Nothobranchius milvertzi, a new species of killifish from the Lushiba Marsh in the Lake Mweru drainage, Zambia (Teleostei: Cyprinodontiformes: Nothobranchiidae)
Ichthyol. Explor. Freshwaters, Vol. 24, No. 4, pp. 347-360, 9 figs., 3 tabs., April 2014
Nothobranchius milvertzi, new species, is described from ephemeral pools of the Lushiba Marsh floodplains, Lake Mweru drainage system in northern Zambia. It can readily be identified as belonging to the N. taeniopygus speciesgroup of which it shows the diagnostic characters: presence of a broad, light submarginal band on both the caudal as well as the anal fin and a dark distal margin of both fins in males. Nothobranchius milvertzi is distinguished from all other species of this species-group by the unique combination of the following characters in males: caudal fin red with an orange semicircular submarginal band and a wide dark red-brown distal margin in males, head length 29-32 % SL, interorbital width 39-46 % HL, and snout length 18-20 % HL.
The genus Nothobranchius includes about sixty valid species, occurring mainly in river basins subject to seasonal rainfall of eastern and southeastern Africa (Seegers, 1997; Watters, 2009). It is the most species rich and geographically widespread genus of seasonal nothobranchiid killifishes in Africa (Wildekamp, 2004). All known species are annual fishes in their mode of reproduction, living in temporary pools and swamps formed during the rainy season (Skelton, 2001; Watters, 2009). Nothobranchius species are sexually highly dimorphic and dichromatic; males are usually robust and colourful while females are slightly smaller and dull (Wildekamp, 2004). Most of the northern part of Zambia and the adjacent Katanga province, previously called Shaba, of Democratic Republic of Congo are part of the Congo River drainage. Northern Zambia and Katanga has already been identified as a * region with particularly complex phylogeographic patterns in aquatic organisms (Lévêque, 1997), where speciation has been especially active and with a high level of endemism (Balon & Stewart, 1983; Jackson, 1986; Malaisse, 1997; Cotterill, 2005). The area has been the object of several ichthyological studies focused on cyprinodontiform fishes (Poll, 1963, 1976; Wildekamp, 1978; Valdesalici & Amato, 2011). Two of the main tributaries of the Congo River, the Lualaba and the Luapula, host six Nothobranchius species (Valdesalici & Wildekamp, 2004, 2005; Wildekamp, 1978; 2004). The first report of a species of Nothobranchius from Zambia and the adjacent Katanga province was that of Poll (1938) when describing N. brieni on the basis of specimens collected by P. Brien during the preceding year. This remained the only species described from the area for the following forty years (Wildekamp, 1978; Sainthouse, 1985). However, the species name N. brieni was…