It looks like 2017 could become some kind of genuine annus horribilis for the established scientific consensus on human evolution. It all began with five discoveries that made worldwide headlines earlier this year:
- After years of hot debate, a new phylogenetic analysis by Argue et al. (2017) finally revealed that the “Hobbit,” Homo floresiensis from Indonesia, is not a dwarfed descendent of Homo erectus, as had become the majority view, but a descendent of an archaic African hominin close to Homo habilis that should neither exist at that remote place outside of Africa nor at that late time more than 1.75 million years after the supposed extinction of such forms (Australian National University 2017).
- A new study by Dirks et al. (2017) proved that Homo naledi from a cave in South Africa, which was celebrated as missing link between ape-like australopithecines and our own genus Homo, is really only 250,000 years old and a contemporary of more modern humans. Consequently, it is much too young to be an evolutionary link (Barras 2017a), but on the other hand also much too primitive for its young age.
- As reported by Gibbons (2017), Australopithecus sediba, another failed “missing link,” was refuted as an ancestor in the Homo lineage by paleoanthropologist Bill Kimble in a new phylogenetic analysis, and instead attributed to a far removed South African australopithecine clade of more ape-like beasts (Evolution News 2017).
- Next, a further story of the standard narrative of human origins fell apart: Holen et al. (2017) demonstrated in the journal Nature that humans did not first arrive in America only 14,000 years ago, but roamed in southern California some 130,000 years ago. This discovery rewrites the history of mankind and, as we read at the time, “will spark a firestorm of controversy” (Greshko 2017).
- Finally, in June the discovery of 315,000-year-old early Homo sapiens skull fragments and stone tools from Jebel Irhoud in Morocco (Hublin et al. 2017, Richter et al. 2017) overturned the established wisdom that Homo sapiens originated more than 100,000 years later and 3,000 miles farther east in Ethiopia. This discovery did indeed “shake [the] foundations of the human story” (Sample 2017) by showing that “our species evolved much earlier than thought” (Tarlach 2017a) and by “disputing the popular notion that there’s an East African ‘Eden’ or cradle of humanity” (Newitz 2017).
So five previously “undisputable facts” of human evolution turned out to be nothing but bogus claims this year. But of course evolutionary storytelling is flexible enough to accommodate all these new “facts” in a revised just-so story. Alternatively, it may prefer simply to dismiss the evidence as false, as in the last case of the oldest Americans. But 2017 is not done with human evolution yet.
On August 31, news from Uppsala University in Sweden announced, “Fossil footprints challenge established theories of human evolution.” The discovery indeed is a bombshell that will likely create considerable further controversy. The technical publication by Gierliński et al. describes fossil footprints from Trachilos in western Crete that are reliably dated to a Late Miocene age of about 5.7 million years. These footprints are indubitably from a large bipedal primate with human-like feet, and it is precisely the shape of our foot “that is one of the defining characteristics of being part of the human clade” (Ahlberg & Bennett 2017). As Discover Magazine reports, “In a year of big shake-ups in the story of human evolution, a study published in the Proceedings of the Geologists’ Association may be the biggest shock yet” (Tarlach 2017b). That is because of the following enigmas:
- The fossil footprints are out of place because they are much too old: even though radiometric datings seem to be lacking, the biostratigraphic dating is very well established by marine microfossils called foraminifera as index fossils in the layers above and below the horizon with the footprints, as well as a typical signature for the climax of the Messinian Salinity Crisis (5.6 ma) in the sediments directly above them (Ahlberg & Bennett 2017). With an age of 5.7 million years, these footprints are 2.5 million years older than the iconic Lucy fossil and even 1.3 million years older than Ardi. Among the alleged hominin ancestors only the two dubious taxa Sahelanthropus tchadensis from Chad (about 7 million years old) and Orrorin tugenensis from Kenya (about 6 million years old) as well as the imprecisely dated Ardipithecus kadabba from Ethiopia (5.8-5.2 million years old) may be older. However, none of them has the feet preserved, so that we do not know whether they were ape-like or human-like.
- The fossil footprints are out of place because they occur in the wrong geographical region: all of the early hominins that are older than 1.8 million years have only been found in Africa, which led to the well-known standard textbook knowledge that humans originated in Africa and only after the advent of our own genus Homo migrated to other continents in several “Out of Africa” events. A European hominin at such an early age simply does not fit the common narrative and refutes the beautiful “Out of Africa” story.
