This genus was erected by Costa to fascilitate a. till today, single species named Mucurilebias leitaoi.

This taxon was originally described as Leptolebias leitaoi. It distinguished from all related genera by 7 unique conditions, eye large, occupying great part of head side, dorsal and ventral margins of orbit in close proximity to dorsal and ventral surface of head, respectively, in lateral view (vs. eye never so large, margins separated by dorsal and ventral surfaces by broad space), low number of Caudal fin rays (21 vs. 23-30), distal portion of epural much broader than distal portion of parhypural (vs. epural and parhypural equal in width), presence of an oblique red bar through opercle in both sexes (vs. absence), isthmus bright red in males (vs. never red pigmented), presence of a white band on distal margin of Dorsal fin in male (vs. absence), presence of a red band on distal margin of Anal fin in male (vs. absence) (Costa, 2014b).  

Note:

Mucurilebias leitaoi is only known systematically by the description; a small relict single species close related to the genus Leptopanchax (Costa 2016) based on minor characters; According to Costa (2014b), not less than 500 km separate Mucurilebias and the closest related genus Leptopanchaxall along the Brasilian coast. Despite renewed collecting efforts this gap is probably due to ancient events and not to recent man destructions of habitat.

Souce: Killi Data with small adaptions.