Mona Lisa smile: The morphological enigma of human and great ape evolution


  • John R. Grehan

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    • Buffalo Museum of Science, 1020 Humboldt Parkway, Buffalo, NY 14211
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    • Dr. Grehan is Director of Science and Collections at the Buffalo Museum of Science and a research associate at the Carnegie Museum of Natural History. His research work in evolutionary biogeography (published as Panbiogeography: Tracking the History of Life) led to an investigation of the competing evolutionary theories for human origin as a foundation for future biogeographic studies of evolution in the higher primates.

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The science of human evolution is confronted with the popular chimpanzee theory and the earlier but largely ignored orangutan theory. The quality and scope of published documentation and verification of morphological features suggests there is very little in morphology to support a unique common ancestor for humans and chimpanzees. A close relationship between humans and African apes is currently supported by only eight unproblematic characters. The orangutan relationship is supported by about 28 well-supported characters, and it is also corroborated by the presence of orangutan-related features in early hominids. The uniquely shared morphology of humans and orangutans raises doubts about the almost universal belief that DNA sequence similarities necessarily demonstrate a closer evolutionary relationship between humans and chimpanzees. A new evolutionary reconstruction is proposed for the soft tissue anatomy, physiology, and behavioral biology of the first hominids that includes concealed ovulation, male beard and mustache, prolonged mating, extended pair-bonding, “house” construction, mechanical “genius,” and artistic expression. Anat Rec (Part B: New Anat) 289B:139–157, 2006. © 2006 Wiley-Liss, Inc.