overview of fossil primates Flashcards
derived traits
distinct traits
- orthograde: upright body position
- forward facing eyes
evolution during cenozoic
time period divided into 7 epochs:
1) paleocene
2) Eocene
3) Oligocene
4) Miocene
5) Pliocene
6) pleistocene
7) Holocene
Paleocene
65 mya; primate-like mammals
Eocene
55.8 mya; first true primates (prosimians)
oligocene
33 mya; precursors to monkeys and apes emerge
Miocene
23 mya; monkeys and apes emerge, first humanlike creatures appear
pliocene
5.3mya; early humans diversify
pleistocene
1.8 mya; early homo develops
Holocene
(0.01 mya; present epoch)
last common ancestor
hypothetical species that was last to exist before diverging into meyriad of sister orders related to primates
crown group
all taxa that come after major speciation events
stem groups
taxa in a clade before major speciation event
origin of primates
between 90 and 65 mtya
altiatlasius
- a possible earliest true primate known from a handful of teeth from morocco
- no other terrestrial mammalian fossils are known from this time in africa
- comparison are difficult
Eocene Euprimates
- forward facing eyes
- greater encephalization
- postorbital bar
- nails, not claws
- opposable big toe
Eociene primates features
- forward eye rotation
- small eye socket
- weighed less than 1 ounce
y-5 molar pattern
molars that have 5 cusps, oriented in a manner forming a y-shaped groove pattern on the surface
bilophodonty
molars that have 4 usps, oriented in 2 parallel rows, characteristic of old world monkeys
paleoprimatologist
a person who specializes in the study of the nonhuman primate fossil record
old world monkey characteristics (relative to ape)
-narrow nose and palate
-smaller brain
-bilophodont molars
-smaller average body size
-longer torso
=shorter arms
=tail
ape characteristic (relative to old world monkeys)
- broader nose and palate
- larger brain
- y-5 molars
- larger average body size
- shorter torso
- longer arems
- no tail
