▁This ▁defect ▁might ▁have ▁been ▁caused ▁by ▁the ▁lack ▁or ▁in hib ition ▁of ▁the ▁subst ance ▁that ▁forms ▁inter verte br al ▁dis ks ▁or ▁joint s . ▁It ▁has ▁been ▁proposed ▁that ▁the ▁wh ips ▁could ▁have ▁been ▁used ▁in ▁combat ▁and ▁defense , ▁but ▁the ▁t ails ▁of ▁di pl od oc ids ▁were ▁quite ▁light ▁and ▁narrow ▁compared ▁to ▁Sh un osa urus ▁and ▁m amen ch is aur ids , ▁and ▁thus ▁to ▁inj ure ▁another ▁animal ▁with ▁the ▁tail ▁would ▁sever ely ▁inj ure ▁the ▁tail ▁itself . ▁ ▁Pale o ec ology ▁ ▁The ▁Mor r ison ▁Form ation ▁is ▁a ▁sequence ▁of ▁shall ow ▁marine ▁and ▁all uv ial ▁sed iments ▁which , ▁according ▁to ▁radi ometric ▁d ating , ▁dates ▁from ▁between ▁ 1 5 6 . 3 my a ▁at ▁its ▁base , ▁and ▁ 1 4 6 . 8 my a ▁at ▁the ▁top , ▁placing ▁it ▁in ▁the ▁late ▁Oxford ian , ▁Kim mer id g ian , ▁and ▁early ▁T ith onian ▁stages ▁of ▁the ▁Late ▁Jur ass ic ▁period . ▁This ▁formation ▁is ▁interpreted ▁as ▁origin ating ▁in ▁a ▁locally ▁sem iar id ▁environment ▁with ▁distinct ▁wet ▁and ▁dry ▁seasons . ▁The ▁Mor r ison ▁Bas in , ▁where ▁din osa urs ▁lived , ▁stretch ed ▁from ▁New ▁Mexico ▁to ▁Al berta ▁and ▁S ask atch ew an ; ▁it ▁was ▁formed ▁when ▁the ▁prec urs ors ▁to ▁the ▁Front ▁Range ▁of ▁the ▁Rock y ▁Mountains ▁started ▁pushing ▁up