Eosimiidae is the possible family of

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

primate Primates is an order (biology), order of mammals, which is further divided into the Strepsirrhini, strepsirrhines, which include lemurs, galagos, and Lorisidae, lorisids; and the Haplorhini, haplorhines, which include Tarsiiformes, tarsiers a ...

s believed to be the earliest simians.

Taxonomy

When they were discovered, the possibility that eosimiids were outside and ancestral to simians was considered (Culotta 1992), but subsequent work showed them to be true simians (Kay et al. 1997, Ross et al. 1998). Some scholars continue to question whether the eosimiids are simians, as they seem closer to Tarsiiformes - Gunnell and Miller (2001), for instance, found that eosimiid morphology did not match up to anthropoid (i.e. simian) morphology.Primate Adaptation and Evolution: 3rd Edition, Ch. 13, p 279-281 However, most experts now place eosimiids as stem simians - Williams, Kay and Kirk (2010) note more and more evidence points to that conclusion. Williams, Kay and Kirk note that (as at late 2009), accounting for all proposed species, there would be 11 species in total in 6 genera ( Amphipithecidae, '' Anthrasimias'', '' Bahinia'', '' Eosimias'', '' Phenacopithecus'', '' Phileosimias''). 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.'' (2005) 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.
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Williams, Kay and Kirk (2010) note that both Gunnell et al. (2008) and Kay et al. (2009) 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 (i.e. simians), there is a lack of certainty as they show resemblances to adapiforms and omomyiforms as well as to catarrhine simians.

Phylogeny

Below is a phylogenic tree with some of the extinct simian species with the more modern species emerging within the Eosimiidae. ''Anthrasimias'' is not shown. The simians originated in Asia, while the crown simians were in Afro-Arabia. It is indicated approximately how many million years ago (Mya) the clades diverged into newer clades. In this tree, Eosimiidae as conventionally defined, shown as italic, is a paraphyletic, 'grade' or stem group in this assessment. Paraphyletic groupings are problematic, as one can not talk precisely about their phylogenic relationships, their characteristic traits and literal extinction. Cladistically the 'higher' monkeys are included. The Ekgmowechashaladea are usually placed in Tarsiiformes, in which case Eosimiidae may become equivalent to the simians. Alternatively, with '' Phileosimias'' and Amphipithecidae placed outside of Eosimiidae ''sensu stricto'', monophyly would be restored.

References

External links

* * {{Taxonbar, from=Q3055654 Eocene primates Oligocene primates Eocene first appearances Oligocene extinctions Prehistoric mammal families Primate families Simians

Taxonomy

Phylogeny

See also

References

External links