- The fossil footprints are far too modern in their appearance: with their long sole with characteristic ball and big toe in line with the other toes (all lacking claws), these footprints differ from those of all other land animals, including the more ape-like feet (without ball and with the big toe sticking out sideways) of the much younger Ardipithecus ramidus, which is the earliest hominin with well-preserved feet, discovered in 4.4-million-years-old layers from Ethiopia. The Crete footprints rather resemble the famous Laetoli footprints from Tanzania that have been dated to an age of 3.66 million years and attributed to Australopithecus afarensis as the oldest known human footprints until now, but look rather similar to modern human footprints.
This implies that the well-established scenarios of human evolution must be false, not only concerning their geographical location and timing, but also concerning the pattern of character origins and the alleged lineage leading from Ardipithecus via australopithecines to humans. When the oldest known evidence for hominin feet predates the alleged African ancestors such as Ardi and Lucy but already shows relatively modern human footprints, what is more congruent with this new evidence when looked at without bias: a gradual Darwinian evolution, or rather a saltational origin that requires intelligent design?
Another obvious and apparently difficult question is how such bipedal animals, whether hominin or ape, could reach the island of Crete at all. However, in this case there could be an elegant solution indeed: right at the geological time when the footprints originated, Crete was connected to mainland Greece because the Mediterranean Sea had largely evaporated during an event, already noted, that is called the Messinian Salinity Crisis (5.96-5.33 million years ago), caused by a closure of the Strait of Gibraltar.
Interestingly, earlier this year Fuss et al. (2017) published an article in PLOS ONE that proposed hominin affinities of Graecopithecus (also called “El Graeco”) from the Late Miocene (c. 7.2 million years old) of Greece and Bulgaria. There are only a few jaw fragments, but they are claimed to allow an attribution of El Graeco to the human lineage. This is based on the small roots of the canine teeth, suggesting their reduced size as in hominins, as well as a fusion of the roots of the premolar teeth that is typical for hominins, but very rare in recent chimps. If this attribution is correct, it would make Graecopithecus the oldest known hominin, and the possible ancestor of the hominin that produced the Trachilos footprints in Crete (Ahlberg & Bennett 2017, Gierliński et al. 2017). Fuss et al. suggested that the chimp-human split may have occurred about 8 million years ago in Southeast Europe rather than in Africa. Yet even though this hypothesis did not in any way contradict the idea of a Darwinian evolution of humans, it still attacked the cherished scientific consensus of the “Out of Africa” hypothesis, which of course invited strong criticism of these “heretical” ideas (Barras 2017b, Curnoe 2017).
Unsurprisingly, such criticism was not restricted to the technical arguments but extended to ad hominem attacks on the character of the researchers. For example, David Alba from the Catalan Institute of Paleontology in Barcelona said that the study’s co-author David Begun has been arguing for twenty years that the great apes first appeared in Europe, so that “It is not surprising at all that Begun is now arguing that hominins as well originated in Europe” (Barras 2017b). “Sergio Almécija, … at George Washington University, says it is important to bear in mind that primates seem particularly prone to evolving similar features independently. ‘Single characters are not reliable to make big evolutionary [claims]’” (Barras 2017b). It is interesting that the latter argument is very rarely used by paleoanthropologists to question the attribution of the African alleged hominins like Lucy to the human lineage. Apparently, questionable evidence is acceptable as long as it agrees with the preferred evolutionary narrative.
It is revealing that the title of the new article is followed by a question mark, since the authors have no other reason to be skeptical about their discovery than the inconvenient age and geographical location of the fossil footprints. This is actually admitted by the last author of the study, distinguished paleontologist Per Ahlberg from Uppsala University, who says “What makes this controversial is the age and location of the prints, … This discovery challenges the established narrative of early human evolution head-on and is likely to generate a lot of debate” (Uppsala Universitet 2017).
It is already becoming evident that many evolutionists will try to get rid of this cumbersome conflicting evidence by considering these footprints as having been made by an European Miocene ape, which convergently evolved a bipedal locomotion. This is even though the fossil footprints themselves do not suggest any difference from human tracks that could support such an ad hoc assumption (Ahlberg & Bennett 2017). In any event, independent (convergent) origin of similar structures is a very common phenomenon in the history of life, which is quite unexpected if Darwinian evolution would be true. Therefore, such an assumption of convergence would create another problem in this particular case: there are only a few characters that allow an attribution of the earliest hominin fossils to the human lineage, such as small canine teeth and adaptations for bipedal locomotion. However, if bipedal locomotion evolved several times among unrelated apes, as may also be suggested by Oreopithecus bambolii from the Late Miocene of Italy (Rook et al. 1999; but see Russo & Shapiro 2013), then one of the strongest character complexes looses much of its force.
