|I propose to study the mechanics of the sauropoda (Dinosauria), with the research including elements of engineering, anatomy and evolution.
My interest started out as purely mechanical, to do with sauropod neck posture and the form of the support elements required to attain various postures and move between them. For example, cantilevered necks require an arrangements such as dorsal ligaments acting as tension members to brace rigid columns of centra (Alexander 1985, Tsuihiji 2004). Limitations are imposed on neck flexibility by the size of zygophyseal articular surfaces and condyle/cotyle radii of curvature (Martin 1987, Steven & Parrish 1999). Posture hypotheses may also be formulated by considering how the stress varies at the cervical articulations in various postures (Christian 2002), the consequences of various bracing strategies (Martin et al. 1998) and metabolic considerations arising from different postures (Seymour & Lillywhite 2000). Existing work along these lines has reached contradictory conclusions which should be independently replicated, and reconciled according to results.
It has become apparent that modelling the various elements in purely engineering terms is over-simplistic, and that an appreciation of vertebral anatomy is necessary in order to correctly identify the attachment points of ligaments and muscles (Wedel & Sanders 2002). Only then can sufficiently complex models be built to simulate the actual range of postures and movements that would have been available to the live animals. Accordingly, I plan to increase my understanding of cervical anatomy by studying and describing previously undescribed sauropod material, and then to hypothesise plausible arrangements of soft tissue from which forces and moments can be calculated.
It is further apparent that the various structures contributing to neck length, lightness and strength can only be properly understood within the context of an evolutionary hypothesis (e.g. Wilson 2002). For example, there appears to be a progression from more basal to more derived sauropods exhibiting more complex forms of vertebral pneumatisation, from simple fossae through camarae and camellae to the somphospondylous condition found in titanosaurs (Wedel 2003). It appears that these forms of pneumatisation may not in fact produce progressively
lighter vertebral columns, as would appear intuitively to be the case (unpublished data); so I plan to consider and evaluate possible evolutionary advantages of the more derived forms.
The ultimate goal of this project is to create detailed computer models of various sauropod necks, including the positions, sizes and relations of bones, air-spaces, ligaments and muscles, calculating the forces that can be brought to bear, and so arriving at conclusions about the range of posture and motion that would have been possible in life.
Alexander, R. McNeill (1985). Mechanics of posture and gait of some large dinosaurs. Zoological Journal of the Linnean Society, 83:1-25.
Christian, Andreas (2002). Neck posture and body design in sauropods. Museum fur Naturkunde Berlin. Geowissenschaft Reihe 5, pages 271-281.
Martin, John (1987). Mobility and feeding of Cetiosaurus (Saurischia: Sauropoda) - why the long neck? Occasional Papers of the Tyrrell Museum of Palaeontology #3 (Fourth Symposium on Mezozoic Terrestrial Ecosystems, Drumheller), pages 150-155.
Martin, John, V. Martin-Rolland and E. Frey (1998). Not cranes or masts, but beams: the biomechanics of sauropod necks. Oryctos 1:113-120.
Seymour, Roger S. and Harvey B. Lillywhite (2000). Hearts, neck posture, and metabolic intensity of sauropod dinosaurs. Proceedings of the Royal Society of London 267B:1883-1887.
Stevens, Kent. A., and J. M. Parrish (1999). Neck Posture and Feeding Habits of Two Jurassic Sauropod Dinosaurs: Science 284:798-800.
Tsuihiji, Takanobu (2004). The ligament system in the neck of _Rhea americana_ and its implication for the bifurcated neural spines of sauropod dinosaurs. Journal of Vertebrate Paleontology 24(1):165-172.
Wedel, Matthew J (2003). The Evolution of Vertebral Pneumaticity in Sauropod Dinosaurs. Journal of Vertebrate Paleontology 23(2):344-357.
Wedel, Matthew J. and R. Kent Sanders (2002). Osteological correlates of cervical musculature in Aves and Sauropoda (Dinosauria: Saurischia), with comments on the cervical ribs of Apatosaurus. PaleoBios 22(3):1-12.
Wilson, Jeffrey A. (2002). Sauropod dinosaur phylogeny: critique and cladistic analysis. Zoological Journal of the Linnean Society, 136:217-276.