Description of a New Neolebias (Characiformes; Distichodontidae) from the Upper Zambezi Drainage of Zambia

Abstract

A new distichodontid fish from small streams on the fringes of the Upper Zambezi River floodplain, Zambia, is described. Individuals of the new species, Neolebias lozii n. sp., are small (maximum 18.0 mm SL) and distinguished from all other members of the genus by a series of tall, black vertical bars along the flanks, short caudal peduncle, and broadly rounded, caudal-fin lobes. Neolebias lozii appears to be most closely related to Neolebias (=Dundocharax) bidentatus (Poll, 1967) from the Chicapa River drainage (Zaire basin) of northern Angola. In addition to its unique pigmentation pattern, Neolebias lozii differs from N. bidentatus in having a taller body, a shorter blunter snout, a shorter postorbital head length, shorter predorsal and preanal lengths, broader dorsal and anal fins, and broadly rounded instead of acutely angled caudal-fin lobes. The new species is the only southern African representative of the genus known to occur outside of the Zaire River system. SPECIES of the genus Neolebias Steindachner, 1894, are diminutive fishes of the African characiform family Distichodontidae (Teleostei, Characiformes) that inhabit small streams and swamps. According to Poll and Gosse (1963, 1982), the genus Neolebias contains eight nominal species. Based on a phylogenetic analysis of the Distichodontidae, Vari (1979) synonymized the genera Congocharax Matthes, 1964, and Dundocharax Poll, 1967 with Neolebias to eliminate polyphyletic taxa. Poll and Gosse (1982) challenged Vari's conclusion on the grounds that some skeletal and dentition characters were not given appropriate consideration in the analysis. Recently, Teugels and Roberts (1990) described an additional species, Neolebias powelli, from the Niger River delta. If we accept Vari's taxonomy, N. powelli brings the number of Neolebias species to 11. Here we describe a new species of Neolebias from the Upper Zambezi River drainage of Zambia's Western Province. Prior to this discovery, representatives of the genus were known only from the Zaire and Niger River basins. The new species appears to be most closely allied to Neolebias bidentatus from Angola, a species originally described by Poll (1967) as the sole member of the genus Dundocharax.