I did consider Styracosaurus. But not only is the frill not quite "fancy" enough, but they also predated Triceratops by about 10 million years.
In hindsight, it is pretty amazing that the Purple Dragons were even able to take on those two Triceratons.
And even came ready for at least something.
Your Triceraton is on fire!
(And no, it's not ironic that gas was thrown on it,
because oil doesn't come from dinosaurs.)
I could see one of the turtles talking to Ma'riell and pegging the creation of the Triceratons on Krang somehow, and she'd remark something along the lines of "Krang was an arrogant teenager in military training when that started."
("So I'm going to guess the only thing that didn't change was the arrogance?")