Describer

Williamson & Carr, 2003

Time

Cretaceous Late Maastrichtian

Classification

Ornithischia Genasauria Cerapoda Marginocephalia Pachycephalosauria Pachycephalosauridae [Pachycephalosaurinae]

Diet

Herbivore

Fossilsite

Hell Creek Formation, Carter Co., locality SE¼, Sec. 5, T1S R55E, Montana, US

Possible subjective synonym of Prenocephale

Genus - Typespecies - Skull

Sphaerotholus buchholtzae (Williamson & Carr, 2003) > Sphaerotholus goodwini (Williamson & Carr, 2003)

Possible subjective synonym of Prenocephale

Holotype

TMP 87.113.3: Skull dome

Hypodigm

APK:40/0: Holotype partial skull only, originally referred to the species Stegoceras edmontonense (Giffin, 1989) and thence to Prenocephale edmontonensis (Sullivan, 2000).

Etymology

\\\\\\\"Sphaerotholus,\\\\\\\" from the Greek words for \\\\\\\"ball\\\\\\\" and \\\\\\\"dome\\\\\\\"

Diagnosis

Parietal (in caudal aspect) widely exoosed between squamosals, wide enough to bear parietosquamosal shelf shallowing to greater degree than in Sphaerotholus goodwini, lateral corner node reduce in size relative to Sphaerotholus goodwini, and located above ventral margin of parietosaquamosal bar, nodes in lateral margin of parietosquamosal shelf reduced on squamosal and coalesce into ridge on postorbital (Williamson and Carr, 2002)