The coast-line on Danakil as an open grassland led to the speciation of grazing horses, where Eurygnathohippus woldegabrieli , the descendant of Miocene E. feibeli which lived and ate in forests, co-existed with Ardipithecus ramidus on Danakil 4.4 million years ago[1].
The geography of Pliocene Danakil could have been similar to the island of Crete, one of the most seismically active areas in the eastern Mediterranean.
Once an island is cut off, there is bound to be rapid evolution to fill all the habitat niches, and in parallel with Eurygnathohippus woldegabrieli, the Paranthropus genus also speciated to feed of the grass, with the oldest fossil found 3.5 million years ago[2], living side by side with Australopithecus afarensis and descendant from the interbreeding event 6 million years ago[3].