PhD: Pterosaur flight biomechanics: how did the largest airborne animals get off the ground?

Project Background
With a 10m wingspan and 250kg estimated body mass, giant pterosaurs were the largest vertebrates ever to fly. By contrast the largest extant birds have wingspans of 3m and weigh around 20kg, with fossil birds reaching 6-7m wingspan and 70kg mass. Even giant extinct birds are dwarfed by the largest pterosaurs. When birds take off their legs provide the initial work to accelerate their bodies before the wings take over (Earls 2000, Henry et al 2005, Heers & Dial 2014). Once airborne, the legs serve no useful purpose and act as “baggage”. The difficulties that large birds face in becoming airborne (swans, albatrosses) suggests that take off may limit the maximum size of birds. Pterosaurs adopted a quadrupedal stance, which meant that their forelimbs were used for both flight and locomotion, including launch, so in theory used more available muscle mass and carried less baggage once airborne (Habib 2008).

Project Aims and Methods
The aim of the PhD is to use computational modelling to quantify the launch mechanism of pterosaurs and test if quadrupedal launch enabled pterosaurs to become much larger than any living or extinct bird. Pterosaurs forelimbs were used for both flight and locomotion, including launch, meaning less baggage once airborne. The concept of this quadrupedal launch is widely accepted (Habib 2008), yet the kinematic and anatomical details are poorly understood. The student will create biomechanical models of launch in birds and pterosaurs. This will be achieved by studying pterosaur anatomy – in museums and the literature, and CT scanning of pterosaur fossils, before creating digital pterosaur musculoskeletal reconstructions. Next, kinematic simulation software will be used to create a simple baseline bipedal launch model in birds and pterosaurs, validated against published data for birds and humans and tested for sensitivity to assumptions and modelling detail. This baseline model will then be modified to incorporate pterosaur quadrupedal launch. The student will ultimately produce a series of computer simulations of pterosaur launch mechanics and use these models to evaluate whether quadrupedal launch was more efficient than bipedal launch, and whether such efficiencies enabled pterosaurs to surpass birds and become the largest ever flying animals.

Candidate
The project would suit a student interested in palaeobiology, biomechanics or engineering and evolution. Backgrounds in zoology, geology, palaeobiology, biomechanics and engineering will be considered.

Case Award Description
The project is a CASE award with Dr Palmer at Ginko Enterprises. The student will received an extra £1000 per annum stipend and undertake a short secondment with Ginko based in Bristol, offering experience working with data acquisition and analysis of wind farm data, allowing two-way transfer of data arising from the PhD project to influence future turbine design strategy. The secondment will allow the student to develop their understanding of flight mechanics and aerodynamics, and work directly with Dr Palmer – an expert in aerodynamics with a strong interest in biological systems.

Training
The student will join the large and vibrant Bristol palaeobiology community. They will be able to attend M-Level courses such as Biomechanics and receive direct training in engineering methods from Dr Palmer. Full training in all software required will be provided, directly from the supervisor and her research group of via academic focused training courses (3D modelling software such as Maya and Blender, kinematic software such as Adams and OpenSIMM). The student will have full access to GW4+ and Bristol Doctoral college training courses, with opportunities for undergraduate demonstrating and in later years of their PhD to co-supervise M-Level projects.

References
K. D. Earls, Kinematics and mechanics of ground take-off in the starling Sturnis vulgaris and the quail Coturnix coturnix. Journal of Experimental Biology 203, 725 - 739 (2000).
S. M. Gatesy, & K. P. Dial. 2005. Locomotor modules and the evolution of avian flight. Evolution 50, 331-340
M. B. Habib. 2008. Comparative evidence for quadrupedal launch in pterosaurs. Zitteliana B28, 159-166
A. M. Heers & K. P. Dial. 2014. Wings versus legs in the avian bauplan: Development and evolution of alternative locomotor strategies. Evolution 69, 305-320
Henry H. T. et al.,2005. Performance of guinea fowl Numida meleagris during jumping requires storage and release of elastic energy. Journal of Experimental Biology 208, 3293-3302
Riskin D. K. & Hermanson J. W. 2005. Independent evolution of running in vampire bats. Nature 434, 292.
Witton M. P. 2013. Pterosaurs: Natural History, Evolution, Anatomy (Princeton University Press, Princeton)