I guess it's just because there aren't any ready-made flying dinosaurs whose name they could have used to convey the same idea eh. Gotta think of something!
Anyway, that concept art just makes me super excited. This ride is such a no-brainer it should have happened years ago. I wonder how extensively the trains will be themed? Considering B&M did a really nice job for the Manta trains, I'm sure something equally awesome could be designed for this if Universal are willing to stump up the cash.