I'll start by saying that the dinosaur classifications present in the JW Database all appear to be correct, at least for the species I've unlocked so far.
But in Challenge Mode, you have to research new species before putting them in your parks. These species are broken down into groups: ceratopsids, pachycephalosaurs, sauropods, stegosaurids, etc.
It's been previously mentioned that Dryosaurus is referred to as an ornithomimid in the research system of Challenge mode. If you're going to have the ornithomimids and Dryosaurus in the same chain of unlocks, there's really nothing you could refer to them collectively as other than "small dinosaurs" or "small herbivores." This is because Dryosaurus was an ornithischian and ornithomimids were saurischian so they are on opposite sides of the dinosaur family tree. But you could have the unlocks be referred to as Small Herbivores 1, Small Herbivores 2, etc.
I've also noticed that Muttaburrasaurus and Iguanodon are referred to as hadrosaurs. I think Ouranosaurus is as well, but I haven't unlocked it yet so I'm not sure. Muttaburrasaurus, Iguanodon, and Ouranosaurus were not hadrosaurs. If you are looking for a group which includes Muttaburrasaurus, Iguanodon, and Ouranosaurus plus the hadrosaurs in the game, that would be the Ornithopoda, referred to as "ornithopods."
https://en.wikipedia.org/wiki/Ornithopoda
Dryosaurus was an ornithopod as well, but I understand it might be grouped with the ornithomimids for gameplay reasons. However I respectfully submit that the "hadrosaur" unlock tree should be labeled Ornithopods 1, Ornithopods 2, etc. It's one thing to take artistic license with the appearance of a dinosaur, but I don't think the game should be labelling dinosaurs inaccurately in terms of their classification.
But in Challenge Mode, you have to research new species before putting them in your parks. These species are broken down into groups: ceratopsids, pachycephalosaurs, sauropods, stegosaurids, etc.
It's been previously mentioned that Dryosaurus is referred to as an ornithomimid in the research system of Challenge mode. If you're going to have the ornithomimids and Dryosaurus in the same chain of unlocks, there's really nothing you could refer to them collectively as other than "small dinosaurs" or "small herbivores." This is because Dryosaurus was an ornithischian and ornithomimids were saurischian so they are on opposite sides of the dinosaur family tree. But you could have the unlocks be referred to as Small Herbivores 1, Small Herbivores 2, etc.
I've also noticed that Muttaburrasaurus and Iguanodon are referred to as hadrosaurs. I think Ouranosaurus is as well, but I haven't unlocked it yet so I'm not sure. Muttaburrasaurus, Iguanodon, and Ouranosaurus were not hadrosaurs. If you are looking for a group which includes Muttaburrasaurus, Iguanodon, and Ouranosaurus plus the hadrosaurs in the game, that would be the Ornithopoda, referred to as "ornithopods."
https://en.wikipedia.org/wiki/Ornithopoda
Dryosaurus was an ornithopod as well, but I understand it might be grouped with the ornithomimids for gameplay reasons. However I respectfully submit that the "hadrosaur" unlock tree should be labeled Ornithopods 1, Ornithopods 2, etc. It's one thing to take artistic license with the appearance of a dinosaur, but I don't think the game should be labelling dinosaurs inaccurately in terms of their classification.