1. Copyright © 2013 Pearson Education, Inc. All rights reserved. Exploring Biological Anthropology: The Essentials, 3 rd Edition CRAIG STANFORD JOHN S. ALLEN SUSAN C. ANTÓN

2. Copyright © 2013 Pearson Education, Inc. All rights reserved. Chapter 10 Early Hominins and Australopithecus

3. Copyright © 2013 Pearson Education, Inc. All rights reserved. Becoming a Biped Anatomical Changes – balancing the body’s weight over two limbs Constructing the Bipedal Body Plan Why Bipeds?

4. Copyright © 2013 Pearson Education, Inc. All rights reserved. The Transition to Human Behavior What Made Humans Human? – the anatomical shift from quadrupedalism came after a behavioral shift began – at every stage of the process, natural selection favored the form the evolving protohominin took – at the earliest stages of hominin evolution, brain size and intelligence were quite apelike

5. Copyright © 2013 Pearson Education, Inc. All rights reserved. Will you Know a Hominin When You See One? Bipedality Dentition – Parabolic arch – Size of anterior and posterior teeth – Prognathism – CP 3 – Enamel Cranial Features

6. Copyright © 2013 Pearson Education, Inc. All rights reserved. The First Hominins Sahelanthropus tchadensis (7.0-6.0 MYA) – Chad – 6-7 mya – Less prognathic face – Large brow-ridge – Smaller canines – Anterior foramen magnum – Small brain – U-shaped arcade – Thin enamel

7. Copyright © 2013 Pearson Education, Inc. All rights reserved. The First Hominins (cont’d) Orrorin Tugenensis (6.0 MYA) – Kenya – 6 mya – Arm and femoral fragments may suggest bipedalism – Thick enamel – Small teeth – Large upper canines

8. Copyright © 2013 Pearson Education, Inc. All rights reserved. The First Hominins (cont’d) ramidus 4.4 mya Smaller canine Anterior foramen magnum Apelike molars kadabba 5.8 - 5.2 mya More apelike dentition Originally considered a variant of ramidus Ardipithecus ramidus (4.4 MYA) and Ardipithecus kadabba (5.8-5.2 MYA)

9. Copyright © 2013 Pearson Education, Inc. All rights reserved. Australopithecus and Kin Australopithecus anamensis (4.2-3.9 MYA) – Thickened tibia – Primitive dentition – Lumped with afarensis? – Lived in forested region

10. Copyright © 2013 Pearson Education, Inc. All rights reserved. Australopithecus and Kin (cont’d) Australopithecus afarensis – 3.9-2.9 mya – Lucy – Short, broad pelvis – Tilted femurs – In-line big toe – Sagittal crest – Small brain – Sexually dimorphic

11. Copyright © 2013 Pearson Education, Inc. All rights reserved. Australopithecus and Kin (cont’d) Australopithecus bahrelghazali (3.5-3.0 MYA) – Western Africa – Mandible fragment with seven teeth – A specimen of afarensis?

12. Copyright © 2013 Pearson Education, Inc. All rights reserved. Australopithecus and Kin (cont’d) Kenyanthropus platyops (3.5 MYA) – Flat face – Small molar teeth – afarensis?

13. Copyright © 2013 Pearson Education, Inc. All rights reserved. Australopithecus and Kin (cont’d) Australopithecus garhi (2.5 MYA) – Small brain – Prognathic face – Large canines – Sagittal crest – More human-like postcranial proportions? – Tool use?

14. Copyright © 2013 Pearson Education, Inc. All rights reserved. Australopithecus and Kin (cont’d) Australopithecus africanus (3.5-<2.0 MYA) – Slight brain increase – Rounded vault – No crests – Less projecting face – Bipedal postcranial anatomy

15. Copyright © 2013 Pearson Education, Inc. All rights reserved. Australopithecus and Kin (cont’d) Australopithecus sediba (1.97-1.78MYA) – Discovered 2010 in South Africa – Slight brain increase (420-435 cc) – Characteristics similar to Homo dental anatomy derived face features of the pelvis

16. Copyright © 2013 Pearson Education, Inc. All rights reserved. Australopithecus and Kin (cont’d) 'Robust' Australopithecus (or Paranthropus) – Hard object feeding Sagittal crest Large cheek teeth Flared zygomatic arch Dished face Extreme postorbital construction – Woodland and open woodland habitat

17. Copyright © 2013 Pearson Education, Inc. All rights reserved. Australopithecus and Kin (cont’d) Robust Australopithecines (cont’d) Australopithecus (p.) aethiopicus – 2.7-2.5 mya Australopithecus (p.) boisei – 2.3-1.2 mya Australopithecus (p.) robustus – 2.0-1.5 mya

18. Copyright © 2013 Pearson Education, Inc. All rights reserved. Understanding the Australopithecine Radiation Cohabitation Tools and Intelligence Ancestors and Descendants