Pachycephalosaurus

Pachycephalosaurus was a genus of dinosaur which lived during the last five million years of the Upper Cretaceous. It lived in what is now North America.^[2]

Pachycephalosaurus Temporal range: Late Cretaceous (Maastrichtian), 70–66 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Cast of the "Sandy" specimen, Royal Ontario Museum
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Dinosauria
Order:	†Ornithischia
Suborder:	†Pachycephalosauria
Family:	†Pachycephalosauridae
Tribe:	†Pachycephalosaurini
Genus:	†Pachycephalosaurus Brown & Schlaikjer, 1943
Type species
†Troodon wyomingensis Gilmore, 1931
Species
†P. wyomingensis (Gilmore, 1931) (conserved name) †P. spinifer? (Galton & Sues, 1983)
Synonyms
List Tylosteus ornatus Leidy, 1872 (rejected name) Troodon wyomingensis Gilmore, 1931 Pachycephalosaurus grangeri Brown & Schlaikjer, 1943 Pachycephalosaurus reinheimeri Brown & Schlaikjer, 1943 Stenotholus kohleri Giffin, Gabriel & Johnson, 1988[1] Stygimoloch spinifer? Galton & Sues, 1983 Dracorex hogwartsia? Bakker et al., 2006

This member of the Pachycephalosaurid family is known from a single skull and a few thick skull roofs. From this it is estimated that its length was about 4.5 to 5 metres long (about 15 feet).

Pachycephalosaurus was a herbivore. It lived on a mixed diet of leaves, seeds, and fruit. The sharp, serrated teeth would have been very effective for shredding plants.^[3]

Skeletal mount of Pachycephalosaurus