Killifish experts have described three new species from the Simpsonichthys genus.
The new fish have been named Simpsonichthys virgulatus, S. fasciatus and S. gibberatus in a paper in the latest issue of the systematics journal Zootaxa by Wilson Costa of the Federal University of Rio de Janeiro and Gilberto Brasil of Brazil's Ministerio de Meio Ambiente.
All three of the new rivulid killifish species were discovered in the middle Rio Paracatu drainage, which lies in the middle of the Rio Sao Francisco basin in Brazil, and are members of the Simpsonichthys subgenus Hypsolebias.
Simpsonichthys fasciatus is similar to S. delucai (pictured above) and S. alternatus as it shares a rounded anal fin in males and a spatula-shaped anal fin in females. Unlike delucai and alternatus, fasciatus has a dark grey or black stripe on the distal margin of the dorsal of males.
Costa and Brasil say that S. virgulatus is a typical member of the S. notatus group and has the characteristic A-pattern on its frontal scales and blue spots on the distal margin of the dorsal fin of males.
The authors claim that it is similar to Simpsonichthys auratus and trilineatus in having a golden area at the front of the flanks along with brown or black blotches in males. However, the new species has more bars which extend on to the caudal peduncle and its fins are uncoloured.
Simpsonichthys gibberatus is quite distinctive among the genus in that it has a convex area in front of the dorsal area of females.
For more details on the new tropical fish species see the paper: Costa WJEM and GC Brasil (2006) - Three new species of the seasonal killifish genus Simpsonichthys subgenus Hypsolebias (Teleostei: Cyprinodontiformes: Rivulidae) from the Rio Paracatu drainage, Rio Sao Francisco basin, Brazil. Zootaxa, 1244: 41-55.