MetaHub.info has a blogpost dated July 26th that contains this type of info (see link below), but here is the gist:
Sarcosuchus is a “local anytime” spawn that appears in areas where Common Dilophosaurus, Deinocheirus, and Tenontosaurus spawn.
Dilophosaurus (Rare) is a “local” spawn found during Day/Dawn/Dusk where Euoplocephalus, Lythronax, and Purrusaurus Gen 2 can be seen.
The charts have gotten a little more difficult to interpret with this latest update, but that comes with the added variety of creatures. And yes, in other words, you’ll have to seek out specific types of creatures in different areas until you learn where they tend to be. It’ll be a new learning curve for all of us.
Best of luck and happy hunting!