1. Instituto de Ecología, Universidad Nacional Autónoma de México, México D.F. 04510, México.
2. Department of Biology, Stanford University, Stanford, CA 94304, USA.
3. Department of Integrative Biology and Museums of Paleontology and Vertebrate Zoology, University of California, Berkeley, Berkeley, CA 94720–3140, USA.
4. Estación de Biología Chamela, Instituto de Biología, Universidad Nacional Autónoma de México, Jalisco 48980, México.
5. Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA.
6. Department of Biology, University of Florida, Gainesville, FL 32611–8525, USA.