In English, the common name for some racial or ethnic groups is a fairly neutral English word (e.g. white, black...). Others, however, are named only by reference to a geographic point of origin (e.g. Indian, East Asian, Pacific Islander...)
How do you describe the latter in a work of speculative fiction where Earth and the corresponding locations do not exist? I would like to have ethnically diverse humans in such settings, but I'm having trouble describing them. Of course I can just not describe such physical traits, but then most readers would simply imagine everyone as white.
I know that you can vaguely allude to skin colour as being brown or 'olive' as well as a number of other possibilities, but I feel unable to indicate anything about nose shape, epicanthic folds or other small characteristic physical properties without beginning to sound like a racist treatise from the 1800's.
Is there a good way to do this? Or should I just not bother and settle for racially ambiguous descriptions?