Questionable early occurrences

Eshanosaurus (Hettanginian) was described as a therizinosaur (Xu, Zhao and Clark 2001), but may be a prosauropod.
Yaverlandia (Barremian) was described as a pachycephalosaur (Galton 1971) but has since been proposed as everything except a pebble.
Chaoyangsaurus (Midddle Jurassic) is a good ceratopsian but predates Archaeoceratops by about forty million years.

Eshanosaurus (Hettanginian) was described as a therizinosaur (Xu, Zhao and Clark 2001), but may be a prosauropod.