. ▁ ▁History ▁ ▁Baron ▁Franz ▁N op cs a , ▁in ▁ 1 9 0 2 , ▁proposed ▁a ▁new ▁grouping ▁of ▁din osa urs , ▁A can th oph olid idae , ▁a ▁cla de ▁of ▁light ly - built ▁thy re op hor ans . ▁He ▁included ▁in ▁it ▁the ▁gener a ▁A can th oph olis , ▁Pol ac anth us , ▁Sy ng on osa urus , ▁Str uth ios aur us , ▁and ▁possibly ▁N od osa urus . ▁So on ▁after , ▁he ▁also ▁added ▁Pri od ont ogn ath us ▁and ▁Pala e osc inc us . ▁He ▁considered ▁A can th oph olid idae ▁to ▁be ▁the ▁sister ▁cla de ▁to ▁Ste g osa ur idae , ▁and ▁also ▁stated ▁that ▁it ▁might ▁include ▁Hy la e osa urus , ▁which ▁he ▁found ▁had ▁most ▁of ▁the ▁characteristics ▁of ▁the ▁family . ▁Later , ▁in ▁ 1 9 1 5 , ▁he ▁re arr anged ▁the ▁species ▁included ▁in ▁it . ▁The ▁gener a ▁that ▁were ▁later ▁included ▁were ▁A can th oph olis ▁(= An op l osa urus ), ▁Pol ac anth us , ▁Ste g op elta , ▁Ste g oc eras , ▁and ▁Str uth ios aur us . ▁Al ong ▁with ▁An k yl osa urus , ▁A can th oph olid idae ▁was ▁defined ▁to ▁form ▁a ▁sub family ▁of ▁N od osa ur idae . ▁In ▁ 1 9 2 3 ▁he ▁divided ▁up ▁the ▁family ▁into