Fig. 6: Synopsis of fossil record, body size evolution, and palaeobiogeography of Megaraptoridae (modified and updated from Lamanna et al.⁷ [these authors’ Fig. 13]).

a Stratigraphic distribution of definitive megaraptorid fossils through the Cretaceous. Asterisks adjacent to some records indicate that additional, generically indeterminate megaraptorid materials have been reported from the same stratigraphic unit. Stratigraphic position of Aerosteon riocoloradensis within the upper Coniacian–lower Campanian is uncertain (see ref. ²¹). b Hypothesis of palaeobiogeography and body size evolution in Megaraptoridae. Megaraptorids are considered to have originated in eastern Gondwana (Australia) during the Early Cretaceous, then dispersed to western Gondwana (South America) via Antarctica during the mid- (i.e., late Early or early Late) Cretaceous (see refs. ^7,8,16). Red silhouette represents Australian megaraptorid ca. 5–6 m in total body length; blue silhouette represents ca. 7 m (+) South American megaraptorid. Cretaceous timescale in a from ref. ¹¹⁰; palaeogeographic reconstructions in b are south polar views at (bottom to top) 110, 100, 90, and 80 Ma (©2023 Colorado Plateau Geosystems Inc., used with permission).