Ancestor Lineages (Exam 3)

What is Cladistics?

Looking for characteristics in similar creatures that you can create a broad family tree with

What are Molecular Clocks used for?

Used to estimate evolutionary time

• Mutations add up at a constant rate

  • This rate is the ticking of the molecular clock

  • As more time passes, there will be more mutations

What were the characteristics of mammals in the Mesozoic and Cenozoic Era Separately?

• Mesozoic (250-65mya): mammals small, nocturnal

• Cenozoic (65mya-Present): adaptive radiation of mammals into many niches

What are general Prosimian Characteristics (Strepsirrhines)

1.      Smaller body

2.      Longer snouts, greater emphasis on smell

3.      Postorbital bar

4.      Dental comb

5.      Grooming claw

6.      Unfused mandible

7.      Unfused frontal bone

8.      Smaller brain size relative to body size

What are general Anthropoid Characteristics (Haplorrhines)

1.      1.      Larger body

2.      Shorter snouts, greater emphasis on vision

3.      Postorbital plate

4.      Less specialized detention (no dental comb

5.      Nails instead of claws on all digits

6.      Fused mandible

7.      Fused frontal bone

8.      Larger brain (absolute and relative to body size)

What are Plesiadapiforms and their characteristics?

Archaic primates (?) (65-52mya)

• Some had nails instead of claws, grasping big toe

• Incisors that were not continuously growing and did not self-sharpen like those of rodents

• The tibia and fibula are separate, allowing rotation of the hind-limb

What are the characteristics of Carpolestes?

• Have a divergent big toe

• Have a nail replacement claw on the divergent big toe

What are the Eocene Euprimates and their characteristics?

During the Eocene (55-34mya) mammals existed with distinctive primate features

1. (relatively) forward facing eyes

2. (relatively) greater encephalization

3. Postorbital bar

4. Nails, not claws

5. opposable big toe

Where did the Eocene Primates live?

Found on 4 continents:

1. Africa

2. Europe

3. Asia

4. N. America

What primates were Eocene Primates?

Adapids: Adapis, Notharctus

• Related to Strepsirrhines

• Survive in South Asia during Oligocene, Miocene

Omomyids

• Related to Tarsiers, anthropoids?

In what time frame were the Eocene primates present?

55-34mya

What were characteristics of Adapids?

• Larger bodied prosimians

• Ancestors of the prosimians

• Arboreal quadropeds

What were characteristics of Omomyids?

• Smaller bodied Eocene primates (“prosimians”)

• Insectivorous

• May be ancestral to anthropoids

• Links with modern tarsiers

  • Calcaneous, orbit structure, olfactory portion of the brain

What are the Oligocene Primates?

Anthropoid origins

• Migration into South America (don’t know how)

What are the three types of Oligocene Primates?

• Oligopithecidae: Early anthropoids

  • Catopithecus

• Parapithecidae: anthropoids

  • Apidium

• Propliopithecidae: Early catarrhines

  • Aegyptopithecus

During what time frame were the Oligocene primates present?

34-23mya

What were the characteristics of the Parapithecids?

• Late Eocene/Early Oligocene

• Tiny to medium sized

• Most primitive

• Many fossils of Apidium

• Before divergence of catarrhines and platyrrhines

What were the characteristics of Apidium?

• Early Oligocene anthropoid

• Small (2-3lbs); probably ate fruit and seeds

• Locomotion: arboreal quadrupedal

What are the cranial characteristics of Apidium?

• Primitive dental formula: 2:1:3:3

• Fused mandible & frontal bones

• Post-orbital closure

How are Parapithecids related to later primates?

Many characters link with Platyrrhines

• Probably primitive characteristics

  • Before or after divergence of platyrrhines and catarrhines

Why is it theorized that Parapithecids existed before the divergence of Platyrrhines and Catarrhines?

NWM and OWM share features that are missing in the Parapithecids

• Means that Parapithecids existed before the divergence of platyrrhines & catarrhines: early anthropoids

What are the characteristics of Aegyptopithecus?

• 33-35mya

• Large: 13-20lbs

• Sexually dimorphic canines

• Arboreal, quadruped, diurnal, frugivore

• Long snout, some sagittal crest

How are Propliopithecids related to later primates?

• More primitive than any living catarrhine

• Before Old World Monkey/Hominoid split

What are the characteristics of Propliopithecids?

• Anthropoid characteristics

  • Fused mandible & frontal bones

  • Postorbital closure

• Larger than parapithecids

• Dental formula: 2:1:2:3

• Ape-like molars (not bilophodont)