CoF lists four species as valid:
Current status: Valid as Pronothobranchius kiyawensis (Ahl 1928). Nothobranchiidae. Distribution: Western Africa: Nigeria, Chad and northern Central African Republic.
Current status: Valid as Pronothobranchius seymouri (Loiselle & Blair 1971). Nothobranchiidae. Distribution: Volta River drainage, Ghana.
Current status: Valid as Pronothobranchius chirioi Valdesalici 2013. Nothobranchiidae. Distribution: Niger River dainage in Niger and Burkina Faso.
Current status: Valid as Pronothobranchius gambiensis (Svensson 1933). Nothobranchiidae. Distribution: Gambia River drainage in Gambia and.Senegel.
Krysanov and Demidova 2018 have a good of
Pronothobranchius and where it fits in with similar fish:
"Killishes of the genus
Nothobranchius Peters, 1868 comprise 76 valid species (Eschmeyer et al. 2018, FishBase 2018). The main life-style characteristics of killifishes reside in fact that species and their populations inhabiting in ephemeral pools of East Africa are isolated both geographically and temporarily due to extremely short life cycle (Wildekamp 2004; Reichard 2016).
Phylogenetic data based on molecular markers demonstrated that the genus
Nothobranchius is a monophyletic assemblage and it includes four geographically separated clades (Dorn et al. 2014). Costa (2018) performed taxonomy analysis of the genus on the basis of morphology and phylogenetic data. Six subgenera were recognised:
Adiniops Myers, 1924,
Cynobranchius Costa, 2018,
Nothobranchius Peters, 1868,
Paranothobranchius Seegers, 1985,
Plesiobranchius Costa, 2018, and
Zononothobranchius Radda, 1969.
Karyotypes of 30 species were described earlier and high karyotype variability was revealed (summarized in Arai 2011). The diploid chromosome number (2n) of Nothobranchius species varies from 16 to 50 (Scheel 1990, Krysanov et al. 2016). Two species N.guentheri (Pfeffer, 1893) and N.brieni Poll, 1938 had multiple chromosome system (Ewulonu et al. 1985, Krysanov et al. 2016). Thus, the representatives of the genus Nothobranchius is a good model for studying karyotype differentiation due to high karyotype variability and features of the life cycle."
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6182469/
See also
Valdesalici, Stefano. 2013. Killi-Data Series 2013b. Pronothobranchius chirioi n. sp. a new annual killifish species from the Niger River drainage, with redescriptions of
P. kiyawensis, P. gambiensis and P.
seymouri (Cyprinodontiformes: Nothobranchiidae). Killi-Data Edition, Paris, France.: 21-41, 10 figs., 2 tabs.
https://www.researchgate.net/publication/259580479_Valdesalici_Stefano_2013_Killi-Data_Series_2013b_Pronothobranchius_chirioi_n_sp_a_new_annual_killifish_species_from_the_Niger_River_drainage_with_redescriptions_of_P_kiyawensis_P_gambiensis_and_P_seym
Huber's summary:
"In this study three
Pronothobranchius species previously considered synonymous with
P. kiyawensis are revalidated and a new species from the Niger River drainage is described.
Pronothobranchius kiyawensis inhabits the Lake Chad drainage basin and is diagnosed by males possessing small dots on the flanks and a proximal stripe on the anal fin.
P. gambiensis occurs in the Gambia River drainage basin and is distinguished by males possessing only a few large spots on the flanks and a proximal stripe on the anal fin.
P. seymouri is known from the Volta River drainage and is diagnosed by males possessing spots across the entire flank which form irregular, laterally-elongated stripes, and a few variably-arranged dots on the proximal portion of the anal fin.
P. chirioi spec. nov. occurs in the Niger River drainage and is distinguished from all congeners by males possessing large, proximal spots on the anal fin.
zoobank.org:pub:79B8A19C-F6B9-46FB-8F5A-4FE2E2E79A16"
http://www.killi-data.org/series-kd-2013-Valdesalici.php
