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Figure 1: A simplified representation of some of the sequential, evolutionary radiations that appear from Amniota (I.) to Mammalia (II.) showing, for comparative purposes, the cladistic separation of the synapsids and saurosids as divergent subsets of Amniota. Along the dashed line, the diagram traces the trajectory from the Synapsida to the crown group, Mammalia, with select representatives of various radiating groups and species, shown by the light dashed lines. Bold horizontal lines depict the appearance and duration of each taxonomic group shown. The black triangle at the Jurassic-Cretaceous boundary denotes the end of the age of dinosaurs. The geological timescale and periods appear together at the bottom of the figure which was adapted with alterations from [10].