Genus PACHYCEPHALOSAURUS
Kingdom / Phylum . . . . . . . . Subphylum / Superclass . . . . Class / Subclass . . . . . . . . . . Infraclass / Division. . . . . . . . Subdivision / Infradivision . . . Superorder / Order. . . . . . . . Suborder / Infraorder . . . . . . Superfamily / Family . . . . . . . Subfamily / Genus . . . . . . . . .	Animalia / Chordata Cephalochordata / Gnathostomata Reptilia / Diapsida Archosauromorpha / Archosauria Avemetatarsalia / Ornithodira Dinosauria / Ornithischia Pachycephalosauria / n.a. n.a. / Pachycephalosauridae n.a. / Pachycephalosaurus
Age: Distribution:	Late Cretaceous North America
Depicted on: Antigua & Barbuda, 1995 (15 c.) Barbuda, 1996 (15 c.) Central African Republic, 2001 (position 2 of sheet 1, misnamed Parasaurolophus) Chad, 2021 (sheet margin) Cuba, 2006 (30 c.) Djibouti, 2021 (M.S. margin) Djibouti, 2022 (position 3 of sheet) Gabon, 1995 (position 6 of sheet 1) Gabon, 2000 (position 8 of sheet 1) Gabon, 2000 (225 Fr.) Gambia, 2003 (position 2 on sheet 1, but Parasaurolophus depicted) Grenada - Grenadines, 1994 (1 $.) Guinea, 1999 (position 5 of sheet) Guinea, 2014 (position 4 of sheet) Guinea, 2019 (position 2 of sheet) Guinea, 2022 (sheet margin, M.S. margin, as Troodon) Guinea-Bissau, 2015 (M.S.) Guinea-Bissau, 2023 (M.S. 1 margin) Guyana, 2001 (position 3 of sheet 3) Korea (South), 2012 (position 1 of sheet) Liberia, 1999 (position 2 of sheet 2) Liberia, 1999 (position 8 of sheet 2) Liberia, 2020 (position 6 of sheet) Liberia, 2024 (position 3 of sheet, M.S. 5) Maldives, 1997 (position 2 of sheet 2) Maldives, 2019 (position 2 of sheet) Mozambique, 2018 (position 1 of sheet) Mozambique, 2019 (position 1 of sheet) Saint Vincent & the Grenadines, 1999 (1,10 $.) Sao Tome e Principe, 2006 (position 1 of sheet) Sao Tome e Principe, 2007 (M.S. 3 margin) Sao Tome e Principe, 2014 (position 4 of sheet) Sao Tome e Principe, 2021 (position 3 of sheet, as Troodon) Sierra Leone, 2019 (position 3 of sheet) Solomon Islands, 2016 (position 20 of sheet) Tanzania, 1992 (position 13 of sheet) Togo, 1994 (180 Fr., set in M.S., and stamp in M.S.) Togo, 1997 (position 8 of sheet) Togo, 2015 (position 3 of sheet) Togo, 2020 (position 4 of sheet) Togo, 2022 (M.S. 2 margin) Togo, 2023 (M.S., as Troodon)