Development Team Principal Investigator
Transcript of Development Team Principal Investigator
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Anthropology
Classification and Distribution of Living Primates
Paper No. : 14 Human Origin and Evolution
Module : 09 Classification and Distribution of Living Primates
Prof. Anup Kumar Kapoor Department of Anthropology, University of Delhi
Development Team
Principal Investigator
Paper Coordinator
Content Writer
Content Reviewer
Dr. Satwanti Kapoor (Retd Professor)
Department of Anthropology, University of Delhi
Mr. Vijit Deepani & Prof. A.K. Kapoor
Department of Anthropology, University of Delhi
Prof. R.K. Pathak Department of Anthropology, Panjab University, Chandigarh
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Anthropology
Classification and Distribution of Living Primates
Contents:
Primates: A brief Outline
Classification of Living Primates
Distribution of Living Primates
Summary
Learning Objectives:
To understand the classification of living primates.
To discern the distribution of living primates.
Description of Module
Subject Name Anthropology
Paper Name Human Origin and Evolution
Module Name/Title Classification and Distribution of Living Primates
Module Id 09
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Anthropology
Classification and Distribution of Living Primates
Primates: A brief Outline
Primates reside at the initial stage in the series of evolution of man and therefore constitute the first
footstep of man’s origin. Primates are primarily mammals possessing several basic mammalian
features such as presence of mammary glands, dense body hair; heterodonty, increased brain size,
endothermy, a relatively long gestation period followed by live birth, considerable capacity for
learning and behavioural flexibility.
St. George J Mivart (1873) defined Primates (as an order) as "unguiculate, claviculate, placental
mammals, with orbits encircled by bone; three kinds of teeth, at least at one time of life; brains always
with a posterior lobe and calcarine fissure; the innermost digits of at least one pair of extremities
opposable, hallux with a flat nail or none; a well-developed caecum; pendulous penis; testes with
scrotum; two pectoral mammae."
Thus following characteristics differentiate primates, as a group, from other mammals: (Swindler,
2004; Jurmain et al., 2012)
Prehensile limbs, Pentadactyly and Flattened Nails
Either thumb or great toe is opposable or both are opposable
Presence of well developed clavicle
Fingers and toe possess sensitive tactile pads (enriched with sensory nerve fibers) at the ends of
digits
Generalized dentition
Orbits surrounded by bony rims, enhancement in visual depth perception, binocular vision
Increase in size and complexity of the brain
Primates possess two pectoral mammae, efficient means of fetal nourishment, longer gestation
times.
Primates possess pendulous penis
Diurnal activity pattern (except some prosimians, new world monkey)
Tendency to reside in social groups
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Anthropology
Classification and Distribution of Living Primates
Classification of Living Primates
The term classification is often used interchangeably with terms ‘systematics’ and ‘taxonomy’.
Simpson (1961) defined Systematics as the scientific study of the kinds and diversity of organisms and
of any and all relationships among them. Systematics provides insight into the evolutionary
relationships between organisms and taxonomy deals with classification and nomenclature of
organisms. The key (groups different organisms together if they share one striking character), the
Phenetic (or natural – groups organisms in accordance to their degree of overall resemblance often in
morphology or other observable features, regardless of their phylogeny or evolutionary relation) and
the Phyletic (or phylogenetic – attempts to group organisms in accordance to their evolutionary
relationships) – constitute three major types of classification.
Swedish naturalist Carl Linnaeus had made pivotal contribution to the present hierarchial classification
of animals. Kingdom, phylum or division, class, order, family, genus, species- are seven major
taxonomic ranks and species (or biological species) is designated as the basic unit of classification.
Thus classification of primates simply implies ordering of primates into groups on the basis of their
relationship to each other though descent from a common ancestor. The prime motive of any
classification is therefore to develop a hierarchical system of categories of increasing rank.
