THE NOTHOBRANCHIUS SITE

ZMH H440, lectotype, male, 41.3 mm SL; Tanzania: island of Zanzibar; F. Stuhlmann, 6 Aug 1888; designated by Ladiges et al., 1958.

BMNH 1857.3.9.507-508 (2), BMNH 1864.2.10.9 (1), ZMH H441 (3), ZMH H442 (28).

Nothobranchius guentheri can be distinguished from all congeners by the combination of the following character states: caudal fin red with black posterior margin in males; flank and fins without dark spots in females; pre-dorsal length in males 57.5–61.4% SL; 3 + 12–14 gill-rakers on first branchial arch; 27–28 scales in longitudinal series; 14 series of scales around caudal peduncle; single longitudinal row of scales between anterior supraorbital series of neuromasts; anterior supraorbital series of neuromasts arranged in two sections, anterior section with one well-developed neuromast, posterior with two; three neuromasts in posterior supraorbital series; 26–27 caudal-fin rays; 28 vertebrae; second proximal radial of dorsal fin between neural spines of 10th and 12th vertebrae (Costa, 2017).

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Nothobranchius guentheri can be distinguished from the congeners by the following characters in males: body iridescent blue-green, two to three distinct red oblique bars on the opercula, red caudal fin with black posterior margin in the males, and females with a yellow-brown body and without markings.

Subgenus: Adiniops

Species group: N. guentheri group

Fundulus guentheri was established as a species by Pfeffer in 1893. Ahl assigned the species into the genus Nothobranchius in 1924. For long time, the name Nothobranchius guentheri was frequently used for other populations that are regarded today as N. melanospilus, until Wildekamp (1981) clarified the distribution of the species, limiting the range of N. guentheri to Unguja Island of the Zanzibar archipelago in eastern Tanzania.

Tanzania: Unguja Island, Zanzibar archipelago.

This species is endemic to freshwater seasonal pools and marshes on habitats in coastal Unguja Island, Zanzibar archipelago, eastern Tanzania.

Coastal East Africa (564)

30–63 m

Water parameters based on Watters (personal data) are as follows: temperature of 25–29°C; pH of 7.2–7.7; conductivity of 140–980 µS; and typically turbid (Nagy & Watters, 2019).

N. melanospilus - 20%

This species has a semi-annual life cycle.

Embryonic development under captive conditions in peat moss is about two to three months at room temperature.

Maximum size reported: 41.3 mm SL (ZMH H440, lectotype, male)

Diploid chromosome number 2n = 35 for males and 2n = 36 for females (Ewulonu et al., 1985; Scheel, 1990); NF = 39 for males and 40 for females, karyotype structure 2m+2sm+31st/a for males and 2m+2sm+32st/a for females (Krysanov & Demidova, 2018).

Diploid chromosome number and karyotype structure unique in the genus.

The specific name is given in honour of Dr. Albert C. L. G. Günther, German zoologist.

Endangered B1ab(iii,iv)+2ab(iii,iv) (Nagy & Watters, 2019);

Previous assessment: Least Concern (Hanssens, M. & Snoeks, J. 2006)

    Pfeffer, G. 1893. Ostafrikanische Fische gesammelt von Herrn Dr. F. Stuhlman im Jahre 1888 und 1889. Jahrbuch der Hamburgischen Wissenschaftlichen Anstalten, 10 (2): 129–177. [taxonomy as Fundulus güntheri]

    Ahl, E. 1924. Zur Systematik der altweltlichen Zahnkarpfen der Unterfamilie Fundulinae. Zoologischer Anzeiger, 60 (4): 49–55. [systematic in Nothobranchius]

    Ladiges, W., G. von Wahlert & E. Mohr. 1958. Die Typen und Typoide der Fischsammlung des Hamburgischen Zoologischen Staatsinstituts und Zoologischen Museums. Mitteilungen aus dem Hamburgischen Zoologischen Institut v. 56: 155–167. [lectotype designation]

    Wildekamp, R. H. 1981. Zum Thema Nothobranchius guentheri und Nothobranchius melanospilus. Deutsche Killifisch Gemeinschaft Journal, 13 (2): 25–31. [identification]

    Nagy, B. & B. R. Watters. 2019. Nothobranchius guentheri. The IUCN Red List of Threatened Species: e.T61284A47243542. [conservation]

    Watters, B. R., B. Nagy, P. D. W. van der Merwe, F. P. D. Cotterill & D. U. Bellstedt. 2019. Review of the Nothobranchius taeniopygus species group from central and western Tanzania with descriptions of five new species and redescription of Nothobranchius taeniopygus (Teleostei: Nothobranchiidae). Ichthyological Exploration of Freshwaters, 29 (3): 239–278. [phylogeny]

    Nagy, B. & B. R. Watters. 2020. Threatened - the world is a dangerous place for seasonal fishes. Journal of the American Killifish Association, 53 (4): 141–156. [conservation]

    Nagy, B. & B. R. Watters, 2021. A review of the conservation status of seasonal Nothobranchius fishes (Teleostei: Cyprinodontiformes), a genus with a high level of threat, inhabiting ephemeral wetland habitats in Africa. Aquatic Conservation: Marine and Freshwater Ecosystems, 1–18. [conservation]