THE NOTHOBRANCHIUS SITE

NMK, ICH FW/6014/1, male, 33.6 mm SL; Kenya: ephemeral swamp in south-western coastal area; D.U. Bellstedt, 4 July 2018.

Nothobranchius sylvaticus is distinguished from all other members of the genus by the following combination of characters in males: scales on trunk iridescent light blue covering the entire caudal peduncle; dorsal

portion of head grey with distinct red lobes along supraorbital canal; posterior scale margins on postorbital portion of opercle creating two pronounced brown-red oblique bars; dorsal and anal fins golden, marked with dark grey dots and stripes proximally and medially, merging into uniform dark grey zone distally; caudal fin dark red to red proximally, plain red medially, and with slender black distal band.

Subgenus: Coastal-Inland Clade

Nothobranchius sylvaticus was established as a species by Nagy, Bellstedt & Luke (in Bellstedt et al., 2025).

South-eastern Kenya

Nothobranchius sylvaticus is endemic to south-eastern Kenya.

Tana, Athi, and Coastal drainages (567)

26 m

Water sample taken by P. de Rham in December 1982, revealed the following results: pH = 8.1; conductivity = 465 µS; total hardness = 11.2 °F; carbonate hardness = 7.7 °F; Ca/l = 25.6 mg; Mg/l = 11.7 mg; Cl/l = 98.0 mg; Na/l = 57.0 mg (de Rham, 1991).

None

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: 33.6 mm SL (Bellstedt et al., 2025)

​Karyotype structure unique in the genus.

The specific name sylvaticus is a Latin participial adjective and is given in reference to the distinctive habitat preference of the species, restricted to

ephemeral pools and seeps associated with seasonal forest-streams.

Not Evaluated, recommended as Critically Endangered

    Bellstedt, D. U., B. Nagy, P. D. W. van der Merwe, F. P. D. Cotterill, Q. Luke & B. R. Watters. 2025. The description of a critically endangered new species of seasonal killifish, Nothobranchius sylvaticus (Cyprinodontiformes: Nothobranchiidae), a relict species from an East African forest refugium in south-eastern Kenya. Zootaxa, 5601 (1): 086–108. https://doi.org/10.11646/zootaxa.5601.1.4