3 - 2 . ▁The ▁first ▁met at ars al ▁is ▁the ▁st out est , ▁a ▁feature ▁shared ▁among ▁di pl od oc ids . ▁ ▁Disc overy ▁and ▁species ▁ ▁The ▁first ▁A pat osa urus ▁b ones ▁were ▁discovered ▁by ▁Edward ▁Dr ink er ▁C ope ▁and ▁the ▁name ▁A pat osa urus ▁ajax ▁was ▁co ined ▁in ▁ 1 8 7 7 ▁by ▁C ope ’ s ▁rival ▁O th n iel ▁Charles ▁Marsh , ▁Professor ▁of ▁Pale ont ology ▁at ▁Y ale ▁University , ▁based ▁on ▁a ▁nearly ▁complete ▁ske leton ▁( hol ot ype , ▁Y PM 1 8 6 0 ) ▁discovered ▁in ▁the ▁eastern ▁fo oth ills ▁of ▁the ▁Rock y ▁Mountains ▁in ▁G unn ison ▁County , ▁Colorado . ▁The ▁composite ▁term ▁A pat osa urus ▁comes ▁from ▁the ▁Greek ▁words ▁ap at ē ▁() / apat ē los ▁() ▁meaning ▁" de ception " /" de cept ive ", ▁and ▁sau ros ▁() ▁meaning ▁" l izard "; ▁thus , ▁" de cept ive ▁l izard ". ▁Marsh ▁gave ▁it ▁this ▁name ▁based ▁on ▁the ▁che v ron ▁b ones , ▁which ▁are ▁dis similar ▁to ▁those ▁of ▁other ▁din osa urs ; ▁instead , ▁the ▁che v ron ▁b ones ▁of ▁A pat osa urus ▁showed ▁similar ities ▁with ▁those ▁of ▁mos asa urs . ▁During ▁exc av ation ▁and ▁transport ation , ▁the ▁b ones ▁of ▁the ▁hol ot ype ▁ske leton ▁were ▁mixed ▁with ▁those ▁of ▁another ▁A pat osa