Micropachycephalosaurus hongtuyanensis

Micropachycephalosaurus is an extinct genus of basal marginocephalian dinosaur, containing only the type species, Micropachycephalosaurus hongtuyanensis. It lived in China during the Late Cretaceous (Campanian) and was found in the Jiangjunding Formation. It has the longest name of any dinosaur, with 23 letters in the genus name alone, while the full binomial contains 37 letters.