The detailed anatomy of Rhamphorhynchus II: braincase, pneumatics and jaws

Abstract

This second contribution on Rhamphorhynchus based on an acid-prepared specimen provides a detailed description of the braincase, concentrating on the broken skull and its hollow bones, aiming to gather data on its pneumatisation for comparative studies between crocodiles, pterosaurs and dinosaur-birds. Computed tomographic (CT) scanning was performed to further explore these cavities in the skull bones, which are easily visible especially where the bones are broken. However, it has not been possible to observe their precise origin and connections. The skull regions where the pneumatisation is most evident are the paroccipital processes and the prootics from the endoskeletal braincase, but the precise form of the cavities is not clear, and their origin as paratympanic systems cannot be seen. CT scanning with better resolution might show more details of the skull pneumatics to be used in a phylogenetic analysis.

Keywords::

• pterosaurs
• Rhamphorhynchus
• braincase
• jaws
• skull pneumatics
• Jurassic
• Solnhofen

Acknowledgements

We thankful Sten L. Jakobsen, Geological Museum (SNM) Copenhagen, for photographs of MGHU 1891.738.Aarhus Kommunehospital, X-ray Department and N J Rosenkrants did the CT scanning of the specimen, and it was improved and reconstructed by Dr N Lynnerup and his students, Department of Forensics, Panum Inst, Copenhagen University, as well as by the 3D laboratory, National Museum of Rio de Janeiro (MN-UFRJ), by Dr Sergio Alex K. Azevedo and students (Fernanda, Igor and Bruno), and some of the latter and Dr Luciana B de Carvalho shared a lot of literature with us in discussions about pneumaticity – we thank them all for their help as well as Drs Alex Kellner (MN-UFRJ) and Taissa Rodrigues (UFES, Vitória) for a most informative meeting in Rio de Janeiro and fieldtrip to Ceará. Lorna Steel (NHM, London) kindly contributed the photograph of Rhamphorhynchus longiceps holotype. Rodrigo V. Pêgas (MN-UFRJ) discussed several aspects with us, Samila B. Lisboa helped with text editing, and the following colleagues and institutions made pterosaur material available for us in 2014: Dr M Lamanna, Carnegie Museum, Pittsburgh; Drs Anna Paganoni and Annelisa Aiello, Museo Civico Ist Naturale, Bergamo; and Dr Mariagabriella Fornasiero, Museo di Geologia e Paleontologia in Padova. We thank all of them for their help and hospitality, as well as the editor in Historical Biology for great patience, and two and a half reviewers for helpful remarks and criticism (Drs Ösi, Bennett resp. Martill).

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplemental data

Supplemental data for this article can be accessed here: http://dx.doi.org/10.1080/08912963.2014.993630.

Notes

^1. Email: [email protected]

Additional information

Funding

Fur Museum (Muserum Salling) financially supported N. Bonde's travelling during this study. M.E.C. Leal is supported by a CNPq/ FUNCAP grant [grant numbers CNPq/ 305426/2014-1 and DCR-0024-01186.01.00/14].