Primates from the Baynunah Formation

Fossil primates of the Baynunah Formation are represented by only two cercopithecoid specimens: AUH 35, a male lower canine of an indeterminate cercopithecid from site JDH-3, and AUH 1321, a lower molar of a guenon from site SHU 2-2. Although rare, these cercopithecoid primates are significant in terms of their age and biogeographic implications. AUH 1321 is the earliest known guenon in the fossil record, and at ~8 – 6.5 Ma, it is also one of the earliest cercopithecines known. The age and geographic position of both specimens in the Arabian Peninsula supports late Miocene Eurasian dispersal scenarios for cercopithecoid primates out of Africa and through Arabia before the Messinian Crisis. Whether or not this dispersal included both cercopithecines (macaques) and colobines is unclear, and it re- mains possible that both groups also dispersed across the Mediterranean Basin or Straits of Gibraltar during the Messinian as well. Among the potential Arabian dispersal routes, there is perhaps some support for the southern path over the Straits of Bab el Mandeb based on the presence of ~8 – 5.5 Ma cercopithecine and colobine fossils in the East African fossil record, geographically close to the Horn of Africa.