DIVERSITY AND NICHE EVOLUTION ALONG ARIDITY GRADIENTS IN NORTH AMERICAN LIZARDS (PHRYNOSOMATIDAE)
Article first published online: 8 FEB 2013
© 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.
Volume 67, Issue 6, pages 1715–1728, June 2013
How to Cite
Wiens, J. J., Kozak, K. H. and Silva, N. (2013), DIVERSITY AND NICHE EVOLUTION ALONG ARIDITY GRADIENTS IN NORTH AMERICAN LIZARDS (PHRYNOSOMATIDAE). Evolution, 67: 1715–1728. doi: 10.1111/evo.12053
- Issue published online: 4 JUN 2013
- Article first published online: 8 FEB 2013
- Accepted manuscript online: 18 JAN 2013 08:08AM EST
- Manuscript Accepted: 23 DEC 2012
- Manuscript Received: 9 AUG 2012
- National Science Foundation. Grant Number: 0334966
- species richness
Deserts occupy approximately 12% of the Earth's land surface, and are thought to have species poor but highly specialized biotas. However, few studies have examined the evolutionary origins of desert biotas and of diversity patterns along aridity gradients. Further, it is unclear if species occurring in more extreme conditions on a given niche axis (i.e., precipitation) are more specialized for those conditions (i.e., have narrower niche breadths). We address these questions here using a time-calibrated phylogeny and climatic data for 117 species of phrynosomatid lizards. Phrynosomatids are the most species-rich family of lizards in North America, and are found from deserts to rainforests. Surprisingly, we find that phrynosomatids have higher richness in more arid environments. This pattern occurs seemingly because they have been present in more arid habitats longer (∼55 million years), and lineages in mesic environments are recently derived from more arid-dwelling ancestors. We find little support for the hypothesis that species in more extreme environments are more specialized. Instead, many desert-dwelling species are broadly distributed, and species in the most mesic environments have the broadest niche breadths. In summary, phrynosomatids offer a counterexample to the idea that arid regions are inhabited by a small number of recent and highly specialized lineages.