Spectrolebias Costa & Nielsen

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 : 17

Subgenus Spectrolebias Costa & Nielsen

Spectrolebias Costa & Nielsen, 1997: 258 (type species Spectrolebias semiocellatus Costa & Nielsen , by original designation; first proposed as a genus).

Diagnosis. Distinguished from all other cynolebiatins by two unambiguous synapomorphies: a long hyomandibula (vs. short) and a narrowed proximal tip of the fourth ceratobranchial (vs. wide). It may be also diagnosed by the absence of organs of contact on the flank in males (vs. presence), but secondarily present in S. filamentosus . Another synapomorphy of Spectrolebias is a narrowed metapterygoid (vs. wide), a condition that also occurs in S. constanciae .

Included species. Simpsonichthys chacoensis (Amato) , S. semiocellatus (Costa & Nielsen) , S. filamentosus Costa, Barrera & Sarmiento , S. costai (Lazara) , and S. reticulatus Costa & Nielsen.

Distribution. Southern Amazonian river drainages, including rio Madeira, Xingu, Araguaia and Tocantins, and Paraguayan Chaco, río Paraguay basin.