1
Anthropology 200 – The Origins of Humanity
Lab Exercise: Primate Osteology
Humans belong to the zoological order Primates, which is one of 18 orders of the Class
Mammalia. Today we will 1) review some of the characteristics that distinguish primates from
other mammals and 2) learn about some of the morphological differences and similarities within
the primate order.
Station # 1 – What is a primate?
1. Using the cat skeleton as an out-group (a representative of another mammalian taxon) and the
Rhesus macaque skeleton as a primate representative, compare and describe the following traits
that serve to distinguish Primates from other mammals. Fill in the chart below using yes or no.
Domestic Cat
Monkey (Rhesus macaque)
Prehensile (grasping) hands & feet?
Opposable thumb & hallux (big toe)?
Nails instead of claws?
Pentadactyly (5-digits on hands & feet)?
Clavicle (collarbone)?
Forward-facing eyes?
Post orbital bar or plate?
Reduced prognathism (snout)?
Are there any similarities? If so, which feature(s)? Why do you think this feature is similar?
All of these characteristics can be related to a specific lifestyle that was particular to the
ancestors of all living primates and is typical of most primates living today — locomoting in the
trees by grasping hands and feet. The common ancestor of all living primates was an arboreal
(tree-living) climber with prehensile extremities that probably relied more on its eyes than on its
sense of smell. The ancestor may have had some depth perception, which is a product of
overlapping visual fields made possible by forward-facing eyes. The hands never evolved
specialization for ground running, so they always retained their ability to manipulate objects.
2
2. Now look at the illustration of the visual system in primates (labeled 1d).
a) Describe what it means to have binocular and stereoscopic vision.
b) Why is this type of vision important in the primate order?
c) How is this different from monocular vision?
d) Do predators or prey typically have monocular vision?
3. Now look at the three printouts of the Order Primates (labeled 1a, 1b, and 1c). There are
three different constructions of the taxonomy for our order. Describe the major differences
among these three taxonomies.
1a)
1b)
1c)
3
Station # 2 – Other Mammals
At this station, are the skulls with mandibles (jaws) of a bobcat, coyote, deer, and raccoon.
4. What are some distinguishing morphological features of each? (Hint: Examine the tooth
morphology (shape and structure), degree of prognathism, eye socket placement, and overall
shape of skull of each specimen.)
a) Bobcat
b) Coyote
c) Deer
d) Raccoon
5. What features in the teeth represent adaptations to diet? (Use the specimens and the laminated
sheets labeled 2a, 2b, & 2d to help you.) You can use diagrams to help illustrate your point.
a) Carnivore
b) Herbivore

Folivore (leaf-eater)

Frugivore (fruit-eater)
c) Omnivore
6. How might the position of the eyes be related to the lifestyle of organisms and specifically
these specimens? (Hint: Also use the laminated sheet labeled 2e to help you.)
a) Predator
b) Prey
7. Look at the photocopy of limb orientation in mammals vs. reptiles. Describe the difference.
(Hint: Use the laminated sheet labeled 2f to help you.)
4
Station # 3 – What is a prosimian?
The Order Primates can be divided in two suborders: Prosimii (lemurs, lorises, and tarsiers) and
Anthropoidea (monkeys, apes, and humans). [Recognize that other taxonomic divisions exist.
Review question # 3 in Station # 1.] Fossil prosimians are found to exist as early as the Eocene
about 50 million years ago. Most prosimians today live on the island of Madagascar, but a few
are active at night (nocturnal) in the forests of Africa (galagos) and Asia (lorises and tarsiers).
8. Compare the two prosimian specimens (skulls with mandibles of Lemur catta, ring-tailed
lemur, and a loris) at this station with the help of the laminated sheets. Fill in the chart using yes
or no unless otherwise specified.
Lemur
Loris
Prehensile hands & feet?
Opposable thumb & hallux?
Post-orbital bar or closure?
(bar, closure, or neither)
Size of orbits relative to skull size?
(Rank as large or larger)
Size of brain relative to skull?
(small or large)
Degree of prognathism relative to brain case?
(small or large)
Post-orbital constriction?
Tooth comb?
Dental formula? (2133 or 2123)
How does the dentition of prosimians differ morphologically from other primates with the same
dental formula? (Hint: Examine the lower jaw of these specimens. How has the morphology of
some of their teeth changed?)
5
Station # 4 – Suborder Anthropoidea
We are so proud of our own suborder that it is easy to talk about it as if it is higher, grander,
further up the scale, etc. However, evolution results from adaptation to the immediate
environment without a preordained direction. So don’t be speciocentric!
There are many traits that distinguish Prosimii and Anthropoidea, but most are not
morphological/skeletal. For example, the placenta and fetal membranes are particularly good for
sorting one suborder from the other (see laminated sheet 4b). However, there are still some
skeletal differences that can be easily observed.
9. Compare the anthropoid specimen, which is represented by the skeleton of a spider monkey
(New World monkey), with the two prosimian specimens (lemur & loris) at Station # 3.
Fill in the chart below.
Anthropoid (spider monkey)
Prosimian (lemur & loris)
Degree of prognathism?
(more or less)
Brain case size relative to snout?
(larger or smaller)
Front teeth?
