Primates - SpeedyLook encyclopedia

Characteristics

The primates are characterized by a life in general arboricolous, the presence of nails to the fingers and the toes, the aptitude for the Préhension by opposition of the inch, a prevalence of the Vision on the Olfaction. The presence of a Brain more developed than at the majority of the other mammals is often advanced as characteristic of this group but it is not checked that for the Super-family Hominoïde S. It moreover is divided by others tax, in particular the Dauphin. To these features is added at the Homme (and to differing degree at the others hominidé S) the biped locomotion .

Their size varies between 13 cm (chirogale nice, Microcebus murinus ) and 175 cm, for a going weight of a hundred grams up to 275 kg (Gorille, Gorilla gorilla ).

The first fossil primate goes back to -55 My.

Classification

Traditional classification

In 1758, Carl von Linné created a group including/understanding the man, the Simien S, the Prosimien S, the Dermoptères and the Chiroptères. Hundred years before work of Charles Darwin, it was thus already obvious for Linné which there was a certain proximity between the simiens and the man. He gave to this group the name of “préminient” (in the first place): the primates . It is known today that the dermoptères and the chiroptères form separate groups.

The classification of the primates is not simple and was often called in question, either by the discovery of new species, or by recent work about the Chromosome S, and thus on DNA and the Gène S. It seems however that the old distinction between two sub-orders, that of the Prosimiens (or lower primates) and that of the Simiens (or higher Anthropoïdes , or primates) or always of topicality, even if some prefer to call them Strepsirhinien S and Haplorhinien S . The differences between the two sub-orders are numerous, but one will retain one of them in particular:

at the prosimiens, the face is lengthened in muzzle, with formation of a rhinarium, cutaneous zone without hairs surrounding the nostrils, with absence of welding of the upper lip;
at the simiens, the face is not lengthened any more in muzzle, the rhinarium disappeared and the upper lip is welded.

The only problem is that of the Tarsier, that all brings closer to the prosimiens, but which does not have rhinarium. After long hesitations, most recent work classifies the tarsier among the prosimiens. On will also announce that the Tupaia S were excluded about the primates, to which they are however very close.

Phylogenetic classification

The Phylogeny of the group, in other words the formation and the development of the species, are well established in general, but the particular case of the position of the mankind gave place to many debates. Traditional classification holds for the man the family of the Hominidé S, gathering the two species of chimpanzees, the gorilla and the orang-outang in the family of the Pongidé S. This approach is not retained any more, pongidés not being then Monophylétique S, because it seems well established that the men divide with the chimpanzees and the gorilla an ancestor distinct from that of the orang-outang. The Groupe brother of human made a long time debate between the chimpanzees, the gorilla or the unit {chimpanzees + gorilla}. This debate seems to converge towards the first assumption. The group even is less better located him within the mammals, it enracine in of the Euarchontoglires which it divides inter alia with the great order of the rodents, but the phylogeny of the euthériens is still badly cleared up because of many gaps in the fossils and a very fast diversification.

Position in the phylogenetic tree

See also: phylogenetic Classification of alive the, Mammalia (phylogenetic classification)

The recent genetic studies shows that the position of the primates in the phylogenetic tree is deferent traditional position. Glires are in fact of the close relatives of the primates.

Relative phylogenetic position of the principal sub-orders

Prosimien S (or Strepsirhinien S)

Lémuriformes
Lorisiforme S

Tarsiforme S
Simien S (or Haplorhinien S)

Platyrhinien S
Catarhinien S

Prosimiens

If one excludes unclassable the Tarsier, Prosimiens are divided into two infra-orders, Lémuriformes and Lorisiformes.

