Afrotarsiidae in the context of "Simian"

Afrotarsius is a primate found in the Paleogene of Africa.

The first species to be named, Afrotarsius chatrathi, was named in 1985 on the basis of a single lower jaw from the Oligocene of Fayum, Egypt, and tentatively referred to the tarsier family (Tarsiidae). However, this relationship immediately proved controversial, and in 1987 the animal was placed in a separate family Afrotarsiidae related to simians. A tarsier-like tibiofibula was allocated to Afrotarsius in 1998, but the identity of this bone is controversial. In 2010, a second species of the genus, Afrotarsius libycus, was named from the Eocene of Dur At-Talah, Libya, on the basis of isolated upper and lower teeth. Features of these teeth were interpreted as additional evidence for a relationship between Afrotarsius and anthropoids. A second afrotarsiid genus, Afrasia, was named in 2012 from the Eocene Pondaung Formation of Myanmar. In the same paper, Afrotarsiidae was placed together with the Asian Eosimiidae in an infraorder Eosimiiformes, in the simians. However, some studies indicate that it should be placed in Tarsiiformes.

Afrasia djijidae is a fossil primate that lived in Myanmar approximately 37 million years ago, during the late middle Eocene. The only species in the genus Afrasia, it was a small primate, estimated to weigh around 100 grams (3.5 oz). Despite the significant geographic distance between them, Afrasia is thought to be closely related to Afrotarsius, an enigmatic fossil found in Libya and Egypt that dates to 38–39 million years ago. If this relationship is correct, it suggests that early simians (a related group or clade consisting of monkeys, apes, and humans) dispersed from Asia to Africa during the middle Eocene and would add further support to the hypothesis that the first simians evolved in Asia, not Africa. Neither Afrasia nor Afrotarsius, which together form the family Afrotarsiidae, is considered ancestral to living simians, but they are part of a side branch or stem group known as eosimiiforms. Because they did not give rise to the stem simians that are known from the same deposits in Africa, early Asian simians are thought to have dispersed from Asia to Africa more than once prior to the late middle Eocene. Such dispersals from Asia to Africa also were seen around the same time in other mammalian groups, including hystricognathous rodents and anthracotheres.

Afrasia is known from four isolated molar teeth found in the Pondaung Formation of Myanmar. These teeth are similar to those of Afrotarsius and Eosimiidae, and differ only in details of the chewing surface. For example, the back part of the third lower molar is relatively well-developed. In the Pondaung Formation, Afrasia was part of a diverse primate community that also includes the eosimiid Bahinia and members of the families Amphipithecidae and Sivaladapidae.