Xenurolebias, Costa, 2006

Costa, Wilson J. E. M., 2006, Descriptive morphology and phylogenetic relationships among species of the Neotropical annual killifish genera Nematolebias and Simpsonichthys (Cyprinodontiformes: Aplocheiloidei: Rivulidae), Neotropical Ichthyology 4 (1), pp. 1-26 : 16

Xenurolebias new subgenus

Type species. Simpsonichthys myersi (de Carvalho) .

Diagnosis. Distinguished from all other rivulids by the following unambiguous synapomorphies: presence of filamentous rays on the posterior margin of the anal fin in females (vs. absence), caudal fin lanceolate and asymmetric due to an expansion of the ventral portion of the fin in males (vs. caudal fin rounded or subtruncate, dorsal and ventral portion symmetric), and a unique color pattern consisting of a bar on the posterior portion of the caudal peduncle, posteriorly extending over the dorsal and ventral margins of the caudal fin in males (vs. never a similar color pattern).

Included species. Simpsonichthys izecksohni (da Cruz) and S. myersi (de Carvalho) .

Distribution. Rivers basins of eastern Brazilian coastal plains between rio Jucuruçu, southern Estado da Bahia, and rio Doce, Estado do Espírito Santo.

Distribution. Coastal plains of Estado do Rio de Janeiro, southeastern Brazil.