Fantastic utility Dino. You take oxygen from it passively while riding. The oxygen lasts a long time too; this combined with its speed means you can explore anywhere under water. That and it's a chitin machine ;)
They are skittish but not anywhere near faster than humans. They have low torpor and health, so tranq darts are recommended. Tamed like any carnivore, kibble is Archeopteryx. Can be found anywhere in and around the swamps.