ML phylogram demonstrating the short internodes at the base of Neoaves and highlighting certain extreme examples of rate variation across avian lineages. The phylogenetic tree was rooted to crocodilian outgroups (not shown). Branch colors represent major clades supported in this study: land birds (green), charadriiforms (yellow), water birds (blue), core gruiforms and cuckoos (gray), apodiforms and caprimulgiforms (brown), galloanserae (orange), and paleognaths (purple). Scale bar indicates substitutions per site.
Image: SJ Hackett et al. 2008. DOI: 10.1126/science.1157704.