Biomedical subjects

Emily J Rayfield

Publications and source records attributed to Emily J Rayfield.

3 recordsLinked to original sources

PubMed2006

Ecological and evolutionary implications of dinosaur feeding behaviour.

Dinosaurs had a wide variety of feeding mechanisms that strongly impacted on their ecology and evolution. Here, we show how novel application of technologies borrowed from medicine and engineering, such as CT scanning and Finite Element Analysis, have recently been combined with traditional approaches to result in significant advances in our understanding of dinosaur palaeobiology. Taxon-specific studies are providing quantitative data that can be used to generate and test functional hypotheses relating to jaw mechanics and feeding behaviour. In turn, these data form a basis for investigating larger scale patterns of ecological and macroevolutionary change, such as possible coevolutionary interactions and the influence of feeding adaptations on species richness, which are of more general interest to ecologists and evolutionary biologists.

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PubMed2005

Using finite-element analysis to investigate suture morphology: a case study using large carnivorous dinosaurs.

Finite-element analysis (FEA) can be used to investigate the mechanical significance of sutures and regions of intracranial flexibility in skulls. By modeling the stress response to feeding forces in a finite-element skull model (with appropriate boundary conditions), one can compare the axis of distortion and orientation of stress and strain in the model to the degree of movement at actual sutural contacts in the real skull. Hypotheses detailing the effect of introducing patency or flexibility on mechanical performance can be constructed and subsequently tested. In this study, the correlation between stress environment, cranial strength, and sutural morphology and mobility is investigated in the cranium of the large theropod dinosaur Allosaurus fragilis. Theropods are an especially interesting model system as their skulls were massive (over 100 cm in some cases), may have generated extremely large bite forces, yet patent sutures persisted between many of the facial bones. In this analysis, it was discovered that Allosaurus cranial sutures appear generally capable of accommodating stress and strain patterns generated during biting. This study highlights the potential of FEA in devising and testing hypotheses of form and function and argues that useful information can be obtained from finite-element models of extinct animals, providing that adequate assumptions are made and appropriate questions asked.

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PubMed2004

Cranial mechanics and feeding in Tyrannosaurus rex.

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.

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