Tattersall's take on human evolution.

Yet, despite his call for a more speciose interpretation of early I Homo i , in the illustration early in the book illustrating fossil hominin species through time, Tattersall lumps all the eastern African early I Homo i fossils into a single species. Despite the prodigious efforts of field researchers, the fossil evidence we have now (i.e. the "known fossil record" sensu [1]) is almost certainly much less informative about taxic diversity, geographical range, and temporal span, than the fossil record we imagined in our thought experiment. Researchers who recently tried to estimate the impact of rock availability and collection effort on the first and last appearances of early fossil hominin taxa came to the conclusion that these two factors likely had a profound influence on whether a taxon left an accessible fossil record ([4]). There are cases when one new fossil (e.g. OH 7, the type specimen of I Homo habilis i from Olduvai [now Oldupai] Gorge in Tanzania) is so different from the existing fossil evidence at a site (e.g. OH 5, the type specimen of I Paranthropus boisei i , also from Olduvai Gorge) that the case for taxonomic distinctiveness is obvious, but not many claims for new hominin taxa are as securely based as this example. [Extracted from the article]