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Temporal range: Middle Eocene-Holocene, 40–0  Ma
Old & New World monkey faces.JPG
A catarrhine (chimpanzee) and a platyrrhine (red-faced spider monkey)
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates
Suborder: Haplorhini
Infraorder: Simiiformes
Haeckel, 1866 [1] [2]

sister: Tarsiiformes


monkeys (cladistically incl. apes and humans)


The simians, anthropoids or higher primates are an infraorder (Simiiformes /ˈsɪmi.ɪfɔːrmz/ ) of primates containing the parvorders Platyrrhini and Catarrhini, the latter of which consists of the superfamilies Cercopithecoidea and Hominoidea (including the genus Homo ).

The simians are sister to the tarsiers, together forming the haplorhines. The radiation occurred about 60 million years ago (during the Cenozoic era); 40 million years ago, simians from Afro-Arabia colonized South America, giving rise to the New World monkeys. The remaining simians (catarrhines) split 25 million years ago into Old World monkeys and apes (including humans).

Taxonomy and evolution

In earlier classification, New World monkeys, Old World monkeys, apes, and humans – collectively known as simians or anthropoids – were grouped under Anthropoidea ( /ˌænθrəˈpɔɪdiə/ ; Ancient Greek : άνθρωπος, romanized: anthropos, lit. 'human'; also called anthropoids), while the strepsirrhines and tarsiers were grouped under the suborder "Prosimii". Under modern classification, the tarsiers and simians are grouped under the suborder Haplorhini, while the strepsirrhines are placed in suborder Strepsirrhini. [3] Strong genetic evidence for this is that five SINEs are common to all haplorhines whilst absent in strepsirrhines — even one being coincidental between tarsiers and simians would be quite unlikely. [4] Despite this preferred taxonomic division, "prosimian" is still regularly found in textbooks and the academic literature because of familiarity, a condition likened to the use of the metric system in the sciences and the use of customary units elsewhere in the United States. [5] In the Anthropoidea, evidence indicates that the Old World and New World primates went through parallel evolution. [6]

Primatology, paleoanthropology, and other related fields are split on their usage of the synonymous infraorder names, Simiiformes and Anthropoidea. According to Robert Hoffstetter (and supported by Colin Groves), the term Simiiformes has priority over Anthropoidea because the taxonomic term Simii by van der Hoeven, from which it is constructed, dates to 1833. [1] [7] In contrast, Anthropoidea by Mivart dates to 1864, [8] while Simiiformes by Haeckel dates to 1866, leading to counterclaims of priority. [1] Hoffstetter also argued that Simiiformes is also constructed like a proper infraorder name (ending in "iformes"), whereas Anthropoidea ends in -"oidea", which is reserved for superfamilies. He also noted that Anthropoidea is too easily confused with "anthropoïdes", which translates to "apes" from several languages. [7]

Extant simians are split into three distinct groups. The New World monkeys in parvorder Platyrrhini split from the rest of the simian line about 40 million years ago (Mya), leaving the parvorder Catarrhini occupying the Old World. This group split about 25 Mya between the Cercopithecidae and the apes.

Some lines of extinct simian also are either placed into the Eosimiidae (to reflect their Eocene origin) and sometimes in Amphipithecidae, thought to originate in the Early Oligocene. Additionally, Phileosimias is sometimes placed in the Eosimiidae and sometimes categorised separately. [9]


Phylogeny of living (extant) primates
Primates  (80 Mya)
Haplorhini  (63 Mya)
Simiiformes (42.6 Mya)
Catarrhini  (29.0 Mya)






Cladogram. For each clade, it is indicated approximately how many Mya newer extant clades radiated.[ citation needed ]

The following is the listing of the various simian families, and their placement in the order Primates: [1] [2]

Below is a cladogram with some of the extinct simian species with the more modern species emerging within the Eosimiidae. The simians originated in Asia, while the crown simians were in Afro-Arabia. [10] [11] [3] [12] [5] [13] It is indicated approximately how many Mya the clades diverged into newer clades.

