This species was described in the genus Hypsolebias.

W. Costa (2006) assigned many members of the genus Simpsonichthys to the subgenus Hypsolebias (Costa 2006). Hypsolebias was subsequently elevated to a genus (Costa 2011). According to some scientists, the separation of Hypsolebias from the genus Simpsonichthys is insufficiently substantiated and, therefore, debatable.

Discoverer(s): Wilson J.E.M. Costa, Claudia P. Bove and Bruno B. Costa, January 13. 2005.

Type locality: close to the road BR-030, 14 km west Guanambi, upper Camaiba de Dentro river drainage, São Francisco river basin, municipio de Guanambi, Bahia state, altitude 502 m, (eastern) Brasil.

Superspecies-components:

H. coamazonicus, faouri, flagellatus, flavicaudatus, ghisolfii, gilbertobrasili, guanambi, heloplites, igneus, janaubensis, macaubensis, martinsi, mediopapillatus, nitens, nudiorbitatus, pterophyllus, radiseriatus, sertanejo.

From the description:

Hypsolebias comprises a rich-species clade of annual killifishes endemic to the savannas of central and north-eastern Brazil (Costa, 2006a, 2007, 2010a). It includes over 35 species occurring in an area encompassing the São Francisco, Tocantins, and Itapicuru river basins and the coastal plain areas adjacent to the Jaguaribe and Piranhas river basins (Costa, 2008, 2010a, 2010b, in press), but about 75 % of all species are endemic to the São Francisco River basin. Three species of that basin, H. flavicaudatus (Costa & Brasil), H. flagellatus (Costa) and H. janaubensis (Costa), constitute a well-corroborated clade, hereafter termed the H. flavicaudatus species complex, with members easily recognized by

having iridescent dots on the anal fi n restricted to the posterior portion of the fi n in males (vs. on the whole fi n) and anterior portion of the anal fi n pink and posterior portion yellow in males (vs. never a similar colour pattern) (Costa & Brasil, 1990; Costa, 2003, 2006b).Species of the H. flavicaudatus occupy a broad geographic region, between Santa Maria da Boa Vista, Pernambuco state (about 9° 00' S) and the city of São Francisco, Minas Gerais state (about 15° 30' S). Species of the H. flavicaudatus complex have been identified by a few morphological characters, usually comprising colour patterns and some morphometric data (Costa, 2003, 2006b, 2007). Specimens of an undetermined population from Guanambi, Bahia, northeastern Brazil, exhibit a peculiar combination of morphological features, which suggests they belonging to a distinct undescribed species. The objective of the present study is to analyse morphological and molecular data under different methods of species delimitation in order of determining the status of the Guanambi population. 

This species can be productive, and the fry is small. Immediately after hatching, the fry should be fed with freshly hatched Artemia nauplii (brine shrimp) or better Paramecium. As most annual species do, they spawn by diving entirely into the substrate. It is best to provide a container with a lid on top in which a hole is made to allow the fish access. That container will need to have enough peat in it for the fish to dive completely into it. For most Hypsolebias species, egg development is complete after 8-10 weeks. However, it is wise also to check a few weeks earlier to see if any eggs have fully developed. Do not let the peat dry too far because the Hypsolebias like it moist. The development will be slower at storage temperatures between 21 and 24 Celsius and speed up at 25-29 Celsius. Before watering the eggs, put some eggs in the water of about 18-20 degrees Celsius to see if the eggs hatch

correctly. That usually happens within 2-6 hours. Then, if eggs hatched well and fry, swim correctly, bring all remaining peat in the water. You may need to re-pack the peat after pouring over the first group of fry to a larger tank. With regular water changes and sufficient food, the young will grow quickly, and after about 5-6 weeks, they can already produce their first eggs. Since this genus has an annual life cycle, the expected life span in captivity is not much more than 10 to 12 months. Their life expectancy is limited to when their pool still has water in the wild. This period can vary from 6 to 8 months.

Remark:

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Max. size 40 mm.
Dorsal 21-23 in males, 13-17 in females.
Anal 22-24 in male, 19-21 in females.
D/A -2-4 in males and 6-7 in females,
LL scale: 29-30
Pre- dorsal length to SL.: 52 %
Depth to % SL – 39,5 %

Costa W.J.E.M., & P. F. Amorima, 2011. A new annual killifish species of the Hypsolebias flavicaudatus complex from the São Francisco River basin, Brazilian Caatinga Cyprinodontiformes:Rivulidae) Vertebrate Zoology, 61 (1) 99 –104. (PDF)