PHYLOGENY 



cestors. At the center of the problem is the unsatisfactory dating of these 

 fossils. They have been found in deposits which are very difficult to date. 

 Broom believed that they are at least of late Pliocene age, which would 

 make them more than a million years old, older than any certainly identi- 

 fied human fossil. If this is correct, they would at least be old enough to 

 qualify as ancestors of man. Current opinion favors early Pleistocene, but 

 perhaps not early enough for the Australopithecines to be ancestral to 

 man. Much more exact data are necessary on this important subject.* 



MAN IN THE FOSSIL RECORD 



Pithecanthropus. The known history of man begins with a fossil dis- 

 covered by Dubois in 1891 in Pleistocene deposits of central Java. The 

 fossil consisted of a single skull cap (Figure 68), a jaw fragment, and a 

 femur. This was sufficient to show that its possessor had heavy, ape-like 

 eyebrow ridges, but a much larger brain case (about 900 cubic centi- 

 meters) than any known ape, and occipital condyles apparently set suffi- 

 ciently far forward to permit erect posture. Dubois regarded this as the 

 "missing link" which was then so much under discussion, and he named 

 it Pithecanthropus erectus ( erect ape-man ) to indicate this belief. 



For nearly fifty years, the true nature of the Java fossils was controver- 

 sial, but in 1938, von Koenigswald found a second and more complete 

 skull. Additional finds have raised the total to five skulls, several jaw frag- 



* Mention must be made of one more fossil of this group, found in July, 1959, by 

 L. S. B. Leakey in the Oldovai Gorge of Tanganyika. A fairly complete skull and tibia, 

 of late Lower Pleistocene age, were found in association with stone chopping tools and 

 bones of the fauna of the time. All were sealed between two layers of rock in what 

 Leakey considers to have been an actual living site of early Pleistocene man. Leakey 

 named this fossil Zinjanthropus. While the general characters of this fossil are those of 

 other Australopithecines, the diflFerences are all closer to man. More material and more 

 study will be necessary to assess the significance of this find, but it now appears to 

 strengthen the claim of the Australopithecines to a place in the ancestry of modern 

 man. 



Figure 

 second 

 white 

 Giants, 



Press, 1946.) 



PrniECANTimopus Skulls. The 



broken off along the 



Weidenreich, "Apes, 



University of Chicago 



68 



specimen is 

 line. ( From 

 and Ahui," 



188 



