A fossil of the Compsognathus longipes from the "Solnhofen Archipelago" shows the twisted posture often seen in dinosaur remains.
ARTICLE CONCLUDES THUSLY:
Biomechanics in Watery Graves Convinced that the back arching was generated, not by death throes, but by postmortem alterations of a decaying carcass, the researchers made experiments with plucked chicken necks and thoraxes, immersed in water. Submersed in water, the necks spontaneously arched backwards for more than 90°. Ongoing decay for some months even increased the degree of the pose. Thorough preparation and dissection combined with testing revealed that a special ligament connecting the vertebrae at their upper side was responsible for the recurved necks in the chickens. This ligament, the so-called Ligamentum elasticum, is pre-stressed in living chickens, but also in dead ones.
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"A strong Ligamentum elasticum was essential for all long necked dinosaurs with a long tail. The preloaded ligament helped them saving energy in their terrestrial mode of life. Following their death, at which they were immersed in water, the stored energy along the vertebra was strong enough to arch back the spine, increasingly so as more and more muscles and other soft parts were decaying" conclude the researchers. "It is a special highlight that, in the Compsognathus specimen, these gradual steps of recurvature can be substantiated, too. Therefore, biomechanics is ruling the postmortem weird posture of a carcass in a watery grave, not death throes.