Table 2

Limb developmental events scored in this analysis

Forelimb event

Hindlimb event

External Form

A. bud first distinct

K. bud first distinct

B. AER appears

L. AER appears

C. digital plate crenation (fossae separating digits dorsally)

M. digital plate crenation (fossae separating digits dorsally)

Chondrogenesis

D. humerus appears

N. femur appears

E. ulna appears

O. fibula appears

F. proximal carpal (ulnare) appears

P. proximal tarsal (fibulare) appears

G. carpal distal to ulnare appears

Q. tarsal distal to fibulare appears

H. metacarpal appears

R. metatarsal appears

I. proximal phalanx appears

S. proximal phalanx appears

J. distal phalanx appears

T. distal phalanx appears

Elements in the same horizontal row in the hand and foot are considered serially homologous for the purposes of this study.

Bininda-Emonds et al. BMC Evolutionary Biology 2007 7:182   doi:10.1186/1471-2148-7-182