Volume 21, Issue 4 – 15 October 2015
Dalton Tavares Bressane Nielsen and Didier Pillet: Spectrolebias bellidoi, a new annual fish (Cyprinodontiformes: Rivulidae: Cynolebiatinae) from the upper Río Grande basin, Amazon basin, Bolivia, pp. 180-187
Spectrolebias bellidoi n. sp. is described from a temporary pool from the upper Río Grande, Río Mamoré basin, Departamento Santa Cruz, Bolivia. The new species is distinguished from all congeners by the unique shape of the female’s anal fin, which is composed of two parts, a rounded anterior area, and a posterior portion (from the 14th-15th rays onwards), gradually decreasing in size (vs. entire anal fin with a rounded outline) and a higher number of analfin rays (30 vs. 21-28), in females. It can be additionally distinguished from all congeners, with the exception of S. reticulatus and S. pilleti, by the position of the dorsal fin, which has its origin anterior to the origin of the anal fin in males.