Are Gaps Data? Absence of Evidence in the Interpretation of Miocene Apes and Hominine Origins

The fossil record of Miocene apes is rich, with taxon groups characteristic of each of its major subdivisions, the early, middle, and late Miocene. However, there are gaps among and within these successive radiations, both temporal and geographic, which have contributed to competing hypotheses of ape and human origins. The gaps are sometimes treated as data, informative of patterns of evolution to be discovered once filled. I review the nature of gaps in the fossil record of African apes and humans, their historic and contemporary contexts, and their relevance to the interpretation of the fossil record. I evaluate the premise that gaps in the fossil record represent missing data of in situ evolution in African hominines (African apes and humans), yet to be discovered, in contrast to direct fossil evidence of vicariance.