THE NOTHOBRANCHIUS SITE

MRAC 93-159-P-1, holotype, male, 45.8 mm SL; Uganda: temporary pool at the right side of the road Tororo to Jinja, 1 km west of Busesa, 7 km east of Iganga (00°37.74' N, 33°35.03' E); R. H. Wildekamp, I. Sainthouse, P. Sadler & T. Rowley, 23 Jun 1988, [field code: UG 88-22].

MRAC 93-159-P-2-13 (12)

Nothobranchius ugandensis is a polychromatic species and is known to exist in two basic colour forms, with red and yellow caudal fin phenotypes. Males of the yellow caudal form have an irides­cent blue body coloration and a yellow or yellow-green caudal fin. Males of the red caudal form have iridescent blue or pale blue body colouration, usually with red crossbars or reticulation on the body, and a red caudal fin, often with a wide orange-red subdis­tal band.

Subgenus: Zononothobranchius

Species group: N. ugandensis group

The first account of a Nothobranchius species in Uganda was by Boulenger (1902) in which he listed it as N. taeniopygus. Many of the subsequent publications also referred to the same name until N. taeniopygus was redescribed by Wildekamp (1990) and its range of distribution was limited to drainage systems in Tanzania. Wildekamp established the species Nothobranchius ugandensis from Uganda in 1994, and that status has been since accepted by all authors.

Combined morphometric and molecular analyses from populations across Uganda, including representative material from the Albert Nile drainage in western Uganda, shows that populations from Albert Nile drainage, previously regarded as belonging to N. ugandensis, belong to a distinct species described as Nothobranchius albertinensis by Nagy, Watters & Bellstedt in Nagy et al. (2020).

Uganda: temporary pool at the right side of the road Tororo to Jinja, 1 km west of Busesa, 7 km east of Iganga (00°30'N 33°31'E)

This species is endemic to seasonal freshwater habitats in south-eastern, central and northern Uganda and south-western Kenya. It occurs in ephemeral water bodies in the Victoria Nile drainage and Lake Kyoga basin in central and the Achwa drainage in northern Uganda, as well as in the Lake Vic­toria basin in south-eastern Uganda. It has also been found in seasonal pools and ditches associated with the Sio River in western Kenya, where it drains into Lake Victoria close to the border with Uganda (Wildekamp, 1989, 1994; Nagy, 2010, 2017; Nagy & Watters, 2018; Nagy et al., 2020).

Lake Victoria basin (521)

Upper Nile (522)

1011–1163 m

Water parameters of 40 sites: temperature of 20–34°C (average of 26.9 °C); pH of 6.4–8.5 (average 7.43); conductivity of 20–1540 µS; and typically turbid (Nagy & Watters, 2018).

N. robustus - 4%

N. taiti - 2%

This species has a seasonal life cycle, with populations near Lake Victoria in central and south-eastern Uganda and south-western Kenya that have a semi-annual life cycle whereas those further north in Uganda are more likely to be annual.

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

Maximum size reported: 48.0 mm SL (MRAC 93-159-P-41-43, males)

Diploid chromosome number 2n = 36 (Wildekamp, 1994; Valdesalici, 2015), NF = 58, karyotype structure 8m+14sm+14st/a (Krysanov & Demidova, 2018).

The specific name refers to the distribution of the species, originating from Uganda.

Least Concern (Nagy & Watters, 2021);

Previous assessment: Least Concern (Nagy & Watters, 2019); Least Concern (FishBase team RMCA & Geelhand, 2016)

    Wildekamp, R. H. 1994. The Nothobranchius species from Uganda, with description of a new polymorphic species (Cyprinodontiformes: Aplocheilidae). Ichthyological ExpIorations of Freshwaters, 5 (3): 193–206. [taxonomy as Nothobranchius ugandensis]

    Nagy, B. 2010. Collecting Nothobranchius in 'The pearl of Africa'. Nothobranchius Archives, 1 (1): 14–30. [collecting, distribution, ecology]

    Nagy, B. 2015. Life history and reproduction of Nothobranchius fishes. Journal of the American Killifish Association, 47 (4-6): 182–192. [ecology]

    Nagy, B. 2017. Searching for a mystery Nothobranchius in Uganda. Journal of the American Killifish Association, 50 (6): 162–174. [collecting]

    Nagy, B. & B. R. Watters. 2018. Distribution and habitat conditions of Nothobranchius fishes in Uganda. Journal of the American Killifish Association, 51 (5–6): 176–192. [distribution, ecology]

    Nagy, B., B. R. Watters, P. D. W. van der Merwe, F. P. D. Cotterill & D. U. Bellstedt. 2020. Review of the Nothobranchius ugandensis species group from the inland plateau of eastern Africa with descriptions of six new species (Teleostei: Nothobranchiidae). Ichthyological Exploration of Freshwaters, 30 (1): 21–73. [distribution, phylogeny, systematics]

    Nagy, B. & B. R. Watters. 2021. Nothobranchius ugandensis. The IUCN Red List of Threatened Species: e.T175184008A175184365. [conservation]