THE NOTHOBRANCHIUS SITE

MRAC A7-02-P-9, holotype, male, 75.5 mm TL, 59.8 mm SL; Tanzania: large pool on west side of road between Ifakara and the Kilombero River ferry, 2 km south of Ifakara, 1 km north of the Kilombero River; 8°10.30' S, 36°41.54' E; B. Watters, B. Cooper & O. Schmidt, 10 Jun 2000, [field code: Ifakara TAN 00-13].

MRAC A7-02-P-10-25 (16), 98-008-P-0007-0012 (6)

Nothobranchius lucius is distinguished from all other species of the genus by a more slender, pike-like, appearance (except N. ocellatus), and by the following combination of characters: male: red-brown caudal fin with broad orange-red submarginal band and a distinct black margin; female: pattern of dark brown spots on the head and body, and brown markings on all unpaired fins (vs black spots on the flank and base of the unpaired fins in N. melanospilus, and grey or indistinct grey spots on the flank only of N. makondorum) (Wildekamp et al., 2009).

Subgenus: Adiniops

Species group: N. melanospilus group

​Following its discovery in 1995, populations of this species found in the Kilombero drainage were referred to N. aff. melanospilus, based on some general similarities with that species but also some important differences. Morphometric and molecular analyses confirmed the distinction from N. melanospilus and the species was described as N. lucius by Wildekamp et al. in 2009, including populations from the Kilombero, Mbezi and lower Rufiji drainages, and also from Mafia Island. These latter populations occurring in Mafia Island were separated from the populations on the coastal mainland and described as N. insularis by Costa in 2017.

Tanzania: large pool on west side of road between Ifakara and the Kilombero River ferry, 2 km south of Ifakara, 1 km north of the Kilombero River (8°10.30' S, 36°41.54' E).

This species is endemic to seasonal freshwater habitats in coastal Tanzania. It is known from ephemeral marshes and pools in the drainages of the Kilombero, Mbezi and lower Rufiji, eastern Tanzania.

Coastal East Africa (564)

22–347 m

Water parameters of collecting sites: temperature of 24–31°C; pH of 7.0–8.0; conductivity of 20–120 µS, and one site with exceptionally high value of 4,000 µS; and typically turbid (Nagy & Watters, 2019).

N. lourensi - 43%

N. kilomberoensis - 30%

N. geminus - 23%

N. melanospilus - 23%

N. rubripinnis - 17%

N. ruudwildekampi - 17%

N. luekei - 10%

Populations of this species in near-shore coastal regions have a semi-annual life cycle whereas those further inland, as in the Kilombero area, are more likely to be annual.

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

Maximum size reported: 62.9 mm SL (MRAC A7-02-P-26-27, male)

Diploid chromosome number 2n = 36 (Wildekamp et al., 2009); NF = 58, karyotype structure 6m+16sm+14st/a (Krysanov & Demidova, 2018).

Karyotype structure unique in the species group.

The specific name is formed from lucius (in Latin for pike), as an allusion to the, compared to congeners, stronger dentition, partly predatory behaviour and pike-like appearance.

Near Threatened B1ab(iii) (Nagy & Watters, 2019)

​    Wildekamp, R. H., K. M. Shidlovskiy & B. R. Watters. 2009. Systematics of the Nothobranchius melanospilus species group (Cyprinodontiformes: Nothobranchiidae) with description of two new species from Tanzania and Mozambique. Ichthyological Exploration of Freshwaters, 20 (3): 237–254. [taxonomy as Nothobranchius lucius] 

    Nagy, B. 2010. A la recherche de killis sur l’île de Pemba et dans la partie côtière de la Tanzanie. Killi Revue, Killi Club de France, 2010 (5): 3–11. [collecting]

    Costa, W. J. E. M. 2017. Redescription of Nothobranchius lucius and description of a new species from Mafia Island, eastern Tanzania (Cyprinodontiformes, Aplocheilidae). Zoosystematics and Evolution, 93 (1): 35–44. [systematic]

    Nagy, B. & B. R. Watters. 2019. Nothobranchius lucius. The IUCN Red List of Threatened Species 2019: e.T53904054A58340364. [conservation]

    Watters, B. R., B. Nagy, P. D. W. van der Merwe, F. P. D. Cotterill & D. U. Bellstedt. 2020. Redescription of the seasonal killifish species Nothobranchius ocellatus and description of a related new species Nothobranchius matanduensis, from eastern Tanzania (Teleostei: Nothobranchiidae). Ichthyological Exploration of Freshwaters, IEF-1149, pp. 1–28. [phylogeny]