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ANT100Y1 Lecture Notes - Adapidae, Mosaic Evolution, Parapithecidae

Course Code
Shawn Lehman

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ANT100Y1Y Outline for EVOL ANTH Lecture #4
Lecture Goals
Basic morphological features of fossil primates.
General patterns of morphology and phylogenetics for fossil primates.
What a hominin is in terms of taxonomy
Morphological trends in hominin evolution:
Expansion in brain size
Changes in dental/cranial features
Continental Drift: Past, Present, & Future
Time Frame and Climate
Major Epochs during Tertiary Period
Paleocene “Primates”
Paleocene & Primate-like Mammals: Plesiadapiformes
Body Size, Niche, & Diet
Recent: Plesiadapids NOT Primates
1) No postorbital bar,
2) Claws instead of nails, 3) Eyes placed on side of head, &
4) Enlarged incisors.
More Recent: Plesiadapids & Few Others ARE Primates.
Two Main Eocene Primate Families
1). Adapidae 2). Omomyidae
Oligocene Primates
Three (3) haplorhine features: Fused frontal bone, full postorbital closure, & fused
mandibular symphasis. Three taxonomic groups: Parapithecidae, Propliopithecidae, and
South American Primates
Primates appear for first time in fossil record of South America towards late Oligocene
Origins of South American primate unclear: May have “rafted” over from Africa.
Miocene Primates
3 sequential sub-epochs for apes: Early Miocene apes, Mid Miocene apes, & Late Miocene
apes. Miocene monkeys (see textbook).
Miocene Primates
Early Miocene Mid-Miocene Late Miocene
ANT100Y1Y Outline for EVOL ANTH Lecture #4
Pliocene Primates
Geography and climate.
Two main taxa: Fossil Cercopithecinae & Fossil Colobinae.
Phylogenetic relationships: Unresolved.
Transitional Forms (Apes:Humans)?
1). Modifications of postcranial skeleton for bipedal locomotion
2). Shape and size of canines, especially in males, changes so not pointy or blade-like.
Reduction in level of sexual dimorphism in canine size.
3). Expansion of brain.
What’s a Hominin?
Morphological Trends in Hominin Evolution
Mosaic evolution: major evolutionary changes tend to take place in stages, not all at once.
Increased brain size.
Relative vs. absolute.
Quadrupedalism vs. Bipedalism
Changes in Hominin Brain Size
Hominin Fossils: Transitional Forms
Sahelanthropus tchadensis
Orrorin tugenensis
Ardipithecus ramidus & Ardipithecis kadabba
Kenyanthropus platyops