Human Origins Icon Human Origins
Paleontology Icon Paleontology

Fossil Friday: To Be or Not to Be Homo

Photo credit: Nachosan, CC BY-SA 3.0 , via Wikimedia Commons.

The fossil hominin Homo habilis was described 1964 by famous paleoanthropologist Louis Leakey and his colleagues from the 1.9 million year old Olduvai Gorge locality in Tanzania (Leakey et al. 1964). Even though this taxon is only known from a small and highly incomplete collection of isolated bone fragments, it has become the crucial hominid species that supposedly bridges the gap between the ape-like australopithecines and our human genus Homo. Because of the association of the bones with stone tools it has been named Homo habilis, which means “handy man.” However, its alleged position as transitional form is quite controversial (also see Gibbons 2011, Luskin 20072015), and even the validity of the species has been questioned because it seems to be “a wastebasket taxon, little more than a convenient recipient for a motley assortment of hominin fossils” (Tattersall 1992). Homo habilis certainly was not the ancestor of later Homo species, because he is too recent and coexisted with early Homo ergaster, thus leaving a distinct gap between australopithecines and the genus Homo (Hawks et al. 2000).

A Dubious Attribution?

Since its small brain volume falls within the range of australopithecines, several scientists very early doubted the attribution of H. habilis to the genus Homo. Also the hand and feet are more ape-like and exhibit clear adaptations for climbing. Walker & Shipman (1996: 132) said that H. habilis is even more ape-like than Lucy, and Spoor et al. (1994) even remarked in their comparative study of hominid labyrinthine morphology that “The specimen Stw 53 provisionally attributed to H. habilis, differs from all other hominids … [and] shows greatest similarities to the pattern observed for large cercopithecoids …[which] suggest that Stw53 relied less on bipedal behaviour than the australopithecines”. Holly Smith (1994) concluded from the comparative study of hominid patterns of dental development that gracile australopithecines and H. habilis remain classified with African apes. Wood & Collard (1999a1999b2001), Collard & Wood (2007, 2015) could show that in none of the crucial characters H. habilis is closer to Homo than to Australopithecus.

An Assignment Rejected

Therefore, they suggested that H. habilis should be transferred to the genus Australopithecus, which was also supported by Hartwig-Scherer (1999) and Schwartz & Tattersall (2015). This assignment was rejected by Harcourt-Smith (2007) based on postcranial characters, while Berger et al. (2015) agreed that “postcranial remains of H. habilis appear to reflect an australopith-like body plan”.  Spoor et al. (2015) found that the mandible of H. habilis is remarkably primitive and more similar to Australopithecus afarensis. They also reconstructed a slightly larger brain volume for the holotype and clarified the definition of the taxon Homo habilis, but cautioned that the results raise questions about its phylogenetic relationships. It is also very much contradicting Darwinian expectations, that the oldest specimens of Homo habilis, such as the 2.3 million year old specimen no. AL 666-1, possess more advanced characters than the younger holotype specimen OH 7, which lived more than a half million years later. One of the most striking contradictions is the fact that the bones of Homo habilis and many other animals were found in the context of so-called “butchering sites” together with stone tools, and in the neighbourhood of rock circles that very much look like the stone huts still used by modern nomadic tribes of the region (Leakey 1972: 24).

These rock circles and huts demonstrably originated at the same time as Homo habilis, which obviously suggests that this ape-like creature was rather the animal prey of contemporary human hunters than a human ancestor and producer of stone tools. Otherwise, we would have to believe the highly implausible hypothesis that an ape-like creature with an ape-sized brain and climbing adaptations built stone huts like modern humans. Anyway, the majority of evolutionists of course ignored all such doubts among the experts and blindly embraced Homo habilis as a cherished “missing link” without asking inconvenient and potentially career-threatening questions.