Thalassodraco (meaning "sea dragon") is an extinct genus of ophthalmosaurid ichthyosaur from the Late Jurassic (Tithonian) Kimmeridge Clay Formation of England.

The type species, T. etchesi, was named in 2020, with the epithet in honour of the discoverer of the holotype, Steve Etches.

[2] According to Jacobs & Martill (2020), Etches' museum contains "many ichthyosaurs, including several articulated specimens and numerous isolated skull bones, vertebrae, girdle elements and fore and hind limbs.

"[1] Photographs were provided by Steve Etches when he was notified that the fossil belonged to a new genus in 2016 and the species Thalassodraco etchesi was described in 2020 by Megan L. Jacobs and David M.

[1] The specimens were discovered in strata of the Kimmeridge Clay dating from the Tithonian, the final stage of the Late Jurassic, and belonging to the Pectinatites pectinatus ammonite zone, indicating the fossils were between 149.3 and 149 million years old.

[3][4] Thalassodraco was a medium sized ophthalmosaurid ichthyosaur, reaching up to 2.25 metres (7.4 ft) when fully grown.

The distal ends of the maxilla and dentary are broken off, making exact measurements of the skull impossible, although estimates place it at around 52 centimetres (20 in) when complete.

[1] The teeth of the dentary, maxilla and premaxilla are similar, with slender conical crowns on expanded roots.

On the isolated slabs, there are 16 centra preserved, 13 complete and 2 partial, and one obscured by the rib cage.

[1] The left forelimb has been slightly displaced from the pectoral girdle and is now displayed in dorsal view.

The head of the right humerus is poorly preserved, and is mostly concealed by matrix, meaning that very little useful morphological data can be extracted from it.