Does Serranochromis altus (Teleostei: Cichlidae) exist in the Okavango Delta, Botswana?

  • FH van der Bank
  • M Wink
  • M Soekoe
  • N Smit

Abstract

Two possibly synonymous fish species in the Okavango Delta, Botswana, Serranochromis altus and S. angusticeps, were compared. Ecological data, morphometrics, meristics, allozymes, and genomic fingerprints — generated with six Inter-Simple Sequence Repeat (ISSR) analyses, and DNA barcoding primers — were compared for both species and individuals with intermediate diagnostic characters. Serranochromis altus was the largest species, having the greatest number of anterior teeth rows, whereas S. angusticeps was the smallest with the lowest number of anterior teeth rows. The intermediate group, with overlapping characteristics, had intermediate  body size and teeth row numbers. Morphometric comparisons of mass with the combined individuals’ growth (standard length) showed a high positive correlation (r2 = 0.873). Allozyme analysis of individuals revealed no fixed allele differences, minute differentiation (average FST = 0.018) and high gene flow (NeM = 7.672) between the species. No hybrizymes were found. Allozyme data indicated that these ‘species’ are part of a single, panmictic population, which was confirmed by ISSR analysis and fish DNA barcoding. Genetic and interspecific divergence in allometry between S. altus and S. angusticeps were non-significant. It was initially thought that these fishes represented different life stages of S. angusticeps. However, we found fish of different sizes, yet with similar ages, representing both species. More accurate age/size and other molecular analyses are required in order to determine if these represent different life stages of S. angustiuceps.

African Journal of Aquatic Science 2009, 34(1): 57–68

Author Biographies

FH van der Bank
Department of Zoology, Kingsway Campus, University of Johannesburg, PO Box 524, Auckland Park 2006, South Africa
M Wink
Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, INF 364, 69120, Heidelberg, Germany
M Soekoe
Department of Zoology, Kingsway Campus, University of Johannesburg, PO Box 524, Auckland Park 2006, South Africa
N Smit
Department of Zoology, Kingsway Campus, University of Johannesburg, PO Box 524, Auckland Park 2006, South Africa
Section
Articles

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eISSN: 1727-9364
print ISSN: 1608-5914