Number of taxa sampled per family or subfamily.

Families are listed in order according to Fig 1. For the taxonomy of families and subfamilies, we use Adalsteinsson et al, [26] for Anomalepididae and Leptotyphlopidae, Pyron and Wallach [29] for Gerrhopilidae, Typhlopidae, and Xenotyphlopidae, Pyron et al [30] for Booidea, and Pyron et al [15] for Alethinophidia. The number of species per clade was taken from The Reptile Database (http://www.reptile-database.org/) on 10/01/2015. Percentages of the number of species sampled do not include taxa not assigned to species status. Paraphyletic taxa are included under their traditional family and/or subfamily. In the Total cell for total number of species, the number not in parentheses equals the sum of the values in the table and the number in the parentheses equals the number returned when a search for Serpentes is conducted in The Reptile Database. Percentage for total number of species sampled is based on 3566 species.