1. Center for Macroecology, Evolution, and Climate, Natural History Museum of Denmark, University of Copenhagen, DK-2100 Copenhagen, Denmark;
2. Museum of Vertebrate Zoology & Department of Integrative Biology, University of California, Berkeley, California 94720;
3. Center for Macroecology, Evolution, and Climate, Department of Biology, University of Copenhagen, DK-2100 Copenhagen, Denmark;