Figure 2

Phylogeny of xenarthrans and afrotherians illustrating lack of correlation between QA ratio and face length. The phylogeny of xenarthrans (A, after [24]; position of Chlamyphorus after [25]) and afrotherians (B, after [26, 27]) is given with corresponding facial proportions and QA ratios in selected species using graph at right. Gray boxes represent ratio face-to-skull length (bottom scale; higher values indicate a longer face); black diamonds represent ratio of glutamine to alanine in RUNX2 binding site (top scale). Note relative lack of correlation between large (e.g., Myrmecophaga) vs. short- (e.g., Chlamyphorus) faced species. Specimens shown (not to scale) are Myrmecophaga tridactyla (AMNH 1873), Tamandua tetradactyla (ZMB 38396, image reversed), Priodontes sp. (AMNH 1871), Chaetophractus villosus (AMNH 240), Chlamyphorus truncatus (AMNH 5487), Microgale dobsoni (UMZC 5458-B), Tenrec ecaudatus ZMB 90377), and Hemicentetes semispinosus (ZMB 5007).