s it fair to say the shared ancestor was dark skinned?
This is an accurate map of that shared ancestry. It originated in Iran and spread westwards towards India. I believe this ancestry is responsible for the hairy look. Notice how Italians and Greeks have it as well. It’s what makes them extra hairy compared to other Europeans
Only reason why it’s abundant in India compared to Iran where this ancestry originates is because Iran, Saudi, Egypt etc have other ancestries on top of this one. Below for example you see the shared ancestry Somalis and Arabian have that makes us a bit similar as noted by OP. This ancestry is the Natufian related ancestry. Bedouin groups and other Semites especially lthe Mehri have this at 70%+
Another major ancestry in the mix is the Anatolian farmer that spread into Europe successfully and even reached Morocco and Algeria hence the whiter complexion they have compared to Egyptians, Saudi etc