Lemur Symphysis Chapter 7 Summary
Week Seven Notes:
The Stepsirhines: Lemurs and Lorises
Prosimians(Same thing as Stepsirhines): Lemurs, Lorises, Tarsiers:
Most primitive of the primates
Exhibit the fewest derived traits (as a group) of all primates
Ancestral Characteristics (ie. Inherited from mammals)
• Rely more on olfaction
• Moist noise and long snout
• Eyes slightly more lateral
Classification of Prosimians: Lemurs, Lorises, and Tarsiers
Order- primates
Suborder: Strepsirhines (used to be Prosimians)
• Means “wet-nosed”
• Lemurs and Lorises
Strepsirhines: Shared Anatomical Features
1. Postorbital ring/bar (derived)
2. Unfused frontal bone (ancestral)
3. Unfused Mandibular Symphysis (ancestral)
a. Mandibular symphysis at the midpoint of the chin
4. Tooth …show more content…
Comb present (derived)
a. Aka “dental comb”
b. Lower incisors and canines project forward
c. Used in grooming
5. Dental formula is 2 incisors -1 canine-3premolars -3 molars (derived)
6. Tapetum lucidum present (ancestral)
a. Not unique to strepsirhines
7. Bicornuate uterus (ancestral)(almost like a two horned uterus, almost heart shaped)
a. For multiple offspring
Strepsirhine Infraorder: Lemuriformes (Lemurs)
Only found on Madagascar and nearby islands
Only nonhuman primates on Madagascar
Found many open niches on arrival
Lemurs:
60 surviving species
Larger Lemurs diurnal-active during day
Smaller lemurs nocturnal
One third of lemurs extinct since AD 500
Lemur Behavior:
Most are arboreal (spends most time in trees)
Most are quadrupeds; some are vertical clingers/leapers
Many live in social groups
Strepsirhine Infraorder: Lorisiformes-Lorises
At least 8 species of Lorises
Found in India, SE Asia, and Africa
Slow arboreal quadrupeds
Nocturnal
Lorisiformes-Galagos
6-9 galago species
Mostly under 1kg
Locomotion is vertical clinging and leaping
Nocturnal
Lorisiformes (Lorises and Galagos)
Some lorises and galagos are entirely insectivorous
Both usually solitary foragers
Tarsiers: Prosimians, but not Strepsirhines
3 recognized genera of tarsiers
Restricted to islands in Southeast Asia
Vertical clingers and leapers
Nocturnal insectivores
Tarsiers
Enormous eyes immobile within sockets
No tapetum lucidum
• Different from strepsirhines
Tarsiers: Strepsirhine Traits
1.
Unfused frontal (ancestral)
2. Unfused Mandibular symphysis (ancestral)
3. 2-1-3-3 Dental formula
4. Bicornuate Uterus
Tarsiers: Traits not shared with Strepsirhines
1. Postorbital ring
2. Dental comb
3. Tapetum Lucidum
Tarsiers more like monkeys in their genetics
Primate Fossil Ancestry: Events Preceding Primates
Ca. 500 MYA: first vertebrates in fossil record
Ca. 250 MYA: Pangea II forms- nearly all land is one big continent
Ca. 125 MYA: Pangea is split into Northern and Southern halves
Ca. 125 MYA
• Northern continent is Laurasia o North America, Greenland, Europe, Asia (minus India)
• Southern Continent is Gondwana o South America, Africa, Antarctica, Australia
• Adaptive radiation of angiosperms underway o Angiosperm-flowering plants o Important for later primate evolution (fruits/insects)
• Marsupials have recently evolved
Events Preceding Primates cont:
Ca. 70 MYA: first placental mammals in fossil record
Ca. 65 MYA: Mass extinction of most dinosaurs
50% of animal genera go
extinct
No land animal over 25 kg survives
Cenozoic Era and the First Primates:
Cenozoic Era (65MYA to present)
• Paleocene Epoch (65-55 MYA) o No primates yet o Pre-primates(new world)
• Eocene Epoch (55-35 MYA) o First primates (strepsirhines)
• Oligocene Epoch (35-25 MYA) o First monkeys
• Miocene Epoch (25-05 MYA) o First apes
Paleocene Epoch (65-55MYA)
Adaptive radiation of mammals
• Environmental change opens up many new ecological niches
Plesiadapiformes: pre-primates
• Once thought to be primates (but hands differ too much)
• No primates were alive during Paleocene
Why aren’t Plesiadapiformes primates?
