 The epoccipital is a distinctive bones found lining the frills of ceratopsians . The name is a misnomer , as they are not associated with the occipital bone . Epoccipitals begin as separate bones that fuse during the animal 's growth to either the squamosal or parietal bones that make up the base of the frill . These bones were ornamental instead of functional , and may have helped differentiate species . Epoccipitals probably were present in all known ceratopsids with the possible exception of Zuniceratops . They appear to have been broadly different between short @-@ frilled ceratopsids ( centrosaurines ) and long @-@ frilled ceratopsids ( chasmosaurines ) , being elliptical with constricted bases in the former group , and triangular with wide bases in the latter group . Within these broad definitions , different species would have somewhat different shapes and numbers . In centrosaurines especially , like Centrosaurus , Pachyrhinosaurus , and Styracosaurus , these bones become long and spike- or hook @-@ like . A well @-@ known example is the coarse sawtooth fringe of broad triangular epoccipitals on the frill of Triceratops . When regarding the ossification 's morphogenetic traits , it can be described as dermal . The term epoccipital was coined by famous paleontologist Othniel Charles Marsh in 1889 . 
