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Citation for Study 15509

About Citation title: "Topography as a Driver of Cryptic Speciation in the High-Elevation Cape Sedge Tetraria Triangularis (Boeck.) C. B. Clarke (Cyperaceae: Schoeneae).".
About Study name: "Topography as a Driver of Cryptic Speciation in the High-Elevation Cape Sedge Tetraria Triangularis (Boeck.) C. B. Clarke (Cyperaceae: Schoeneae).".
About This study is part of submission 15509 (Status: Published).

Citation

Britton M.N., Verboom G.A., & Hedderson T. 2014. Topography as a Driver of Cryptic Speciation in the High-Elevation Cape Sedge Tetraria Triangularis (Boeck.) C. B. Clarke (Cyperaceae: Schoeneae). Molecular Phylogenetics and Evolution, .

Authors

  • Britton M.N.
  • Verboom G.A.
  • Hedderson T.

Abstract

Since some speciation mechanisms are more likely to generate morphological disparity than others, the general failure of vascular plant taxonomists to recognize cryptic diversity may bias perceptions about speciation process in plants. While the exceptional floristic richness of the South African Cape has largely been attributed to adaptive divergence (?ecological? speciation), a combination of climatic dynamism and complex topography has likely provided ample opportunities for ?non-ecological? vicariant speciation, a mechanism which is perhaps more likely to produce cryptic species. We explore the role of topography as a driver of ?non-ecological? speciation in the high-elevation sedge Tetraria triangularis. Within this species, molecular and morphological data reveal five cryptic or semi-cryptic lineages of Miocene-Pliocene age which qualify as evolutionary species. At least three of these maintain their distinctness in sites of sympatry, identifying them as biological species. Negligible range overlap, and the identification of topography as a significant predictor of range turnover, identifies speciation as allopatric and a result of impeded gene flow across low-elevation topographic features. Weak morphological and ecological divergence implies a limited role for adaptive divergence in powering speciation, with character displacement in sympatry possibly arising as a consequence of interspecific competition. Although we cannot exclude a role for disruptive selection in species differentiation, we identify isolation of populations on topographically separated mountains as the principal motor of speciation. We suggest that the importance of topography in the genesis of Cape floristic diversity has been inadequately acknowledged.

Keywords

allopatric; 1 Cape Floristic Region; character displacement; climate 2 change; peripatric; vicariant

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  • Canonical resource URI: http://purl.org/phylo/treebase/phylows/study/TB2:S15509
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