Fossil evidence suggests that macronarian dinosaurs lived from the Middle Jurassic (Bathonian)[5] through the Late Cretaceous (Maastrichtian).

Like other sauropods, they are known to have inhabited primarily terrestrial areas, and little evidence exists to suggest that they spent much time in coastal environments.

The following list includes some of the distinguishing characteristics that are diagnostic for Macronaria:[6][7][8] The posture of macronarians is characterized by a novel ‘wide-gauged’ locomotor style, particularly in titanosaurs.

A possible camarasauromorph of indeterminate genus and species was reported from the Middle Jurassic Khadir Formation of India, representing the oldest member of camarasauromorpha.

There is strong geologic evidence that a land bridge between South and North America existed at the end of the Cretaceous allowing for dispersal of organisms between the two landmasses.

Given the large body size of these neosauropod herbivores, it is thought that this type of niche partitioning, characterized by different species taking advantage of different resources, was necessary for coexistence.

The species that survived late into the Cretaceous were characterized by stocky, wide-gauged posture, most notably the highly derived saltasaurines.

[16] Camarasauridae Galvesaurus Phuwiangosaurus Aragosaurus Tastavinsaurus Venenosaurus Brachiosaurus Euhelopus Titanosauria The cladogram below follows José L. Carballido, Oliver W. M. Rauhut, Diego Pol and Leonardo Salgado (2011).

[17] Camarasaurus Europasaurus Galvesaurus Tehuelchesaurus Janenschia Tastavinsaurus Euhelopus Chubutisaurus Wintonotitan Brachiosauridae Phuwiangosaurus Titanosauria Simplified cladogram of Macronaria after D'Emic (2012).