Homalocephale (from Greek ὁμαλός, homalos, "even", and κεφαλή, kephalē, "head") is a genus of pachycephalosaurid dinosaur that lived during the Late Cretaceous period of what is now the Nemegt Formation, Mongolia, about 70 million years ago.
[1] In 2010, a study by Nick Longrich and colleagues suggested that flat-headed pachycephalosaurs were just juvenile forms of dome-headed adults, a view also supported by the earlier analysis of Horner and Goodwin in 2009.
[2] David C. Evans and team in 2018 reported juvenile specimens of Prenocephale from the Nemegt Formation, noting a relatively linear growth in this pachycephalosaur characterized by a rounded dome.
[4] Unlike other definitely adult pachycephalosaurs (though similar to probable juvenile specimens referred to Dracorex and Goyocephale), Homalocephale sported a flat, wedge-shaped skull roof.
[5] Wannanosaurus yansiensis Colepiocephale lambei Hanssuesia sternbergi Stegoceras novomexicanum Stegoceras validum Goyocephale lattimorei Homalocephale calathocercos Tylocephale gilmorei Foraminacephale brevis Amtocephale gobiensis Acrotholus audeti Prenocephale prenes Alaskacephale gangloffi Pachycephalosaurus wyomingensis Sphaerotholus buchholtzae Sphaerotholus goodwini Homalocephale is also noted for having an unusually broad pelvis and some have suggested that the width served to protect vital organs from harm during flank-butting.