How to get another riolu in pokemon platinum?

Question

I know how to get riolu by hatching it from the egg riley gave you, but is there another way to get riolu without a lucario and a ditto?

Answer 1

Nope. That's the only way. By breeding the Lucario.
You CAN also trade from other Gen IV games. (D, P, Pt, Hg, Ss)
D, P, and Pt can get Lucario easily.