page_title: Eurhinosaurus
section_title: Swimming style and movement
hierarchical_section_title: Eurhinosaurus / Palaeobiology / Swimming style and movement
caption_attribution_description: English: Eurhinosaurus longirostris on display in the Urweltmuseum Hauff, Holzmaden, Germany
context_page_description: Eurhinosaurus is an extinct genus of ichthyosaur from the Early Jurassic, ranging between 183 and 175 million years. Fossils of the aquatic reptile have been found in Western Europe. They used to live in the deep, open sea area. Eurhinosaurus was a large genus of ichthyosaurs. An adult individual could reach over 6 metres.
  Eurhinosaurus followed the regular body morphology, with a fish-like fusiform body including well developed dorsal fin, hypocercal caudal fin, paired pectoral and pelvic fins, and remarkably large eyes. Like other ichthyosaurs, Eurhinosaurus did not have gills and used lungs for breathing. Eurhinosaurus had one distinct feature different from other ichthyosaurs: the upper jaw was twice as long as the lower jaw and covered with up and downwards-pointing teeth.
context_section_description: Like other ichthyosaurs, Eurhinosaurus was a high-speed swimmer. Eurhinosaurus used the lateral oscillation of their caudal fluke on a flexible tail stock for swimming. Eurhinosaurus had a slender fusiform body with long limbs and fluke.  
   Neural spines of fluke vertebrae were very short and almost erect.  The relatively large hind limbs of Eurhinosaurus suggested their use in steering and probably propulsion at a very low speed.  The swimming style of Eurhinosaurus was thunniform. Their hypocercal caudal fin, which was mounted on the narrow peduncle, moved through the water in a sinuous curve by the powerful muscles of the posterior trunk and the anterior tail region. From this motion, a strong force would be generated to pull Eurhinosaurus forward.
  Like other ichthyosaurs, Eurhinosaurus probably was a deep diver. Eurhinosaurus had a very large orbit with sclerotic ring, a circular shaped bone that was embedded in their eye. The sclerotic ring was probably used to maintain the shape of their eyes against the high pressure in the deep sea while they were diving. Ichthyosaurs had the biggest eyes of any animal ever known. The big eye of Eurhinosaurus suggested that they had very good visual capacity, which helped them see clearly in the dark environment of the deep sea.
caption: Eurhinosaurus in the Urweltmuseum Hauff
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