These authors contributed equally to this paper.
Correlates of hyperdiversity in southern African ice plants (Aizoaceae)
Article first published online: 3 DEC 2013
© 2013 The Authors. Botanical Journal of the Linnean Society published by John Wiley & Sons Ltd on behalf of The Linnean Society of London.
This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.
Botanical Journal of the Linnean Society
Volume 174, Issue 1, pages 110–129, January 2014
How to Cite
Valente, L. M., Britton, A. W., Powell, M. P., Papadopulos, A. S. T., Burgoyne, P. M. and Savolainen, V. (2014), Correlates of hyperdiversity in southern African ice plants (Aizoaceae). Botanical Journal of the Linnean Society, 174: 110–129. doi: 10.1111/boj.12117
- Issue published online: 16 DEC 2013
- Article first published online: 3 DEC 2013
- Manuscript Accepted: 24 AUG 2013
- Manuscript Revised: 27 MAY 2013
- Manuscript Received: 20 SEP 2012
- Royal Society (UK)
- South African NRF
- European Commission
- Marie Curie IEF ‘BIRDISLAND’
- Leverhulme Trust
- diversification rates;
- Greater Cape Floristic Region;
- Succulent Karoo
The exceptionally high plant diversity of the Greater Cape Floristic Region (GCFR) comprises a combination of ancient lineages and young radiations. A previous phylogenetic study of Aizoaceae subfamily Ruschioideae dated the radiation of this clade of > 1500 species in the GCFR to 3.8–8.7 Mya, establishing it as a flagship example of a diversification event triggered by the onset of a summer-arid climate in the region. However, a more recent analysis found an older age for the Ruschioideae lineage (17 Mya), suggesting that the group may in fact have originated much before the aridification of the region 10–15 Mya. Here, we reassess the tempo of radiation of ice plants by using the most complete generic-level phylogenetic tree for Aizoaceae to date, a revised calibration age and a new dating method. Our estimates of the age of the clade are even younger than initially thought (stem age 1.13–6.49 Mya), supporting the hypothesis that the radiation post-dates the establishment of an arid environment in the GCFR and firmly placing the radiation among the fastest in angiosperms (diversification rate of 4.4 species per million years). We also statistically examine environmental and morphological correlates of richness in ice plants and find that diversity is strongly linked with precipitation, temperature, topographic complexity and the evolution of highly succulent leaves and wide-band tracheids. © 2013 The Authors. Botanical Journal of the Linnean Society published by John Wiley & Sons Ltd on behalf of The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 174, 110–129.