1 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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1
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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Anthropology
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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Anthropology
Classification and Distribution of Living Primates
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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Classification and Distribution of Living Primates
vi. The apes of Africa and Asia and Humans
Fig IV: Six groups of Living Primates
(Source: Martin, 1994)
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Anthropology
Classification and Distribution of Living Primates
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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Anthropology
Classification and Distribution of Living Primates