THE NOTHOBRANCHIUS SITE

MRAC 2019.016.P.0039, holotype, male, 43.4 mm SL; Tanzania: Lake Victoria basin: Moame system: shallow, circular pools and drainage ditches, and flooded grassy areas adjacent to rice fields, 71 km southeast of Mwanza in the direction of Shinyanga on road B6, or 10 km southeast of Mabuki in the direction of Runere, 03°04'13" S, 33°14'33" E; B. Watters, I. Sainthouse & M. Agnew, 16 May 1993, [field code: Runere TAN 93-13].

MRAC 2019.016.P.0040–0046 (5); MRAC 2019.016.P.0047 (1)

Nothobranchius moameensis belongs to the N. ugandensis species group presenting the following combination of characters in males: body coloration light blue with red to red-brown scale margins; frontal part of head red-brown and throat light blue or red; caudal fin uniform red; and anal fin light blue or yellow with red-brown spotted pattern. Nothobranchius moameensis differs from all other members of the N. ugandensis species group by a light blue anal fin with red-brown dots proximally and medially, and with light blue or yellow distal zone without markings; interorbital width 52–59 % HL (vs. 38–51); and caudal peduncle length 111–121 % of its depth (vs. 96–103 or 122–157). Furthermore, it differs from N. attenboroughi, by greater body depth (31.6–33.2 % SL vs. 25.7–31.0); greater head depth (87.1–94.3 % HL vs. 80.1–86.2); and a dorsal fin positioned anterior to the anal fin (preanal length mean 62.2 % SL and predorsal length mean 60.9 % SL vs. posteriorly positioned with mean values of 59.8 % SL and 60.6 % SL, respectively, in N. attenboroughi).

Subgenus: Zononothobranchius

Species group: N. ugandensis group

Populations of this species were regarded as part of a diverse complex generally lumped into Nothobranchius species ‘Lake Victoria’, from the basin of that lake in central and western Tanzania and south-western Kenya, together with populations from drainage systems in central Tanzania. Combined morphometric and molecular analyses have revealed that populations from the Moame system south of Lake Victoria in northern Tanzania represent a different species, which was described as Nothobranchius moameensis by Nagy, Watters & Bellstedt in Nagy et al. (2020).

Tanzania: Lake Victoria basin: Moame system: shallow, circular pools and drainage ditches, and flooded grassy areas adjacent to rice fields, 71 km southeast of Mwanza in the direction of Shinyanga on road B6, or 10 km southeast of Mabuki in the direction of Runere, 03°04'13" S, 33°14'33" E.

Nothobranchius moameensis is endemic to seasonal freshwater habitats in northern Tanzania. It is currently known from ephemeral pools and marshes associated with the Moame and other smaller river systems south of Lake Victoria in the Moame system (Nagy et al., 2020).

Lake Victoria basin (521)

1160–1169 m

Water parameters based on five observations, measured by Watters and Nagy between 1993 and 2019, were as follows: temperature of 23–32°C; pH of 7.4–9.3; conductivity 120–350 µS; and typically turbid (Nagy et al., 2020).

At some of the collecting localities, Nothobranchius moameensis can be found together with N. ottoschmidti, a species belonging to the N. taeniopygus species group (Nagy et al., 2020).

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: 43.4 mm SL; MRAC 2019.016.P.0039, holotype, male (Nagy et al., 2020)

Diploid chromosome number 2n = 36, NF = 54, karyotype structure 6m+12sm+18st/a (Krysanov et al., 2023).

Karyotype structure and fundamental number unique in the species group.

The specific name, moameensis, -e, is given in reference to the Moame River, in which drainage system this species is found. An adjective derived from the geographical name.

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

    Østergaard, K. 1991. Nothobranchius in Sukumaland. Journal of the American Killifish Association, 24: 202–212. [collecting as Nothobranchius sp. Runere] 

    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, IEF-1129, pp. 1–53. [taxonomy as Nothobranchius moameensis, distribution, ecology, phylogeny]

    Nagy, B. 2020. An expedition around Lake Victoria. Tropical Fish Hobbyist, #744, Sep/Oct 2020, 69 (1): 44–50. [collecting]

    Nagy, B. & B. R. Watters. 2021. Nothobranchius moameensis. The IUCN Red List of Threatened Species: e.T175184932A175184941. [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]