Figure 4. Character history of the width of the centrale bone compared to the character history of grasping abilities.

Left tree: character history of the width of the centrale bone. The most parsimonious state for the common ancestor is an intermediate value (green range). The narrowest centrale bone appears independently in Physignatus sp. and Tropidurus sp. (extreme blue on the color gradient), followed by Anolis sp. and Iguana sp. Gekkota also tend to exhibit narrow centrale bones, although not the narrowest. Gymnophthalmidae and Teiidae show a trend of intermediate to high values; including Prionodactylus sp. that has the widest centrale bone in the phylogenetic tree (extreme red on the color gradient). Anguimorpha and Iguania show a trend toward narrow centrale bones, with the exception of Stenocercus sp., which has a wider centrale. Right tree: character history of grasping abilities. The most parsimonious state for the common ancestor is ambiguous. This character shows three independent origins in the tree: Tropidurus sp., Anolis sp., and Gekkota. In this last case, grasping ability is a synapomorphy of the group.