Xijun Ni Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China University of Chinese Academy of Sciences, Beijing, China
Primates are generally accepted as a crown group that includes all the descendants from the last common ancestor of the lemurs, tarsiers and anthropoids. The oldest-known primate fossils came from the earliest Eocene of Europe, North American and Asia almost simultaneously. Solid fossil evidence combined with total-evidence phylogenetic analyses suggested that Asia is the mostly center for primate origin. After their origins in Asia, primates quickly dispersed to Europe and North America via an east route, a west route or routes of both directions. The divergence between the strepsirrhine primates (lemurs and lemur-like primates) and haplorhine primates (anthropoids, tarsiers and tarsier-like primates) is very deep. The oldest-known and most primitive primates can already be divided into these two clades. A partial primate skeleton discovered from the earliest Eocene of China shows both tarsier-like and anthropoid-like features. Phylogenetic analysis based on large data matrix put this primate at the base of tarsiiform clade, probably very close to the divergent point between tarsiiform and anthropoids. It is very likely that the divergence between anthropoids and other primates is also very deep. During the most of the time of the Eocene, the evolutionary center of anthropoids was in Asia. Diverse Eocene anthropoids were discovered in China, Myanmar and Thailand. In late Middle or early Late Eocene, diverse anthropoids dispersed to Africa, and to South America via Africa. During the Eocene-Oligocene transition, Asian basal anthropoids went extinct, but Africa became the new center for the evolution of anthropoids. Old-world monkeys and apes all originated in Africa.