Fig. 14.

Contentious skeletal elements of the chameleon mesopodium. While broadly considered to be a sesamoid, we see the pisiform segmenting from the ventrolateral margin of the ulnare, underscoring its origin from the primary skeleton (a). In ‘true chameleons’ we see what appear to be ectopic and possibly de novo elements on the posterior tarsus. b The two distal elements are actually the tibiale and the intermedium which become shifted distally toward distal tarsals by the enlarged distal epiphysis of the tibia. c Despite the highly modified autopodium, chameleons retain distal tarsal 5