Final answer:
The main differences between Miocene and Oligocene fossil primates lie in the progression from early monkey species with specific dental formulas in the Oligocene, to the earliest evidence of apes in the Miocene with features aligning more closely to modern-day hominids, including changes in limb structure and dental enamel.
Step-by-step explanation:
Differences Between Miocene and Oligocene Fossil Primates
The fossil primates of the Oligocene epoch primarily consisted of early monkeys found at the Fayum site in Egypt, with significant findings such as the Parapithecoidea and Propliopithecoidea groups. These primates had a dental formula characteristic of some of the earliest New World and Old World monkeys, respectively. The Oligocene primates are also notable for the absence of a third premolar.
During the Miocene epoch, the fossil record shifts to evidence of the earliest apes, such as Proconsul and Sivapithecus. Miocene apes, unlike later apes, lacked long, curved digits and a tail, indicating they moved on all four limbs more often than hanging from branches. Sivapithecus in particular, with its thick dental enamel and skull resembling that of the modern orangutan, is indicative of evolutionary developments in Miocene apes, which align more closely with modern-day hominids, contrasting with the dental patterns and bodily structures of Oligocene primates.