PhD: The anatomy, function and evolutionary history of the pterosaur bauplan – a taphonomic approach

The basic construction, ‘bauplan’, of pterosaurs, Mesozoic flying reptiles, has been hotly debated for more than two centuries and remains highly controversial. The fundamental question is this: what was the extent of the flight membranes and how did they connect the limbs? Were pterosaurs bat-like with flight surfaces that linked the hind limbs to each other, and to the fore limbs, forming in effect a single anatomical and functional module? Or, were they more bird-like, with flight surfaces confined to individual limbs, resulting in a bauplan composed of multiple independent modules? These questions, which have yet to be resolved despite more than two centuries of study, are of critical importance to understanding pterosaurs because, as birds and bats show, anatomical and functional linkage, or independence, of the limbs has profound implications for flight and terrestrial locomotion. Locomotory abilities, in turn, are primary determinants of ecological diversity and, it is widely assumed, played a key role in shaping the macroevolutionary history of flying vertebrates.

The aim of this project is to show that combining different types of taphonomic data can provide a robust approach to reconstructing the bauplan of pterosaurs. Quantitative analyses of skeletal completeness, degree of articulation and the geometry of limb bones will generate data sets that capture key constructional attributes of pterosaurs such as correlations of integrity between and within limbs.

Analyses of the preservation of flight membranes will help underpin rigorous new evaluations of the extent of these integumentary structures and their relationship to the fore and hind limbs. Combined, the skeletal and soft tissue data sets will permit the development of robust, accurate, testable models of the basal pterosaur and pterodactyloid bauplan. Understanding of the relationship between flight membranes and the skeleton will be used to generate models for multiple species that span the morphological, systematic and temporal range of pterosaurs. Alongside reconstructions that can be used for more refined analyses of the flight, terrestrial abilities and palaeoecology of pterosaurs these models, set within a phylogenetic framework, will provide new insights into the evolutionary history of pterosaurs and vertebrate flight more generally.