Interactions between Xenopus species (Anura Pipidae)

Abstract

The patterns of geographical distribution shown by the species of Xenopus (Anura Pipidae) are briefly reviewed; some areas of sympatry are identified and various implications are discussed. The potential exchange of parasite infections between host species is facilitated in areas of sympatry. However, evidence from the host specificity of monogenean, cestode and nematode parasites shows that, despite the sharing of habitats, several Xenopus may maintain species-specific infections. The disjunctions in the host distribution of these parasites corresponds with genome duplication in the series of Xenopus species. Sympatry facilitates hybridisation. In South Africa, interbreeding of X. gilli Rose & Hewitt and X. laevis (Daudin) gives rise to gene introgression and, potentially, to polyploidisation. In Central Africa, hybridisation and polyploidisation have been important factors in evolution; the genus contains an allopolyploid series with species possessing 2n = 20, 36, 72 and 108 chromosomes. There is evidence of a major change in species distributions in one area of sympatry. X. laevis bunyoniensis Loveridge was abundant in lakes of SW Uganda in 1913-1939, but apparently has since been totally replaced by X. vestitus Laurent and X. wittei Tinsley et al., species which were previously absent from the lakes. The replaced bunyoniensis is unknown outside this area and may now be near to extinction. © 1981 Taylor & Francis Group, LLC.