Haplorhini  (64)

Tarsiiformes Saugethiere vom Celebes- und Philippinen-Archipel (Taf. III) (white background) (1).jpg

Simians (54)
Ekgmowechashalidae  (39)

Muangthanhinius (†32 Mya)


Gatanthropus micros (†30)

Bugtilemur (†29)


Eosimiidae  (52)
Eosimiidae s.s.(50)

Eosimias (†40)

Phenocopethicus (†42)


Bahinia  [ fr ] (†32)

Nosmips aenigmaticus (†37)

Phileosimias (†46)


Amphipithecidae (†35)


Parapithecidae (†30)

Proteopithecidae (†34)

Crown Simians (40)
Platyrrhini  (35)

Perupithecus (†)


Chilecebus (†20)


Tremacebus (†20)


Homunculus (†16)

Dolichocebus (†20)


Branisella (†26)

Crown Platyrrhini (New World Monkeys) Die Saugthiere in Abbildungen nach der Natur, mit Beschreibungen (Plate 8) (white background).jpg

Catarrhini Cynocephalus doguera - 1700-1880 - Print - Iconographia Zoologica - Special Collections University of Amsterdam - (white background).tiff

Usually the Ekgmowechashalidae are considered to be Strepsirrhini, not Haplorhini. [14] A 2018 study places Eosimiidae as a sister to the crown haplorhini. [15] In 2020 papers, the Proteopithecidae are part of the Parapithecoidea, [13] [16] and Nosmips aenigmaticus (previously in Eosimidae [11] ) is a basal simian. [16]

Key biological features

In a section of their 2010 assessment of the evolution of anthropoids (simians) entitled "What Is An Anthropoid", Williams, Kay, and Kirk set out a list of biological features common to all or most anthropoids, including genetic similarities, similarities in eye location and the muscles close to the eyes, internal similarities between ears, dental similarities, and similarities on foot bone structure. [4] The earliest anthropods were small primates with varied diets, forward-facing eyes, acute color vision for daytime lifestyles, and brains devoted more to vision and less to smell. [4] Living simians in both the New World and the Old World have larger brains than other primates, but they evolved these larger brains independently. [4]

See also

Related Research Articles

Primate An order of mammals

A primate is a eutherian mammal constituting the taxonomic order Primates. Primates arose 85–55 million years ago first from small terrestrial mammals, which adapted to living in the trees of tropical forests: many primate characteristics represent adaptations to life in this challenging environment, including large brains, visual acuity, color vision, a shoulder girdle allowing a large degree of movement in the shoulder joint, and dextrous hands. Primates range in size from Madame Berthe's mouse lemur, which weighs 30 g (1 oz), to the eastern gorilla, weighing over 200 kg (440 lb). There are 190–448 species of living primates, depending on which classification is used. New primate species continue to be discovered: over 25 species were described in the 2000s, and 11 since 2010.

New World monkey Parvorder of mammals

New World monkeys are the five families of primates that are found in the tropical regions of Mexico, Central and South America: Callitrichidae, Cebidae, Aotidae, Pitheciidae, and Atelidae. The five families are ranked together as the Ceboidea, the only extant superfamily in the parvorder Platyrrhini . Platyrrhini means broad-nosed, and their noses are flatter than those of other simians, with sideways-facing nostrils. Monkeys in the family Atelidae, such as the spider monkey, are the only primates to have prehensile tails. New World monkeys' closest relatives are the other simians, the Catarrhini ("down-nosed"), comprising Old World monkeys and apes. New World monkeys descend from African simians that colonized South America, a line that split off about 40 million years ago.

Catarrhini Group of Old World monkeys and apes

The parvorder Catarrhini, catarrhine monkeys or Old World anthropoids are the sister group to the New World monkeys, the Platyrrhini. The Platyrrhini emerged within "monkeys" by migration to South America from Afro-Arabia, likely by ocean. With respect to the ones that stayed behind, Geoffroy in 1812 grouped the apes (Hominoidea) and the Cercopithecoidea together and established the name Catarrhini, "Old World monkeys",. There has been some resistance to directly designate apes as monkeys despite the scientific evidence, so "Old World monkey" may be taken to mean the Cercopithecoidea or the Catarrhini. That apes are monkeys was already realized by Georges-Louis Leclerc, Comte de Buffon in the 18th century. The apes are further divided into the lesser apes or gibbons and the great apes, consisting of the orangutans, gorillas, chimpanzees and humans. The Catarrhini are all native to Africa and Asia. Members of this parvorder are called catarrhines.