(Normal incisors or grooming comb)
Post-orbital bar or closure?
(bar, closure, or neither)
Now let’s consider the features of this particular infraorder. The spider monkey is a New World
monkey, meaning it lives in South America and is a Platyrrhine (which means flat-nosed).
Conversely, the Rhesus macaque in Station # 1 is an Old World monkey, meaning it lives in
Africa or Asia, and is a Catarrhine (which means broad-nosed).
10. Using the illustrations of nose shape in the New- vs. Old-World monkeys on the laminated
sheet labeled 4d, describe how the nose shape differs between the two groups. You can also
diagram it if this helps to illustrate your point.
a) New World monkey
b) Old World monkey
6
11. Another difference between platyrrhines and catarrhines is in the dental formula. What is the
dental formula for New- vs. Old-World monkeys? (Hint: Use the laminated sheet labeled 4e to
help you.)
a) New World monkeys
b) Old World monkeys
12. The New World monkeys can be further divided into the callitrichids (marmosets and
tamarins) and cebids (e.g., spider monkey and cebus monkey). [Recognize that other taxonomic
divisions also exist.] Compare these two groups using the spider monkey skeleton as a cebid
representative and the laminated sheets labeled 4f, 4g, 4h, 4i, & 4j. Note the features that
differentiate the two groups.
a) Cebids
b) Callitrichids
7
Station # 5 – Cercopithecoidea (Old World monkeys) and Hominoidea (apes & humans)
The superfamily Hominoidea is comprised of the small-bodied apes (gibbons & siamangs), great
apes (chimpanzees, bonobos, gorillas, and orangutans), and humans. At this station, the gibbon
specimen will serve as the representative for the superfamily Hominoidea.
13. The presence or absence of what common morphological feature can be used to distinguish
monkeys from all apes? Where are gibbons geographically located?
14. Compare the gibbon skeleton to that of the Rhesus macaque (Old World monkey
representative) skeleton at Station # 1. Use the laminated sheets to help you. Fill out the chart
below.
Gibbon
Degree of prognathism?
(reduced or pronounced)
Shape of rib cage? (dorso-ventrally vs. laterally)
(barrel or funnel/narrowed)
Length of forelimbs relative to trunk?
(longer or equal)
Length of forelimb relative to hindlimb?
(longer or equal)
Length of clavicle?
(shorter or longer)
Presence of tail?
Post-orbital closure?
Brain-size relative to body size?
(smaller or larger)
Position of scapula (shoulder blade)?
(more dorsal (on the back) or more lateral (to the side))
Rhesus
8
15. Some of the features you just examined are closely related to locomotion. What is the
gibbon’s primary form of locomotion? Is this type of locomotion unique to apes? If so, what
morphological feature do apes possess that other primates lack? In comparison, how does a
Rhesus or spider monkey typically locomote? (Hint: Use laminated sheets labeled 5b & 5c to
help you.)
16. The Old World monkeys can be further subdivided into the colobines and cercopithecines.
Using the laminated sheet labeled 5d, what are some of the major differences between these two
groups? (Hint: Some of these differences relate to dietary adaptations.) Try to speculate about
the diets of these two groups based on the morphological and physiological differences
illustrated on the photocopies.
9
Station # 6 – Superfamily Hominoidea
In front of you are a human skeleton and three great ape specimens for comparison. The three
great ape representatives include a full [adult male] gorilla skeleton, a juvenile orangutan
skeleton, and the skull with mandible of a chimpanzee.
17. Compare these specimens and fill out the chart below using the specimens and the laminated
sheets. Use yes or no unless otherwise specified.
Orangutan
Sagittal vs. nuchal crests?
(sagittal, nuchal, or neither)
Dental formula? (What is it?)
Canine size?
(large/well-pronounced,
medium, or indiscriminable)
Brain-case size relative to body-size?
(medium or large)
Degree of prognathism relative to
brain-case size?
(more pronounced, reduced, or
absent)
Forehead?
Pelvic blade length & shape?
(paddle = long & narrow or
saddle = short & broad)
Arm length relative to body?
(short or long)
Shape of face?
(prognathic or flat)
Length & shape of digits?
(long or short, curved or flat)
Shape of rib cage?
(barrel = compressed ventrodorsally or funnel)
Presence of tail?
Y-5 pattern in molars? (sheet 6d)
Gorilla
Chimpanzee
Human
10
Orangutan
Limb proportions?
(long arms, short legs vs short arms,
long legs)
Post-orbital constriction?
Position of hallux?
(opposable or aligned)
Shape of toes?
(curved or flat)
Arch in foot?
Grasping foot?
Presence of chin?
Position of scapula?
(dorsal or lateral)
Simian shelf? (sheet 6b)
Type of Locomotion?
(fist-walker, knuckle-walker,
or bipedal)
Shape of vertebral column?
(c-shaped or s-shaped)
Size of vertebrae from neck to pelvis?
(similar or increasing)
Gorilla
Chimpanzee
Human
11
18. Identify the following bones on the gorilla and human skeletons, and write/circle them
below: humerus, radius, ulna, calcaneus, femur, tibia, fibula, illium, ischium, pubis, clavicle
(collarbone), & scapula. Note: Appendix B in your textbook also has a labeled human
skeleton.
12