Sauropod

Abstract 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 coexisted,
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.

Although diplodocoid sauropods from Africa and the Americas are well known, their European record remains largely neglected. Here we redescribe Dinheirosaurus lourinhanensis from the Late Jurassic of Portugal. The holotype comprises two posterior cervical vertebrae, the dorsal series and a caudal centrum. Redescription demonstrates its validity on the basis of three autapomorphies:(1) posteriorly restricted ventral keel on posterior cervical vertebrae;(2) three small subcircular fossae posterior to the lateral coel ...

The necks of the sauropod dinosaurs reached 15 m in length: six times longer than that of the world record giraffe and five times longer than those of all other terrestrial animals. Several anatomical features enabled this extreme elongation, including: absolutely large body size and quadrupedal stance providing a stable platform for a long neck; a small, light head that did not orally process food; cervical vertebrae that were both numerous and individually elongate; an efficient air-sac-based respiratory system; and distinctive cervical architecture. Relevant features of sauropod cervical vertebrae include: pneumatic chambers that enabled the bone to be positioned in a mechanically efficient way within the envelope; and muscular attachments of varying importance to the neural spines, epipophyses and cervical ribs. Other long-necked tetrapods lacked important features of sauropods, preventing the evolution of longer necks: for example, giraffes have relatively small torsos and larg...