Definition
"Marginocephalia" is a clade (group) of ornithischian dinosaurs characterized by a bony shelf or ridge at the back of their skulls. This group includes both the pachycephalosaurs (bone-headed dinosaurs) and the ceratopsians (horned dinosaurs). 🧠 The name literally means "margin-headed," referring to the distinct cranial feature. It is a key characteristic that unites these otherwise diverse dinosaurs. Think of it like a family reunion, where everyone has the same weird uncle with the distinctive forehead.