Synthetic phylogeny of testudinatans highlighting many of the species and clades mentioned in the text. Based mainly on Joyce (2017), Sterli et al. (2021), and Thomson et al. (2021). Ages of divergences between extant groups are based on the estimates of Thomson et al. (2021). The stratigraphic spans of extant species and clades are not depicted. The ages of the nodes that are directly ancestral to extinct species are arbitrary.