Caractéristiques

they are arboricolous
they do not have a prehensile tail
they are night and insectivorous (ancestral primitive characters)
developed brachiation: articulation of the head humérale compared to the cavity glénoïde
articulations of the rear limbs developed

Lémuriformes

They live all with Madagascar, island which they colonized in the absence of other more advanced primates. One classifies them as various families:

Lemuridae (Lémuridés), comprising the maki in particular.
Indriidae , with the rear limbs more developed than the former ones (Indri, avahi, sifaka).
Megaladapidae , family represented by the kind Lepilemur .
Daubentoniidae : only one kind and only one species, the Aye-aye.

Lorisiformes

All of small size, met in Africa and Asia, they gather the following families:

Cheirogaleidae , living in Madagascar and resembling more squirrel S that with monkeys. The position of this family varies according to the authors, sometimes among the lorisiformes, sometimes among the lémuriformes as in the taxonomic revision suggested by J.G. Fleagle in 1999.
Galagidae , alive in Africa, comprising the kind Galago .
Loridae , alive in Africa and Asia (kinds Loris , Nycticebus , Perodicticus and Arctocebus ).

The tarsier (Tarsiidae)

With famous person and the globulous eyes, he lives in Indonesia and with the Filipino . He has two pairs of udders (pectoral and abdominal).

Simiens

The distinction between Simiens is initially a business of Nez, secondarily a question of tail. Two infra-orders indeed are distinguished:

that of Platyrhiniens, with isolated nostrils and long and prehensile tail, all originating in Central America and the South (they are also called “monkeys of the New World”);
that of Catarhiniens, with brought closer nostrils, tail sometimes absent and in any event never prehensile (another name: “monkeys of the Old world”).

The Platyrhinien S

In addition to the distinction above, one will specify that they have almost all 36 teeth (against 32 at Catarhiniens). They are divided into three families:

Cebidae (Cébidé S), family to which belongs the Sapajou, the Atèle (or monkey-spider), the Monkey-woolly and the monkey-hurleur.
Callithricidé S , with in particular the tamarin S and the ouistiti S.
Pitheciidae (Mivart, 1865) - family recently individualized with two subfamilies the Callicebinae and the Pitheciinae, before kinds of the Cébidé S.

The Catarhinien S

One divides them into two super-families:

Cercopithecoidea , training only one family, the Cercopithecidae , itself divided into two subfamilies:

the Cercopithéciné S, comprising the Cercopithèque S, the Macaque S and the Baboon S;
the Colobinés, with in particular the nasic.

Hominoidea , or Anthropomorphic, composed of four families. The oldest known specimen is the Purgatorius , old of 70 million years. Purgatorius is however closer to the Dermoptère S than of the primates. The oldest fossils of indisputable primates are adapidés the Donrusselia and Cantius (- 55 million years).

Ecology

One finds the various species of primates in the intertropical zones on all the continents except the Australia. There exist however two exceptions: certain macaques of China and the Japan, and the man, who colonized all the grounds until - beyond polar circle.

In Europe, except the man, the only species of primate which one can find in natural habitat is the monkey nest egg of Gibraltar ( Macaca sylvanus ), probably introduced by the Moors before the colonization of the rock by the British.

Primarily arboricolous, the primates live the raised forests, plains and high mountains. Some species adopted a secondary return to the terrestrial locomotion, and populate savannas and the steppes.

Ethology

Social structures

The companies of primates are extremely varied. These animals can live isolated, in permanent groups or temporary groups.

The large monkeys and the men seem to share a single social dimension: culture. In 2001, Frans de Waal showed in a innovating study that the large monkeys (as the chimpanzees) could share cultural characteristics (practices learned and not innate which are transmitted inside a group but unknown outwards). Without falling into excesses from the sociobiology or evolutionary psychology, that opens the door with an interesting evaluation of the social structures of the primates by bringing closer the large monkeys to the man.

