The biomechanical design and morphofunctional evolution of presacral vertebrae in Sauropodomorpha deduced from shape analysis and FESS
Final Report Abstract
Sauropodomorph dinosaurs have long been known for their very complex vertebral structures, especially in the presacral vertebrae, the neural arches of which consist of a multitude of delicate laminae. These laminae have long been suggested to be of biomechanical and functional significance, but neither their function nor their evolution in sauropodomorphs have so far been studied in detail. In the current project, we used a combination of different methods, including classic comparative anatomy, morphofunctional studies, muscle reconstructions, geometric morphometrics and finite element biomechanics to study the presacral vertebra column of a basal sauropodomorph, Plateosaurus, and a derived sauropod, Diplodocus. The results indicate that biomechanical forces play a major role in shaping the presacral vertebral column in sauropodomorph dinosaurs. In the basal sauropodomorph Plateosaurus, lateral flexibility is general larger throughout the presacral series than either ventral or dorsal flexibility. This lateral flexibility is especially pronounced at the base of the neck, indicating that lateral sweeping motions of the neck and head were important in the animal’s feeding behaviour. In an evolutionary perspective, there is no notable neck elongation at the origin of Sauropodomorpha, and the reduction of skull size in this clade, with the resulting reduction of stresses acting on the cervical vertebral column, resulted in a simplification of vertebral laminae. In contrast, the increase in cervical vertebral number at the base of Sauropoda resulted in a notable increase in neck length and thus in modifications in the vertebral articulations (amphicoelous to opisthocoelous) and an increase in complexity in vertebral lamination, both obviously connected to changing biomechanics of the neck. Shape analysis of cervcical vertebrae found a separation of “prosauropod” and sauropod taxa, with the latter covering a much larger morphospace than the former. Within sauropodomorphs, phylogeny seems to be an important descriptor of vertebral shape. Further studies of vertebral function and biomechanics in the separate groups are needed to further explore the relationship between phylogenetic inheritance and vertebral function.
Publications
- (2008): Locomotion and feeding behaviour of Plateosaurus based on a morphofunctional analysis of the presacral vertebral column. In: Calvo, J. O., Juarez Valieri, R., Porfiri, J. D. & dos Santos, D. (ed.), III Congreso Latinamericano de Paleontología de Vertebrados, Libro de Resúmenes, 168, Neuquén
Moser, K., Rauhut, O. W. M. & Witzel, U.
- (2008): Morphology and function of the neck of Plateosaurus. - Journal of Vertebrate Paleontology, 28: 118A-119A
Moser, K., Rauhut, O. W. M. & Witzel, U.
- (2009): A comparative morphometric analysis of sauropodomorph necks. - Journal of Vertebrate Paleontology, 29: 66A
Böhmer, C., Moser, K. & Rauhut, O. W. M.
- (2009): Function and biomechanics of the presacral vertebral column: a FESS model of Plateosaurus. - Terra Nostra, 2009/3: 82
Moser, K. & Witzel, U.
- (2010): 3D morphometric analysis of the presacral vertebrae of Plateosaurus: implications for vertebral evolution in sauropodomorph dinosaurs. - Journal of Vertebrate Paleontology, 30: 61A
Böhmer, C. & Rauhut, O. W. M.
- (2011): Biology of the sauropod dinosaurs: the evolution of gigantism. - Biological Reviews, 86: 117-155
Sander, P. M., Christian, A., Clauss, M., Fechner, R., Gee, C. T., Griebeler, E.-M., Gunga, H.-C., Hummel, J., Mallison, H., Perry, S. F., Preuschoft, H., Rauhut, O. W. M., Remes, K., Tütken, T., Wings, O. & Witzel, U.
- (2011): Comparative shape analysis of the neck in extinct and extant archosaurs: implications for vertebral evolution in sauropodomorph dinosaurs. - Journal of Vertebrate Paleontology, 31: 73-74
Böhmer, C., Rauhut, O. W. M. & Wörheide, G.
- (2011): How to get big in the Mesozoic: the evolution of the sauropodomorph body plan. In: Klein, N., Remes, K., Gee, C. T. & Sander, P. M. (ed.), Biology of the sauropod dinosaurs: understanding the life of giants, 119-149, Bloomington and Indianapolis (Indiana University Press)
Rauhut, O. W. M., Fechner, R., Remes, K. & Reis, K.
