Fig. 18

Phylogenetic reversal to a ‘typical’ lizard conformation of the autopodia. Despite retaining the cleft, an increase in mesopodial elements leads to increase wrist flexion in higher chameleons. Concomitant with the increase in the number of carpal and tarsal elements, we see a bifurcation where the syndactylous bundles are almost 180° separate in the early diverged lineages (‘leaf chameleons’; Brookesia (a, b), Rieppeleon (c, d), and Rhampholeon (e, f)) with the angle decreasing in Bradypodion (g, h, h’). ‘True chameleon’ syndactylous bundles shift toward the distal midline as is present in the basal squamate plan (with the cleft remaining as the constraint). While Chamaeleo (i-j) show an anteromedial transition of digit bundles, Furcifer (k, l) and Trioceros (m, n), the taxa with greater number of carpal and tarsal elements in this study, exemplify this the best through a greatly reduced angle between syndactylous bundles as digits move closer together along the distal midline. FL: refers to Forelimb with HL: referring to hindlimb. The numbers associated with each lineage on the phylogeny correlate to the same order of illustrations from Fig. 15 and represent formulae for number of elements present in the mesopodium in association with a representative image for autopodial morphology of a preserved specimen. FL: X/X refers to the number of elements in the two mesopodial rows while FL: X/X(X) refers to the two mesopodial rows with the number in parentheses representing the presence or absence of the sesamoid of the fibularis brevis. No centralia are present in chameleons, which would have made the standard 3 rows of mesopodial elements. Genera in “<>” are currently recognized taxa, but were specimens were not obtained in this study