The largest dinosaurs who ever lived became increasingly front-heavy over time:
The team found that these linked trends in size, body shape and weight distribution did not end with the evolution of fully quadrupedal sauropods. In the Cretaceous period — the last of the three ages of the dinosaurs — many earlier sauropod groups dwindled. In their place, a new and extremely large type of sauropod known as titanosaurs evolved, including the truly massive Argentinosaurus and Dreadnoughtus, among the largest known animals ever to have lived.
The team’s computer models suggest that in addition to their size, the titanosaurs evolved the most extreme ‘front heavy’ body shape of all sauropods, as a result of their extremely long necks.
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Dr Philip Mannion from Imperial College London, a collaborator in the research, added: “These innovations in body shape might have been key to the success of titanosaurs, which were the only sauropod dinosaurs to survive until the end-Cretaceous mass extinction, 66 million years ago.”
It would be interesting to know why huge was an advantage.