Oryctos
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Accès privé :
| volume 1, 1998 |
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John Martin, Valérie Martin-Rolland & Eberhard Frey, Not cranes or masts but beams. The biomechanics of sauropod necks. Oryctos 1, 113-120.
The mechanics of sauropod necks are still poorly understood, judging from many recent life reconstructions. Only seven or eight sauropod taxa have necks well-enough known for their mobility and posture to be reconstructed fully and reliably. In these animals, the limits of mobility imposed by the zygapophyseal and central articulation structures may be calculated. Simple biomechanics shows that sauropod necks were segmented beams, and that the way in which segmented beams must be braced adds further limits to mobility. The bracing systems implied by the vertebral anatomy can be reconstructed, based partly on an appreciation, from extant animals, of what soft-tissue structures were possible given a particular set of bone geometries. Sauropod necks were dorsally-braced, ventrally-braced or a combination of the two: each system was associated with a distinctive, exclusive, group of vertebral features - high, low or divided neural spines, large or small transverse processes and short or elongated cervical ribs. The two sets of mobility-controlling systems (joint morphology and bracing) made the necks of all "popular" sauropods relatively, or very, rigid structures, and also show that they were habitually carried with the ventral aspect "down" with respect to gravity - in other words as beams, not masts.
Keywords : Dinosaur, sauropod, biomechanics, necks, life reconstructions.
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