▁forms , ▁there ▁is ▁a ▁notable ▁size ▁increase ▁among ▁sau rop od omorph s , ▁although ▁sc ant y ▁remains ▁of ▁this ▁period ▁make ▁interpretation ▁conject ural . ▁There ▁is ▁one ▁definite ▁example ▁of ▁a ▁small ▁derived ▁sau rop od omorph : ▁An ch is aur us , ▁under ▁, ▁even ▁though ▁it ▁is ▁closer ▁to ▁the ▁sau rop ods ▁than ▁Pl ate osa urus ▁and ▁Rio jas aur us , ▁which ▁were ▁up wards ▁of ▁ ▁in ▁weight . ▁ ▁E vol ving ▁from ▁sau rop od omorph s , ▁the ▁sau rop ods ▁were ▁huge . ▁Their ▁giant ▁size ▁probably ▁resulted ▁from ▁an ▁increased ▁growth ▁rate ▁made ▁possible ▁by ▁t ach ym et abol ic ▁end oth erm y , ▁a ▁trait ▁which ▁evol ved ▁in ▁sau rop od omorph s . ▁Once ▁branch ed ▁into ▁sau rop ods , ▁sau rop od omorph s ▁continued ▁stead ily ▁to ▁grow ▁larger , ▁with ▁smaller ▁sau rop ods , ▁like ▁the ▁Early ▁Jur ass ic ▁Bar ap as aur us ▁and ▁Kot as aur us , ▁evol ving ▁into ▁even ▁larger ▁forms ▁like ▁the ▁Middle ▁Jur ass ic ▁M amen ch is aur us ▁and ▁Pat ag osa urus . ▁Res pond ing ▁to ▁the ▁growth ▁of ▁sau rop ods , ▁their ▁ther op od ▁pred ators ▁grew ▁also , ▁as ▁shown ▁by ▁an ▁All osa urus - s ized ▁co el oph y so id ▁from ▁Germany . ▁ ▁Size ▁in ▁Ne os au rop oda ▁Ne os au rop oda