Shifting sands and shifty lizards

Molecular phylogeny and biogeography of African flat lizards (Platysaurus)

Ian A W Scott, J. Scott Keogh*, Martin J. Whiting

*Corresponding author for this work

Research output: Contribution to journalArticle

28 Citations (Scopus)

Abstract

The African flat lizard genus Platysaurus is widely distributed on rock outcrops in southern Africa and is found both east and west of the Kalahari Desert and between major river drainage systems. We assembled a molecular phylogeny for the genus in order to test several biogeographic hypotheses. Sequence data were obtained from 29 specimens representing 14 taxa of Platysaurus that span the geographic range of the genus. We targeted a fragment of the mitochondrial genome comprising the 3′ half of the ND4 gene and most of the flanking tRNA-HSL cluster. The edited alignment comprised 864 characters, of which 479 (55%) were variable and 461 (96%) parsimony informative. Overall, the phylogeny was well resolved and supported by high bootstrap values. Four major clades were identified comprising two to seven species: P. mitchelli and P. maculatus maculatus from the north-eastern range of the genus; P. broadleyi and P. capensis from the western range; P. imperator, P. torquatus, and P. intermedius rhodesianus; P. i. intermedius, P. monotropis, P. minor, P. i. nigrescens, P. lebomboensis, P. i. wilhelmi, and P. o. orientalis. Platysaurus has been suggested to represent a recent adaptive radiation where rapid speciation was fuelled by population fragmentation brought on by vicariant events and possibly divergent sexual selection. The traditional explanation for the radiation of the genus is that the eastern migration of the Kalahari sands fragmented populations in the Plio-Pleistocene, resulting in conditions favorable for speciation. Our genetic data strongly suggests that many of the speciation events in Platysaurus already had occurred prior to the Plio-Pleistocene. Moreover, vicariant events associated with the formation of the major river systems played an additional role in the evolution and distribution of Platysaurus species. Our topology displays long internodes and long terminal branches, suggesting that the radiation is much older than previously believed.

Original languageEnglish
Pages (from-to)618-629
Number of pages12
JournalMolecular Phylogenetics and Evolution
Volume31
Issue number2
DOIs
Publication statusPublished - May 2004
Externally publishedYes

Keywords

  • Adaptive radiation
  • Kalahari Desert
  • ND4
  • Phylogeography
  • Reptile
  • Sub-Saharan Africa

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