THE NOTHOBRANCHIUS SITE

MRAC 2021.001.P.0001, male, 24.4 mm SL; Tanzania: lower Matandu drainage: Zinga system: ephemeral pool, about 9 km southeast of Njinjo township, 08°51’09” S, 38°57’14” E; A. Nikiforov, V. Korolev, S. Streltsov & S. Torgashev, 14 June 2017, [field code: TTKSN 2017-02].

MRAC 2021.001.P.0002-4 (3), MRAC 2021.001.P.0005-6, (2)

Nothobranchius nikiforovi is distinguished from all other congeners, except N. eggersi, by males presenting two phenotypes; the blue phenotype having a bright iridescent light blue to blue-green body, with narrow red-brown scale margins creating irregular reticulated pattern forming chevron-shaped crossbars on posteroventral portion of body and median fins light blue with red-brown dotted pattern; the red phenotype has a dark red head, light blue dorsal and anal fins proximally and medially, dark red distally, with dark red stripes parallel to the fin rays, and plain dark red caudal fin.

Nothobranchius nikiforovi differs from N. eggersi by male colour pattern, the blue phenotype having median fins with dark grey distal portion, some of the rays of dorsal and anal fins with white tips (vs. median fins with distinct slender white distal band), and the caudal fin lacking a spotted pattern (vs. dots arranged into irregular curved stripes); the red phenotype with golden stripe between the nape and dorsal-fin origin (vs. light-blue stripe), the dorsal and anal fins with a plain red distal portion and lacking a light distal band (vs. with distinct narrow white distal band), the pelvic fin lacking a distal band (vs. with distinct slender light blue to white distal band), and morphometric differences.

Subgenus: Adiniops

Species group: N. guentheri group

Populations of this species from the lower Matandu drainage in south-eastern coastal Tanzania were previously referred to as Nothobranchius species or N. cf. eggersi, based on some similarities in colour pattern of males. It was retrieved as phylogenetically distinct lineage in in van der Merwe et al. (2020) and in Nagy et al. (2021). Based on combined morphometric and molecular analyses it was established as a distinct species by Nagy, Watters & Raspopova (Nagy et al. 2021).

Tanzania: lower Matandu drainage: Zinga system: ephemeral pool, about 9 km southeast of Njinjo township (08°51’09” S, 38°57’14” E).

Nothobranchius nikiforovi is currently known from temporary pools formed in the floodplain of the lower reaches of the seasonal Matandu River drainage in coastal eastern Tanzania.

Coastal East Africa (564)

13–190 m

At the end of the rainy season, the habitat was a shallow pool, about 10 m long and less than 5 m wide, and less than 1 m at the deepest point. The water was turbid, the bottom of the pool was not visible.

Accompanying congeners consisted of N. cf. melanospilus.

This species has an annual life cycle.

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

Maximum size reported: 24.5 mm SL (paratype)

Karyotype structure shared with some members of the subgenus Adiniops (Krysanov. pers. comm.)

The specific name is given in honour of Andrei Nikiforov, from Russia, who participated in several field surveys aimed at research on Nothobranchius fishes in Tanzania, and he is co-discoverer of the new species and co-collector of the type specimens. A noun in genitive.

Vulnerable B1ab(iii)+B2ab(iii) (Nagy & Watters, 2022)

    Nagy, B., B. R. Watters & A. A. Raspopova. 2021. Nothobranchius nikiforovi, a new species of seasonal killifish from the lower Matandu drainage in south-eastern coastal Tanzania (Cyprinodontiformes: Nothobranchiidae). Zootaxa, 4950 (1): 103–122. [taxonomy as Nothobranchius nikiforovi, distribution, phylogeny]

    Nagy, B. & B. R. Watters. 2022. Nothobranchius nikiforovi. The IUCN Red List of Threatened Species: e.T209447383A209447564

[conservation]