234 



INTRODUCTION TO EVOLUTION 



The teeth were strikingly human. Australopithecines agreed with Homo 

 sapiens (p. 232) in that (1) the dental arch was a smoothly rounded 

 parabola (Fig. 1 1.6), (2) the canine teeth did not project beyond the level 

 of the other teeth, (3) there was no simian gap, and (4) the first lower 

 premolar was not sectorial. 



We conclude, therefore, that the upright posture and the character of the 

 teeth warrant the inclusion of the australopithecines in Family Hominidae. 

 What were their most striking differences from Homo sapiens himself? 

 The skulls of these little people were notable for large jaws and teeth and 



IroikjM 



FIG. 11.9. Restored skull of an australopithecine (Ausfralopithecus) (left) compared to 

 a modern human skull (Tasmanian aboriginal), als, alisphenoid. fr, frontal, ma, malar. 

 mast., mastoid process, mx, maxilla, na, nasal, oc. cond., occipital condyle, pa, parietal, 

 soc, supraoccipitol. sq, squamosal. (From Gregory, Evolution Emerging, Vol. 2, p. 977. 

 Copyright 1951, by American Museum of Natural History. Used by permission of The 

 Macmillan Company, publishers.) 



small brain cases. The teeth were actually larger than those of modern 

 man. As a result of the tooth and jaw development the face was progna- 

 thous and lacking a chin (Fig. 11.9). Eyebrow ridges projected over the 

 eyes. 



The small, flat brain case stood in marked contrast to the large face. Casts 

 of the interior of the skulls reveal that the brain was of human form but 

 was so small as to be outside the range for normal brains of Homo sapiens. 

 Australopithecine brain capacity ranged from about 450 cc. up to 700 cc. 

 (Le Gros Clark, 1959). We have seen that the smallest normal capacity 



