THE NOTHOBRANCHIUS SITE

MRAC 76-49-P-55, male, 42.9 mm SL; Tanzania: Morogoro district: swamp pool about 7 km from Kimamba in the to Kilosa, 06°46’30” S, 37°12’30” E; R. H. Wildekamp, 11 Jun 1976, [field code: T 76-5].

MRAC 76-49-P-56-64 (8), MRAC 76-49-P-43-54 (12)

Nothobranchius proganthus differs from all other species of the N. melanospilus complex in possessing lower jaw anteriorly projecting beyond upper jaw (vs. not projecting), pelvic fins medially united in males (vs. bases just in contact, but not united), and presence of three longitudinal series of scales on frontal region (vs. two) (excerpt from Costa, 2019).

Subgenus: Adiniops

Species group: N. melanospilus group

Fundulus melanospilus was established as a species by Pfeffer in 1896 after four female specimens from Longo-Bay, present Ilonga in Tanzania. Furthermore, Pfeffer (1896) also mentioned specimens from the Seychelles. This latter locality is clearly misidentified for Zanzibar (Wildekamp, 1981; Costa, 2012). Ahl (1935) restricted the type locality of the species to Longo-Bay, and the remaining specimens mentioned by Pfeffer (1896) originating from the Seychelles are described in the same work by Ahl (1935) as N. seychellensis.

Nothobranchius seychellensis Ahl, 1935 from Zanzibar (erroneously Seychelles islands) are regarded as synonyms (Wildekamp 1981, 2004).

Costa (2017) redescribed N. melanospilus, and designated lectotype from the specimens originating from Zanzibar.

Based on morphological analyses and minor colour pattern differences, Costa (2019) separated two cryptic species from peripheral parts of the range of N. melanospilus, thus populations found in the upper Wami drainage, including the area around Ilonga, which locality was regarded by Ahl (1935) and by Wildekamp (1981, 2004) as the type locality of N. melanospilus, were described as N. prognathus. However, its status is currently controversial.

Tanzania: Morogoro district: swamp pool about 7 km from Kimamba in the to Kilosa, 06°46’30” S, 37°12’30” E.

This species is endemic to eastern Tanzania. It is known from seasonal pools and swamps in the Tendigo swamp area, Mkata River floodplains, upper Wami River drainage in eastern Tanzania.

Coastal East Africa (564)

372–509 m

Water parameters are as follows: temperature of 23–30°C; pH of 7.1–8.0; conductivity of 100–400 µS; and typically turbid (Watters unpublished data).

N. steinforti - 1%

This species has an annual life cycle.

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

Maximum size reported: 42.9 mm SL; MRAC 76-49-P-55, holotype, male, (Costa, 2019)

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

The specific name is formed from the Latin prognathus (=prognathous), referring to the distinctive lower jaw of the new species that is anteriorly projected slightly beyond the upper jaw. An adjective.

Near Threatened B1b(iii)+2b(iii) (Nagy & Watters, 2021);

    Costa, W. J. E. M. 2019. Two new species of seasonal killifishes of the Nothobranchius melanospilus species complex from the East Africa biodiversity hotspot (Cyprinodontiformes: Aplocheilidae). Vertebrate Zoology, 69 (1): 73–82. [taxonomy as Nothobranchius prognathus]

    Bartáková, V., B. Nagy, M. Polačik, R. Blažek, H. Lamtane & M. Reichard. 2020. Genetic diversity of a widespread annual killifish from coastal Tanzania. BMC Evolutionary Biology, 20: 1, 13 pp. [genetics]

    Nagy, B. & B. R. Watters. 2021. Nothobranchius prognathus. The IUCN Red List of Threatened Species: e.T158619903A158619911. [conservation]