THE NOTHOBRANCHIUS SITE

MRAC 81-59-P-1, holotype, male, 39.1 mm SL; Tanzania: Pool on the north bank of the Ruhoi River, adjacent to the bridge on the road from Kibiti to Ndundu, 21 km north of Ndundu or 18 km south of Kibiti, eastern Tanzania, approx. 07°51' S, 38°58' E; collected by G. Eggers, C. Kasselmann & L. Seegers, 29 Dec 1980.

BMNH 1981.9.4.1-5 (5), MRAC 81-59-P-2-5 (4), SMF 16369-73 (5)

"Nothobranchius eggersi unterscheidet sich von allen bisher beschriebenen Arten der Gattung durch die besondere Zeichnung, eine dunkelrote Marmorierung auf gelblichem bzw. grünem Grund, besonders in den Flossen" (Seegers, 1982).

[Nothobranchius eggersi differs from all other previously described species of the genus by the particular markings, a dark red marbled pattern on yellowish or green basis, especially in the fins.]

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This species occurs as two phenotypes. The blue phenotype has a light blue body with irregular red-brown crossbars; the median fins are light blue with irregular red-brown spots and a white distal margin. The red phenotype has a light blue body with deep red scale borders, creating a reticulated pattern, and irregular crossbars on the posteroventral part of body; the caudal fin is red; the dorsal and anal fins are light blue with extensive irregular dark red markings.

Subgenus: Adiniops

Species group: N. guentheri group

Nothobranchius eggersi was established as a species by Seegers in 1982, and that status has since been accepted by all authors.

"Ein Tümpel am linken Flussufer des Ruhoi, neben der Brücke an der Strasse Kibiti - Ndundu, Ost-Tansania" (Seegers, 1982).

[Tanzania: Pool on the north bank of the Ruhoi River, adjacent to the bridge on the road from Kibiti to Ndundu, 21 km north of Ndundu or 18 km south of Kibiti, eastern Tanzania, 07°51' S, 38°58' E.]

This species is endemic to freshwater habitats in coastal Tanzania. It is known from temporary pools, marshes and ditches in the drainage of the lower Rufiji, lower Ruvu, lower Wami and lower Mligasi river systems in eastern Tanzania.

Coastal East Africa (564)

1–107 m

Personal observation at collecting sites:

Water temperature: 29.5–31.5 °C

pH: 7.18–7.60

TDS: 12–330 ppm

Conductivity: 24–660 µS

N. melanospilus - 62%

N. janpapi - 45%

N. ocellatus - 14%

N. annectens - 13%

N. flammicomantis - 2%

This species has a semi-annual life cycle.

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

Maximum size reported: 39.1 mm SL (MRAC 81-59-P-1, holotype, male)

Diploid chromosome number 2n = 36 (Scheel, 1990), NF 40, karyotype structure 4m+32st/a (Krysanov & Demidova, 2018).

Karyotype structure shared with some members of the subgenus Adiniops. 

The specific name is given in honour of Gerhard Eggers, from Kaarst near Düsseldorf in Germany, for his companionship during two trips to Tanzania, which ultimately led to the discovery of the new species. In addition, during many previous trips to Africa, Mr. Eggers has collected material from plants and animals, in particular fish, and made them generally accessible.

Least Concern (Nagy & Watters, 2019);

Previous assessment: Least Concern (Hanssens & Snoeks, 2006)

​    Seegers, L. 1982. Nothobranchius eggersi n. sp. aus dem Rufiji-Einzug in Tanzania mit Bemerkungen zum Vorkommen von Nothobranchius melanospilus (Pfeffer, 1896) (Pisces, Atheriniformes, Rivulinae). Ichthyologische Ergebnisse aus Tanzania, 1. Revue de Zoologie Africaine, 96 (3): 539–558. [taxonomy as Nothobranchius eggersi]

    Nagy, B. & B. R. Watters. 2019. Nothobranchius eggersi. The IUCN Red List of Threatened Species: e.T60328A47183480. [conservation]

    Watters, B. R., B. Nagy, P. D. W. van der Merwe, F. P. D. Cotterill & D. U. Bellstedt. 2020. Redescription of the seasonal killifish species Nothobranchius ocellatus and description of a related new species Nothobranchius matanduensis, from eastern Tanzania (Teleostei: Nothobranchiidae). Ichthyological Exploration of Freshwaters, IEF-1149, pp. 1–28. [phylogeny]

    Nagy, B., B. R. Watters & A. A. Raspopova. 2021. Nothobranchius nikiforovi, a new species of seasonal killifish from the lower Matandu drainage in south-eastern coastal Tanzania (Cyprinodontiformes: Nothobranchiidae). Zootaxa, 4950 (1): 103–122. [phylogeny]