1. (noun) extinct terrestrial reptiles having bird-like pelvises: armored dinosaurs (thyreophorans); boneheaded and horned dinosaurs (marginocephalians); duck-billed dinosaurs (euronithopods)

• order ornithischia

1. (noun) extinct terrestrial reptiles having bird-like pelvises: armored dinosaurs (thyreophorans); boneheaded and horned dinosaurs (marginocephalians); duck-billed dinosaurs (euronithopods)

• animal order

1. (noun) extinct terrestrial reptiles having bird-like pelvises: armored dinosaurs (thyreophorans); boneheaded and horned dinosaurs (marginocephalians); duck-billed dinosaurs (euronithopods)

• archosauria
• subclass archosauria

1. (noun) extinct terrestrial reptiles having bird-like pelvises: armored dinosaurs (thyreophorans); boneheaded and horned dinosaurs (marginocephalians); duck-billed dinosaurs (euronithopods)

• euronithopod
• euronithopoda
• ornithopoda
• suborder euronithopoda
• suborder ornithopoda
• genus pisanosaurus
• genus staurikosaurus
• marginocephalia
• marginocephalian
• suborder marginocephalia
• ornithischian
• ornithischian dinosaur
• suborder thyreophora
• thyreophora
• thyreophoran