Human evolution: homo habilis reconsidered (Introduction)

by David Turell , Friday, January 19, 2024, 19:36 (307 days ago) @ David Turell

This ancestor may be more primitive than originally proposed:

https://evolutionnews.org/2024/01/fossil-friday-new-research-questions-the-human-nature...

"Last year, I wrote an article (Bechly 2023) for Fossil Friday about the questionable status of the East African fossil hominin Homo habilis as a member of our genus rather than being just another ape-like australopithecine. This is a crucial issue for human origins, because Homo habilis is often proclaimed as the transitional form connecting our genus with australopithecines. As I elaborated in my article, this notion was challenged by several mainstream experts, and it was challenged from quite early on (e.g., Wood 1987). But this challenge is far from being a thing of the past. Two new articles relevant to the status of Homo habilis appeared last year in the 50th anniversary edition of the Journal of Human Evolution.

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"In other words, based on our current knowledge of the fossil record and the human brain, the scientists did not find compelling the claims of Tobias (1987) who had originally “suggested that the neuroanatomy of this species evidenced a clear change toward many cerebral traits associated with our genus.”

"It is also quite interesting that the lead author commented on his blog site (Bruner 2022):

"This taxon [Homo habilis], much debated in the last 20 years, has not found a proper taxonomic validation yet, which suggests at least a lack of robust evidence, in this sense. … The attention of the mass media for science and research is prompting a compulsive marketing based on appearance and fast vending news, at the expense of content and quality. Paleontological fields are characterized by issues that can be hardly proven, charming topics, and harmless conclusions (in the sense that they have no direct consequences on people’s welfare). These three features make these fields more sensitive to contamination associated with personal, institutional, and economic interests, generating a conflict between scientific proficiency and public visibility. Excessive speculations, in this sense, can seriously harm the reputation of the discipline.

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"...the second article was published by Antón & Middleton (2023), who re-evaluated the fossil record of early Homo, especially H. erectus, H. habilis, and H. rudolfensis. Their conclusion is jaw-dropping: “Chronologically and morphologically H. erectus is a member of early Homo, not a temporally more recent species necessarily evolved from either H. habilis or H. rudolfensis”. So much for the latter two taxa as missing links between ape-like australopithecines and real humans of the genus Homo. Homo erectus coexisted with Australopithecus and tools associated with “Homo” habilis may have been used by Homo erectus on Australopithecus habilis rather than being produced and used by the latter, which is suggested by the distribution of fossils and artifacts at the Olduvai gorge site in Tanzania (Bechly 2023). Habilis was likely not a handy man but the ape bush meat of real humans.

"This is not just my humble opinion, but is also supported by a brand-new study by Davies et al. (2024) in Nature Communications on the dental morphology of Homo habilis. The authors found this “morphology in H. habilis is for the most part remarkably primitive, supporting the hypothesis that the H. habilis hypodigm has more in common with Australopithecus than later Homo.”

"Thus, the most recent research confirms the previous and early critique that H. habilis should be classified as Australopithecus. So, the latter view cannot be dismissed as obsolete and outdated science, and it can also not be dismissed by a mere appeal to a scientific consensus. Science is not about consensus but about empirical evidence and rational arguments. A consensus is scientifically worthless when it is driven by worldview bias and peer pressure rather than by an unbiased inference to the best explanation. Here is what Jurassic Park author Michael Crichton famously said about this issue: “I regard consensus science as an extremely pernicious development that ought to be stopped cold in its tracks. Historically, the claim of consensus has been the first refuge of scoundrels; it is a way to avoid debate by claiming that the matter is already settled.'”

Comment: Bechly's opinions aside, it appears homo habilis is probably more ancient than originally thought. As for 'consensus' it has to be arrived at by many people researching and a meld of personal opinions reaches an accepted conclusion.