, ▁quad ru ped al ▁animal ▁with ▁a ▁long , ▁wh ip - like ▁tail . ▁Its ▁for el im bs ▁were ▁slightly ▁shorter ▁than ▁its ▁h ind lim bs . ▁Most ▁size ▁estimates ▁are ▁based ▁on ▁spec imen ▁C M 3 0 1 8 , ▁the ▁type ▁spec imen ▁of ▁A . lou is ae . ▁In ▁ 1 9 3 6 ▁this ▁was ▁measured ▁to ▁be ▁, ▁by ▁meas uring ▁the ▁verte br al ▁column . ▁Current ▁estimates ▁are ▁similar , ▁finding ▁that ▁the ▁individual ▁was ▁ ▁long ▁and ▁had ▁a ▁mass ▁of ▁. ▁A ▁ 2 0 1 5 ▁study ▁that ▁estimated ▁the ▁mass ▁of ▁vol um et ric ▁models ▁of ▁D read n ought us , ▁A pat osa urus , ▁and ▁G ira ff at itan ▁estimates ▁C M 3 0 1 8 ▁at ▁, ▁similar ▁in ▁mass ▁to ▁D read n ought us . ▁Past ▁estimates ▁have ▁put ▁the ▁creature ' s ▁mass ▁as ▁high ▁as ▁. ▁Some ▁spec im ens ▁of ▁A . ajax ▁( such ▁as ▁O M N H 1 6 7 0 ) ▁represent ▁individuals ▁ 1 1 3 0 % ▁longer , ▁suggesting ▁masses ▁twice ▁that ▁of ▁C M 3 0 1 8 ▁or ▁, ▁potentially ▁riv alling ▁the ▁largest ▁tit an osa urs . ▁ ▁The ▁sk ull ▁is ▁small ▁in ▁relation ▁to ▁the ▁size ▁of ▁the ▁animal . ▁The ▁j aws ▁are ▁l ined ▁with ▁sp at ulate ▁( ch is el - like ) ▁teeth ▁su ited ▁to ▁an