THE NOTHOBRANCHIUS SITE

MRAC 97-089-P-0011, holotype, male, 34.3 mm SL; Zambia: Kasanka National Park, Luwombwa River, close to Luwombwa lodge, approx. 12°30’ S, 30°08’ E; collected by P. Goudswaart, 8 Aug 1997.

MRAC 97-089-P-0012 (1), 97-089-P-0013 (1); MSNG 51933 (1) [this specimen belongs now to N. cooperi]; MSNG 51934 (1)

Nothobranchius rosenstocki is distinguished from all other species of the genus by the following combination of unique characters: 15–17 dorsal fin rays; 16–17 anal fin rays; male colouration consisting of an irregular red reticulation contrasting with a light blue background colour on the entire body. The frontal and superior portion of the head is red; the anal fin has a red distal part. The caudal fin base is red spotted; the distal part is transparent light blue. The anterior part of the base of the dorsal fin has distinct black spots and barely visible papillae. The sides of the female, in contrast to those of the male, are not marked but have narrow brown scale margins (after Valdesalici & Wildekamp, 2005).

Subgenus: Zononothobranchius

Species group: N. brieni group

Nothobranchius rosenstocki was established as a species by Valdesalici & Wildekamp in 2005, and that status has since been accepted by all authors.

Populations from the Mansa River drainage, discovered in 1989, were also included in the group of populations regarded as N. rosenstocki, but subsequent morphological and molecular studies showed these populations to represent a distinct species described as Nothobranchius cooperi, by Nagy, Watters & Bellstedt in 2017 in Nagy et al. (2017).

Zambia: Kasanka National Park, Luwombwa River, close to Luwombwa lodge, in the shallows among shore vegetation, approx. 12°30’ S, 30°08’ E.

This species is endemic to freshwater habitats in northern Zambia. It is known from temporary water bodies in several smaller river systems within the upper Luapula drainage in northern Zambia.

Bangweulu–Mweru (544)

1166–1194 m

Personal observation at collecting sites (8 locations):

Water temperature: 21.3–27.2 °C (average 24.7 °C)

pH: 5.40–7.50 (average: 6.70)

TDS:  5–282 ppm (average: 49)

Conductivity: 10–564 µS (average: 98)

None

This species has an annual life cycle.

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

Maximum size reported: 36.9 mm SL (MSNG 51934, male)

Diploid chromosome number 2n = 36, NF = 62, karyotype structure 14m+12sm+10st/a (Krysanov & Demidova, 2018).

The specific name is given in honour of John Rosenstock of Hellerup, Denmark, who collected this new species [actually discovered the species in 1989] during one of his many journeys in Africa for the Danish Development Assistance Organisation.

Vulnerable B1ab(iii) (Nagy & Watters, 2019);

Previous assessment: Endangered B1ab(iii)+2ab(iii) (Moelants, 2010)

    Rosenstock, J. 1991. Zambia 1989. Journal of the American Killifish Association, 24 (4–6): 213–220. [collecting]

    Valdesalici, S. & R. H. Wildekamp. 2005. A new species of the genus Nothobranchius (Cyprinodontiformes: Nothobranchiidae) from Luapula River basin, Zambia. Aqua, International Journal of Ichthyology, 9 (3): 89–96. [taxonomy as Nothobranchius rosenstocki]

    Nagy, B., F. P. D. Cotterill & D. U. Bellstedt. 2016. Nothobranchius sainthousei, a new species of annual killifish from the Luapula River drainage in northern Zambia (Teleostei: Cyprinodontiformes). Ichthyological Exploration of Freshwaters, 27 (3): 233–254. [phylogeny]

​    Nagy, B., B. R. Watters, P. D. W. van der Merwe, F. P. D. Cotterill & D. U. Bellstedt. 2017. Nothobranchius cooperi (Teleostei: Cyprinodontiformes) a new species of annual killifish from the Luapula River drainage, northern Zambia. African Journal of Aquatic Science, 42 (3): 201–218. [distribution, phylogeny, systematics]

    Nagy, B. & B. R. Watters. 2019. Nothobranchius rosenstocki. The IUCN Red List of Threatened Species: e.T141974164A58327977. [conservation]