Evidence for a Polyphyletic Origin of the Piciformes

Despite two recent anatomical studies to the contrary, the order Piciformes appears to be polyphyletic.The structure of the zygodactyl foot in the Galbulae is very distinct from that in the Pici, and no unique shared derived characters of the tarsometatarsus have been demonstrated for these two taxa.The supposedly three-headed origin of M. flexor hallucis longus shared by the Galbulae and Pici is doubtfully homologous between the two groups, leaving only the Type VI deep flexor tendons as defining the order Piciformes.This condition is probably a convergent similarity.Evidence is presented supporting a close relationship between the Galbulae and the suborder Coracii and between the Pici and the Passeriformes.There are fewer character conflicts with this hypothesis than with the hypothesis that the Piciformes are monophyletic.Problems concerning fossil taxa are also addressed.