▁very ▁wide ▁be ak ▁together ▁with ▁a ▁compar able ▁she ath ▁on ▁the ▁short ▁pred ent ary ▁b one ▁at ▁the ▁extreme ▁front ▁of ▁the ▁lower ▁j aws . ▁However , ▁after ▁a ▁rather ▁large ▁di ast ema ▁with ▁the ▁be ak , ▁there ▁were ▁large ▁batter ies ▁of ▁che ek ▁teeth ▁on ▁the ▁sides ▁of ▁the ▁j aws : ▁the ▁g aps ▁between ▁the ▁teeth ▁crow ns ▁were ▁filled ▁by ▁the ▁points ▁of ▁a ▁second ▁generation ▁of ▁replacement ▁teeth , ▁the ▁whole ▁forming ▁a ▁continuous ▁surface . ▁Con tr ary ▁to ▁the ▁situation ▁with ▁some ▁related ▁species , ▁a ▁third ▁generation ▁of ▁er upt ed ▁teeth ▁was ▁lack ing . ▁There ▁were ▁twenty - two ▁to oth ▁positions ▁in ▁both ▁lower ▁and ▁upper ▁j aw , ▁for ▁a ▁total ▁of ▁eight y - e ight . ▁ ▁Post c ran ial ▁ske leton ▁▁ ▁The ▁most ▁consp ic uous ▁feature ▁of ▁Our an osa urus ▁is ▁a ▁large ▁" s ail " ▁on ▁its ▁back , ▁supported ▁by ▁long , ▁wide , ▁neural ▁sp ines , ▁that ▁sp anned ▁its ▁entire ▁r ump ▁and ▁tail , ▁res emb ling ▁that ▁of ▁Sp in osa urus , ▁a ▁well - known ▁meat - e ating ▁din osa ur ▁also ▁known ▁from ▁northern ▁Africa . ▁These ▁tall ▁neural ▁sp ines ▁did ▁not ▁closely ▁res emble ▁those ▁of ▁sail - back s ▁such ▁as ▁Dim et rod on ▁of ▁the ▁Perm ian ▁Period . ▁The ▁supporting ▁sp ines ▁in ▁a ▁sail back ▁become ▁th inner