MAN 181 



stem from the other primates as far back as the 

 Oligocene, perhaps 30,000,000 years ago. 



One major difficulty in determining the proper evolu- 

 tionary position of the South African forms is the un- 

 certainty of dating fossils or associated materials when 

 the age ranges from, say, 100,000 to 1,000,000 years or 

 more, because within this range no good chemical or 

 isotopic method is yet shown to be applicable. If the 

 australopiths were evolved during the Middle Pleisto- 

 cene (ca. 500,000 years), and if others of the accepted 

 homininds are this old or older, then the australopiths 

 could not be ancestral to man, no matter what their 

 anatomical features, because, as Simpson has observed, 

 one of the basic laws of biology is that a man cannot be 

 ancestral to his grandfather. However, the dating prob- 

 lem, though still on a relative rather than absolute scale, 

 has now improved to the point where Dart's interpreta- 

 tion can be accepted without oflFense to Simpson's 'law.' 

 The earliest australopithecine remains so far known 

 (Early Pleistocene) apparently antedate the oldest 

 member of the Hominidae, Pithecanthropus (Middle 

 Pleistocene) by some hundreds of thousands of years. 

 Though no one of the several local variants of the genus 

 Australopithecus now known from South Africa may 

 have been directly ancestral to the genus Pithecan- 

 thropus, and though both genera may have coexisted 

 at some interval, the two types at least present a proper 

 sequence in time. 



Anatomically, Australopithecus conforms so closely, 

 in multitudinous and highly distinctive details, to the 

 requirements for the connecting link between the an- 

 thropoid-ape stem and Pithecanthropus that a true an- 

 cestral relationship seems extremely probable. In recent 

 years the tendency to erect a new species or even genus 

 on every jawbone or cranial fragment has given way to 

 taxonomic consolidation, owing, in part, to increased 

 recognition of the reality and importance of the ana- 

 tomical variation observable in any one species (such, 



