The simians, anthropoids, or higher primates are an infraorder (Simiiformes ) of

primate Primates are a diverse order of mammals. They are divided into the strepsirrhines, which include the lemurs, galagos, and lorisids, and the haplorhines, which include the tarsiers and the simians ( monkeys and apes, the latter includin ...

s containing all animals traditionally called

monkey Monkey is a common name that may refer to most mammals of the infraorder Simiiformes, also known as the simians. Traditionally, all animals in the group now known as simians are counted as monkeys except the apes, which constitutes an incomple ...

s and apes. More precisely, they consist of the parvorders New World monkeys (Platyrrhini) and

Catarrhini The parvorder Catarrhini , catarrhine monkeys, Old World anthropoids, or Old World monkeys, consisting of the Cercopithecoidea and apes (Hominoidea). In 1812, Geoffroy grouped those two groups together and established the name Catarrhini, "Old ...

, the latter of which consists of the superfamilies Cercopithecidae ( Old World monkeys in the stricter sense) and apes ( Hominoidea; including the genus ''

Homo ''Homo'' () is the genus that emerged in the (otherwise extinct) genus '' Australopithecus'' that encompasses the extant species ''Homo sapiens'' ( modern humans), plus several extinct species classified as either ancestral to or closely rela ...

''). The simians are sister group to the tarsiers (Tarsiiformes), together forming the

haplorhines Haplorhini (), the haplorhines ( Greek for "simple-nosed") or the "dry-nosed" primates, is a suborder of primates containing the tarsiers and the simians (Simiiformes or anthropoids), as sister of the Strepsirrhini ("moist-nosed"). The name is ...

. The radiation occurred about 60 million years ago (during the Cenozoic era); 40 million years ago, simians colonized

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sou ...

, giving rise to the New World monkeys. The remaining simians (catarrhines) split about 25 million years ago into

Cercopithecidae Old World monkey is the common English name for a family of primates known taxonomically as the Cercopithecidae (). Twenty-four genera and 138 species are recognized, making it the largest primate family. Old World monkey genera include baboons ...

and apes (including

human Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, cultu ...

s).

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 (; ), while the strepsirrhines and tarsiers were grouped under the suborder " Prosimii". Under modern classification, the tarsiers and simians are grouped under the suborder

Haplorhini Haplorhini (), the haplorhines ( Greek for "simple-nosed") or the "dry-nosed" primates, is a suborder of primates containing the tarsiers and the simians (Simiiformes or anthropoids), as sister of the Strepsirrhini ("moist-nosed"). The name is so ...

, while the strepsirrhines are placed in suborder Strepsirrhini. Strong genetic evidence for this is that five

SINEs Sines () is a city and a municipality in Portugal. The municipality, divided into two parishes, has around 14,214 inhabitants (2021) in an area of . Sines holds an important oil refinery and several petrochemical industries. It is also a popular ...

are common to all haplorhines whilst absent in strepsirrhines — even one being coincidental between tarsiers and simians would be quite unlikely. 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 The metric system is a system of measurement that succeeded the decimalised system based on the metre that had been introduced in France in the 1790s. The historical development of these systems culminated in the definition of the Intern ...

in the sciences and the use of

customary units United States customary units form a system of measurement units commonly used in the United States and U.S. territories since being standardized and adopted in 1832. The United States customary system (USCS or USC) developed from English uni ...

elsewhere in the United States. In the Anthropoidea, evidence indicates that the Old World and New World primates went through parallel evolution.

Primatology Primatology is the scientific study of primates. It is a diverse discipline at the boundary between mammalogy and anthropology, and researchers can be found in academic departments of anatomy, anthropology, biology, medicine, psychology, vete ...

paleoanthropology Paleoanthropology or paleo-anthropology is a branch of paleontology and anthropology which seeks to understand the early development of anatomically modern humans, a process known as hominization, through the reconstruction of evolutionary kinsh ...

, and other related fields are split on their usage of the synonymous infraorder names, Simiiformes and Anthropoidea. According to

Robert Hoffstetter Robert Julien Hoffstetter (11 June 1908 in Fargniers – 29 December 1999 in Gennevilliers) was a French taxonomist and herpetologist who was influential in categorizing reptiles Reptiles, as most commonly defined are the animals in the clas ...