Ethical and political stakes

The fact that the man forms part about the primates gives to this group of animals a special character. This idea is defended for example by Peter Singer, the author of the Projet large monkeys aiming at recognizing a special statute for the anthropomorphic monkeys. Peter Singer would like indeed to grant certain rights to the large monkeys (closest to the man genetically) and thus to create, as for the Man with her charter of the Human rights, a charter defining the rights of the primates. This thought belongs to a movement that one calls the animal Libération; one can quote for example documentary the Koko, the gorilla which speaks (1978) about Barbet Schroeder, or by learning the sign language to a gorilla, this one started to invent words by joining already learned words. This debate is one of most surging moment, because some see that like a lowering of the Man on the level of the primate, which raises certain questions as for major nature of the Man and in particular in the tackled questions: finally what a Human ? and finally can the Man itself define the Man? In fact philosophical questions more , and involve various ethical problems.

The kind Homo

The emergence of the kind Homo

The most former representatives of the kind Homo , the Homo habilis and the Homo rudolfensis , seem to appear in Africa towards 2,5 MY, whereas important climate changes take place: the formation of the Arctic icecap involves a dryness in Africa, which causes the retreat of the forests.

The kind Homo is defined by a stronger cranial capacity (higher than 600 DC), a rounder brain-pan, a reduction of the apparatus masticator and face, small canines, and a nearly exclusive bipédie. Homo habilis was still adapted to the arboricolous life. The visible prints on the bones of the brain-pan prove that there existed already an asymmetry between the brains right and left, which suggests a greater capacity to manufacture and use the tools. He invents the cut rollers (Oldowayenne industry).

Homo rudolfensis was more corpulent and had a large brain and jaws more powerful (to be put in relation to a food mode probably more vegetarian that Homo habilis ). Although it is known little, it is thought that its bipédie was to be more advanced than that of Homo habilis . Homo habilis and Homo rudolfensis disappear towards 1,6 MY.

Contemporary of the last Homo habilis and Paranthropus , the Homo ergaster has characteristics which bring it much closer to the modern man: cut more important, bipédie exclusive, strong capacity cranial (higher than 800 DC), quite round brain-pan and which dominates the face, reduced face,…. Its tools start to be more sophisticated: double-side,… (industry acheuléenne). He tames fire as of 1 MY (and even perhaps front….).

Its good adaptation to biped walk and the race enables him to traverse long distances and it leaves to the conquest the old world (Asia and Europe), as of 1,8 MY, probably year following its preys to the liking of the climate changes. Its new tools enable him to adopt a food mode containing much more meat (it is a true hunter). Lastly, it can communicate as a practitioner an articulated language (probably already outlined at Homo habilis ).

The Homo ergaster installed in Asia are probably at the origin of the Homo erectus , with the very robust skeleton, but with the high cranial capacity and the reduced face. The latter perpetuate the Oldowayenne tradition.

Origins of the modern man

The Homo ergaster of Africa settle in Europe. Going down from the first men who conquered Europe and the Middle East, and which probably were isolated during certain periods of glaciation, Homo neanderthalensis (Man of Neandertal) lived from 100.000 to 30.000 years. Its body presents cold adaptations. It is probably him which " invente" funerary rites.

One finds representatives of a line prénéandertalienne between 1MA and 120.000 years, but the true origins are far from being cleared up (there perhaps would have been continuity in Asia, but replacement in Europe…).

Other populations of Homo ergaster coming from Africa and the Close East are at the origin of the " Proto-Cro-Magnon" , then of Cro-Magnon ( Homo sapiens ).

Around 40.000 years, Homo neanderthalensis between thus in competition with Homo sapiens (Man of Cro-Magnon) which comes to settle in Europe, and which constitutes the first representative of our species. Its morphology longiligne translates origins most probably African.

Protection

In addition, 75 of the 188 species of Primates are threatened of disappearance. All the species of primates are registered with the Annexe II or for the most threatened with the Annexe I of the QUOTE.

See too

detailed List of the families and kinds of primates
alphabetical List of the kinds of primates
alphabetical List of the vernacular names of primates
Monkey, Primatologie compared
Eucaryote, Chordé, Vertebrate, Euthérien.

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