Dental formula: 3-1-4-3
No postorbital Bar
Claws, not nails
No opposable thumb
Eocene (55-35 MYA)
Warm, tropical forests in Eurasia
Primate fossils from 55 MYA
First primates similar to nocturnal prosimians
Probably visual predators on insects
Eocene Primate Example
Adapis (in the Adapid family): 35 MYA
1-2 kg
Rounded molar cusps
Longer prosimian snout
Postorbital bar
2-1-3-3 dental formula
Halopherines
Anthropoids: Monkeys, Apes, and Humans
Evolved later in time that the strepsirhines
More derived characters than prosimians
Reduced reliance on smell
Color vision: 3 primary colors
Classification of Anthropoids: Monkeys, apes, and humans
Order: primates
Suborder: haplorhines
Means “dry nosed”
Includes monkeys, apes, humans, and tarsiers
Haplorhines: Shared anatomical features
1. Postorbital closure (derived)
2. Fused frontal boned
3. Fused mandibular symphysis (derived)
4. Tooth comb absent (derived)
5. Tapetum Lucidum absent (tissue that gathers light) (derived)
6. Non-bicornuate, simple uterus
7. Dental formula is mixed within the Haplorhines
a. 2-1-3-3 or 2-1-2-3
Haplorhines: Other shared characteristics
Longer maturation periods
Increased parental care
More mutual grooming
More complex social structure
Monkeys
The majority of all primate species
Two major groups
• New world monkeys o Central and South America
• Old World monkeys o Africa and Asia
Separated by geography and 30 million years of evolutionary history
Catarrhines(Infraorder): Old World monkeys, apes, and humans
“Catarrhine” =”downward facing nose”
Most widely distributed primates
Sub-Saharan Africa and Asia
Tropical forest to semiarid desert
Catarrhines: Shared Anatomical Characteristics:
1. Downward facing nostrils/narrow noses
2. Ear tube present
3. Dental Formula 2-1-2-3 (derived)
Old World Monkeys
Baboons, macaques, langurs, and guenons
Diets are varied
Many have Ischial callosities: “sitting pads”
Locomotor Behavior:
• Arboreal quadrupeds
• Terrestrial quadrupeds o Most monkeys are quadrupeds
• Semibrachiators o Leaping and limited swinging by arms
Sexually Dimorphic
• Males larger than females
Several types of social organization
• Multi-male, multi-female groups
• Polygamous groups
New World Monkeys: Infraorder: Platyrhines
Platyrhine=flat nose
Wide range of size, diet, and adaption
Smallest is 12oz
Largest is 20lbs
New world monkeys: shared anatomical features
1. Broad noses, laterally facing nostrils
2. Dental formula 2-1-3-3 (ancestral)
3. Ring-like structure instead of ear tube
New world monkeys: other characteristics
All diurnal except one species
Almost exclusively arboreal
Some are semi-brachiators
Some have prehensile tails
• Prehensile=ability to grip the branch
New World Monkeys: Two major subgroups
1. Marmosets and Tamarins
a. Small
b. Claw-like nails
2. Cebids
a. Larger some have prehensile tails
Oligocene Epoch (35-25 MYA)
Cooler temperatures than Eocene
• As much as 18*F cooler
Tropical forests contract toward equator
More seasonality
Early Haplorhines: Oligocene (35-25 MYA)
Cooling trend leads to mass extinction event
Haplorhine radiation begins soon after
New World Monkeys (Central and South America)
Old World Monkeys (Africa and Asia)
New World Monkey origins (ca. 30MYA)
South America and Africa were much closer than today
New world monkeys most similar to African monkeys
How did new world monkeys get to South America?
Rafting on vegetation is the best explanation
Fossil monkeys from the Fayum, Egypt
Aegyptpithecus (30MYA): OW monkey ancestor?
• Projecting snout (strepsirhine)
• Slow arboreal quadruped (streps)
• 2-1-2-3 dental formula (haplorhine)
• Postorbital closure (Hap)
• Fused frontal and mandible (Hap)
Apidium (34 MYA): NW monkey ancestor?
• 1 kg in size
• Quadrupedal leaper
• 2-1-3-3 dental formula (NW monkey-like?)
