geographic what if

Okay, so I found this map of Africa on the Imaginary Maps reddit: ...and I have been picturing an Africa in an alternate Earth where the lands of Turkey, Iran and the Arabian Peninsula never physically existed. Combine all of those features, and how would Africa's landmass be affected...

Up until the late 15th century, it was possible to walk between India and Sri Lanka, because Adam's Bridge was entirely above sea level. Then, in about 1480, a cyclone hit the bridge, causing parts of it to be permanently submerged. What if Adam's Bridge had remained passable on foot?