Chapter 9

Overview of the Fossil Primates

Chapter Outline• Introduction• Primate Origins• Paleocene Primate-like Mammals• Eocene Primates• Oligocene Primates• Miocene Primates

Orthograde• 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• 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 • The superorder

designated for thesister orders of tree shrews, flying lemurs,plesiadapiforms, and primates.

Seven Epochs of the Cenozoic• 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• 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)• The final evolutionary link between two

related groups.

Question• Monkeys, apes and the first humanlike

creatures appeared during the:a) Pliocene.b) Eocene.c) Paleocene.d) Miocene.

Answer: d • Monkeys, apes and the first humanlike

creatures appeared during the Miocene.

Carpolestes

• 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• Fossil primates from the Eocene display

distinctive primate features. • Looking at the whole array of Eocene

primates, it is certain that they were:1. Primates2. Widely distributed3. Mostly extinct by the end of the

Eocene.

Teilhardina• (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

• The rapid westward dispersal of euprimates of the genus Teilhardina.

Early Eocene Primates: Features• 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• The teeth of the

amphipithecids are misleading, but the mandibles betray their phylogenetic affinity as lower primates.

Convergent Evolution

• 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• Bone not old enough to have become

completely mineralized as a fossil.

Bilophodonty• Molars that have 4 cusps, oriented in 2

parallel rows, that resemble ridges or “lophs.”

• This is characteristic of Old World Monkeys.

Paleoprimatologist• A person who specializes in the study of

the nonhuman primate fossil record.

General Prosimian Characteristics1. Smaller body size.2. Longer snouts with greater emphasis on

smell.3. Eye sockets not completely enclosed in

bone.4. Dental comb.5. Small simple premolars.

General Prosimian Characteristics6. Primitive triangle-shaped molars.7. Grooming claw.8. Artery running through the middle ear bone.9. Unfused mandible.10. Unfused frontal bone.11. Smaller brain size relative to body size.

General Anthropoid Characteristics1. Generally larger body size2. Shorter snouts with greater emphasis on

vision3. Back of eye socket formed by bony plate4. Less specialized dentition, as seen in absence

of dental comb and some other features5. Larger and more complex premolars6. Derived square-shaped molars with new cusp

General Anthropoid Characteristics7. Nails instead of claws on all digits8. Loss of the artery running through the middle

ear bone9. Fusion of the two sides of the mandible to

form one bone10. Fusion of the two sides of the frontal bone11. Larger brain (in absolute terms and relative to

body weight)

Catopithecus• Three specimens of

Catopithecus the earliestanthropoid genus to preserve a skull.

• These give us our first view of early catarrhine cranial anatomy including fully enclosed orbits.

Oligocene Primates• 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• Parapithecus belongs

to the group of Fayum anthropoids that are most closely related to the ancestry of New World monkeys.

Aegyptopithecus• Skull of

Aegyptopithecus.• This genus has been

proposed as the ancestor of both Old World monkeys and hominoids.

Homunculus• Skull of Homunculus,

a middle Miocene descendant of the earliest platyrrhine radiation.

Question• 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• 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

• 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

Old World Monkeys1. Downward facing

nostrils2. Tube-like ear hole3. Dental formula of 2.1.2.34. Ischial callosities5. Distribution: Africa,

southern Asia and Japan

New World Monkeys1. Sideways facing nostrils2. Ring-like ear hole with

no tube3. Dental formula of 2.1.3.34. Grasping tail5. Distribution: Mexico and

South America

Sister Group• Two lineages that diverged from a

particular common ancestor. • Since sister groups share a common

ancestor, they are each other’s closest relatives.

Victoriapithecus• Skull of

Victoriapithecus, the first Old World monkey.

Theropithecus• 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

• 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 Y-shaped valley runs between them.

Y-5 Molar• Molars that have 5 cusps with grooves

running between them, forming a Y shape.

• This is characteristic of hominoids.

Dental Ape• 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

• 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• Skull of Proconsul,

the best known of the early Miocene dental apes.

Pliopithecus• 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

Ape1. Broad nose and palate2. Even larger brain3. Y-5 molars4. Larger average body

size5. Shorter torso6. Longer arms7. No tail

Old World Monkey1. Narrow nose and palate2. Smaller brain3. Bilophodont molars4. Smaller average body

size5. Longer torso6. Shorter arms7. Tail

Dryopithecus• Skull of Dryopithecus,

the earliest European ape.

• The left side is reconstructed as a mirror image of the complete right side.

Ouranopithecus• 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• 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

• 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

• An artist’s rendering of Gigantopithecus enjoying a meal of the tasty, but tough, tropical fruit known as durian.

Lufengpithecus

• Skull of a Lufengpithecus juvenile from the late Miocene of Yunnan Province, China.

Biomolecular Primate Family Tree