THE NOTHOBRANCHIUS SITE

​MRAC 2019.016.P.0017, male, 50.4 mm SL; Uganda: Albert Nile drainage: shallow remnant pools in seasonal riverbed, 20 km north of Pakwach, 02°36'19" N, 31°23'04" E; B. Watters, R. Wildekamp & B. Cooper, 10 Jun 1999 [field code: Olobodagi UG 99-23].

​MRAC 2019.016.P.0018–0022 (5), MRAC 2019.016.P.0023–0025 (3), MRAC 2019.016.P.0026 (1)

Nothobranchius albertinensis is distinguished from all other species of the genus, with the exception of N. ugandensis, by the following combination of characters in males: body coloration light blue with red-brown scale margins; frontal part of head and snout red-brown and throat light blue; caudal fin uniform red. Furthermore, it differs from N. ugandensis by a dorsal fin with red-brown stripes in medial part parallel to fin rays (vs. with red-brown spots and irregular stripes perpendicular to fin rays); yellow anal fin without markings (vs. light blue and occasionally with red-brown spots); anal fin positioned anterior to dorsal fin (preanal length mean 59.8 % SL and predorsal length mean 60.7 % SL vs. posteriorly positioned with 60.9 % SL and 60.2 % SL, respectively, in N. ugandensis); and greater anal-fin base length 22.5–25.9 % SL (vs. 19.3–22.2).

​Subgenus: Zononothobranchius

Species group: N. ugandensis group

​Populations of this species were regarded as belonging to Nothobranchius ugandensis, which species was described by Wildekamp (1994) from collections made near Busesa, north of Lake Victoria, and which species is known from the drainage systems of the upper Nile and Lake Kyoga in central and northern Uganda, as well as in the drainage system of Lake Victoria in south-eastern Uganda and south-western Kenya. Combined morphometric and molecular analyses from populations across Uganda, including representative material from the Albert Nile drainage in western Uganda, shows that populations from the Albert Nile drainage, previously regarded as belonging to N. ugandensis, belong to a distinct species described as N. albertinensis by Nagy, Watters & Bellstedt in Nagy et al. (2020).

Uganda: Albert Nile drainage: shallow remnant pools in seasonal riverbed, 20 km north of Pakwach, 02°36'19" N, 31°23'04" E.

Nothobranchius albertinensis is endemic to seasonal freshwater habitats in north-western Uganda. It is currently known from ephemeral pools and marshes associated with the Albert Nile drainage, as well as small river systems draining into the north-eastern part of Lake Albert.

Upper Nile (522)

​626–728 m

​At the type locality, the water was turbid; the bottom of the pool was not visible. The water had a temperature of 29 °C, the pH was 8.5, and the conductivity was 340 µS (measured by Watters). During another visit at the type locality by Nagy on 9 June 2017, in the early afternoon, the water had a temperature of 34 °C, the pH was 7.8, and the conductivity was 310 µS (Nagy et al. 2020).

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: 50.4 mm SL; MRAC 2019.016.P.0017, holotype, male (Nagy et al., 2020)

Diploid chromosome number 2n = 36, NF = 58, karyotype structure 6m+16sm+14st/a (Krysanov et al., 2023).

Karyotype structure unique in the species group.

​The specific name, albertinensis, -e, is given in reference to the Albertine Rift, in which valley the species is found in the northern Lake Albert basin and extending into the Albert Nile drainage. An adjective derived from the geographical name.

Vulnerable B1ab(iii)+2ab(iii) (Nagy & Watters, 2021)

    Wildekamp, R. H. 1989. 1989. Fisch-Safari in Uganda. Die Aquarien und
Terrarien Zeitschrift, 42: 358-362. [collecting as Nothobranchius sp.]

    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, 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. [taxonomy as Nothobranchius albertinensis, distribution, ecology, phylogeny, systematics]

    Nagy, B. & B. R. Watters. 2021. Nothobranchius albertinensis. The IUCN Red List of Threatened Species: e.T175184725A175184769. [conservation]

    Krysanov, E. Y., B. Nagy, B. R. Watters, A. Sember & S. A. Simanovsky. 2023. Karyotype differentiation in the Nothobranchius ugandensis species group (Teleostei, Cyprinodontiformes), seasonal fishes from the east African inland plateau, in the context of phylogeny and biogeography. Comparative Cytogenetics, 17 (1): 13–29. [chromosomes]