Fig. 3

Simplified phylogeny of synapsids demonstrating how the definition provided by Kielan-Jaworowska et al. (2003; the common ancestor of Sinoconodon, morganucodontans, monotremes, marsupials, and placentals, plus any species nested within this group) delimits mammals. The definition uses patterns of common ancestry found in the phylogeny to denote which animals belong to the group Mammalia and which animals fall outside of that group. Names shown in bold are those used in the definition of Mammalia