Transcript Chapter 9 Overview of the Fossil Primates

Chapter 9
Overview of the Fossil Primates
Chapter Outline
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Introduction
Primate Origins
Paleocene Primate-like Mammals
Eocene Primates
Oligocene Primates
Miocene Primates
Orthograde
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An upright body position.
This term relates to the position of the
head and torso during sitting, climbing,
etc., and doesn’t necessarily mean an
animal is bipedal.
Archonta
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The superorder designated the sister
orders of tree shrews, flying lemurs,
plesiadapiforms, and primates.
Map Showing Location of the
Fossil Primates
Map Showing Location of the
Fossil Primates
Archonta
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The superorder
designated for the
sister orders of tree
shrews, flying lemurs,
plesiadapiforms, and
primates.
Seven Epochs of the Cenozoic
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Paleocene (65 mya; primate-like mammals,
aka Plesiadapiformes)
Eocene (55.8 mya; first true primates,
Prosimians)
Oligocene (33 mya; early Catarrhines,
precursors to monkeys and apes, emerge)
Miocene (23 mya; monkeys and apes emerge,
first humanlike creatures appear)
Seven Epochs of the Cenozoic
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Pliocene (5.3 mya; early humans diversify)
Pleistocene (1.8 mya; early Homo develops)
Holocene (0.01 mya; the present epoch)
Last Common Ancestor (LCA)
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The final evolutionary link between two
related groups.
Question
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Monkeys, apes and the first humanlike
creatures appeared during the:
a) Pliocene.
b) Eocene.
c) Paleocene.
d) Miocene.
Answer: d
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Monkeys, apes and the first humanlike
creatures appeared during the Miocene.
Carpolestes
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Nearly complete skeleton of Carpolestes discovered in
the Clarks Fork Basin of Wyoming. (a) Carpolestes as it
was discovered. (b) Reconstructed skeleton (c) Artist’s
rendering.
Eocene Primates
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Fossil primates from the Eocene display
distinctive primate features.
Looking at the whole array of Eocene
primates, it is certain that they were:
1. Primates
2. Widely distributed
3. Mostly extinct by the end of the
Eocene.
Teilhardina
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(a) View of the skull
of Teilhardina from
the top.
(b) An artist’s
reconstruction of
Teilhardina, with
areas in gray
representing missing
fragments.
Teilhardina
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The rapid westward dispersal of euprimates of the
genus Teilhardina.
Early Eocene Primates:
Features
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Chinese fossils dating from the early Eocene
(55–45 m.y.a.) have three interesting features:
Forward rotation of the eyes makes them
distinct from the lemur-loris lineage.
The cranium shows small eye sockets,
suggesting they may have been diurnal.
They were all apparently extremely small,
weighing less than 1 ounce.
Amphipithecids
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The teeth of the
amphipithecids are
misleading, but the
mandibles betray
their phylogenetic
affinity as lower
primates.
Convergent Evolution
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An example of convergent evolution: the skull of
Archaeolemur (left) and a macaque monkey.
Note how the lemur resembles the monkey in the shape
of the jaw, teeth, and overall cranial form.
Subfossil
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Bone not old enough to have become
completely mineralized as a fossil.
Bilophodonty
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Molars that have 4 cusps, oriented in 2
parallel rows, that resemble ridges or
“lophs.”
This is characteristic of Old World
Monkeys.
Paleoprimatologist
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A person who specializes in the study of
the nonhuman primate fossil record.
General Prosimian
Characteristics
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Smaller body size.
Longer snouts with greater emphasis on
smell.
Eye sockets not completely enclosed in
bone.
Dental comb.
Small simple premolars.
General Prosimian
Characteristics
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Primitive triangle-shaped molars.
Grooming claw.
Artery running through the middle ear bone.
Unfused mandible.
Unfused frontal bone.
Smaller brain size relative to body size.
General Anthropoid
Characteristics
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Generally larger body size
Shorter snouts with greater emphasis on
vision
Back of eye socket formed by bony plate
Less specialized dentition, as seen in absence
of dental comb and some other features
Larger and more complex premolars
Derived square-shaped molars with new cusp
General Anthropoid
Characteristics
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Nails instead of claws on all digits
Loss of the artery running through the middle
ear bone
Fusion of the two sides of the mandible to
form one bone
Fusion of the two sides of the frontal bone
Larger brain (in absolute terms and relative to
body weight)
Catopithecus
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Three specimens of
Catopithecus the
earliest
anthropoid genus to
preserve a skull.
These give us our
first view of early
catarrhine cranial
anatomy including
fully enclosed orbits.
Oligocene Primates
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The Oligocene (34–23 m.y.a.) yielded fossil
remains of several species of early anthropoids.
By the early Oligocene, continental drift had
separated the New World from the Old World.
