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Anth 125 Introduction to Biological Anthropology
Dr. Darlene Applegate
Spring 2008
GROUP LAB PROJECT 2:
NON-HUMAN PRIMATE IDENTIFICATION


INTRODUCTION

The primates are an order of mammals that evolved about 60-65 million years ago. It is the group of mammals to which humans belong. Study of non-human primates aids in understanding human biology and helps to answer the question “What is a human?” (Relethford 2005). Though behavioral traits are important, for this assignment students will examine morphological characteristics of skull specimens and photographs to distinguish primates from other mammals and to identify different types of primates.


OBJECTIVES


KEY TERMS

DISTINGUISHING PRIMATES FROM OTHER MAMMALS

Traits that distinguish primates from other orders of mammals are referred to as derived traits. Primate derived traits likely represent adaptations to some aspect of living in an arboreal habitat, especially locomotion (moving through the trees) or subsistence (finding food in the trees).

Primate derived traits include opposable thumb and big toe, prehensile hands and feet, nails instead of claws on the digits, ability to sit for extended periods of time in an upright position without using the upper limbs for balance, reliance on vision, and reduced sense of smell. For this assignment, however, we will focus on primate derived traits expressed in the skull. The following table summarizes the differences between primates and other mammals that are observable in the skull. It is important to use a series of traits, not a single trait, in distinguishing primates from non-primate mammals.

TRAIT PRIMATE
 NON-PRIMATE
skull shape rounded not rounded
cranial capacity larger
 smaller
eye placement forward
 side
eye orbit
 encircled by bony ring or completely
enclosed in bony socket		 incomplete bony ring
eye size
 larger
 smaller
location of eyes and nose
 below forehead
 level with forehead
snout size
 smaller, shorter  
larger, longer
dental formula 2-1-2-3 or 2-1-3-3 usually 4-1-3-3 or 4-1-4-3
foramen magnum * toward center of skull
toward rear of skull
* the large opening on the inferior (bottom) surface of the skull

    
DISTINGUISHING PRIMATES BASED ON SKULL TRAITS

While primates possess the aforementioned derived skull traits due to common ancestry, there is variation in the skulls of different types of primates. Skull variation among primates is, in part, reflective of adaptations to different niches, especially variation in diet. The following table summarizes the differences among primates that are observable in the skull. Again, it is important to use a series of traits, not a single trait, in distinguishing among different types of primates.

TRAIT
 PROSIMIAN
 NWM
 OWM
 APE
eye orbit
 bony ring
 bony socket
 bony socket bony socket
lower jaw bone(s)
 two fused halves single bone single bone single bone
lower jaw shape V
 U
 U
 U
dental formula 2-1-2-3 or 2-1-3-3 2-1-3-3 2-1-2-3 2-1-2-3
tooth comb
 may be present
 absent
 absent absent
sectorial lower first premolar *
 absent absent may be present present in great apes
molar pattern four cusps four cusps four cusps Y-5
* the first premolar in the lower jaw has a single cusp or ridge


DISTINGUISHING PRIMATES BASED ON POST-CRANIAL TRAITS

In addition to variation in skull traits, primate also differ in the post-cranial skeleton (bones from below the skull). Post-cranial variation among primates is, in large part, reflective of different locomotor adaptations. The following table summarizes the differences among primates that are observable in the skull. Again, it is important to use a series of traits, not a single trait, in distinguishing among different types of primates.

TRAIT
 PROSIMIAN
 NWM
 OWM
 APE
backbone upward curving upward curving straight straight to upward curving
tail bones present present present absent
arm:leg lengths
 equal
 equal
 equal
 arms longer than legs
finger/toe bone lengths equal
 toes longer than fingers
 toes longer than fingers fingers longer than toes
shoulder blades sides of chest sides of chest sides of chest toward the backbone


DISTINGUISHING PRIMATES BASED ON MORPHOLOGICAL TRAITS

Soft-tissue morphological traits may also be used to distinguish among different types of primates. The following table summarizes the soft-tissue morphological differences among primates that are observable in the skull. Again, it is important to use a series of traits, not a single trait, in distinguishing among different types of primates.

TRAIT PROSIMIAN
 NWM
 OWM
 APE
eye size larger
smaller
 smaller
 smaller
nose
rhinarium
 nostrils point to sides
 nostrils point downward
 nostrils point downward
external tail
present, not prehensile
 present, prehensile present, not prehensile absent
grooming claw may be present
 absent
 absent absent
arm:leg lengths equal equal equal arms longer than legs
locomotion
arboreal quadrupedalism
vertical clinging/leaping
terrestrial quadrupedalism
 arboreal quadrupedalism
semi-brachiation
 arboreal quadrupedalism
terrestrial quadrupedalism
 brachiation
knuckle walking


ASSIGNMENT

The primate identification assignment will be completed in class by students working in groups of three. Each group will complete one answer sheet in pencil.

Examine each of the thirteen skull specimens and photographs. Answer the corresponding questions about each specimen or photograph and record the answer clearly on the answer sheet. Do not provide more information than what is requested.

Each group will have about five minutes to work with each specimen or photograph.

The group project will be completed within the allotted class time.


REFERENCES

France, Diane
2004  Lab Manual and Workbook for Physical Anthropology (5th ed.), Thomson Wadsworth, Belmont, CA.

Relethford, John
2005  The Human Species (6th ed.). McGraw-Hill, Boston.


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Page composed by Darlene Applegate, darlene.applegate@wku.edu
Last updated on February 26, 2008
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