Green land ) ▁might , ▁however , ▁indicate ▁the ▁occurrence ▁of ▁the ▁group ▁in ▁the ▁Late ▁Tri ass ic . ▁By ▁the ▁Late ▁Jur ass ic ▁( 1 5 0 ▁million ▁years ▁ago ), ▁sau rop ods ▁had ▁become ▁w ides p read ▁( es pecially ▁the ▁di pl od oc ids ▁and ▁bra ch ios aur ids ). ▁By ▁the ▁Late ▁C ret ace ous , ▁those ▁groups ▁had ▁mainly ▁been ▁replaced ▁by ▁the ▁tit an osa urs , ▁which ▁had ▁a ▁near - global ▁distribution . ▁However , ▁as ▁with ▁all ▁other ▁non - av ian ▁din osa urs ▁alive ▁at ▁the ▁time , ▁the ▁tit an osa urs ▁died ▁out ▁in ▁the ▁C ret ace ous – P ale ogene ▁ext inction ▁event . ▁F oss il ised ▁remains ▁of ▁sau rop ods ▁have ▁been ▁found ▁on ▁every ▁continent , ▁including ▁Ant arct ica . ▁ ▁The ▁name ▁Sau rop oda ▁was ▁co ined ▁by ▁O . C . ▁Marsh ▁in ▁ 1 8 7 8 , ▁and ▁is ▁derived ▁from ▁Greek , ▁meaning ▁" l izard ▁foot ". ▁Sau rop ods ▁are ▁one ▁of ▁the ▁most ▁recogn izable ▁groups ▁of ▁din osa urs , ▁and ▁have ▁become ▁a ▁fi xture ▁in ▁popular ▁culture ▁due ▁to ▁their ▁impress ive ▁size . ▁ ▁Complete ▁sau rop od ▁foss il ▁finds ▁are ▁rare . ▁Many ▁species , ▁especially ▁the ▁largest , ▁are ▁known ▁only ▁from ▁isolated ▁and ▁dis art ic ulated ▁b ones . ▁Many ▁near - complete ▁spec im ens ▁lack