The term ‘Primates’ was first used by Carolus Linnaeus to encompass four genera: Homo (man), Simia
(all monkeys and apes of the Old world and New world then known), Lemur and Verspetilio (bats) and
later bats were removed from the order (Swindler, 2004). In 1971, J. F. Blumenbach proposed a
primate classification where he categorized primates into two orders, Binama (included man) and
Quadrumana (included apes, monkeys and lemurs) (Shukla and Rastogi, 2011). The classification was
not accepted worldwide.
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Anthropology
Classification and Distribution of Living Primates
Fig I: Taxonomic classification of animals
(Source: Lewis et al., 2007).
Figure I depicts classification scheme of animals and thus the taxonomic specification of order Primate
can be represented as:
Category Taxon
Kingdom Animalia
Subkingdom Metazoa
Phylum Chordata
Subphylum Vertebrata
Class Mammalia
Order Primates
G.G. Simpson in 1945 proposed a primate classification, whereby the morphological resemblance
among the primate species was utilized as basic and sole criteria of classification. His classification
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Classification and Distribution of Living Primates
proposal was comparatively simple. He differentiated man (Hominidae) from apes (Pongidae) at
family level and classified australopithecines (hominins) with pongids and if the morphological
resemblance exhibits evolutionary relationship, then the traditional classification emphasized that
hominid branch was first to separate from pongids which later differentiated into all extant ape genera
and species (Ayala and Cela-conde,2017).
Figure II (below) exhibits the classification of living primates. The order primate order is a part of a
larger group, the class Mammalia (phylum Chordata). The former is categorized into two traditional
suborders, namely, categories, Prosimii (all the prosimians: lemurs, lorises, and, customarily, the
tarsiers) and Anthropoidea (all the monkeys, apes, and humans). An important point to be emphasized
here is that the suborder distinction is more specific than the order (Jurmain et al., 2012). At the
suborder level, the prosimians form a separate group which is different from all the other primates. The
above statement is biological and evolutionary relevant. Similarly, all anthropoid species are more
closely linked to each another than they are to the prosimians.
An alternative classification scheme was also supported by certain section of Primatologists in which
tarsiers and anthropoids were grouped in the suborder Haplorhini and lemurs, lorises and galagos were
placed in suborder Strepsirhini (Ayala and Cela-conde, 2017). The anatomy of the nose was the base of
this classification as the nose of strepsirhine primates is composed of a moist rhinarium and a lateral
slit or crease (‘strepsis’ meaning twisting) and the nose of haplorhine primates lacked moist rhinarium
(‘haplos’ meaning simple and unadorned condition).
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Anthropology
Classification and Distribution of Living Primates
Fig II: Difference in the structure of strepsirhine and haplorhine primate nose
(Source: Swindler, 2004).
Traditionally, taxonomic classification relied upon physical similarities between species and lineages
but with the advent of genetic technologies (such as the DNA-sequencing techniques), surplus genetic
evidence have emerged over the past few years that provide direct between-species comparisons of
DNA sequences (Jurmain et al., 2012). Goodman and his colleagues emphasized that humans and
chimpanzees have only a 1.6% difference in the non-coding portions of their globin gene clusters,
whereas there is a 2.1 percent difference between chimpanzees and gorillas (Gibbons, 1990) and when
the entire genome is considered, reported differences between chimpanzees and humans range from 2.7
percent (Cheng et al., 2005) to 6.4 percent (Demuth et al., 2006). Genetic similarities in relation with
fossil evidence highlighted that humans and chimpanzees last shared a common ancestor around 6–8
mya.
Prosimians (Halbaffen or before-apes) are referred to as the lower primates owing to their primitive
morphology and behaviour. The suborder Prosimii included three infraorder namely, Lemuriformes
(all lemurs), Lorisiformes (all Lorises and Galagos) and Tarsiformes (all Tarsiers). On the other hand,
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anthropoids (monkeys, apes and man) - ‘manlike’ primates- are termed the higher primates. The
suborder Anthropoidea comprised of two infra-orders Platyrrhini (all New World Monkeys) and
Catarrhini (all Old World Monkeys, apes and humans).
