Big Monties - anatomical study of Edmontosaurus annectens

Muscular and life reconstructions of two Edmontosaurus annectens, demonstrating facultative switching between a quadrupedal and bipedal mode of gait.

The "small" one (though it's still over 8 metres in length, so not really "small") is based on AMNH 5730, and the absolutely gigantic individual are those same skeletal proportions scaled to match the huge tail of MOR 1142, nicknamed "X-Rex". The AMNH skeleton, which was formerly classified as Anatotitan copei (now generally seen to be synonymous with E. annectens), has the skeletal morphology of a mature individual, yet seems almost tiny next to the the projected size of the gigantic X-rex. This feels almost unusual, as multiple studies have demonstrated that hadrosaur growth rate generally plateaus in the later stages. Maybe X-rex was just really, really lucky, and really, really old.

Useful dinosaur muscle resources: https://www.dropbox.com/s/zomk6qwjqcn48lt/Muscle%20References.pdf?dl=0