Nothobranchius brieni

• Both Bell-Cross and Scheel based their opmwn on the N. brieni phenotype, as published in van den Nieuwenhuizen's photos and this according the first identification given by Poll of the Likasi-Lubumbashi aquarium material. Observations on the type material of N. brieni in the Tervuren museum convinced me that this is without doubt a valid species with characteristic morphological features and colour pattern, the light lobe in the lower part of caudal being one of the most remarkable distinguishing marks. Our observations and results then were compared to other Nothobranchius-material from Shaba and from the Tanzanian central plains and to the available literature. Of great value to this tudy was without doubt the fact that Prof. Poll placed all his study material and notes concerning the Shaba Nothobranchius at the disposal of the present author, for which I am very grateful. J ubb already pointed out the importance of the colour pattern for species distinction in the genus Nothobranchius, as based on individual recognition. Scheel (pers. com.) has the opinion that species separation in Nothobranchius based on this evidence, is not tenable, because a Nothobranchius male will pair with any female he encounters and very often the female is willing to cooperate if she is ripe. The present authors opinion is that the differences in colour pattern indeed play a vital role in the speciation of these morphologically closely related species and may lead to a species recognition. Next to this it has to be said that circumstances in the wild never can be compared with the artificial aquarium conditions. Differences in colour pattern are most likely the results of a simultaneous but separate evolution and where two or more species can occur together this was achieved in a different time rate. The separate evolution has led to a genetic barrier, between these sympatric species. Preliminary results in interbreeding different Nothobranchius species living sympatric in the wild, always led to an interruption in the early stages of egg development, what resulted in the death of the embryo. Poll described N. brieni after 24 specimens collected by Prof. Brien in May 1937 in some pools connected to the Lualaba river, in the neighbourhood of Bukama. His description gives a good reproduction of the morphological features of this species and a good impression of the characteristic colour pattern of which the light triangular lobe in the lower part of the caudal is the most striking. N. brieni was also found by G.F. de Witte in the Sanga river and near Mabwe, both collecting sites being close to the lake Upemba, in the Upemba National Park also belonging to the Lualaba drainage, about
• km northeast ofBukama. The determination of this de Witte material was done by Poll (Poll, 1976). Although the preserved Upemba specimens, show minor differences in colour and colour pattern, these do not justify a preliminary division into subspecies. Jackson in 1961 was the first who reported the collecting of N. brieni, from another locality, nl. from Kapalala, in the Luapula-Bangweulu
• Redescription of Nothobranchius brieni Poll 1938, and the description of three new Nothobranchius species from the Province of Shaba, Zaire R.H. Wildekamp and Germert Nederlands 136

• More on the search for Nothobranchius brieni Béla Nagy 2

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