Several traits differentiate anthropoids, as a group, from prosimians (and most other placental
mammals). Jurmain et al. (2012) provided account of these traits:
1. Generally larger body size
2. Larger brain (in absolute terms and relative to body weight)
3. Reduced dependence on the sense of smell, as indicated by absence of a rhinarium
4. Increased reliance on vision, with forward-facing eyes at the front of the face
5. Greater degree of color vision
6. Back of eye socket formed by a bony plate
7. Blood supply to brain different from that of prosimians
8. Fusion of the two sides of the mandible at the midline to form one bone (in prosimians they are two
bones joined by fibrous tissue)
9. Less specialized dentition, as seen in the lack of a dental comb and some other features
10. Differences in female internal reproductive anatomy
11. Longer gestation and maturation periods
12. Increased parental care
13. More mutual grooming
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Classification and Distribution of Living Primates
Fig III: Classification of Living Primates
(Source: Jurmain et al., 2012)
In present scenario, the living primates can be categorized into following six natural groups- (Martin,
1994)
i. Lemurs of Madagascar
ii. The Lorises and bush babies of Africa and Asia
iii. The Tarsiers of Southeast Asia
iv. The New World Monkeys of Central and South America
v. The Old World Monkeys of Africa and Asia and
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vi. The apes of Africa and Asia and Humans
Fig IV: Six groups of Living Primates
(Source: Martin, 1994)
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Living Primates: Distribution
Zoogeography is scientific study of distribution of living animals. Today, majority of primate species
inhabit tropical or semitropical regimes of the New and Old Worlds (with certain exceptions). In New
World, these regions comprise of Southern Mexico, parts of South America and Central America and
in Old World, these areas include Africa, Southeast Asia (including numerous islands), India and
certain areas of China and Japan.
Fig V: Geographical distribution of extant nonhuman primates
(Source: Martin, 2012)
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Fig VI: Primate Hands: the Family tree
(Source Link: https://s-media-cache-
ak0.pinimg.com/originals/63/37/9a/63379aa03e55ba77bf82759f356a9a92.jpg)
Most of the primate species are mostly arboreal and inhabit forest or woodland ecological settings
(Jurmain et al., 2012). Certain primate species (such as baboons) have adapted to life on the ground in
places where trees are sparsely distributed. The African apes, namely, gorillas, chimpanzees, and
bonobos also invest much time on the ground in forested and wooded ecological settings. But no
nonhuman primate is adapted to a complete terrestrial lifestyle and thus they spend some time in the
trees.
Lemurs and lorises
Lemurs and lorises constitute most primitive primates as they have retained several ancestral traits,
such as a more pronounced dependence on the sense of smell (greater olfactory capabilities). Besides
Lemurs and lorises also exhibit a distinctive character termed as “dental comb”.
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Lemurs are specifically found in the island of Madagascar. They also inhabit nearby islands off the east
coast of Africa. Lemurs have successfully adapted to occupy numerous open ecological niches in
absence of competition from monkeys and apes as they made their way to Madagascar. Lorises
primarily inhabit tropical forest and woodland habitats of Africa, Southeast Asia, India and Sri Lanka.
Nycticebus or slow loris resides in jungles of Southeast Asia and some of the western islands of the
Indonesian archipelago
Tarsiers
They are small nocturnal primates and supreme leapers. They relate to one genus, Tarsius, which
includes five tarsier species and the species are restricted to island regime in Southeast Asia and the
Philippine Islands. These primates reside in a wide array of habitats ranging from tropical forest to
backyard gardens and prefer small vertebrates and insects as their prey. Tarsiers are nocturnal
insectivores that leap from lower branches and shrubs onto prey (which may include small vertebrates)
and the basic tarsier social unit is a mated pair and their young offspring. They are characterized by
enormous eyes, which dominate much of their facial region.
