Previously unknown dolphin species were present in Switzerland
About 20 million years ago, as the climate became warmer, sea levels rose and flooded the low-lying areas of Europe. At that time, Switzerland was part of an island landscape populated by fish, sharks and dolphins with mussels and sea urchins on the seabed.
Paleontologists from the University of Zurich have now examined around 300 fossils of whales and dolphins from this period. Switzerland’s major natural history and paleontological collections mostly contain fragments of teeth, vertebrae and ear bones found in the Upper Marine Molasse, suggesting that strong currents dragged the animal skeletons across the seabed and scattered the bones.
hearing reconstruction
The bones from the inner ear are the most interesting for research, as they enable allocation to individual species. The problem is that these bone types are less common. “Nevertheless, we managed to identify two dolphin families that were previously unknown in Switzerland,” says paleontologist Gabriel Aguirre, summarizing the study results.
Using micro-computed tomography, the researchers were able to reconstruct the softer organs around the hard ear bones to create 3D models of the ears. “This helped us to better analyze the dolphins’ hearing ability,” explains Aguirre. According to the study data, the extinct animals are related to the sperm whales and ocean dolphins living today.
Literature:
Gabriel Aguirre-Fernández, Jürg Jost and Sarah Hilfiker. First records of extinct kentrodontid and squalodelphinid dolphins from the Upper Marine Molasse (Burdigal Period) of Switzerland and a reassessment of the Swiss whale fauna. PeerJ, May 16, 2022. Doi: 10.7717/peerj.13251