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Diplodocus skull feeding biomechanics

From: Ben Creisler

A new online paper:

Mark T. Young, Emily J. Rayfield, Casey M. Holliday, Lawrence M.
Witmer, David J. Button, Paul Upchurch and Paul M. Barrett (2012)
Cranial biomechanics of Diplodocus (Dinosauria, Sauropoda): testing
hypotheses of feeding behaviour in an extinct megaherbivore.
Naturwissenschaften (advance online publication)
2012, DOI: 10.1007/s00114-012-0944-y

Sauropod dinosaurs were the largest terrestrial herbivores and pushed
at the limits of vertebrate biomechanics and physiology. Sauropods
exhibit high craniodental diversity in ecosystems where numerous
species co-existed, leading to the hypothesis that this biodiversity
is linked to niche subdivision driven by ecological specialisation.
Here, we quantitatively investigate feeding behaviour hypotheses for
the iconic sauropod Diplodocus. Biomechanical modelling, using finite
element analysis, was used to examine the performance of the
Diplodocus skull. Three feeding behaviours were modelled:
muscle-driven static biting, branch stripping and bark stripping. The
skull was found to be ‘over engineered’ for static biting, overall
experiencing low stress with only the dentition enduring high stress.
When branch stripping, the skull, similarly, is under low stress, with
little appreciable difference between those models. When simulated for
bark stripping, the skull experiences far greater stresses, especially
in the teeth and at the jaw joint. Therefore, we refute the
bark-stripping hypothesis, while the hypotheses of branch stripping
and/or precision biting are both consistent with our findings, showing
that branch stripping is a biomechanically plausible feeding behaviour
for diplodocids. Interestingly, in all simulations, peak stress is
observed in the premaxillary–maxillary ‘lateral plates’, supporting
the hypothesis that these structures evolved to dissipate stress
induced while feeding. These results lead us to conclude that the
aberrant craniodental form of Diplodocus was adapted for food
procurement rather than resisting high bite forces.