On mobile (may work on other platform to idk) these guy have lot of amor so even if you try using a spino that deal 500+ damage, to it will only be about 100 damage. Trust me i tried

There is one simple cheap way to kill them but time consuming is to lure them into the ocean(i use high lv pter) make sure the ocean is deep enough to cover it whole body then use a aquatic or creature that can swim(i use high lv spino).Next just attack it from above, thank to it huge hit box, you can keep hitting it from above while it just swiming around unable to stomp you

Just dont go below it as it still can stomp while underwater