A new approach to understanding the origins of the bird respiratory system

Crucial to the spectacular evolutionary success of modern birds is their uniquely efficient respiratory system. Dinosaur skeletons show that this system first appeared in fossil ancestors of birds. However, its earliest evolution is cryptic and poorly understood. We will break a current impasse by analysing the internal histology of bones of dinosaurs and their relatives, searching for a recently identified hard tissue that is correlated with the presence of this system. This tissue type is normally identified through destructively sampling fossils, limiting its use in rare and scientifically significant specimens. We aim to test whether synchrotron tomography is able to detect this bone tissue, which is composed of tiny asbestiform densely packed fibres of <60μm, providing a non-destructive way to study this tissue. Our work will reveal the early evolutionary history of bird respiration, answering key questions about the success of dinosaurs, birds and their kin.