Strepsirrhini A suborder of primates which includes lemurs, galagos, pottos and lorises

Strepsirrhini or Strepsirhini is a suborder of primates that includes the lemuriform primates, which consist of the lemurs of Madagascar, galagos ("bushbabies") and pottos from Africa, and the lorises from India and southeast Asia. Collectively they are referred to as strepsirrhines. Also belonging to the suborder are the extinct adapiform primates that thrived during the Eocene in Europe, North America, and Asia, but disappeared from most of the Northern Hemisphere as the climate cooled. Adapiforms are sometimes referred to as being "lemur-like", although the diversity of both lemurs and adapiforms does not support this comparison.

Prosimian Obsolete primate taxon

Prosimians are a group of primates that includes all living and extinct strepsirrhines, as well as the haplorhine tarsiers and their extinct relatives, the omomyiforms, i.e. all primates excluding the simians. They are considered to have characteristics that are more "primitive" than those of simians.

Haplorhini Suborder of primates

Haplorhini, the haplorhines or the "dry-nosed" primates, is a suborder of primates containing the tarsiers and the simians, as sister of the Strepsirrhini ("moist-nosed"). The name is sometimes spelled Haplorrhini. The simians include catarrhines, and the platyrrhines.

Tarsiiformes Group of primates

Tarsiiformes are a group of primates that once ranged across Europe, northern Africa, Asia, and North America, but whose extant species are all found in the islands of Southeast Asia. Tarsiers are the only living members of the infraorder, and also include the extinct Tarsius eocaenus from the Eocene and Tarsius thailandicus from the Miocene. Two extinct genera, Xanthorhysis and Afrotarsius, are considered to be close relatives of the living tarsiers and are generally classified within Tarsiiformes, with the former grouped within family Tarsiidae and the latter listed as incertae sedis (undefined). Omomyids are generally considered to be extinct relatives, or even ancestors, of the living tarsiers and are often classified within Tarsiiformes. Other fossil primates, which include Microchoeridae, Carpolestidae, and Eosimiidae, have been included in this classification, although the fossil evidence is debated. Eosimiidae has also been classified under the infraorder Simiiformes. Likewise, Carpolestidae is often classified within the order Plesiadapiformes, a very close, extinct relative of primates. These conflicting classifications lie at the heart of the debate over early primate evolution. Even the placement of Tarsiiformes within suborder Haplorhini is still debated.

Lemuriformes Infraorder of primates

Lemuriformes is an infraorder of primate that falls under the suborder Strepsirrhini. It includes the lemurs of Madagascar, as well as the galagos and lorisids of Africa and Asia, although a popular alternative taxonomy places the lorisoids in their own infraorder, Lorisiformes.

<i>Aegyptopithecus</i> Extinct single-species genus of primate

Aegyptopithecus is an early fossil catarrhine that predates the divergence between hominoids (apes) and cercopithecids. It is known from a single species, Aegyptopithecus zeuxis, which lived around 38-29.5 million years ago in the early part of the Oligocene epoch. It likely resembled modern-day New World monkeys, and was about the same size as a modern howler monkey, which is about 56 to 92 cm long. Aegyptopithecus fossils have been found in the Jebel Qatrani Formation of modern-day Egypt. Aegyptopithecus is believed to be a stem-catarrhine, a crucial link between Eocene and Miocene fossils.

Adapiformes Extinct order of primates

Adapiformes is a group of early primates. Adapiforms radiated throughout much of the northern continental mass, reaching as far south as northern Africa and tropical Asia. They existed from the Eocene to the Miocene epoch. Some adapiforms resembled living lemurs.

Monkey Animal of the "higher primates" (the simians), but excluding the apes

Monkey is a common name that may refer to certain groups or species of simian mammals of infraorder Simiiformes. The term is applied descriptively to groups of primates, such as families of New World monkeys and Old World monkeys. Many monkey species are tree-dwelling (arboreal), although there are species that live primarily on the ground, such as baboons. Most species are mainly active during the day (diurnal). Monkeys are generally considered to be intelligent, especially the Old World monkeys of Catarrhini.

