Well, back to the topic..
I can see where you think they are alike. However, there are several differences that make them unique. First of all, Cubone is a bit.. Chubbier than Charmander. It also has a stubbier tail. Plus, if you have ever heard of Missingno, you would know that Cubone and Marowak were supposed to be children of Kangaskhan who's mother was killed and they took the skull.