It has been suggested that late in the Eocene or
very early in the Oligocene, the first anthropoids
arose in Africa and reached South America by
“rafting” over the water separation on drifting
chunks of vegetation.
Phyletic Relationships of Fayum Early
Anthropoids and Living Catarrhines
Parapithecus
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Parapithecus belongs
to the group of
Fayum anthropoids
that are most closely
related to the
ancestry of New
World monkeys.
Aegyptopithecus
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Skull of
Aegyptopithecus.
This genus has been
proposed as the
ancestor of both Old
World monkeys and
hominoids.
Homunculus
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Skull of Homunculus,
a middle Miocene
descendant of the
earliest platyrrhine
radiation.
Question
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The majority of Old World primate fossils
of the Oligocene epoch (33-24 m.y.a)
come from:
a) China.
b) the Fayum Depression in Egypt.
c) East Africa.
d) the Arabian Peninsula.
Answer: b
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The majority of Old World primate fossils
of the Oligocene epoch (33-24 m.y.a)
come from the Fayum Depression in
Egypt.
Cladogram Of Extant Groups
of New World Monkeys
Continental Relationships
During the Late Eocene
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The broken white line
and surrounding
shades of blue
represent seafloor
spreading, which
caused continents to
drift apart.
New World Monkey vs. Old
World Monkey Characteristics
New World Monkeys
1. Sideways facing nostrils
2. Ring-like ear hole with
no tube
3. Dental formula of
2.1.3.3
4. Grasping tail
5. Distribution: Mexico and
South America
Old World Monkeys
1. Downward facing
nostrils
2. Tube-like ear hole
3. Dental formula of
2.1.2.3
4. Ischial callosities
5. Distribution: Africa,
southern Asia and
Japan
Sister Group
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Two lineages that diverged from a
particular common ancestor.
Since sister groups share a common
ancestor, they are each other’s closest
relatives.
Victoriapithecus
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Skull of
Victoriapithecus, the
first Old World
monkey.
Theropithecus
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Skull of brumpti, the most
bizarre fossil monkey
(inset).
An artist’s rendering of
Theropithecus on the
landscape in the Omo
Basin of Ethiopia about 3
mya.
Comparison of Bilophodont
Molars
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Comparison of
bilophodont molars as
found in cercopithecoids
and Y-5 molars as seen
in hominoids.
(a) Notice that the 4
cusps are positioned in 2
parallel rows or lobes.
(b) See how the 5 cusps
are arranged so that a Yshaped valley runs
between them.
Y-5 Molar
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Molars that have 5 cusps with grooves
running between them, forming a Y
shape.
This is characteristic of hominoids.
Dental Ape
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An early ape that postcranially resembles
a monkey, but dentally is hominoid (i.e.,
has a Y-5 molar configuration).
Diversity of Early Miocene
Ape Mandibles
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The shapes and sizes of
these mandibles and
teeth illustrates the
adaptive diversity of apes
during this time.
They ranged in size from
that of a male orangutan
through half the size of a
modern gibbon and ate
foods as varied as hard
roots and soft fruit.
Proconsul
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Skull of Proconsul,
the best known of the
early Miocene dental
apes.
Pliopithecus
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Pliopithecus, from the
middle Miocene of
Europe.
The pliopithecoids were
the first catarrhines to
leave Africa.
Since this skull is of a
female, no sagittal crest
is present, though strong
temporal lines indicate
the individual enjoyed a
diet of hard plant items.
Old World Monkey vs. Ape
Characteristics
Old World Monkey
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Narrow nose and palate
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Smaller brain
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Bilophodont molars
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Smaller average body
size
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Longer torso
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Shorter arms
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Tail
Ape
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Broad nose and palate
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Even larger brain
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Y-5 molars
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Larger average body
size
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Shorter torso
6. Longer arms
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No tail
Dryopithecus
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Skull of Dryopithecus,
the earliest European
ape.
The left side is
reconstructed as a
mirror image of the
complete right side.
Ouranopithecus
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Ouranopithecus, possible
ancestor of the African
apes.
Notice that the face
shares many features
with living African great
apes, including large
browridges and a wide
distance between the
eye orbits.
Sagittal Crest
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A ridge of bone that runs down the middle
of the cranium like a short Mohawk.
This serves as the attachment for the
large temporal muscles, indicating strong
chewing.
Comparison of Chimpanzee,
Sivapithecus and Orangutan
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Modern chimpanzee (left), Sivapithecus (middle), and
modern orangutan (right).
Sivapithecus and the orangutan exhibit a dished face,
broad cheekbones, and projecting maxilla and incisors.
Gigantopithecus
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An artist’s rendering of Gigantopithecus
enjoying a meal of the tasty, but tough, tropical
fruit known as durian.
Lufengpithecus
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Skull of a Lufengpithecus juvenile from the late Miocene
of Yunnan Province, China.
Biomolecular Primate Family Tree