THE NOTHOBRANCHIUS SITE

MRAC 2019.016.P.0027, male, 43.3 mm SL; Tanzania: upper Ruaha drainage: extensive, shallow pools on both sides of the road at a culvert, 1 km southwest of the railroad at Itigi, 05°41'56" S, 34°28'48" E; collected by B. Watters, B. Cooper & W. Bishopp, 20 May 2003 [field code: Itigi TAN 03-8].

MRAC 2019.016.P.0028–0035 (8)

Nothobranchius itigiensis 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; anal-fin base light blue or yellow with red-brown spotted pattern. Nothobranchius itigiensis differs from all other members of the N. ugandensis species group by an anal fin yellow with red-brown spots proximally, that are merged medially to a pattern parallel to fin rays and may be fused distally to form a slender marginal band; caudal peduncle length 14.9–15.7 % SL (vs. 16.1–23.8), and 96–103 % of its depth (vs. 111–157); and head width 68–72 % of its depth (vs. 73–83) (Nagy et al., 2020).

Subgenus: Zononothobranchius

Species group: N. ugandensis group

Nothobranchius itigiensis was described by Nagy, Watters & Bellstedt in Nagy et al. (2020).

Tanzania: upper Ruaha drainage: extensive, shallow pools on both sides of the road at a culvert, 1 km southwest of the railroad at Itigi, 05°41'56" S, 34°28'48" E.

Nothobranchius itigiensis is endemic to seasonal freshwater habitats in central Tanzania. It is currently known from ephemeral pools and marshes associated with the upper Ruaha drainage and the Bahi Swamp area. The type locality, near Itigi, is associated with marshy terrain drained by the Mlumbi and Kisigo streams in the extreme north-western headwaters of the Ruaha River system.

Southern Eastern Rift (566)

836–1303 m

At the type locality, the water was turbid, the bottom of the pool not visible. The water temperature of the type locality measured at 5 pm was 24 °C, the pH was 8.4, and the conductivity was 500 µS. Water parameters of another observation that can be associated with this species are as follows: temperature of 25°C; pH of 7.9; conductivity of 200 µS; and turbid (Nagy et al., 2020).

At the type locality, N. itigiensis is syntopic with N. angelae and N. neumanni, whereas, at two other locations, associated with the Bahi wetland area, it is syntopic with N. neumanni only.

This species has an annual life cycle.

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

Maximum size reported: 43.3 mm SL; MRAC 2019.016.P.0027, holotype, male (Nagy et al., 2020)

Diploid chromosome number 2n = 36, NF = 60, karyotype structure 8m+16sm+12st/a (Krysanov et al., 2023).

Karyotype structure and fundamental number unique in the species group.

​The specific name is given in reference to Itigi township in central Tanzania, near which place the type locality is situated. An adjective derived from the geographical name.

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

    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 itigiensis, distribution, ecology, phylogeny, systematics]

    Nagy, B. & B. R. Watters. 2021. Nothobranchius itigiensis. The IUCN Red List of Threatened Species: e.T175184906A175184918. [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]