2024-L11 The role of the hind limbs in pterosaur flight

Project highlights

Gain expertise in 3D digital modelling, morphometrics, photogrammetry and phylogenetics
Data collection in key palaeontological collections in the UK, Europe, USA, China and Japan
Generation of the first model of pterosaur flight that fully integrates the fore and hind limbs.

Overview

The aerial ability of pterosaurs, Mesozoic flying reptiles, has been the focus of attention for more than two centuries. Efforts aimed at determining the shape and extent of the wing panels, the kinematics of the flight stroke and, ultimately, the aerodynamic performance of pterosaurs, have almost exclusively focused on the forelimb. By contrast the contribution of the hind limbs has been largely ignored, in part because of uncertainty as to the extent to which they were incorporated into the wings. Traditionally, pterosaurs were considered to be rather bat-like with extensive wing membranes that attached to the legs (Unwin, 2005). Contradicting this idea, some researchers argued for a much-reduced degree of attachment, or even complete exclusion of the hind limbs from the flight apparatus as, for example, in birds (Padian and Rayner 1991). Recent finds of exceptionally well-preserved fossils with complete wing membranes have resolved this problem, showing that the bat-like’ model is correct (Elgin et al., 2010). Despite this few, if any, recent analyses of pterosaur flight have considered the role of the hind limbs even though they are likely to have played a key role in this locomotory activity.

This project will combine a broad range of approaches to determine how pterosaurs used their hind limbs for flight including: comparative skeletal morphology with a focus on the arthrology of the hip joint; morphometric analyses of hind limb proportions and the constraints they imposed on the shape and extent of the flight membranes; reconstruction of muscles of the pelvis and hind limbs combined with biomechanical analysis to determine forces that could be generated and exerted by the hindlimbs during flight; and 3D digital modelling, based on data generated by photogrammetry, aimed at reconstruction of the kinematics of the hind limb during the flight stroke.

Data sets generated by these approaches will be synthesised into the first generalised model of pterosaur flight that incorporates both the fore and hind limbs. Several data sets, principally those relating to comparative anatomy, arthrology and morphometrics of the hind limbs, will encompass a wide range of taxa. Analysis of this data within a phylogenetic context, will be used to understand how the hind limbs contributed to the evolution of flight ability across Pterosauria, beginning with early, small, relatively short-winged forms and concluding with giants with wingspans in excess of 10 m.

Figure 1: The exceptionally well-preserved, 3D pelvis and hind limbs of the Early Cretaceous pterosaur Tupuxuara (Iwaki Coal and Fossil Museum 1052). Inset: reconstruction of Tupuxuara in flight mode (image courtesy of the American Museum of Natural History, 2014).

Host

University of Leicester

Theme

Organisms and Ecosystems

Supervisors

Project investigator

David Unwin, University of Leicester ([email protected])

Co-investigators

Tom Harvey, University of Leicester (thph2@le.ac.uk)

Richard Butler, University of Birmingham ([email protected])

Stephan Lautenschlager, University of Birmingham (S.Lautenschlager@bham.ac.uk)

How to apply

Each host has a slightly different application process.
Find out how to apply for this studentship.
All applications must include the CENTA application form.
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Methodology

This project will take advantage of recently developed digital approaches to analysing and reconstructing locomotion in fossil vertebrates (Benton 2020). Comparative anatomy and arthrology of the pelvis and hind limbs will be investigated using range of movement (ROM) techniques (e.g. Manafazdeh et al., 2021) based primarily on exceptionally well preserved 3D skeletal remains of pterosaurs from the Santana Formation of Brazil (Veldmeijer, 2006). Morphometrics and landmark data will be employed to analyse variation in the dimensions of the hind limb and the geometry of the flight surfaces (e.g. Webster and Sheets 2010). 3D digital techniques (Lautenschlager, 2021), will be used to develop a model simulating the kinematics of the hind limb during the flight stroke. Reconstruction of the evolutionary history of the pterosaur flight apparatus, supervised by Butler, will use quantitative approaches set within a phylogenetic framework comparable, for example, to a recent study by Yu et al. (2023).

Training and skills

Students will be awarded CENTA2 Training Credits (CTCs) for participation in CENTA2-provided and ‘free choice’ external training. One CTC equates to 1⁄2 day session and students must accrue 100 CTCs across the three years of their PhD.

Specialist training will include comparative anatomy and arthrology of pterosaur skeletal anatomy, supervised by Unwin, morphometrics as applied to fossil material, supervised by Unwin and Butler, and photogrammetry and development of 3D digital models supervised by Lautenschlager. The student will also receive training, supervised by Butler, in data base construction with a particular emphasis on the statistical analysis of phylogenetic data.

Partners and collaboration

Dr Unwin has 40+ years of experience of research on pterosaurs, holds extended datasets on pterosaur skeletal anatomy and has access to key specimens that will be studied during this project. Dr Harvey has extensive experience of research and management of palaeontological projects. Dr Lautenschlager is a leading authority on the application of digital techniques and computer simulations to reconstruct function in extinct organisms and has published on a broad range of fossil vertebrates including pterosaurs. Prof Butler has published widely on fossil reptiles, including pterosaurs, and has extensive experience in the application of quantitative approaches to analysis of palaeontological data.

Further details

Further details on how to contact the supervisor for this project and how to apply for this project can be found here:

For any enquiries related to this project please contact David Unwin, ([email protected]).

To apply to this project:

You must include a CENTA studentship application form, downloadable from: CENTA Studentship Application Form 2024.
You must include a CV with the names of at least two referees (preferably three) who can comment on your academic abilities.
Please submit your application and complete the host institution application process via: https://le.ac.uk/study/research-degrees/funded-opportunities/centa-phd-studentships. Please scroll to the bottom of the page and click on the “Apply for NERC CENTA Studentship” button. Your CV can uploaded to the Experience section of the online form, the CENTA application form 2024 can be uploaded to the Personal Statement section of the online form. Please quote CENTA 2024-L11-CENTA2-SGGE3-UNWI  when completing the application form.

Applications must be submitted by 23:59 GMT on Wednesday 10th January 2024.

Possible timeline

Year 1

Familiarisation with literature. Assemblage and analysis of morphometric data on hindlimbs and flight surfaces. Collections visits in the UK and Europe to gather comparative data on skeletal morphology and arthrology. Analysis of these data. Presentation at PalAss (UK) and SVPCA (UK).

Year 2

Collections visits in Japan and China to conduct photogrammetric studies of key specimens and collect further morphological, arthrological and morphometric data. Analysis of these data and generation of muscle reconstructions. Initial work on 3D digital models of hind limb kinematics. Publication and presentation at SVPCA (UK), EAVP (Europe).

Year 3

Collections visits in USA. Completion of 3D digital models. Synthesis of results of comparative morphology, arthrology, morphometric studies, muscle reconstructions and digital kinematics into general model of hind limb function in flight. Develop outline of the evolution of the hind limb as part of the pterosaur flight apparatus. Publication and presentation at SVPCA (UK), SVP (USA). Write and submit thesis.