What were all once called Rivulus has become a major area of change over the past ten to fifteen years. Dr. Jean Huber of France began the diversification of of the genus into several separate subgenera in the early 1990s. Hobbyists have had a hard time separating the different genera both from discomfort in changing everything they have known for many years as well as recognizing fish from the different groups easily. While there are many beautiful Rivulus species, a fair percentage are less attractive (females tend to look the same) and have many similarities.
Dr. Wilson J.E.M. Costa of Brazil has added dozens of new species to the different groups during this time frame.
Killienutz Online has determined to use Dr. Glen Collier’s genetic work as the basis for how we determine what species belongs to what group.
Rivulus Poey, 1860. Poey, F. 1860. Poissons de Cuba, espèces nouvelles. pp. 115-336, plates 10-12,14 In: Memorias sobre la historia de la isla de Cuba: acompañadas de sumarios latinos y extractos en francés. Imprenta de la Viuda de Barcina, Habana, Cuba. volume 2. [pp. 307-308, 383] [published in parts] [See Norman (1938) for the dating of Poey’s works.]
Type species: Rivulus cylindraceus Poey, 1860, by monotypy.
Anablepsoides Huber, 1992. Huber, J. H. 1992. Review of Rivulus, ecobiogeography– relationships, the most widespread Neotropical cyprinodont genus. Cybium, Société Française d’Ichthyologie, Paris, France. 586 pp. [description: pp. 43-44]
Type species: Rivulus atratus Garman, 1895, by monotypy.
Cynodonichthys Meek, 1904. Meek, S. E. 1904. The fresh-water fishes of Mexico north of the Isthmus of Tehuantepec. Field Columbian Museum (Publication 93) Zoological Series 5: i-lxiii + 1-252, 72 figs., 17 plates, map. [description: p. 101]
Type species: Cynodonichthys tenuis Meek, 1904, by monotypy, proposed as a genus.
Laimosemion Huber, 1999. Huber, J. H. 1999. Updates to the phylogeny and systematics of the Neotropical cyprinodont genus Rivulus and its allied (Cyprinodontiformes: Rivulinae). Cybium23 (1): 29-52, fig., 3 tables. [description: pp. 49-50]
Type species: Rivulus geayi Vallaint, 1899, by original designation.
Oditichthys Huber, 1999. Huber, J. H. 1999. Updates to the phylogeny and systematics of the Neotropical cyprinodont genus Rivulus and its allied (Cyprinodontiformes: Rivulinae). Cybium23 (1): 29-52, fig., 3 tables. [description: p. 49]
Type species: Rivulus igneus Huber, 1991, by original designation.
Vomerivulus Fowler, 1944. Fowler, H. W. 1944. Freshwater fishes from northwestern Colombia. Proceedings of the Academy of Natural Sciences of Philadelphia 96: 227-248, 25 figs. [description: p. 244]
Type species: Rivulus leucurus Fowler, 1944, by original designation, monotypic.