Bile salts of Squamata. The bile salt variation of lizards is overlaid on a tree that represents a summary of current knowledge of squamate phylogeny based on molecular data. Groups of squamates are color-coded following the nomenclature in the review by Hedges and Vidal . Major bile salts are those constituting more than 50% of total biliary bile salts. Minor bile salts account for less than 50% but more than 10% of total bile salts. The bile salts of Iguania (group A) are dominated by 5α (allo) bile acids. The C27 bile acids of species within Anguimorpha (group B) are almost entirely varanic acid. The bile salts of Laterata (group C) are mainly CA with minor fractions of alloCA in some species. The bile salts of species sampled within Scinciformata showed the most diversity of any of the five squamate groups surveyed, with some species having mainly varanic acid (C27 bile acid) and others having mainly alloCA. Species within Gekkota (group E) had mainly CA and CDCA as major bile salts. Abbreviations: alloCA, allo (5α)-cholic acid; CA, cholic acid; CDCA, chenodeoxycholic acid.