyletic assemblage. The new species is distinguished from those two species by having fewer pelvic-fin rays and by the absence of contact organs on flank scales in males. It also differs from R. haraldsiolii by having fewer scales in the longitudinal series, fewer vertebrae, and dorsal fin more anteriorly placed on trunk, and from R. luelingi, by a different caudalfin color pattern in males and by having more vertebrae.
Costa, W.J.E.M. & Lanés, L.E.K.
Ichthyological Exploration of Freshwaters, 20 (1): 91-94, 2009.