I looked around and couldn't find an answer to this question, so I'll ask it:
Are all "normal" Matoran like the Metru Nui Matoran? Because I noticed that every other type appears to have an explanation for why they don't look like the Metruans.
Mata Nui Matoran were shrunk by the spheres
Voya Nui Matoran were "fixed" by Karzahni
Mahri Nui Matoran were mutated by the Pit
Karda Nui Av-Matoran are extra large when they're in Karda Nui
The only Matoran sets I can't find a reason for are Mazeka, Vultraz, and Vican (although we can possibly just explain that away because they came out at the same time as the Av-Matoran).
So, does anyone know if the Metru form is considered standard and, if so, what's up with these three exceptions?