A taphonomic and palaeoecological approach to the study of palaeocolour

Abstract

The field of palaeocolour has greatly improved our understanding of how many extinct animals looked and behaved. Preservation of the pigment melanin allows for several aspects of colour patterns to be revealed and inferences of likely ecologies and behaviours made based on comparisons to living taxa. Additionally, important aspects of soft tissue taphonomy in fossils have been ascertained through the study of fossil melanin. The field is still in its infancy however, leaving much to be understood in terms of what is preserved, how and what biases may exist. There is also debate as to the nature and preservation of soft tissue features important to palaeocolour, such as feathers and skin. In this thesis, I explore the nature of soft tissue preservation in the integument of several non-avian dinosaurs, crown group avians and Jurassic ichthyosaurs, revealing their melanin-based colouration using chemical and microscopy approaches. Issues surrounding previous interpretations of soft tissue anatomy in ichthyosaurs and the Early Cretaceous theropod Sinosauropteryx are addressed and comprehensive re-descriptions carried out allowing palaeocolours to be reconstructed and ecological implications explored. The palaeocolour of the non-avian theropod, Caudipteryx is also investigated in the same manner. Methods for revealing melanosomes (organelles containing melanin) from modern feathers are investigated and revised, allowing comparisons to fossil examples. Using these revised methods, the palaeocolours of several extinct Eocene birds are reconstructed and their likely habitats and ecologies investigated in a phylogenetic framework using melanosome data from their closest living relatives. Novel data on modern melanosomes and the evolution of iridescent colouration in several crown group bird clades are also revealed. My work advances the field of palaeocolour in terms of taphonomic biases involved, how to sample and infer colour patterning with these in mind and finally how to integrate extant and fossil colour data in a phylogenetic comparative framework.

Date of Award	25 Jun 2019
Original language	English
Awarding Institution	University of Bristol
Supervisor	Jakob Vinther (Supervisor), Innes C Cuthill (Supervisor) & Daniel Field (Supervisor)