Lorisoidea Superfamily of primates

Lorisoidea is a superfamily of nocturnal primates found throughout Africa and Asia. Members include the galagos and the lorisids. As strepsirrhines, lorisoids are related to the lemurs of Madagascar and are sometimes included in the infraorder Lemuriformes, although they are also sometimes placed in their own infraorder, LorisiformesGregory, 1915.

Eosimiidae is the family of possibly extinct primates believed to be the earliest simians.

Altiatlasius is an extinct genus of mammal, which may have been the oldest known primate, dating to the Late Paleocene from Morocco. The only species, Altiatlasius koulchii, was described in 1990.

<i>Darwinius</i> Extinct genus of primates

Darwinius is a genus within the infraorder Adapiformes, a group of basal strepsirrhine primates from the middle Eocene epoch. Its only known species, Darwinius masillae, lived approximately 47 million years ago based on dating of the fossil site.


The sublingua ("under-tongue") is a muscular secondary tongue found below the primary tongue in tarsiers and living strepsirrhine primates, which includes lemurs and lorisoids. Although it is most fully developed in these primates, similar structures can be found in some other mammals, such as marsupials, treeshrews, and colugos. This "second tongue" lacks taste buds, and in lemuriforms, it is thought to be used to remove hair and other debris from the toothcomb, a specialized dental structure used to comb the fur during oral grooming.

<i>Afrasia djijidae</i> Eocene fossil primate from Myanmar

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 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.

Evolution of primates The origin and diversification of primates through geologic time

The evolutionary history of the primates can be traced back 57-85/90 million years. One of the oldest known primate-like mammal species, Plesiadapis, came from North America; another, Archicebus, came from China. 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 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 Amphipithecidae were simian primates that lived in Late Eocene and Early Oligocene. Fossils have been found in Myanmar, Thailand, and Pakistan. The limited fossil evidence is consistent with, but not exclusive to, arboreal quadrupedalism. In other words, the species may have moved about in trees on four legs, but not with regular leaping as seen in later simians.

Phileosimias is an extinct genus of primates with two species, P. kamli and P. bahuiorum, that are believed to be amongst the earliest simians.


