Bone histological correlates for air sacs and their implications for understanding the origin of the dinosaurian respiratory system.

ABSTRACT: Air sacs are an important component of the avian respiratory system, and corresponding structures also were crucial for the evolution of sauropod dinosaur gigantism. Inferring the presence of air sacs in fossils so far is restricted to bones preserving internal pneumatic cavities and foramina as osteological correlates. We here present bone histological correlates for air sacs as a new potential identification tool for these elements of the respiratory system. The analysis of several avian and non-avian dinosaur samples revealed delicate fibres in secondary trabecular and secondary endosteal bone that in the former case (birds) is known or in the latter (non-avian dinosaurs) assumed to have been in contact with air sacs, respectively. The bone histology of this 'pneumosteal tissue' is mark

SUBMITTER: Lambertz M 

PROVIDER: S-EPMC5803587 | biostudies-literature | 2018 Jan

REPOSITORIES: biostudies-literature