Avalonianus

"Avalonianus" was first believed to be a dinosaur. It was first described in 1898 by Seeley from teeth from the Late Triassic of England, but the name was preoccupied (Walcott, 1889), so Kuhn renamed it in 1961. It was thought to be a prosauropod, as additional, prosauropod postcranial remains were added to it (which would eventually be named "Camelotia"). Later analysis revealed it was actually a chimera of prosauropod remains ("Camelotia") and teeth from a non-dinosaurian archosaur (or possibly an early theropod).

References

* [http://www.dinosauria.com/dml/names/dinoc.htm Go to "Camelotia"] for more information
* http://www.dinosauria.com/dml/genera.htm