this what different trek series/movies say that a (pure) Andorians should look like.
- The orginal TOS andorians. Blue skin, white hair and thick antennae protruding from back of their head (almost on top of their ears), other wise they look like human (only males seen).
- the TMP Andorians, almost idential to TOS andorians, but have different antennae (thinner and not so insectoid and they come from forehead ridges) and their hair is bit yellow.
- ST IV Andorians. Anntennae closer to TOS design (but still as thin as the TMP design) and the hair is again pure white (only males seen).
- TNG Andorian(from the Offspring". This seem to be B&B at work here. Dark green skin, very thin ridged antennae protruding from same place as TOS andorians (only female hologram seen (thought it looked like a male)).
- ENT Andorian. compromise between the TOS and TMP design. Blue skin, white hair and thin antennae that move (both males and females(and these do not only look female, but sometimes even a bit sexy) seen.
the position (and shape) of the Antennae could Racial difference.
But the TNG srew-up cannot be just different race (it's too different)
the ENT episode "The Aenar" have Andorian Sub-species called The Aenar who pale and blind(, but telepathic), this can explain the TNG Andorians as different sub-species.
so get (pure) Andorians with at least two races(TOS and ENT) and two sub-species the Aenar and the (unnamed)TNG Andorians.
so what do you think?

