Lab 10 Oligocene Fossil Primates

Oligocene Epoch

33.9-23.03 Ma

Included: Aegyptopithecus, Parapithecus, and an extinct galago

Where were they?

The omomyid primates eventually give rise to the haplorrhine primates. Among these were the first-known monkeys (Parapithecidae) from which a slightly younger group arose (Propliopithecidae). By far, the best-known and oldest fossils come from Oligocene localities in the Fayum Depression in the Sahara Desert of Egypt.

• warm and humid climate of Africa supported a tropical rainforest biome! 

Oligocene Primate Traits

• Forward-facing eyes

• Nose below eyes

• Post-orbital bar

• Nails on digits

• Divergent hallux

Oligocene Haplorrhine Traits

• Closed eye orbits

• Dry nose

• Internal lacrimal ducts

Parapithecidae: (Superfamily Parapithecoidea)

Have the diagnostic traits of the Infraorder Platyrrhini and appear to be ancestral to:

1. New World monkeys (Platyrrhini)

2. Propliopithecidae

Oligocene Platyrrhini Traits in PARAPITHECIDAE:

• 2.1.3.3 dental formula (3 premolars)

• Zygomatic-parietal cranial bone contact

• NO ear tubes

Propliopithecidae: (Superfamily Propliopithecoidea)

Have the diagnostic traits of the Infraorder Catarrhini and appear to be ancestral to:

1. Old World monkeys (Cercopithecoidea)

2. Apes and humans (Hominoidea)

Oligocene Catarrhini Traits in PROPLIOPITHECIDAE:

• 2.1.2.3 dental formula (2 premolars)

• Frontal-sphenoid cranial bone contact

• Ear tubes

Oligocene Primate Classification

Parapithecidae & Propliopithecidae

PARAPITHECIDAE ADAPTIVE PROFILE

• PLATYRRHINI TRAITS:  2.1.3.3 dental formula, no ear tubes, zygomatic-parietal cranial bone contact

• ACTIVITY: Diurnal (examine the relative size of the eye orbit for skull length)

• DIET: Some frugivorous, some folivorous (TBM above 500 g, premolars & molars have low-rounded cusps OR high-crested cusps)

• LOCOMOTION: Quadrupedal (look at relative limb lengths)

• FOSSIL SPECIES: Apidium, Parapithecus

• GOOD MODERN PRIMATE MODEL:  Titi monkeys in South America

PROPLIOPITHECIDAE ADAPTIVE PROFILE:

• CATARRHINI TRAITS:  2.1.2.3 dental formula, ear tubes, frontal-sphenoid cranial bone contact

• ACTIVITY: Diurnal (examine the relative size of the eye orbit for skull length)

• DIET: Some frugivorous, some folivorous (TBM above 500 g, premolars & molars have low-rounded cusps OR high-crested cusps)

• LOCOMOTION: Quadrupedal (look at relative limb lengths)

• SEXUAL DIMORPHISM: Yes, see below

• FOSSIL SPECIES:  Aegyptopithecus, Propliopithecus

• GOOD MODERN PRIMATE MODEL: Macaque monkeys in northern Africa and Asia