210 - 230 Mya
||Smith et al., Body size evolution across the Geozoic, Annual Review of Earth and Planetary Sciences, Vol. 44 :523-553, 2016 DOI: 10.1146/annurev-earth-060115-012147 link p.533 2nd paragraph
||Benson RB, Campione NE, Carrano MT, Mannion PD, Sullivan C, et al. 2014. Rates of dinosaur body mass evolution indicate 170 million years of sustained ecological innovation on the avian stem lineage. PLOS Biol. 12:e1001853 doi: 10.1371/journal.pbio.1001853.PubMed ID24802911
||P.533 2nd paragraph: "Life on land:There has yet to be a complete synthesis of body size evolution in terrestrial environments over the Geozoic. However, there are some interesting patterns in the interactions of several dominant clades since the end of the Permian (Lyons et al. 2015). For example, although mammals and dinosaurs originated at roughly the same time (∼230–210 Ma), dinosaurs quickly expanded their body size over the Mesozoic (primary source), filling most ecological roles within terrestrial communities (Figure 3b). The “early burst niche-filling pattern” (primary source) was followed by reduced evolutionary rates in most lineages."