No photos, I saw three different groups of them in area, but failed to be quick enough to get any pictures of the fleeing monkeys.
I did get a decent, albeit quick, look at one. And I was also with somebody who recognized their alarm calls and knows Bioko's primates well.
small-bodied, leaf litter skink
2x individuals seen in same small area
May be same individuals as http://www.inaturalist.org/observations/56149
black bird pair