Given the fact that the evolutionary trees are built on only a few characters, which have weak support because of incongruent (homoplastic) distribution, these trees do not justify the often bold claims about the allegedly well-established lineage of intermediate hominin fossils bridging the gap between chimps and modern humans. At the very least, after the dramatic experiences of the 2017 discoveries, paleoanthropologists should be more humble and admit that we know far less than we thought and what we know is much less certain than what is still taught to pupils and students as well as presented to the general public by science popularizers in the media. Human evolution is still a highly controversial field, and given the large number of data studied with the most modern methods, this might give some reason for pause.
Tarlach (2017b) comments that “In a year when we’ve learned our species is at least twice as old as we thought, and some researchers have claimed that hominins were in the Americas more than 100,000 years before the conventional arrival date, hey, anything goes.” Well, “anything” surely only refers to anything that does not question the Darwinian paradigm of human origins as such, even when more and more evidence accumulates against it.
But 2017 is still not over. Maybe further surprises are ahead.
- Ahlberg P, Bennett MR 2017. Our controversial footprint discovery suggests human-like creatures may have roamed Crete nearly 6m years ago. The Conversation August 31, 2017.
- Argue D, Groves CP, Lee MSY, Jungers WL 2017. The affinities of Homo floresiensisbased on phylogenetic analyses of cranial, dental, and postcranial characters. Journal of Human Evolution 107: 107-33.
- Australian National University 2017. Origins of Indonesian Hobbits finally revealed. Science Daily April 21, 2017.
- Barras C 2017a. Homo naledi is only 250,000 years old — here’s why that matters. New Scientist 25 April 2017.
- Barras C 2017b. Our common ancestor with chimps may be from Europe, not Africa. New Scientist 22 May 2017.
- Curnoe D 2017. Did humans evolve in Europe rather than Africa? We don’t have the answer just yet. The Conversation May 23, 2017.
- Dirks PHGM et al. 2017. The age of Homo naledi and associated sediments in the Rising Star Cave, South Africa. eLife 2017;6:e24231.
- Evolution News 2017. Science Magazine: Australopithecus sediba “Ousted from the Human Family.” Evolution News April 25, 2017.
- Fuss J, Spassov N, Begun DR, Böhme M 2017. Potential hominin affinities of Graecopithecus from the Late Miocene of Europe. PLOS ONE.
- Gibbons A 2017. A famous “ancestor” may be ousted from the human family. Science April 23, 2017.
- Gierliński GD et al. 2017. Possible hominin footprints from the late Miocene (c. 5.7 Ma) of Crete? Proceedings of the Geologist’s Association.
- Greshko M 2017. Humans in California 130,000 Years Ago? Get the Facts. National Geographic April 26, 2017.
- Holen SR et al. 2017. A 130,000-year-old archaeological site in southern California, USA. Nature 544: 479-83.
- Hublin J-J et al. 2017. New fossils from Jebel Irhoud, Morocco and the pan-African origin of Homo sapiens. Nature 546: 289-92.
- Newitz A 2017. 300,000 year-old “early Homo sapiens” sparks debate over evolution. Ars Technica June 11, 2017.
- Richter D et al. 2017. The age of the hominin fossils from Jebel Irhoud, Morocco, and the origins of the Middle Stone Age. Nature 546: 293-96.
- Rook L, Bondioli L, Köhler M, Moyà-Solà S, Macchiarelli R 1999. Oreopithecus was a bipedal ape after all: evidence from the iliac cancellous architecture. PNAS 96(15): 8795-9.
- Russo GA, Shapiro LJ 2013. Reevaluation of the lumbosacral region of Oreopithecus bambolii. Journal of Human Evolution 65(3): 253-65.
- Sample I 2017. Oldest Homo sapiens bones ever found shake foundations of the human story. The Guardian June 7, 2017.
- Tarlach G 2017a. Meet The New Oldest Homo Sapiens — Our Species Evolved Much Earlier Than Thought. Discover Magazine June 7, 2017.
- Tarlach G 2017b. What Made These Footprints 5.7 Million Years Ago? Discover Magazine September 1, 2017.
- Uppsala Universitet 2017. Fossil footprints challenge established theories of human evolution. Press release 2017-08-31.
Photo: Trachilos footprints, by Andrzej Boczarowski, via Uppsala University.