I think there might be a couple Vulcan background characters with forehead ridges. My guess is that a significant portion of the early Vulcans that rejected Surak’s teachings were from a particular ethnicity, and the group that left the planet and rebranded as Romulans included most of that ethnicity.
And some forehead ridges, sometimes. Early phenotypical signs of genetic divergence?
I think there might be a couple Vulcan background characters with forehead ridges. My guess is that a significant portion of the early Vulcans that rejected Surak’s teachings were from a particular ethnicity, and the group that left the planet and rebranded as Romulans included most of that ethnicity.