Protoceratops

Protoceratops ( /ˌproʊtoʊˈsɛrətɒps/; from Greek proto-/πρωτο- "first", cerat-/κερατ- "horn" and -ops/-ωψ "face", meaning "First Horned Face") is a genus of sheep-sized (1.5 to 2 m long) herbivorous ceratopsian dinosaur, from the Upper Cretaceous Period (Campanian stage) of what is now Mongolia. It was a member of the Protoceratopsidae, a group of early horned dinosaurs. Unlike later ceratopsians, however, it was a much smaller creature that lacked well-developed horns and retained some primitive traits not seen in later genera.

Protoceratops had a large neck frill, which may have served to protect the neck, to anchor jaw muscles, to impress other members of the species, or combinations of these functions. Described by Walter W. Granger and W.K. Gregory in 1923, Protoceratops was initially believed to be an ancestor of the North American ceratopsians. Researchers currently distinguish two species of Protoceratops (P. andrewsi and P. hellenikorhinus), based in part by their respective sizes.

In the 1920s, Roy Chapman Andrews discovered fossilized eggs in Mongolia that were interpreted as belonging to this dinosaur, but which turned out to be those of Oviraptor.