Explaining global species richness patterns is a “Holy Grail” of ecology and evolution. These richness patterns are often attributed to spatial variation in diversification rates (speciation minus extinction). Surprisingly, prominent studies of birds, fish, and angiosperms reported higher diversification rates at higher latitudes (mismatched with richness). Yet these studies only examined diversification rates at relatively recent timescales. Here, we quantify global richness patterns among lizard and snake species (10,213; 94%) and explore their underlying causes. We found that diversification rates at more recent timescales in squamates also show mismatched patterns of rates and richness. However, diversification rates at deeper timescales were positively related to richness. These observations may help resolve the paradoxical results of previous studies. Remarkably, these diversification patterns are largely unrelated to climate. Instead, higher tropical richness is related to ancient occupation of tropical regions. Thus, these large-scale diversity patterns are only understood by considering climate, deep-time diversification rates, and the time spent in different regions.

This data set contains range shapefiles for the majority of terrestrial squamates globally.  It is an update to GARD 1.0.  Range shapefiles for new species were created using the same methods as version 1.0, described fully in:

Roll, U., Feldman, A., Novosolov, M., Allison, A., Bauer, A., Bernard, R., Bohm, M., Chirio, L., Collen, B., Colli, G.R., Dabul, L., Das, I., Doan, T., Grismer, L., Herrera, F.C., Hoogmoed, M., Itescu, Y., Kraus, F., LeBreton, M., Lewin, A., Martins, M., Maza, E., Meirte, D., Nagy, Z., Nogueira, C.C., Pauwels, O.S.G., Pincheira-Donoso, D., Powney, G., Sindaco, R., Tallowin, O., Torres-Carvajal, O., Trape, J.F., Uetz, P., Vidan, E. Wagner, P., Wang, Y.Z., Orme, D., Grenyer, R. and Meiri, S. 2017. The global distribution of tetrapods reveals a need for targeted reptile conservation. Nature Ecology & Evolution 1: 1677-1682. doi.org/10.1038/s41559-017-0380-7.