Abstract
It has been suggested that the large theropod dinosaur Tyrannosaurus rex was capable of producing extremely powerful bite forces and resisting multi-directional loading generated during feeding. Contrary to this suggestion is the observation that the cranium is composed of often loosely articulated facial bones, although these bones may have performed a shock-absorption role. The structural analysis technique finite element analysis (FEA) is employed here to investigate the functional morphology and cranial mechanics of the T. rex skull. In particular, I test whether the skull is optimized for the resistance of large bi-directional feeding loads, whether mobile joints are adapted for the localized resistance of feeding-induced stress and strain, and whether mobile joints act to weaken or strengthen the skull overall. The results demonstrate that the cranium is equally adapted to resist biting or tearing forces and therefore the 'puncture-pull' feeding hypothesis is well supported. Finite-element-generated stress-strain patterns are consistent with T. rex cranial morphology: the maxilla-jugal suture provides a tensile shock-absorbing function that reduces localized tension yet 'weakens' the skull overall. Furthermore, peak compressive and shear stresses localize in the nasals rather than the fronto-parietal region as seen in Allosaurus, offering a reason why robusticity is commonplace in tyrannosaurid nasals.
Full Text
The Full Text of this article is available as a PDF (1.0 MB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Biewener A. A. Bone strength in small mammals and bipedal birds: do safety factors change with body size? J Exp Biol. 1982 Jun;98:289–301. doi: 10.1242/jeb.98.1.289. [DOI] [PubMed] [Google Scholar]
- Blob RW, Biewener AA. In vivo locomotor strain in the hindlimb bones of alligator mississippiensis and iguana iguana: implications for the evolution of limb bone safety factor and non-sprawling limb posture . J Exp Biol. 1999 May;202(Pt 9):1023–1046. doi: 10.1242/jeb.202.9.1023. [DOI] [PubMed] [Google Scholar]
- Buckland-Wright J. C. Bone structure and the patterns of force transmission in the cat skull (felis catus). J Morphol. 1978 Jan;155(1):35–61. doi: 10.1002/jmor.1051550104. [DOI] [PubMed] [Google Scholar]
- Herring S. W., Teng S. Strain in the braincase and its sutures during function. Am J Phys Anthropol. 2000 Aug;112(4):575–593. doi: 10.1002/1096-8644(200008)112:4<575::AID-AJPA10>3.0.CO;2-0. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Jaslow C. R. Mechanical properties of cranial sutures. J Biomech. 1990;23(4):313–321. doi: 10.1016/0021-9290(90)90059-c. [DOI] [PubMed] [Google Scholar]
- Rafferty K. L., Herring S. W. Craniofacial sutures: morphology, growth, and in vivo masticatory strains. J Morphol. 1999 Nov;242(2):167–179. doi: 10.1002/(SICI)1097-4687(199911)242:2<167::AID-JMOR8>3.0.CO;2-1. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rafferty Katherine L., Herring Susan W., Marshall Christopher D. Biomechanics of the rostrum and the role of facial sutures. J Morphol. 2003 Jul;257(1):33–44. doi: 10.1002/jmor.10104. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rayfield E. J., Norman D. B., Horner C. C., Horner J. R., Smith P. M., Thomason J. J., Upchurch P. Cranial design and function in a large theropod dinosaur. Nature. 2001 Feb 22;409(6823):1033–1037. doi: 10.1038/35059070. [DOI] [PubMed] [Google Scholar]
- Smith K. K., Hylander W. L. Strain gauge measurement of mesokinetic movement in the lizard Varanus exanthematicus. J Exp Biol. 1985 Jan;114:53–70. doi: 10.1242/jeb.114.1.53. [DOI] [PubMed] [Google Scholar]
- Thomason J. J., Grovum L. E., Deswysen A. G., Bignell W. W. In vivo surface strain and stereology of the frontal and maxillary bones of sheep: implications for the structural design of the mammalian skull. Anat Rec. 2001 Dec 1;264(4):325–338. doi: 10.1002/ar.10025. [DOI] [PubMed] [Google Scholar]
- Thomason J. J., Russell A. P. Mechanical factors in the evolution of the mammalian secondary palate: a theoretical analysis. J Morphol. 1986 Aug;189(2):199–213. doi: 10.1002/jmor.1051890210. [DOI] [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.