• Postcranial more like NW monkeys
The Stepsirhines: Lemurs and Lorises
Prosimians(Same thing as Stepsirhines): Lemurs, Lorises, Tarsiers:
Most primitive of the primates
Exhibit the fewest derived traits (as a group) of all primates
Ancestral Characteristics (ie. Inherited from mammals)
• Rely more on olfaction
• Moist noise and long snout
• Eyes slightly more lateral
Classification of Prosimians: Lemurs, Lorises, and Tarsiers
Order- primates
Suborder: Strepsirhines (used to be Prosimians)
• Means “wet-nosed”
• Lemurs and Lorises
Strepsirhines: Shared Anatomical Features
1. Postorbital ring/bar (derived)
2. Unfused frontal bone (ancestral)
3. Unfused Mandibular Symphysis (ancestral)
a. Mandibular symphysis at the midpoint of the chin
4. Tooth …show more content…
Comb present (derived)
a. Aka “dental comb”
b. Lower incisors and canines project forward
c. Used in grooming
5. Dental formula is 2 incisors -1 canine-3premolars -3 molars (derived)
6. Tapetum lucidum present (ancestral)
a. Not unique to strepsirhines
7. Bicornuate uterus (ancestral)(almost like a two horned uterus, almost heart shaped)
a. For multiple offspring
Strepsirhine Infraorder: Lemuriformes (Lemurs)
Only found on Madagascar and nearby islands
Only nonhuman primates on Madagascar
Found many open niches on arrival
Lemurs:
60 surviving species
Larger Lemurs diurnal-active during day
Smaller lemurs nocturnal
One third of lemurs extinct since AD 500
Lemur Behavior:
Most are arboreal (spends most time in trees)
Most are quadrupeds; some are vertical clingers/leapers
Many live in social groups
Strepsirhine Infraorder: Lorisiformes-Lorises
At least 8 species of Lorises
Found in India, SE Asia, and Africa
Slow arboreal quadrupeds
Nocturnal
Lorisiformes-Galagos
6-9 galago species
Mostly under 1kg
Locomotion is vertical clinging and leaping
Nocturnal
Lorisiformes (Lorises and Galagos)
Some lorises and galagos are entirely insectivorous
Both usually solitary foragers
Tarsiers: Prosimians, but not Strepsirhines
3 recognized genera of tarsiers
Restricted to islands in Southeast Asia
Vertical clingers and leapers
Nocturnal insectivores
Tarsiers
Enormous eyes immobile within sockets
No tapetum lucidum
• Different from strepsirhines
Tarsiers: Strepsirhine Traits
1.
Unfused frontal (ancestral)
2. Unfused Mandibular symphysis (ancestral)
3. 2-1-3-3 Dental formula
4. Bicornuate Uterus
Tarsiers: Traits not shared with Strepsirhines
1. Postorbital ring
2. Dental comb
3. Tapetum Lucidum
Tarsiers more like monkeys in their genetics
Primate Fossil Ancestry: Events Preceding Primates
Ca. 500 MYA: first vertebrates in fossil record
Ca. 250 MYA: Pangea II forms- nearly all land is one big continent
Ca. 125 MYA: Pangea is split into Northern and Southern halves
Ca. 125 MYA
• Northern continent is Laurasia o North America, Greenland, Europe, Asia (minus India)
• Southern Continent is Gondwana o South America, Africa, Antarctica, Australia
• Adaptive radiation of angiosperms underway o Angiosperm-flowering plants o Important for later primate evolution (fruits/insects)
• Marsupials have recently evolved
Events Preceding Primates cont:
Ca. 70 MYA: first placental mammals in fossil record
Ca. 65 MYA: Mass extinction of most dinosaurs
50% of animal genera go
extinct
No land animal over 25 kg survives
Cenozoic Era and the First Primates:
Cenozoic Era (65MYA to present)
• Paleocene Epoch (65-55 MYA) o No primates yet o Pre-primates(new world)
• Eocene Epoch (55-35 MYA) o First primates (strepsirhines)
• Oligocene Epoch (35-25 MYA) o First monkeys
• Miocene Epoch (25-05 MYA) o First apes
Paleocene Epoch (65-55MYA)
Adaptive radiation of mammals
• Environmental change opens up many new ecological niches
Plesiadapiformes: pre-primates
• Once thought to be primates (but hands differ too much)
• No primates were alive during Paleocene
Why aren’t Plesiadapiformes primates?
