INTRODUCTION

The australopithecines are an extinct subfamily (Australopithecinae) of hominids that appeared at the end of the Miocene Epoch and continued into the Pliocene and Pleistocene Epochs.  The australopithecines lived in Africa during a time of climatic changes.  A cooling trend that began during the Oligocene Epoch continued, reducing forest areas, increasing savanna grasslands, and shifting the climate from tropical to subtropic conditions.  Most fossils are found in limestone caves in South Africa and near present or ancient water sources in east Africa.

At least five genera of australopithecines have been identified: Ardipithecus, Australopithecus, Paranthropus, Kenyanthropus and Sahelanthropus.  These genera are divided into at least eleven species, which are lumped into three groups - provisional, gracile and robust based on their classificatory status and skull morphology.  This diversity of australopithecines probably represents an adaptive radiation in the early history of hominids.

The physical characteristics of the australopithecines are a mixture of primitive and derived traits.  Generally speaking, the post-cranial skeleton developed more derived traits, especially those related to bipedal locomotion, than did the cranial skeleton, which retained a number of primitive primate traits.  The australopithecines also exhibit a number of traits that are transitional between modern humans and other apes.

There is little evidence of cultural developments associated with australopithecine skeletal remains.  For decades it has been known that "simple" stone core tools and modified bone tools are associated with australopithecine remains, but those fossils come from stratigraphic layers that also yield Homo fossils; so the question of who to credit with tool use is unanswered.  However, recent discoveries in Ethiopia suggest that at least one species of australopithecines used stone tools and butchered animals.
 

OBJECTIVES

Upon successful completion of this lab, students will

• understand and identify the anatomical differences among australopithecines, especially gracile and robust forms.

• understand behavioral implications of anatomical variability.

• evaluate and identify australopithecine skulls.

• consider phylogenetic relationships and develop a phylogeny for the australopithecines.

READINGS

Complete/review the readings prior to class.

• Lewin and Foley (2004) - Chapters 9 and 10
  

• France (2004) - Chapter 9

ASSIGNMENT

Answers to all exercises will be neatly written in pencil on the answer sheets provided in lab.  Exercises that do not require examination of skeletal specimens may be completed in or outside class time.  Genus and species names must be written according to biological convention. 

A. Answer the following questions in Exercise 9.1 of the France lab manual.

Question 1:  List two ways in which the australopithecine os coxa pictured in Figures 9.1 and 9.3 are similar to the modern human os coxa.  List one difference.

Question 3:  List two similarities of the australopithecine and ape phalanges and one similarity of the australopithecine and modern human phalanges based on Figure 9.4.

Question 7:  List two differences between the robust australopithecine and modern human proximal femora in Figure 9.10.
 

C.  Based on the information covered in lab and lecture, develop your own phylogeny of the australopithecines that includes, minimally, all gracile and robust species covered in class.
 

REFERENCES

Lewin, Roger and Robert Foley
2004   Principles of Human Evolution (2nd edition). Blackwell Publishing, Oxford.