New World Monkeys
The New World monkeys or platyrrhines (included in the superfamily Ceboidea.) constitute tropical
arboreal primates residing in the forest areas of Central and South America and Mexico. They are
dichotomized into two families: Callitrichidae (marmosets and tamarins) and Cebidae (all other New
World Monkeys). New World monkeys are diurnal with only one exception (Aotus), and some never
come to the ground. Like Old World monkeys, all except one species (the owl monkey) are diurnal.
Marmosets and Tamarins (Callitrichids)
They are the smallest of the New World monkeys. They are arboreal quadrupeds having claws on all
their digits. Their diet consists largely of insects, although marmosets eat gums from trees, and
tamarins eat fruits. Socially, these small monkeys live in family groups usually composed of a mated
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pair, or a female and two adult males, and their offspring. Unlike other primates, marmosets and
tamarins usually give birth to twins, and they’re among the few primate species in which males are
extensively involved in infant care.
Cebids
The family Cebidae is comprised of eleven primate genera which further encompass a wide range of
animals. Cebids are larger in size in comparison to Callitrichids. Cebids are only primates
characterized with prehensile tail. Most cebid exhibit quadrupedal locomotion; but some (such as
muriquis and spider monkeys) are semi-brachiators. The members of Cebidae reside in communities
(exception: night monkeys).
Old world Monkeys
Old world Monkeys are placed under superfamily Cercopithecoidea and one taxonomic family
Cercopithecidae and this family is further subdivided into two subfamilies namely, the Cercopithecinae
(non-leaf eating) and Colobinae (leaf eating). Cercopithecines are different from the colobines because
former lack sacculated stomach and possess cheek pouches (for temporary food storage).
Leaf eating monkeys such as Colobus monkey, Proboscis monkey, Snub-nosed monkey, Hanuman
Langurs reside in Africa (only one genus Colobus), India, Indonesia, Malaysia, Java, Sumatra, Borneo
and China. Old World monkeys represent the most widely distributed living primates except Humans
because they inhabit a wide array of ecological domains ranging from tropical jungle habitats to
semiarid desert throughout sub-Saharan Africa and southern Asia and even to seasonally snow-covered
regions in northern Japan.
Non-leaf eating primate species such as Macaques and Baboons have also colonized wide
environmental settings such as rain forests, arid scrublands, grasslands and mountainous slopes. They
are found throughout Africa and Asia. They have omnivorous diet and eat about anything which is
edible in their environmental setting. Today, the genus Macaca exhibit widest geographical distribution
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among all Old world Monkeys ranging from Morocco in North-western Africa to the Northern end of
Honshu Island in Japan.
Most of Old World monkeys are quadrupedal and primarily arboreal, but certain species such as
baboons, macaques, and langurs exhibit terrestrial lifestyle and spend much of the day on the ground.
Sexual dimorphism is a typical trait among some terrestrial species and particularly pronounced in
baboons.
Females of certain species, especially baboons and some macaques, exhibit marked cyclical changes of
the external genitalia.
Apes and humans
The anthropoid apes and Humans are grouped under superfamily Hominoidea. The superfamily
Hominoidea encompasses three families, namely, Hylobatidae, Pongidae and Hominidae. Apes and
humans are differentiated from monkeys on the basis of following attributes: (Jurmain et al., 2012)
1. Generally larger body size, except for gibbons and siamangs
2. Absence of a tail
3. Shorter and more stable lower back
4. Arms longer than legs (apes only)
5. Differences in position and musculature of the shoulder joint, which is adapted for suspensory
behaviors (brachiation and/or feeding)
6. Generally more complex behavior
7. More complex brain and enhanced cognitive abilities
8. Increased period of infant development and dependency
Apes
The anthropoid apes can be dichotomized into two broad groups:
(a) Gibbon – the lesser apes – family Hylobatidae
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(b) Chimpanzee, Gorilla and Orangutan – the Great apes – family Pongidae
The gibbons and siamangs belong to gibbon family. The gibbons (comprised of several species) are
found to inhabit various parts in Southeast Asia, including Northeast India and Burma and also in
many of the islands of the Indo-Malayan archipelago. The Siamangs are found in the island of
Sumatra. Gibbons are true brachiators and the acrobats of the primates (Swindler, 2004).
