Primate
:''For the ecclesiastical use of this term, see
primate (religion)
A
primate is any member of the biological
order Primates, the group that contains all
lemurs,
monkeys, and
apes, including
humans. The English singular
primate is a back-formation from the
Latin name
Primates, which itself was the plural of the Latin
primas (''"one of the first, excellent, noble"''). Colin Groves lists about 350 species of primates in
Primate Taxonomy.
All primates have five fingers (pentadactyly), a generalized dental pattern, and a primitive (unspecialized) body plan. Another distinguishing feature of primates is fingernails. Opposing thumbs are also a characteristic primate feature, but are not limited to this order;
opossums, for example, also have opposing thumbs. In primates, the combination of opposing
thumbs, short fingernails (rather than claws) and long, inward-closing
fingers is a relic of the ancestral practice of
brachiating through trees. Forward-facing color
binocular vision was also useful for the brachiating ancestors of humans, particularly for finding and collecting food. All primates, even those that lack the features typical of other primates (like lorises), share eye orbit characteristics that distinguish them from other taxonomic orders.
As the table below illustrates, in many primate species, the males are larger than the females. However this picture is incomplete. All but one of these are
Old World species, and in this group the
mating system is usually
polygynous;
sexual dimorphism is expected with this kind of social structure. As the table shows, sexual dimorphism is much less in the marmosets (
New World) than in the other species listed, and this is characteristic of New World monkeys in comparison with the Old World monkeys and
apes. This is because the New World monkeys generally form
pair bonds.
Classification and evolution
The Primate
order lies in a tight clustering of related orders (the
Euarchontoglires) within the
Eutheria, a subclass of Mammalia. Recent molecular genetic research on primates, flying lemurs, and
tree shrews has shown that the two species of flying lemur (Dermoptera) are more closely related to the primates than the tree shrews of the order Scandentia, even though the tree shrews were at one time considered primates. These three orders make up the
Euarchonta clade. This clade combines with the
Glires clade (made up of the Rodentia and
Lagomorpha) to form the Euarchontoglires clade. Variously, both Euarchonta and Euarchontoglires are ranked as superorders.
Euarchontoglires
-Glires|
|
-rodents (Rodentia)
|
-rabbits, hares, pikas (Lagomorpha)
\\--Euarchonta
-tree shrews (Scandentia)
\\--N.N.
-flying lemurs (Dermoptera)
\\--primates ('''Primates''')
In modern, cladistic reckonings, the Primate order is also a true clade. The suborder Strepsirrhini, the "wet-nosed" primates, split off from the primitive primate line about 63 million years ago. The seven strepsirhine families are the four related lemur families and the three remaining families that include the lorises, the Aye-aye, the galagos, and the pottos. Some classification schemes wrap the Megaladapidae into the Lemuridae and the Galagonidae into the Loridae, yielding a three-two family split instead of the four-three split as presented here.
The Aye-aye is difficult to place in Strepsirrhini. Its family, Chiromyiformes, could be a lemuriform primate and its ancestors split from lemur line more recently than the lemurs and lorises split, about 50 mya. Otherwise it is sister to all of the other strepsirrhines, in which case in evolved away from the main strepsirrhine line between 50 and 63 mya.
The suborder Haplorhini, the "dry-nosed" primates, is composed of two sister clades. The prosimian tarsiers in family Tarsiidae (monotypic in its own infraorder Tarsiiformes), represent the most primitive division at about 58 mya. The Simiiformes contain the two unranked clades the New World monkeys in one, and the Old World monkeys, humans and the other apes in the other. This division happened about 40 mya.
In older classifications, the Primates were divided into two superfamilies: Prosimii and Anthropoidea. The Prosimii included all of the prosimians: all of Strepsirrhini plus the tarsiers. The Anthropoidea contained all of the simians.
- ORDER PRIMATES
- * Suborder Strepsirrhini: non-tarsier prosimians
- ** Infraorder Lemuriformes
- *** Superfamily Cheirogaleoidea
- **** Family Cheirogaleidae: dwarf lemurs and mouse-lemurs
- *** Superfamily Lemuroidea
- **** Family Lemuridae: lemurs
- **** Family Megaladapidae: sportive lemurs
- **** Family Indridae: woolly lemurs and allies
- ** Infraorder Chiromyiformes
- *** Family Daubentoniidae: Aye-aye
- ** Infraorder Loriformes
- *** Family Loridae: lorises, pottos and allies
- *** Family Galagonidae: galagos
- * Suborder Haplorrhini: tarsiers, monkeys and apes
- ** Infraorder Tarsiiformes
- *** Family Tarsiidae: tarsiers
- ** Infraorder Simiiformes
- *** Platyrrhini: New World monkeys
- **** Family Cebidae: marmosets, tamarins, capuchins and squirrel monkeys
- **** Family Nyctipithecidae: night monkeys, owl monkeys, douroucoulis
- **** Family Pitheciidae: titis, sakis and uakaris
- **** Family Atelidae: howler, spider and woolly monkeys
- *** Catarrhini
- **** Superfamily Cercopithecoidea
- ***** Family Cercopithecidae: Old World monkeys
- **** Superfamily Hominoidea
- ***** Family Hylobatidae: gibbons or "lesser apes"
- ***** Family Hominidae: great apes, including humans
References
- Primate Taxonomy (Smithsonian Institute Press, 2001), Colin Groves ( Order: ISBN 156098872X)
- Primates in Question (Smithsonian Institute Press, 2003), Robert W. Shumaker & Benjamin B. Beck ( Order: ISBN 1-58834-176-3)
Category:Mammals
ca:Primat
da:Primater
de:Primaten
es:Primate
eo:Primatoj
fr:Primate
it:Primati
la:Primates
lt:Primatas
nl:Primates
ja:サル目
pl:Naczelne
pt:Primatas
ru:Приматы
zh:灵长目
Category:Primates