Electrophoretic analysis of the Cordylus cordylus species group in the southwestern Cape, South Africa

Abstract

Abstract Allozyme frequencies were used to test a proposed hypothesis on the evolution and biogeography of the taxa in the Cordylus cordylus species group in the southwestern Cape. The population structures of the three species were also analysed. Low levels of heterozygosity were found in C.oelofseni and C.niger which have small distribution ranges, and intermediate levels in C.cordylus which has an extensive distribution range. Genetic distances were calculated among species and approximate times of divergence were estimated. These divergence times do not agree with the times suggested by other authors. Both phenetic and cladistic approaches were used to assess relationships among the three species. The results suggest that C.niger is monophyletic, but that C.oelofseni is polyphyletic, the population at Landdroskop in the Hottentots Holland Mountains being closer to C.cordylus than to the remaining C.oelofseni populations. It is demonstrated that average genetic distance is not a reliable aid in decisions regarding the taxonomic status of C.oelofseni. Proposed relationships within, as well as monophyly of this group, remain unconfirmed as conflicting results were obtained.