I had to scan some hominid pictures today; came across this old classic and thought it worth using here.
Produced by Adrienne Zihlman, the picture has been used to support Zihlman’s ‘pygmy chimpanzee hypothesis’ (Zihlman et al. 1978): this being the idea that the Bonobo Pan paniscus is ‘the best prototype for the common ancestor of humans and [other] African apes’ (Zihlman 1984, p. 39). Many recent discoveries have shown that at least some australopithecines really were more chimp-like than used to be thought, and the old idea that fossil hominins were just prototype versions of Homo is now very much dead. However, fossils like Sahelanthropus and Ardipithecus have also highlighted the fact that chimps, bonobos and other modern great apes are anatomically specialised too (e.g., Lovejoy et al. 2009), and are not relicts that necessarily reflect an ‘ancestral’ morphology.
So… is the ‘pygmy chimpanzee hypothesis’ still viable, or is it defunct? One doesn’t see it getting much discussion these days, and the proposal that fossil African hominids were closely similar to the bonobo in proportions and so on has not been supported; so I think it is no more. But, hey, I’m no palaeoanthropologist.
On an entirely unrelated note, a really interesting new evolution-themed blog launched yesterday: Scott Sampson’s The Whirlpool of Life. Be sure to check it out!
Refs – –
Lovejoy, C. O, Suwa, G., Simpson, S. W., Matternes, J. H. & White, T. D. 2009. The great divides: Ardipithecus ramidus reveals the postcrania of our last common ancestors with African apes. Science 326, 100-106.
Zihlman, A. 1984. Pygmy chimps, people, and the pundits. New Scientist 104 (1430), 39-40.
– ., Cronin, J. E., Cramer, D. L. & Sarich, V. M. 1978. Pygmy chimpanzee as a possible prototype for the common ancestor of humans, chimpanzees and gorillas. Nature 275, 744-746.