  1. 1 2 3 4 Groves, C. P. (2005). "Simiiformes". In Wilson, D. E.; Reeder, D. M. (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Baltimore: Johns Hopkins University Press. p. 128. ISBN   0-801-88221-4. OCLC   62265494.
  2. 1 2 Rylands AB, Mittermeier RA (2009). "The Diversity of the New World Primates (Platyrrhini)". In Garber PA, Estrada A, Bicca-Marques JC, Heymann EW, Strier KB (eds.). South American Primates: Comparative Perspectives in the Study of Behavior, Ecology, and Conservation. Springer. ISBN   978-0-387-78704-6.
  3. 1 2 Cartmill, M.; Smith, F. H (2011). The Human Lineage. John Wiley & Sons. ISBN   978-1-118-21145-8.
  4. 1 2 3 4 Williams, Blythe A; Kay, Richard F; Kirk, E Christopher (January 2010). Walker, Alan (ed.). "New perspectives on anthropoid origins". PNAS . 107 (11): 4797–4804. Bibcode:2010PNAS..107.4797W. doi:10.1073/pnas.0908320107. PMC   2841917 . PMID   20212104.
  5. 1 2 Hartwig, W. (2011). "Chapter 3: Primate evolution". In Campbell, C. J.; Fuentes, A.; MacKinnon, K. C.; Bearder, S. K.; Stumpf, R. M (eds.). Primates in Perspective (2nd ed.). Oxford University Press. pp. 19–31. ISBN   978-0-19-539043-8.
  6. Lull, Richard Swann (1917). "XXXVII: The Evolution of Man". Organic Evolution (1929 ed.). New York: The Macmillan Company. pp. 641–86 via Google Books.
  7. 1 2 Hoffstetter, R. (1974). "Phylogeny and geographical deployment of the Primates". Journal of Human Evolution. 3 (4): 327–350. doi:10.1016/0047-2484(74)90028-1.
  8. Tobias, P. V. (2002). "The evolution of early hominids". In Ingold, T (ed.). Companion Encyclopedia of Anthropology: Humanity, Culture and Social Life. Taylor & Francis. p. 35. ISBN   978-0-415-28604-6.
  9. Marivaux; et al. (June 2005). "Anthropoid primates from the Oligocene of Pakistan (Bugti Hills): Data on early anthropoid evolution and biogeography". PNAS . 102 (24): 8436–41. Bibcode:2005PNAS..102.8436M. doi:10.1073/pnas.0503469102. PMC   1150860 . PMID   15937103. (Full text PDF)
  10. Marivaux, Laurent; Antoine, Pierre-Olivier; Baqri, Syed Rafiqul Hassan; Benammi, Mouloud; Chaimanee, Yaowalak; Crochet, Jean-Yves; Franceschi, Dario de; Iqbal, Nayyer; Jaeger, Jean-Jacques (2005-06-14). "Anthropoid primates from the Oligocene of Pakistan (Bugti Hills): Data on early anthropoid evolution and biogeography". Proceedings of the National Academy of Sciences of the United States of America. 102 (24): 8436–8441. Bibcode:2005PNAS..102.8436M. doi:10.1073/pnas.0503469102. ISSN   0027-8424. PMC   1150860 . PMID   15937103.
  11. 1 2 Seiffert, Erik R.; Boyer, Doug M.; Fleagle, John G.; Gunnell, Gregg F.; Heesy, Christopher P.; Perry, Jonathan M. G.; Sallam, Hesham M. (2017-04-10). "New adapiform primate fossils from the late Eocene of Egypt". Historical Biology. 0 (1–2): 204–226. doi:10.1080/08912963.2017.1306522. ISSN   0891-2963. S2CID   89631627.
  12. Ryan, Timothy M.; Silcox, Mary T.; Walker, Alan; Mao, Xianyun; Begun, David R.; Benefit, Brenda R.; Gingerich, Philip D.; Köhler, Meike; Kordos, László (2012-09-07). "Evolution of locomotion in Anthropoidea: the semicircular canal evidence". Proceedings of the Royal Society of London B: Biological Sciences. 279 (1742): 3467–3475. doi:10.1098/rspb.2012.0939. ISSN   0962-8452. PMC   3396915 . PMID   22696520.
  13. 1 2 Seiffert, Erik R.; Tejedor, Marcelo F.; Fleagle, John G.; Novo, Nelson M.; Cornejo, Fanny M.; Bond, Mariano; de Vries, Dorien; Campbell, Kenneth E. (2020-04-10). "A parapithecid stem anthropoid of African origin in the Paleogene of South America". Science. 368 (6487): 194–197. Bibcode:2020Sci...368..194S. doi:10.1126/science.aba1135. ISSN   0036-8075. PMID   32273470. S2CID   215550773.
  14. Ni, Xijun; Li, Qiang; Li, Lüzhou; Beard, K. Christopher (2016-05-06). "Oligocene primates from China reveal divergence between African and Asian primate evolution". Science. 352 (6286): 673–677. Bibcode:2016Sci...352..673N. doi: 10.1126/science.aaf2107 . ISSN   0036-8075. PMID   27151861.
  15. Holroyd, Patricia A.; Silcox, Mary T.; López-Torres, Sergi (2018-09-22). "New omomyoids (Euprimates, Mammalia) from the late Uintan of southern California, USA, and the question of the extinction of the Paromomyidae (Plesiadapiformes, Primates)". Palaeontologia Electronica. 21 (3): 1–28. doi: 10.26879/756 . ISSN   1094-8074.
  16. 1 2 Seiffert, Erik R.; Tejedor, Marcelo F.; Fleagle, John G.; Novo, Nelson M.; Cornejo, Fanny M.; Bond, Mariano; de Vries, Dorien; Campbell, Kenneth E. (2020-04-10). "A parapithecid stem anthropoid of African origin in the Paleogene of South America". Science. 368 (6487): 194–197. Bibcode:2020Sci...368..194S. doi:10.1126/science.aba1135. ISSN   0036-8075. PMID   32273470. S2CID   215550773.