I went to raid a base with 4 buddies, a rex, 3 carnos, and a bronto with a platform saddle and cannons. All we heard was a whistle and i swear about 50 of these little devil's swarmed the whole group, killing everyone in the group and one carno, the turrets shredded everything else, but the rex must have ran off and we never got a death message so its still out there in the jungle.
When in areas that have many dimorphadon remember to be careful and not to hit one by accident when fighting other creatures as you can easily be overwhelmed.your mount will not be able to save you as they deal damage directly to the rider.
Whatever you do, DO NOT piss these things off when you have low level dinos. You accidentally hit one while attacking something else, and 6 more will pop out of nowhere, and swarm you-killing 2 mid level pteranodons, your FIRST 2 EVER Argies, and leaving you 300 metal and crystal in the negative.