THE NOTHOBRANCHIUS SITE

MRAC 77-16-P-28, holotype, male, 40.6 mm SL; Tanzania: pool along the main road from Morogoro to Dar-es-Salaam between the bridge over the Ruvu and Kwaraza village, approx. 06°41.9' S, 38°42.3' E; collected by J. Lourens, Jul 1976, [field code: T 76-8].

MRAC 77-16-P-29 (1), 77-16-P-30-33 (4)

Nothobranchius lourensi males have blue-green scales with dark brown posterior scale margins, creating a reticulation on the body, with a chevron pattern on the posterior part of trunk; the anal and caudal fins have a striped pattern; the caudal fin has a light blue to yellow subdistal band and a black distal margin. The female has a grey-brown body colouration, with a dark grey chevron pattern on the posterior half of trunk.

Subgenus: Aphyobranchius

Species group: N. lourensi group

Nothobranchius lourensi was established as a species by Wildekamp in 1977, and that status has since been accepted by all authors.

"Tümpel entlang der Hauptstraße Morogoro-Dar es Salaam, zwischen der Brücke über den Ruvu und Kwaraza, Tansania."

Pool along the main road from Morogoro to Dar-es-Salaam between the bridge over the Ruvu and Kwaraza village, Tanzania.

approx. 06°41.8' S, 38°42' E, (field code T 76-8)

[same type locality as N. janpapi]

This species is endemic to seasonal freshwater habitats in coastal Tanzania. It is known from temporary swamps in the drainages of the Kilombero, Ruvu, Mbezi and lower Rufiji rivers, eastern Tanzania.

Coastal East Africa (564)

20–303 m

Water parameters (Wildekamp, 1977):

Water temperature: 27 °C; pH: 6.5–7.0.

Water parameters based on Watters (personal data) are as follows: temperature of 24–31°C; pH of 6.5–8.0; conductivity of 20–160 µS; and typically turbid (Nagy & Watters, 2019).

N. geminus - 32%

N. kilomberoensis - 27%

N. janpapi - 23%

N. melanospilus - 23%

N. fuscotaeniatus - 9%

N. luekei - 5%

N. rubripinnis - 5%

N. ruudwildekampi - 5%

Populations of this species in near-shore coastal regions have a semi-annual life cycle whereas those further inland, as in the Kilombero area, are more likely to be annual.

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

Maximum size reported: 40.6 mm SL (MRAC 77-16-P-28, holotype, male) 

Diploid chromosome number 2n = 32 (Scheel, 1981; Scheel, 1990); ​diploid chromosome number 2n = 27 for males and 2n = 28 for females (Simanovsky et al., 2018); karyotype structure 7m+20st/a for males and 6m+22st/a for females (Krysanov & Demidova, 2018).

Diploid chromosome number and karyotype structure unique in the genus.

The specific name is given in honor of Jan Lourens, working at that time for the United Nations Development Programme in Tanzania, and discoverer of the species.

Near Threatened B2ab(iii) (Nagy & Watters, 2019);

Previous assessment: Vulnerable D2 (IUCN Red List 2006)

    Wildekamp, R. H. 1977. Nothobranchius lourensi sp. nov. und Nothobranchius janpapi sp. nov., zwei neue Rivulinen aus Ost Afrika. Das Aquarium, 11 (98): 326–331. [taxonomy as Nothobranchius lourensi]

    Nagy, B. & B. R. Watters. 2019. Nothobranchius lourensi. The IUCN Red List of Threatened Species 2019: e.T61288A47243786. [conservation]