I can see how it would be hard to tell. There are three others here from my version of Earth, as best I can tell. Jacob and Evie Frye, and Ezio Auditore. And we definitely do not have horse-sized lizards. The closest we'd have to that are alligators or crocodiles, but they're a bit too low to the ground to ride. And also vicious carnivores.
Speaking of horses, though, did you want to give the iron horse a try? I should warn you it goes quite fast and we haven't gotten around to building any safety equipment yet, so you'd be taking your life into your own hands a bit. It is fun, though.