Riolu is not Lucario and never will be. To say that Riolu is the same species as a Lucario is to say that a person is the same thing as a firefighter. It is possible that one could become another, but they cannot be defined as each other and they are not equal.
The biggest point for my argument is the caterpillar analogy and the fact that Riolu is not a steel type.
Also, if something has to undergo a flashy lightshow just to "grow up" then something's wrong.
Also, it's possible for there to be wild Lucarios, and baby Lucarios via gameshark. How do you explain them if Riolu must become emotionally attached to a trainer in order to evolve?
Obviously, Lucario can have baby Lucario, meaning that your argument has a serious flaw.
It is not possible for Riolu to evolve at night. If 'flashy lightshow" is the sun, then yes, it does need a flashy lightshow to evolve.
I never said a thing about a Riolu to have to become emotionally attached to a trainer. I Riolu can run around and eat berries till its happyness is where it needs to be. Then one day fight something, and win. Resulting in a evolution. Now you have a wild Lucario, without a trainer.
And lucario cannot come out of an egg by normal game measures. With a gameshark, it can.
Also, Charmeleon and Charizard. Same species, different evolutions. Charmeleon is just a fire type, while Charizard is Fire and Flying. But because Charmeleon is the 2nd evolution and Charziard is the 3rd from the 2nd. They are the same species.
Riolu, first evolution, fighting type, lucario is Steel and Fighting, but is the second evoultion of the first. They are the same, but with differences.
A person is not a firefighter, but a firefighter is a person.
A Lucario is not a Roilu, but a Roilu is a Lucario.
-t2