So there are a couple of interesting developments about fossil apes. One is the retraction by the author of the claim 14 years ago to have found a jaw bone that was evidence of Homo habilis, a precursor species (arguably) of H erectus, in a recent Nature. Previously he and his coauthor had claimed that erectus may have evolved in Asia and then returned back to Africa. On a re-examination of the evidence, Russell Ciochon now thinks that there is a “mystery ape”, around chimpanzee size, in the Asian forests, a possible precursor to orangutans. In the light of Homo floresiensis in the Indonesian Archipelago, however, it is clear that there had to be another hominid in South East Asia apart from erectus, as it is not likely to have evolved from an erectus precursor. If I recall a talk given by Colin Groves, of the ANU, he thinks that it is likely to have been a descendent of H heidelbergensis, which many paleoprimatologists think was also the ancestor of H neanderthalensis habilis.
So what is going on around 4-1 million years ago in Asia? There has long been a debate over two competing hypotheses: the Out of Africa hypothesis, and the Multiregional Hypothesis, for H sapiens, but this is independent of sapiens‘ evolution. More recently, Alan Templeton argued on genetic grounds that there were several Out of Africa events over a period of nearly two million years, with gene flow back to Africa as well. This, ironically, leads back into the other paper [pdf], by Jeffrey Schwartz and John Grehan, in the Journal of Biogeography, which argues that humans are more closely related to orangutans than to chimps and gorillas [razib has a good summary], a view Schwartz has argued before.