The orangutans (encompass two species- Pongo pygmaeus pygmaeus and P. pygmaeus abelli)-only
great ape from Asia - are confined to Islands of Borneo and Sumatra. This frugivorous pongid resides
in dense rain forests and follows arboreal lifestyle and rarely come to ground. They do not brachiate
and spend much of their time in trees suspended by their long arms as they slowly progress through the
dense forests (Swindler, 2004).
The Gorillas are considered the largest and stoutest among all living primates owing to their body
dimensions. There are three geographical variants of gorilla- a Western lowland gorilla, Eastern
lowland and a Mountain gorilla (Rosen, 1974). They are regarded as single species with three
subspecies. Gorillas (Gorilla gorilla) inhabit forested areas of western and eastern equatorial Africa
and the mountain gorilla specifically inhabit the Virunga range of extinct volcanic mountains of
Uganda and Rwanda. They are knuckle walkers and spend most of their time on the ground and follow
a vegetarian diet.
Chimpanzees and Bonobos
The Chimpanzee (Pan troglodytes) and Bonobos (Pan paniscus) ( sometimes called “pygmy
chimpanzees”) are the remaining great apes. The former are found in equatorial Africa, in an area that
stretches from the Atlantic Ocean in the west to Lake Tanganyika in the east and the latter are confined
in an area south of the Zaire River in the Democratic Republic of the Congo (DRC) (Jurmain et al.,
2012). Chimpanzees follow arboreal lifestyle and are capable of standing and walking erect. They
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prefer to eat large amount of fruits, seeds and vegetables but occasionally they prefer to hunt in groups
and kill small mammals such as red colobus monkeys, young baboons, bush pigs, and antelope.
Humans
The family Hominidae is represented by Homo sapiens - the only extant member of the genus Homo.
Homo sapiens are the most widely dispersed primate species because they have successfully inhabited
diverse ecological domains. They represent one of the final products of an evolutionary radiation
which also led to the evolution of other species in the same genus such as Homo neanderthalensis
(which have now become extinct).
Summary
The present attempt throws light upon taxonomic specifications and geographical distribution of living
primates. Taxonomic classification helps scientists to organize living organism in a hierarchial system
of categories of increasing rank on the basis of biological and evolutionary relationships among living
creatures. It provides better understanding and communication of extant and extinct living creatures.
In the present context, classification of primates basically refers to hierarchial ordering of primates into
groups on the basis of their relationship to each other though descent from a common ancestor.
Primates constitute a diverse and vast group of mammals represented by humans, monkeys, prosimians
and apes. All the primate species share several common characteristics at order level but as we move
towards more specific classification levels (such as superfamily, family and genus) a great deal of
variation is exhibited and all criteria of relationships are centered upon essential identities of structure
and development. Primate classification is in transitional state owing to surplus genetic evidence that
has emerged over the past few years with advancement in genetic technologies (such as DNA
sequencing techniques).
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Primates reside in complex environmental settings characterized by constantly changing attributes.
Today nonhuman primates exist in five of the seven continents as there are no living primates in
Antarctica and Australia (exception being humans). Most of the nonhuman primate species follow
arboreal lifestyle and reside in Africa, Asia and South America, and their nearby islands. Primate
species have successfully inhabited a wide array of habitats ranging from dry and arid deserts to
tropical forests. Most of the primate species reside in tropical forests of different kinds and may also
occupy different niches even within a particular forest.
Certain primate species such as baboons and patas monkeys follow partially terrestrial lifestyle and
few species such as geladas and humans are fully terrestrial. Also certain primate species such as
mountain gorilla and black snub-nosed monkey have also inhabited high altitude settings.