Here, you can share and discuss your personal headcanons and theories about the franchise. Here is one of mine.
Ingen hasn't really managed to clone dinosaurs from earlier then the Cretaceous like Brachiosaurus and Stegosaurus, due to DNA degradation making it unsuitable for use in the genome. Instead, what its done is its took DNA samples from cretaceous dinosaurs and modified the genome (with the requisite frog DNA of course) to look like them. Specifically, Brachiosaurus are modified from Alamosaurus DNA, Stegosaurus from various Ornithopod and Ceratopsian DNA, Dilophosaurus and Compsognathus from small theropod DNA, and Allosaurus and Ceratorsaurus from Tyrannosaur DNA.