Named By: W. Bock - 1945.
Classification: Chordata, Reptilia, Archosauromorpha, Prolacertiformes, Tanystrophidae.
Species: G. erici (type).
Size: Roughly estimated to be about 18 centimetres long.
Known locations: USA, Pennsylvania - Lockatong Formation.
Time period: Norian of the Triassic.
Fossil representation: Partial and fragmentary remains.
During its taxonomic history Gwyneddosaurus has been identified as being several different types of animals, from a theropod dinosaur to a protosaur. Today however the wider consensus is that Gwyneddosaurus was a relative to the better known Tanystropheus, and marine reptile noted for having a particularly long neck. The type specimen of Gwyneddosaurus however is of a vastly smaller individual than what we usually see in Tanystropheus. There is speculation that Gwyneddosaurus may be synonymous with the genus Tanytrachelos, however if this were the case it would be preferable to preserve Tanytrachelos as a valid name since this genus is based upon vastly superior fossil remains than Gwyneddosaurus, which may have fossils from a coelacanth fish accidentally confused with it.
- A new small reptile from the Triassic of Pennsylvania. - Notulae Naturae 154:1-8. - W. Bock - 1945.
- Notes on Gwyneddosaurus. - The American Journal of Science, series 5 246:208-213. - Friedrich von Huene - 1948.