Outline

This analysis uses data (Table D.1) extracted from Table 5 in Wood and Collard (1999). There are 12 gnathic variables from 8 taxa related to the present day Homo sapiens. Wood and Collard conclude that H. habilis and H. rudolfensis do not belong in the genus and that the earliest taxa to satisfy the criteria are H. ergaster or early African H. erectus. The other genera are Paranthropus and Australopithecus.

The data

Descriptive statistics and relationships between variables

It is very clear from Figure D.1 that most of the variables are highly correlated and contribute little independent information. If the data are subjected to a principal components analysis 89% of the variance is retained in the first component, whose eigen value is 9.76. The second component, with an eigen value of 0.87, retains a further 7.9% of the variance giving a total of 96.6% for the first two components.