The Ceratosaurus like every other dinosaurs in Jurassic Park Builder, can evolve 3 times into three different evolutions. Each evolution has their own baby and adult stage where they will change forms and become even stronger.
When you first discover and create a new dinosaur like the Ceratosaurus they will be at level 1, when you feed the dinosaur to level 5 he will evolve into its adult form for that evolution. Once you reach level 10 you can research and evolve this Ceratosaurus into its second evolution which is generally a different color.
After you have researched the Ceratosaurus he will become a baby again but in its second evolution. You can evolve him into any adult at level 15 where he will continue to grow in that form until level 20.
At level 20 you will be able to research the Ceratosaurus to help him evolve into its third form, which generates you more earnings and changes color once again. Once in its final form you can evolve him into an adult at level 25 then up to level 30.