ANT 3514C – Introduction to Biological Anthropology
Lab 6: Primate Anatomy & Taxonomy
Summer C 2019
Lab Objectives:
Evaluate the dental formula of an unknown primate and place it within a major clade
Interpret the difference between gradistic and cladistic methods of grouping primates
Identify the anatomical synapomorphies that distinguish the major primate clades
Draw a cladogram to illustrate the modern, broadly-accepted primate phylogeny
Purpose: To examine the skeletal traits that distinguish the major primate clades.
The study of non-human primates has been recognized since ancient times as relevant to
understanding human anatomy. This was perhaps best recognized by a wide audience of scholars
for the first time in 1735 when Carolus Linnaeus, despite his strong creationist views, included
humans with other apes and monkeys in the group Anthropomorpha. By the tenth edition of his
Systema Naturae in 1758 he had abandoned this term and began calling the group by the familiar
name we now use: Order Primates. Linnaeus was motivated to group humans with other primates
because of the many anatomical similarities that he perceived uniting them. In modern biological
terms, we now refer to these structures as synapomorphies, or ‘shared derived traits.’ For
instance, all primates have a broad, flat nail on their big toe, which is a structure unlike any of the
narrow claws found in other mammals. We use synapomorphies like these to reconstruct patterns
of shared ancestry and build cladograms to better understand the pattern of primate evolution and
where humans belong in it. This method of reconstructing relationships between taxa based on
shared derived characteristics is known as cladistics.
While morphology and phylogeny have shared a close relationship for centuries, the reliance on
synapomorphies to group organisms is relatively recent. In the early 20th century, primatologists
such as Wilfrid Le Gros Clark (famous for helping to debunk the Piltdown Man fraud) grouped
primates based on their overall similarity in appearance. This method was reminiscent of Aristotle’s
“Great Chain of Being,” with primitive primates at the base and humans at the apex. This way of
thinking has been called gradistic, because it suggests primate evolution proceeds in a simple,
uniform direction for all traits from primitive to derived. While this system has intuitive appeal, it
does not correspond with the way we think evolution proceeds. Modern primatologists and
anthropologists use cladistic methods based on a nested hierarchy of synapomorphies, because
we believe these more accurately reflect how evolution works.
Although phylogenetic trees are built today using cladistic methods, it is clear that gradistic thinking
still subconsciously underlies much of our approach to reconstructing evolution. You may have
already noticed that phylogenetic trees that include humans tend to place them at one extreme end
of the tree, implying some directionality or end goal to evolution, even though there is no reason
they need to be placed there! Within the primate order the shift from gradistic to cladistic thinking
has impacted how we perceive the relationships of many taxa, most notably the tarsier, which we
will investigate more in Station 3. You will be exposed to more examples of gradistic thinking when
looking at the human fossil record, where many features (such as brain size) are continuous, and
identifying synapomorphies can be particularly difficult. For this lab we will investigate many of the
important skeletal synapomorphies that define the largest primate clades.
Station 1: What defines a primate? (0.6 pt.)
1
, A college happened upon a mystery skull while looking through a mammalian skeletal collection.
She thinks it may be a primate and comes to you for your expert opinion. She cannot mail you the
skull so she emails you several photos. Examine the photos below. Use the list of primate features
(found in the lab reading for this week) to help you make the distinctions.
Is this animal a primate? Why or why not? List at least 2 features that lead you to this conclusion.
This animal is not a primate. For one, this animal has a prognathic (long) muzzle.
Secondly, this animal has no forward-facing orbits, meaning this animal has eye-sockets
2
Lab 6: Primate Anatomy & Taxonomy
Summer C 2019
Lab Objectives:
Evaluate the dental formula of an unknown primate and place it within a major clade
Interpret the difference between gradistic and cladistic methods of grouping primates
Identify the anatomical synapomorphies that distinguish the major primate clades
Draw a cladogram to illustrate the modern, broadly-accepted primate phylogeny
Purpose: To examine the skeletal traits that distinguish the major primate clades.
The study of non-human primates has been recognized since ancient times as relevant to
understanding human anatomy. This was perhaps best recognized by a wide audience of scholars
for the first time in 1735 when Carolus Linnaeus, despite his strong creationist views, included
humans with other apes and monkeys in the group Anthropomorpha. By the tenth edition of his
Systema Naturae in 1758 he had abandoned this term and began calling the group by the familiar
name we now use: Order Primates. Linnaeus was motivated to group humans with other primates
because of the many anatomical similarities that he perceived uniting them. In modern biological
terms, we now refer to these structures as synapomorphies, or ‘shared derived traits.’ For
instance, all primates have a broad, flat nail on their big toe, which is a structure unlike any of the
narrow claws found in other mammals. We use synapomorphies like these to reconstruct patterns
of shared ancestry and build cladograms to better understand the pattern of primate evolution and
where humans belong in it. This method of reconstructing relationships between taxa based on
shared derived characteristics is known as cladistics.
While morphology and phylogeny have shared a close relationship for centuries, the reliance on
synapomorphies to group organisms is relatively recent. In the early 20th century, primatologists
such as Wilfrid Le Gros Clark (famous for helping to debunk the Piltdown Man fraud) grouped
primates based on their overall similarity in appearance. This method was reminiscent of Aristotle’s
“Great Chain of Being,” with primitive primates at the base and humans at the apex. This way of
thinking has been called gradistic, because it suggests primate evolution proceeds in a simple,
uniform direction for all traits from primitive to derived. While this system has intuitive appeal, it
does not correspond with the way we think evolution proceeds. Modern primatologists and
anthropologists use cladistic methods based on a nested hierarchy of synapomorphies, because
we believe these more accurately reflect how evolution works.
Although phylogenetic trees are built today using cladistic methods, it is clear that gradistic thinking
still subconsciously underlies much of our approach to reconstructing evolution. You may have
already noticed that phylogenetic trees that include humans tend to place them at one extreme end
of the tree, implying some directionality or end goal to evolution, even though there is no reason
they need to be placed there! Within the primate order the shift from gradistic to cladistic thinking
has impacted how we perceive the relationships of many taxa, most notably the tarsier, which we
will investigate more in Station 3. You will be exposed to more examples of gradistic thinking when
looking at the human fossil record, where many features (such as brain size) are continuous, and
identifying synapomorphies can be particularly difficult. For this lab we will investigate many of the
important skeletal synapomorphies that define the largest primate clades.
Station 1: What defines a primate? (0.6 pt.)
1
, A college happened upon a mystery skull while looking through a mammalian skeletal collection.
She thinks it may be a primate and comes to you for your expert opinion. She cannot mail you the
skull so she emails you several photos. Examine the photos below. Use the list of primate features
(found in the lab reading for this week) to help you make the distinctions.
Is this animal a primate? Why or why not? List at least 2 features that lead you to this conclusion.
This animal is not a primate. For one, this animal has a prognathic (long) muzzle.
Secondly, this animal has no forward-facing orbits, meaning this animal has eye-sockets
2
