Nedoceratops

Nedoceratops (meaning "insufficient horned face") is a controversial genus of ceratopsid dinosaur from the Late Cretaceous period Lance Formation of North America. It is known only from a single skull discovered in Wyoming. Its status is the subject of ongoing debate among paleontologists: some authors consider Nedoceratops a valid, distinct taxon, while others consider it to be an unusual specimen of Triceratops.

History of discovery

The nearly complete skull USNM 2412, the holotype specimen of Nedoceratops hatcheri, was found in eastern Wyoming in 1891, in Niobrara County near Lightning Creek.

The paper that described Nedoceratops was originally part of O. C. Marsh's magnum opus, his Ceratopsidae monograph. Marsh died in 1899 before the work was completed, and John Bell Hatcher endeavored to complete the Triceratops section. However, he died of typhus in 1904 at the age of 42, leaving the paper still incomplete. It fell to Richard Swann Lull to complete the monograph in 1905, publishing Hatcher's description of a skull separately and giving it the name Diceratops hatcheri; Diceratops means "two horned face."

Since the Diceratops paper had been written by Hatcher, and Lull had only contributed the name and published the paper after Hatcher's death, Lull was not quite as convinced of the distinctiveness of Diceratops, thinking it primarily pathological. By 1933, Lull had second thoughts about Diceratops being a distinct genus and he put it in a subgenus of Triceratops: Triceratops (Diceratops) hatcheri, including T. obtusus; largely attributing its differences to being that of an aged individual.

Because the Diceratops name was already in use for a hymenopteran (Förster, 1868), Andrey Sergeevich Ukrainsky gave the animal its current name Nedoceratops in 2007.