228 INTRODUCTION TO EVOLUTION 



(Fig. 11.2) which lived in late Miocene or early Pliocene times, some 

 13 million years ago. Many fossils of this form have been found in a 

 lignite mine in Tuscany, Italy. Preliminary studies seem to indicate that 

 Oreopithecus resembled man, and differed from apes and monkeys, in 

 so many characteristics that it belongs in the same family with man, 

 Family Hominidae (Hiirzeler, 1958). (Apes, fossil and living, are placed 

 in Family Pongidae.) If this interpretation is correct Oreopithecus 

 "represents our first glimpse of a Tertiary hominid of any sort" (Straus, 

 1957). The teeth are unlike those of both monkeys and apes; rather they 

 resemble human dentition in some respects. The canine teeth were rela- 

 tively small, the face was short, and the pelvis was so broad as to suggest 

 that the creature might have walked upright ( Simons, 1 960 ) . 



If further investigation firmly establishes the position of Oreopithecus 

 in Family Hominidae, that fact will not in itself indicate that Oreopithecus 

 was ancestral to later members of the family. We recall that the "channel" 

 of human evolution has many subdivisions some of which (probably the 

 majority of them) terminated without giving rise to new forms. This is as 

 likely to be true of human evolution as it is demonstrably true of the 

 evolution of, for example, the horses and the proboscideans (pp. 204 and 

 211). But human evolution may well have gone through a stage in which 

 the actual ancestors resembled Oreopithecus in many respects. 



Were there other members of Family Hominidae living in the Pliocene? 

 Doubtless, but we must await further discoveries before we know anything 

 of their nature. As indicated in our diagram (Fig. 11.2), the next known 

 hominid fossils come from Pleistocene deposits — the australopithecines 

 from South Africa. 



Characteristics of "Homo sapiens" 



Before we discuss the characteristics of Pleistocene hominids it will be 

 useful to call attention to the characteristics of the species of man living at 

 the present time, our own species. Doing so conforms with our practice of 

 enumerating the characteristics of Equus before describing those of 

 Hyracotherium, Mesohippus, and so on, and of describing the structure 

 of modern elephants before discussing ancestral proboscideans. What are 

 the characteristics of Homo sapiens for the evolution of which we should 

 be watching as we study hominid fossils? 



For the most part we shall concentrate upon anatomical characteristics 

 which affect the skeletal system and hence can be studied in fossils. 



1. Brain. The large brain of Homo sapiens causes the brain case or 



