I have stated this before. It is impossible for a Rabbit to naturally evolve into a Mimiga and there is no evidence that Rabbits ever existed in cave story's world. Same goes for most other species on the island.
Therefore we likely wouldn't have names for most of the unevolved forms of the species in the island's ecosystem.
Futhermore before anyone states that CS' world is Earth you must take Ikachan's world into account as it's species also bear similarities to our own, and note that the use of "Earth" in the script was a mistranslation of "surface". Sorry but I can't be bothered
@Gir: I think MS is talking about his idea that they were made using magic.
@MS: Misery lacks the power to produce true manipulation of matter, Ballos' couldn't either by the looks (not that he was sane enough to do so anyway), and Jenka is weaker than Ballos and quite frankly would consider it morally wrong. Without true manipulation of matter a transformed species would produce the original species during reproduction. It wouldn't work.
So MS, you state that someone more powerful than Ballos in some far off time made the creatures on the island with "magic" for shits and giggles? Seriously?
Ladies and gentlemen, I welcome you to the long running CS Earth debate.