Final answer:
The Miocene epoch brought forth significant early apes like Proconsul and Sivapithecus, which demonstrate key evolutionary traits that connect them to modern primates. These characteristics include a 2.1.2.3 dental formula and similarities with orangutans in Sivapithecus. The Pliocene featured hominin species like Australopithecus afarensis, with 'Lucy' as a pivotal discovery.
Step-by-step explanation:
The Miocene epoch is characterized by the presence of early apes such as Proconsul, which is considered a proconsuloid and signifies an important stage in primate evolution. These apes moved generally on all four limbs and lacked tails, distinguishing them from monkeys. One notable aspect of Proconsul is that their teeth, which followed the pattern of 2.1.2.3, a trait shared with both Old World monkeys and apes, hinting at their evolutionary relationships.
A distinct Miocene ape, Sivapithecus, exhibits characteristics remarkably similar to the modern orangutan, with a thick dental enamel that suggests a diet of hard foods. Their fossils are abundant throughout Asia, contributing valuable insights into ape evolution and dietary adaptations. The cranial features shared with orangutans point towards similar phylogenetic pathways.
Other epochs such as the Oligocene highlight the first fossil monkeys with new and Old World classifications, and the Eocene epoch marks significant evolutionary advancements like development of postorbital bars and specific dental traits.
The Pliocene epoch is vital for understanding the evolutionary trajectory of hominins, epitomized by species like Australopithecus afarensis, with 'Lucy' being the most famous specimen of this species that underscores crucial evolutionary trends in humans such as reduced dentition and prognathic jaws.