Imaging a newly discovered giant fossil marine reptile flipper with extensive soft tissues and bone-like serrations

Ichthyosaurs were a highly successful group of ancient marine reptiles whose fossils have been studied for more than 200 years. Here we focus on a recently collected, ~1.2 m long, articulated forelimb with a virtually intact soft-tissue outline. This unique fossil includes the first known soft parts of Temnodontosaurus, a giant 10–12 m long apex predator of the Jurassic seas. The fossil illustrates – for the first time – and contrary to all other marine tetrapods (both extinct and extant ones), that the distal fin was unsupported by skeletal elements and that the trailing edge contained bony serrations embedded in the skin. We propose to combine two imaging techniques (using neutrons and X-rays) to better understand the distribution of the soft tissues, to identify important skeletal elements and to visualise the unique 3D dermal ossifications. The expected results will greatly assist in our understanding of the hunting behaviours of this enormous ichthyosaur and whether its unusual forelimb anatomy, combined with its gigantic eyes, helped it to rely on stealth while hunting under the cover of darkness using powerful night-vision.