>>12546145Dugtrio are three different Digletts living off a common body, when a Diglett evolves it develops two other life-forms similar to it's original form. Meaning that they cannot separate, and if they do (by an external force) they would die since they are dependent on one provider.
>>12546149It's not a Meiotic process since Manaphy is a single organism who divides into two without the need of two (sexually) different gametes.