Almost 20 million years ago, Switzerland was a part of an Island populated by fish, sharks, and dolphins, with mussels and sea urchins on the seabed. Paleontologists at the University of Zurich have investigated over 300 whale and dolphin fossils from this period. Strong currents pulled the animal skeletons across the ocean floor. They scattered the bones, according to the important natural history and paleontology collections in Switzerland, which mainly contain fragments of teeth, vertebrae, and ear bones found in the Upper Marine Molasse.
Scientists have discovered two previously unknown species related to modern sperm whales and oceanic dolphins based on their found earbones.
While classifying individual species, they identified bones from the inner ear. These bones are less commonly found.
Paleontologist Gabriel Aguirre, summarizing the study results, said, “Nevertheless, we managed to identify two families of dolphins previously unknown in Switzerland.”
Scientists used micro-computed tomography to reconstruct the softer organs around the hard ear bones to create 3D models of the ears. This helped scientists to analyze the dolphins’ hearing ability better.
The study suggests that the extinct animals are related to sperm whales and oceanic dolphins living today.
Journal Reference:
- Gabriel Aguirre-Fernández, Jürg Jost and Sarah Hilfiker. First records of extinct kentriodontid and squalodelphinid dolphins from the Upper Marine Molasse (Burdigalian age) of Switzerland and a reappraisal of the Swiss cetacean fauna. PeerJ, 2022. Doi: 10.7717/peerj.13251