Notharctus is a genus of adapiform primate that lived in North America and Europe during the early to middle Eocene.
The body form of Notharctus is similar to that of modern rats. Its fingers were elongated for clamping onto branches, including the development of a thumb. Its spine is flexible and the animal was about 40 centimetres (16 in) in length, excluding the long tail.
The evolutionary history of the primates can be traced back 57-90 million years. One of the oldest known primate-like mammal species, Plesiadapis, came from North America; another, Archicebus, came from China. Other such early primates include Altiatlasius and Algeripithecus, which were found in Northern Africa. Other similar basal primates were widespread in Eurasia and Africa during the tropical conditions of the Paleocene and Eocene.Purgatorius is the genus of the four extinct species believed to be among the earliest example of a primate or a proto-primate, a primatomorph precursor to the Plesiadapiformes, dating to as old as 66 million years ago.
The surviving tropical population of primates, which is seen most completely in the upper Eocene and lowermost Oligocene fossil beds of the Faiyum depression southwest of Cairo, gave rise to all living species—lemurs of Madagascar, lorises of Southeast Asia, galagos or "bush babies" of Africa, and the anthropoids: platyrrhine or New World monkeys, catarrhines or Old World monkeys, and the apes, including Homo sapiens.
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