November 13 , 2016:

by D.M. Unwin

Overview

Project Highlights:
Gain expertise in the generation of high fidelity 3D digital data sets for fossils
Conduct fieldwork at key palaeontological sites in the USA and Europe
Develop a new model for the palaeoecology and evolution of pterosaurs in terrestrial environments

Pterosaurs, Mesozoic flying reptiles, were long considered to have been almost exclusively confined to aerial niches, with only limited mobility when on the ground (Unwin, 2005). Two lines of evidence have challenged this view. (1) A rapidly accumulating and increasingly diverse pterosaur track record (pteraichnites) that spans more than 80 million years. (2) Digital modelling, based on skeletal remains and tracks, of pterosaur’s terrestrial locomotory abilities. These studies show that pterosaurs used a flat-footed, four-legged, but nevertheless highly efficient, stance and gait. They have also uncovered some unexpected behaviours, such as a quadrupedal launch, that point to a far more effective ability to take-off and land than previously suspected. These new findings suggest that pterosaurs played a much bigger role in Mesozoic terrestrial communities than previously realised (Witton, 2013), but the extent and evolutionary significance of this phenomenon remains unclear and controversial.

This project will use a multidisciplinary approach to reassess the contribution of pterosaurs to Mesozoic continental biotas and their impact on co-evolving groups such as early birds (Benson et al, 2014). New techniques including photogrammetric ichnology will form part of the first systematic analysis of the pterosaur track record. This work will generate a range of data sets that capture fine detail of prints and tracks that can be combined with contextual data including sedimentology, stratigraphy and associated ichnological and body fossil evidence.

These data sets will underpin three complementary strands of the PhD: (1) reconstruction of the locomotory styles and abilities of pterosaurs (stance, gait, speed, take-of and landing modes) based on key sites in the USA and Europe. (2) The first comprehensive integration of the ichnological and body fossil record of pterosaurs via 3D digitisation of prints and well preserved skeletal remains. (3) Identification and reconstruction of specific behaviours (e.g. feeding, flocking) set within current interpretations of the palaeoenvironments in which they occurred.

Results of these three studies will be combined with data on the relationships and temporal and biogeographic distribution of pterosaurs to determine the extent to which they contributed to Mesozoic terrestrial biotas and influenced the evolution of contemporaneous groups such as birds.

Methodology

New approaches to collecting and interpreting prints and tracks including photogrammetry, pioneered by Breithaupt (e.g. Lockely et al., 2016) will be used to generate high fidelity 3D digital data sets based on key sites in the USA (Wyoming), France (Crayssac) and Spain (Asturias) that contain multiple individuals and exceptionally high quality impressions (Unwin, 2005; Witton, 2013).

Identification of track-makers will take advantage of our rapidly expanding knowledge of pterosaur skeletal anatomy and the possibility of highly accurate comparisons between digitised sets of tracks and 3D skeletal elements of the hand and foot. This approach will be located within a well established phylogenetic framework developed by Unwin and others. Digital models have been shown to be highly effective at constraining likely stance, gait, velocity and manoeuvrability for extinct taxa (Falkingham and Gatesy, 2014) and will be applied here to both ichnological and skeletal data. The reconstruction of behaviours, palaeoenvironments and the evolutionary history of pterosaur terrestrial palaeoecology, supervised by Butler, will use quantitative approaches set within a phylogenetic framework.
Training and Skills

Students will benefit from 45 days training throughout their PhD including a 10 day placement. Initially, students will be trained as a single cohort on research methods and core skills. Training will progress to master classes, specific to projects and themes. Specialist training will include identification and interpretation of pterosaur tracks and skeletal anatomy, supervised by Unwin, photogrammetry as applied to palaeoichnology, supervised by Breithaupt and Butler, and analysis of locomotion, supervised by Falkingham. The student will also receive training, supervised by Butler, in data base construction with a
particular emphasis on the statistical analysis of palaeontological data.
Timeline

Year 1:
Familiarisation with literature, existing datasets and palaeoichnological techniques including photogrammetry. Fieldwork in the USA to collect pterosaur track data. Analysis of these data. Presentation at PalAss (UK) and SVPCA (UK).

Year 2:
Fieldwork in Spain and France to collect pterosaur track data. Continued analysis of all track data and integration with body fossil record. Analysis of pterosaur locomotory styles. Publication and presentation at SVPCA (UK), EAVP (Europe).

Year 3:
Synthesis of results on locomotory abilities, behaviours and palaenvironments. Develop evolutionary history of pterosaurs in terrestrial environments. Publication and presentation at SVPCA (UK), SVP (USA). Write and submit thesis.
Partners and collaboration (including CASE)

Dr Unwin has 30+ years experience of research on pterosaurs, holds extended datasets on pterosaur skeletal anatomy, and palaeoichnology and has access to key specimens that will be studied during this project. Prof Purnell has expertise in analysis of 3D surface datasets in the context of vertebrate ecology and function. Dr Falkingham has worked on fossil footprints for over a decade, using computational techniques including simulation (FEA, DEM, MBD) and digitization (laser scanning, photogrammetry) to study locomotion and footprint formation. Dr Butler has published widely on fossil reptiles, including pterosaurs, and has extensive experience in the application of quantitative approaches to analysis of palaeontological data. Dr Breithaupt has pioneered the development of photogrammetric ichnology, including its application to pterosaur tracks.
Further Details

Ideally, applicants should have a first degree in the geological or biological sciences and an aptitude for quantitative analysis. At Leicester you will join a dynamic group of researchers, PhD and Masters students developing novel approaches to the analysis of palaeoecology and evolution in fossil vertebrates.