Eosimiidae
Eosimiidae is the possible family of extinct primates believed to be the earliest simians.
Taxonomy
When they were discovered, the possibility that eosimiids were outside and ancestral to simians was considered, but subsequent work showed them to be true simians. Some scholars continue to question whether the eosimiids are simians, as they seem closer to Tarsiiformes - Gunnell and Miller, for instance, found that eosimiid morphology did not match up to anthropoid morphology. However, most experts now place eosimiids as stem simians - Williams, Kay and Kirk note more and more evidence points to that conclusion.Williams, Kay and Kirk note that, accounting for all proposed species, there would be 11 species in total in 6 genera. There appears to be a wealthy diversity of eosimiids in China.
With several genera, such as Phileosimias, and Anthrasimias, their classification as eosimiids appears to be unclear. Marivaux et al. suggest three definite groups of Eosimiidae: Bahinia, Phenacopithecus and Eosimias. They announced their discovery of fossils of two new species, Phileosimias kamali and Phileosimias brahuiorum. They concluded that Phileosimias are also early simians, and that the more modern simians may have emerged as their sister group. Williams, Kay and Kirk note that both Gunnell et al. and Kay et al. argue that Anthrasimias should be classified as Adapiforms, and that Rosenberger and Hogg express doubts about Bahinia pondaungensis. They also note that whilst most analyses link Amphipithecidae to anthropoids, there is a lack of certainty as they show resemblances to adapiforms and omomyiforms as well as to catarrhine simians.