Wannanosaurus
Wannanosaurus is a genus of basal pachycephalosaurian dinosaur from the Maastrichtian-aged Xiaoyan Formation, about 70 million years ago, in what is now Anhui, China. The type species Wannanosaurus yansiensis was described by Hou Lian-Hai in 1977.
It is known from a single partial skeleton, including a partial skull roof and lower jaw, a femur and tibia, part of a rib, and other fragments. Because it has a flat skull roof with large openings, it has been considered primitive among pachycephalosaurs. Sometimes it has been classified as a member of the now-deprecated family Homalocephalidae, now thought to be an unnatural assembly of pachycephalosaurs without domed skulls.
Although its remains are from a very small individual, with a femur length of approximately and an estimated overall length of about, the fused bones in its skull suggest that it was an adult at death. Like other pachycephalosaurs, it was probably herbivorous or omnivorous, feeding close to the ground on a variety of plant matter, and possibly insects as well.