The incubators listed for the Jurassic Ruins are not the ones I’m receiving for battle gameplay. I have NEVER received the creature dna listed for this battleground, such as sinoceratops.
The incubators you win in the arena have a chance to contain the dinos associated with your current arena and all previous ones as well.
So basically, the higher you climb in arena your rewards grow into even bigger 
sandwiches
Rule of thumb: Don’t ever expect to get what’s on the cover and you’ll never be disappointed. Although my rewards have been better lately, historically, most of it is still junk. You may have a better chance to receive new DNA, but you will still have a chance to receive the DNA from previous arenas as well. I do receive quite a bit of galli DNA, and a 2nd random epic has become common as well…still tons of crap, so dont get your hopes up.