Barbus radiatus, sometimes called the "Redeye barb," is a wide-ranging species and a member of Lake Malawi's shoreline fauna of small barbs (see discussion of distribution and synonymy below). FishBase provides a few details of its biology: "Prefers marshes and marginal vegetation of streams, rivers and lakes. Active in subdued light and at night.... Feeds on invertebrates.... Max. size: 12.0 cm SL."
Jubb (1967) describes the coloration of South African specimens thus:
Preserved individuals of B. radiatus can be distinguished immediately from all other small barbs in the Malawi fauna, if one has a good hand lens or low-power microscope. It is the only species in the region with "...well developed sensory pitlines covering the head" (Stewart, 1977: 120). An excellent drawing of the pitlines is given by Jubb (1967, fig. 115). Because of this trait, the fish belongs to the Barbus subgenus Enteromius (previously known under the junior synonym Beirabarbus). In addition, B. radiatus is recognizable by the combination of (1) a flexible, unenlarged, unserrated last unbranched dorsal fin ray and (2) the absence of any spots or distinct, wide stripe along the body (modified from Jackson, 1961: 595).
Barbus radiatus occurs in its typical form from Uganda through the region west of Lake Malawi and south to the Limpopo River in South Africa. [In Malawi, B. radiatus is known at least from 20 specimens collected on the lakeshore at Deep Bay and Bar House by Christy (Stewart, 1977: 115).] Populations throughout the Congo basin were formerly recognized as a separate subspecies, B. radiatus aurantiacus. However, Stewart (1977) performed a detailed morphological analysis of populations over the entire range of the species. He reported that the "...results indicate a populational mosaic of highly variable morphs rather than two discrete, allopatric morphs." Therefore, Stewart synonymized B. r. aurantiacus with B. r. radiatus, so that the species is now simply called Barbus radiatus throughout its range. (FishBase, for some reason, still recognizes both subspecies.) Synonyms of B. radiatus at the species level seen in the Malawi literature are B. bangwelensis (often misspelled banguelensis) and B. rogersi.
The above color painting by Elizabeth Tarr is copyright © by the South African Institute for Aquatic Biodiversity (formerly known as the J.L.B. Smith Institute of Ichthyology). It is reproduced here from Skelton (1993) with the kind permission of Prof. P.H. Skelton.
The illustration below is by Hilda M. Jubb, from Jubb (1967), and is used here through the permission of Mr. A. T. Balkema of A. A. Balkema Publishers, Rotterdam.
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|Last Update: 13 October 2000
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