Dental formula: 3-1-4-3
No postorbital Bar
Claws, not nails
No opposable thumb
Eocene (55-35 MYA)
Warm, tropical forests in Eurasia
Primate fossils from 55 MYA
First primates similar to nocturnal prosimians
Probably visual predators on insects
Eocene Primate Example
Adapis (in the Adapid family): 35 MYA
1-2 kg
Rounded molar cusps
Longer prosimian snout
Postorbital bar
2-1-3-3 dental formula
Halopherines
Anthropoids: Monkeys, Apes, and Humans
Evolved later in time that the strepsirhines
More derived characters than prosimians
Reduced reliance on smell
Color vision: 3 primary colors
Classification of Anthropoids: Monkeys, apes, and humans
Order: primates
Suborder: haplorhines
Means “dry nosed”
Includes monkeys, apes, humans, and tarsiers
Haplorhines: Shared anatomical features
1. Postorbital closure (derived)
2. Fused frontal boned
3. Fused mandibular symphysis (derived)
4. Tooth comb absent (derived)
5. Tapetum Lucidum absent (tissue that gathers light) (derived)
6. Non-bicornuate, simple uterus
7. Dental formula is mixed within the Haplorhines
a. 2-1-3-3 or 2-1-2-3
Haplorhines: Other shared characteristics
Longer maturation periods
Increased parental care
More mutual grooming
More complex social structure
Monkeys
The majority of all primate species
Two major groups
• New world monkeys o Central and South America
• Old World monkeys o Africa and Asia
Separated by geography and 30 million years of evolutionary history
Catarrhines(Infraorder): Old World monkeys, apes, and humans
“Catarrhine” =”downward facing nose”
Most widely distributed primates
Sub-Saharan Africa and Asia
Tropical forest to semiarid desert
Catarrhines: Shared Anatomical Characteristics:
1. Downward facing nostrils/narrow noses
2. Ear tube present
3. Dental Formula 2-1-2-3 (derived)
Old World Monkeys
Baboons, macaques, langurs, and guenons
Diets are varied
Many have Ischial callosities: “sitting pads”
Locomotor Behavior:
• Arboreal quadrupeds
• Terrestrial quadrupeds o Most monkeys are quadrupeds
• Semibrachiators o Leaping and limited swinging by arms
Sexually Dimorphic
• Males larger than females
Several types of social organization
• Multi-male, multi-female groups
• Polygamous groups
New World Monkeys: Infraorder: Platyrhines
Platyrhine=flat nose
Wide range of size, diet, and adaption
Smallest is 12oz
Largest is 20lbs
New world monkeys: shared anatomical features
1. Broad noses, laterally facing nostrils
2. Dental formula 2-1-3-3 (ancestral)
3. Ring-like structure instead of ear tube
New world monkeys: other characteristics
All diurnal except one species
Almost exclusively arboreal
Some are semi-brachiators
Some have prehensile tails
• Prehensile=ability to grip the branch
New World Monkeys: Two major subgroups
1. Marmosets and Tamarins
a. Small
b. Claw-like nails
2. Cebids
a. Larger some have prehensile tails
Oligocene Epoch (35-25 MYA)
Cooler temperatures than Eocene
• As much as 18*F cooler
Tropical forests contract toward equator
More seasonality
Early Haplorhines: Oligocene (35-25 MYA)
Cooling trend leads to mass extinction event
Haplorhine radiation begins soon after
New World Monkeys (Central and South America)
Old World Monkeys (Africa and Asia)
New World Monkey origins (ca. 30MYA)
South America and Africa were much closer than today
New world monkeys most similar to African monkeys
How did new world monkeys get to South America?
Rafting on vegetation is the best explanation
Fossil monkeys from the Fayum, Egypt
Aegyptpithecus (30MYA): OW monkey ancestor?
• Projecting snout (strepsirhine)
• Slow arboreal quadruped (streps)
• 2-1-2-3 dental formula (haplorhine)
• Postorbital closure (Hap)
• Fused frontal and mandible (Hap)
Apidium (34 MYA): NW monkey ancestor?
• 1 kg in size
• Quadrupedal leaper
• 2-1-3-3 dental formula (NW monkey-like?)
• Postcranial more like NW monkeys