Jurassic World Evolution

This won't be obtainable until late in the game when all islands are unlocked as to unlock some dig sites you have to have 5 total expedition centers.
Obviously you will need to have at least 50% genome for all dinoaurs, however some need to first be unlocked.
Go to the research tab and click on fossils. The fossil access part needs to all be researched. Some may first require a certain reputation level on certain islands. THE FALLEN KINGDOM FOSSIL ACCESS IS NOT REQUIRED! I know this because I got the achievement without having released a Indoraptor or Allosaurus.
You will also need the Indominus Rex which can be researched in the Genetic Research tab and requires 100% genone for the T-rex and Velociraptor.
If you have at least 50% genome for all dinosaurs and are unsure what you need, i'd recommend heading to Isla Nublar. Hit the pause menu which has sandbox options. Have no escapes active and build a massive enclosure with multiple Hammond creation labs attached. Create one of every dinosaur and hopefully you'll find the one you need. Doing this means money isn't a problem as Isla Nublar has unlimited money,

Hope this helps!