K-T boundary

Primateorigin

Primate Origins

• Challenge is to minimize speculation on things that do not fossilize.

• We live in the Cenozoic Era (past 65 m.y.)• Earliest primate fossils date from c. 63 mya;

Eocene Epoch• Originated from primate-like mammals

An EoceneAn Eocenemammalmammal

An EoceneAn Eoceneprimateprimate

Post-orbitalPost-orbitalbarbar

Anthropoid Origins

Aegyptopithecus Aegyptopithecus Basal to the ape-Basal to the ape-Old World monkeyOld World monkeyseparation ca.separation ca.33 mya33 mya

A transitional? group

• Genus Proconsul• Many species• Mixture of monkey-like

and ape-like characteristics

• 23 mya• Africa

*

* the only extant tailless monkey is the‘Barbary Ape.’

East Africa, Rift Valley systemmajor hominid sites

Adjusting branch-points anongoing process

e.g., fossil dated at 6-7 mya

Rocky Mountain News - July 11, 2002

Rocky Mountain News - July 11, 2002

Sahelanthropustchadensis

Early Hominids

• Ardipithecus ramidus (5.8 mya)• Australopithecus anamensis (4.2 mya)

– basal to other australopithecines)– definitive evidence of bipedalism.

• Derivative australopithecines divided into “gracile” and “robust” species groups

Genetic evidencefor split

Australopithecus afarensis“Lucy” (Hadar, Ethiopia)

3.8 mya

Australopithecusafarensis?

Why?

Australopithecus afarensis(Hadar, Ethiopia). Most complete skull found to date

Prognathism

Australopithecus afarensis

= Diastema

Parallel Parallel or slightlyconvergent

DivergentC-shape

Dental arcade

Australopithecus afarensis to A. africanus

“Taung child”

Australopithecusafricanus1925South Africa

Age at death?