THE NOTHOBRANCHIUS SITE

MRAC 2018.015.P.0014, male, 54.7 mm SL; Tanzania: residual pool at a bridge over the Manonga River, about 1 km south of Walezo village or 31 km north of Nzega, on Shinyanga-Nzega road, 03°57.8' S, 33°08.5' E; B. Watters, B. Cooper & O. Schmidt, 7 Jun 2000, [field code: Manonga River TAN 00-8].

MRAC 2018.015.P.0015, MRAC 2018.015.P.0016-0019 (4), MRAC 2018.015.P.0020, MRAC 2018.015.P.0021, MRAC 2019.005.P.0001-3 (3)

Nothobranchius ottoschmidti is distinguished from all other species of the genus by the following characters in males: body coloration light blue to blue-green with red-brown to grey-brown scale margins; anal fin light brown to yellow-grey with irregular red-brown to brown spots proximally, followed by a narrow brown to red-brown submedial band, a slender cream, yellow or light brown medial band with red-brown spots on the membrane, and a broad black distal band; caudal fin light grey or brown with small red-brown spots proximally, a slender semitranslucent grey subdistal band and a narrow irregular dark grey to black distal band; pelvic fin light blue-grey in basal zone, with broad yellow medial band and narrow black distal band. Furthermore, it differs from the other members of the N. taeniopygus species group in central and western Tanzania by a head width 67-73 % HL (vs. 54-66); and caudal peduncle length 121-130 % of its depth (vs. 119 and 132-169). (Watters et al., 2019)

Subgenus: Zononothobranchius

Species group: N. taeniopygus group

​Following its discovery in 1940 by Vanderplank, populations representing this species were regarded by Wildekamp (1990) as variants of N. taeniopygus, based on some general similarities of colour pattern with that species, although lacking in the prominent white subdistal band in the caudal fin.

Since the redescription by Wildekamp (1990), many more populations of members of the N. taeniopygus group across a wide distribution range in western and central Tanzania have been found. These resulted in the name N. taeniopygus or N. aff. taeniopygus being attached to various populations, and notable differences, primarily in colour pattern, led to the informal designation of numerous ‘phenotypes’ by Wildekamp (2004).

Populations of this species had been regarded as associated to ‘phenotype 2’ (Wildekamp 2004). Morphometric and molecular analyses confirmed the distinction from N. taeniopygus and the species was described as N. ottoschmidti by Watters et al. in 2019.

Tanzania: residual pool at a bridge over the Manonga River, about 1 km south of Walezo village or 31 km north of Nzega, on Shinyanga-Nzega road, 03°57.8' S, 33°08.5' E.

This species is endemic to north-central Tanzania. It is known from seasonal pools and marshes associated with the Wembere and Manonga river systems, including the Mhwala and Nyahua tributaries; the Igombe and Kigosa river components of the upper, eastern and northeastern parts of the Gombe/Malagarasi system; and smaller stream systems draining into Lake Victoria in the Mwanza area, including the Maome River. The type locality is situated in the Manonga drainage.

Lake Victoria basin (521)

Malagarasi–Moyowosi (543)

Southern Eastern Rift (566)

1035–1298 m

Water parameters are as follows: temperature of 20–30°C; pH of 6.7–8.6; conductivity of 40-400 µS; and turbid (Nagy & Watters, 2020).

N. neumanni - 8%

N. hoermanni - 6%

N. torgashevi - 6%

N. moameensis - 3%

N. serengetiensis - 3%​

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: 55.4 mm SL; MRAC 2018.015.P.0016-0019, paratype, male, (Watters et al., 2019)

​Karyotype structure unique in the genus (Krysanov, pers. comm.).

The specific name is given in honour of Otto Schmidt, a keen birder and fish enthusiast, for his long-time and significant contributions to the study of fishes of the genus Nothobranchius. A noun in genitive.

Least Concern (Nagy & Watters, 2020)

    Vanderplank, F. L. 1940. A study of Nothobranchius taeniopygus in its natural habitat. The Aquarist, 10: 247–249.​ [biology as seasonal life cycle, ecology]

    Østergaard, K. 1991. Nothobranchius in Sukumaland. Journal of the American Killifish Association, 24 (4–6): 202–212. [collecting]

    Watters, B. R., B. Nagy, P. D. W. van der Merwe, F. P. D. Cotterill & D. U. Bellstedt. 2019. Review of the Nothobranchius taeniopygus species group from central and western Tanzania with descriptions of five new species and redescription of Nothobranchius taeniopygus (Teleostei: Nothobranchiidae). Ichthyological Exploration of Freshwaters, IEF-1110, pp. 1–41. [taxonomy as Nothobranchius ottoschmidti, systematics, distribution, genetics, ecology]

    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. 2020. Nothobranchius ottoschmidti. The IUCN Red List of Threatened Species: e.T156302239A156302249 [conservation]