First ichthyosaur remains from Denmark within glacial erratics

Ichthyosaurs were widespread and diverse across Europe from the Triassic to the beginning of the late Cretaceous. However, they are relatively rare within Scandinavia, with specimens only known from Arctic Norway. In Denmark, plesiosaur fossils are known from the Jurassic of the island of Bornholm, but no ichthyosaur remains have ever been published either in situ or ex situ. Here we report, for the first time, an ichthyosaur vertebra found in a loose block on the shore at Lodbjerg Klint in western Jylland, and a second block containing ribs from an indeterminate marine reptile, most likely a plesiosaur. The vertebra can be identified as originating from the anterior portion of the tail in a thunniform ichthyosaur and shows similarity to several Jurassic taxa including Ichthyosaurus communis, Eurhinosaurus longirostris, Temnodontosaurus trigonodon and Ophthalmosaurus, although an exact determination is not possible. The most prolific sites for ichthyosaurs in the neighbouring countries, in the UK and Germany, are ruled out as a source due to long distance, and lack of glacial transport from these directions. We postulate the origin of the specimen is from Jurassic outcrops within the Skagerrak–North Sea region, transported by south and south-westerly flow of Pleistocene glaciers.