Funktionelle Schädelmorphologie archaeoceter und mysticeter Wale und der mögliche Verlust von Schädelasymmetrie in Verbindung mit der Entwicklung des niedrigfrequenten Hörens bei Bartenwalen

• Antragsteller: Privatdozent Dr. Oliver Hampe, seit 8/2016
• Fachliche Zuordnung: Paläontologie
• Förderung: Förderung von 2012 bis 2017
• Projektkennung: Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 231473506

Whales evolved from small terrestrial artiodactyls, and all Neoceti (toothed and baleen whales) originate from within Eocene archaeocetes. Directional cranial asymmetry in toothed whales (Odontoceti) is well known and supposed to be related to the dual function of their nasal apparatus in breathing and high-frequency sound production (echolocation). Recent research shows that archaeocete whales also have directionally asymmetrical skulls, and that this asymmetry is likely linked to directional hearing of mid-to-high frequencies in water. Baleen whales (Mysticeti) that produce and hear low frequencies have commonly been assumed to have symmetrical skulls. The working hypothesis of the proposed project is that cranial symmetry in extant mysticetes – if they are truly symmetrical – is secondary, and that asymmetry was reduced during mysticete evolution when the ability to hear low frequencies evolved.Based on currently conducted research, and in collaboration with other researchers, this project aims to understand the evolution and functional morphology of cranial asymmetry in whales in relation to the frequencies they hear or heard. For this purpose, neutron computer tomography (CT) and photogrammetry are going to be used in addition to conventional x-ray CT and laser scanning in order to produce three-dimensional (3D) models of archaeocete and mysticete skulls. From these, asymmetry shall be quantified using morphometrical approaches. Simultaneously, the internal anatomy of selected skulls will be studied in order to detect possible connections between asymmetry and the development or reduction of cranial structures, especially those related to pneumatization and sound production. This study is going to yield insight into the mechanisms of the evolution and diversification of whales with special regard to the changes of terrestrial cranial structures during adaptation to an aquatic environment and specialization within it. General implications for similar mechanisms in other secondarily aquatic vertebrates are expected. A subsequent evaluation of the scanning and visualization techniques used shall provide implications for a more efficient use of these methods in future paleontological studies.

• DFG-Verfahren: Sachbeihilfen
• Ehemalige Antragstellerin: Dr. Julia M. Fahlke, bis 8/2016