(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. In contrast, Anthropoidea by

Mivart St. George Jackson Mivart (30 November 1827 – 1 April 1900) was an English biologist. He is famous for starting as an ardent believer in natural selection who later became one of its fiercest critics. Mivart attempted to reconcile ...

dates to 1864, while Simiiformes by

Haeckel Ernst Heinrich Philipp August Haeckel (; 16 February 1834 – 9 August 1919) was a German zoologist, naturalist, eugenicist, philosopher, physician, professor, marine biologist and artist. He discovered, described and named thousands of new s ...

dates to 1866, leading to counterclaims of priority. 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. 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

and the apes. Some lines of extinct simian also are either placed into the

Eosimiidae Eosimiidae is the possible family of extinct primates believed to be the earliest simians. Taxonomy When they were discovered the possibility that Eosimians were outside and ancestral to Simians was considered (Culotta 1992), but subsequent w ...

(to reflect their

Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', ...

origin) and sometimes in Amphipithecidae, thought to originate in the Early Oligocene. Additionally, '' Phileosimias'' is sometimes placed in the Eosimiidae and sometimes categorised separately.

Classification

The following is the listing of the various simian families, and their placement in the order Primates: * Order

Primate Primates are a diverse order of mammals. They are divided into the strepsirrhines, which include the lemurs, galagos, and lorisids, and the haplorhines, which include the tarsiers and the simians ( monkeys and apes, the latter includin ...

s ** Suborder

Strepsirrhini 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. Co ...

: non

tarsier Tarsiers ( ) are haplorhine primates of the family Tarsiidae, which is itself the lone extant family within the infraorder Tarsiiformes. Although the group was once more widespread, all of its species living today are found in Maritime Southeas ...

prosimians ** Suborder

: tarsiers and monkeys, including apes *** Infraorder

Tarsiiformes 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 (family Tarsiidae) are the only living members ...

***Infraorder Simiiformes **** Parvorder Platyrrhini: New World monkeys ***** Family

Callitrichidae The Callitrichidae (also called Arctopitheci or Hapalidae) are a family of New World monkeys, including marmosets, tamarins, and lion tamarins. At times, this group of animals has been regarded as a subfamily, called the Callitrichinae, of the ...

: marmosets and tamarins ***** Family

Cebidae The Cebidae are one of the five families of New World monkeys now recognised. Extant members are the capuchin and squirrel monkeys. These species are found throughout tropical and subtropical South and Central America. Characteristics Cebid m ...

: capuchins and squirrel monkeys ***** Family Aotidae: night or owl monkeys (douroucoulis) ***** Family Pitheciidae: titis, sakis, and uakaris ***** Family Atelidae: howler, spider, and woolly monkeys **** Parvorder

***** Superfamily Cercopithecoidea: Old World monkeys ****** Family

***** Superfamily Hominoidea ****** Family

Hylobatidae Gibbons () are apes in the family Hylobatidae (). The family historically contained one genus, but now is split into four extant genera and 20 species. Gibbons live in subtropical and tropical rainforest from eastern Bangladesh to Northeast Indi ...

: gibbons ****** Family

Hominidae The Hominidae (), whose members are known as the great apes or hominids (), are a taxonomic family of primates that includes eight extant species in four genera: '' Pongo'' (the Bornean, Sumatran and Tapanuli orangutan); ''Gorilla'' (the ...

: great apes, including humans **** † Amphipithecidae **** †

**** †'' Aseanpithecus'' 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. It is indicated approximately how many Mya the clades diverged into newer clades. Usually the Ekgmowechashalidae are considered to be

, not Haplorhini. A 2018 study places Eosimiidae as a sister to the crown haplorhini. In 2020 papers, the Proteopithecidae are part of the Parapithecoidea, and ''

Nosmips aenigmaticus ''Nosmips aenigmaticus'' is a rare fossil primate known only from 12 teeth. Most teeth were found at a site in the Fayum Depression about outside Cairo, Egypt. ''Nosmips aenigmaticus'' probably lived 37 million years ago in Africa and h ...

'' (previously in Eosimidae) is a basal simian.

Biological key-features

In a section of their 2010 assessment of the evolution of anthropoids (simians) entitled "What is an Anthropoid", Williams, Kay, and Kirk set ou
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. 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. Living simians in both the New World and the Old World have larger brains than other primates, but they evolved these larger brains independently.

References

External links

BioMed Central Full text Gene conversion and purifying selection of a placenta-specific ERV-V envelope gene during simian evolution

Taxonomy browser (Simiiformes)

* ttps://web.archive.org/web/20121018195118/http://news.sciencemag.org/sciencenow/2010/10/mouse-sized-primates-shed-light.html Mouse-Sized Primates Shed Light on Human Origins {{Taxonbar, from=Q5452918 Primate taxonomy

Taxonomy and evolution

Classification

Biological key-features

See also

References

External links