Frontal bone pneumatisation in Tragoportax and Miotragocerus (Mammalia, Bovidae) from the Late Miocene of Greece

ABSTRACT

Bovidae display a distinctive cranial architecture, characterised by multifarious frontal sinuses varying in size and shape. These features are usually considered to be of phylogenetic importance and their functional importance still remains elusive. Pneumatisation is the process in which cranial sinuses result from the resorption and deposition of the bone in response to biomechanical stress. In this study, we use high resolution computed tomography (CT-scanning) to identify these internal cranial structures on 12 bovid cranial specimens from Upper Miocene Greek localities. The present study focuses on two genera, Tragoportax and Miotragocerus, so as to explore the variance inside this group in terms of frontal sinuses. The non-destructive nature of this method allows 3D digital representation of cranial internal features of fossilised material in high resolution, providing also volumetric data of the sinuses. We demonstrate the unique internal morphology that these species possess. This morphology is comprised by wide frontal sinuses conforming closely to the shape of the frontal bone and that extend up to the base of their horn cores. The volume of the sinuses was strongly correlated to the frontal bone size and cranial volume.

KEYWORDS:

• Tragoportax
• Miotragocerus
• frontal sinus
• CT
• late Miocene

Acknowledgments

We would like to thank the reviewers for their insightful comments. For access to material from Aristotle University of Thessaloniki and permission to CT scan them we thank Prof. Emeritus G. Koufos and Prof. D. S. Kostopoulos. For access to CT medical equipment special thanks deserve to Dr. Koliakos N. and Saradeas Ι. at the Attikon University Hospital, to Dr. Maniatis P. and his team (especially to Dr. Moschouris P. and Dr. Tsipra E.) at the Konstantopouleio General Hospital ‘Agia Olga’ and Dr. Kalogera A. and her team at the University General Hospital of Thessaloniki ‘AHEPA’. Finally, for his constant help and support we would like to thank Prof. Emeritus G. Theodorou (AMPG).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This research is co-financed by Greece and the European Union (European Social Fund-ESF) through the Operational Programme «Human Resources Development, Education and Lifelong Learning 2014-2020» in the context of the project with MIS 5047959.