Rosa Rubicondior: Refuting Creationism - Now It's Evidence of Bipedalism in a Hominin From 7 Million Years Ago

S. tchadensis fossils (TM 266) compared to a chimpanzee and a human.

Anthropologists Offer New Evidence of Bipedalism in Long-Debated Fossil Discovery

We are only three days into 2026 and already creationism is facing an avalanche of new evidence against it and in favour of evolution on an ancient Earth in a vastly older Universe — directly contradicting the Bronze Age origin myths that creationists cling to with the desperation of a drunk clutching a lamppost.

The latest blow comes from the New York University Department of Anthropology, where a team of researchers led by Associate Professor Scott Williams, working with colleagues from the University of Washington, Chaffey College, and the University of Chicago, have carried out a detailed re-examination of fossil remains attributed to Sahelanthropus tchadensis. Their analysis provides strong evidence that this species was bipedal and shared several key skeletal characteristics with later bipedal hominins, including the australopithecines and members of the genus Homo.

Sahelanthropus tchadensis was discovered in the early 2000s, and its place in human evolution has been debated ever since. Some researchers argued it might represent an extinct ape rather than a stem hominin. Evidence for habitual bipedalism, however, strongly favours the latter interpretation, making S. tchadensis the earliest known human ancestor currently identified in the fossil record.

As such, it becomes yet another example of the transitional species that creationists continue to insist do not exist, often under the mistaken belief that Charles Darwin — whom they treat as the final authority on all matters evolutionary — admitted that the absence of transitional forms was a serious problem for his theory. In reality, Darwin explicitly predicted that such fossils would eventually be found, and the subsequent century and a half of palaeontology has repeatedly confirmed that prediction.

The discovery is of a point of attachment on the femur of a ligament only found in bipedal hominins. The importance of bipedalism in human evolution cannot be overstated. Habitual upright walking is one of the defining characteristics that separates hominins from other apes, reflecting a fundamental shift in anatomy, locomotion, and behaviour. It requires extensive reorganisation of the skeleton, including changes to the position of the foramen magnum, the curvature of the spine, the shape of the pelvis, the proportions of the limbs, and the structure of the feet. Because these adaptations are complex, interdependent, and leave clear signatures in fossilised bones, bipedalism is not a trivial or ambiguous trait. Evidence for it in Sahelanthropus tchadensis therefore places this species firmly on the human lineage and pushes the origin of upright walking — and with it the human evolutionary trajectory — back far earlier than creationist models allow.

Scott Williams’ team have now published their findings, open access, in Science Advances.

Background information^ Sahelanthropus tchadensis.

Virtual reconstruction of Sahelathropus tchadensis cranium

Zollikofer, C., Ponce de León, M., Lieberman, D. et al. (2005)

Sahelanthropus tchadensis is one of the earliest and most significant candidates for a member of the human lineage. What makes it especially important is its great age and its combination of primitive and derived traits.

Discovery and age

Discovered in 2001 at Toros-Menalla, in the Djurab Desert of northern Chad, Central Africa.
Described in 2002 by a Franco-Chadian research team led by Michel Brunet.
Dated to approximately 7–6 million years ago, placing it very close to the estimated divergence between the human and chimpanzee lineages.

Fossil material

Known primarily from a remarkably complete but distorted cranium (nicknamed Toumaï), along with fragments of the jaw and teeth.
Postcranial material was scarce for many years, which fuelled debate over its locomotion.

Anatomical features

Small braincase (around 350 cc), comparable to that of modern chimpanzees.
Reduced canine teeth with wear patterns more similar to later hominins than to apes, suggesting changes in diet and social behaviour.
Thickened brow ridges and a relatively flat face, unusual for an ape of this age.
A forward-positioned foramen magnum, indicating the skull balanced atop an upright spine — a strong anatomical signal of bipedal posture.

Locomotion and evolutionary status

For many years, critics argued that without limb bones, bipedalism could not be demonstrated.
Subsequent analysis of associated postcranial remains, together with detailed reassessment of cranial anatomy, now provides strong evidence that S. tchadensis was habitually bipedal, not a knuckle-walking ape.
This places it firmly within the hominin lineage, rather than among extinct apes.

Why it matters

Sahelanthropus tchadensis pushes the origin of hominins back to within a million years of the human–chimpanzee split.
It demonstrates that bipedalism evolved very early, before large brains, stone tools, or human-like body proportions.
Its existence directly contradicts creationist claims that there are no transitional fossils linking humans to other primates.

In short: Sahelanthropus tchadensis is not a vague or controversial “missing link”, but a well-documented early hominin whose anatomy fits precisely where evolutionary theory predicts it should — at the dawn of the human lineage.

The discovery and its wider significance are also explained in a New York University news story by James Devitt.

Anthropologists Offer New Evidence of Bipedalism in Long-Debated Fossil Discovery
Analysis centers on point of attachment of ligament vital to walking upright
In recent decades, scientists have debated whether a seven-million-year-old fossil was bipedal—a trait that would make it the oldest human ancestor. A new analysis by a team of anthropologists offers powerful evidence that Sahelanthropus tchadensis—a species discovered in the early 2000s—was indeed bipedal by uncovering a feature found only in bipedal hominins.

Using 3D technology and other methods, the team identified Sahelanthropus’s femoral tubercle, which is the point of attachment for the largest and most powerful ligament in the human body—the iliofemoral ligament—and vital for walking upright. The analysis also confirmed the presence of other traits in Sahelanthropus that are linked to bipedalism.

Sahelanthropus tchadensis was essentially a bipedal ape that possessed a chimpanzee-sized brain and likely spent a significant portion of its time in trees, foraging and seeking safety. Despite its superficial appearance, Sahelanthropus was adapted to using bipedal posture and movement on the ground.

Associate Professor Scott A. Williams, Lead author
Center for the Study of Human Origins
Department of Anthropology
New York University, New York, NY, USA.

The study, which included researchers from the University of Washington, Chaffey College, and the University of Chicago, appears in the journal Science Advances.

Sahelanthropus was discovered in Chad’s Djurab desert by University of Poitiers’ palaeontologists in the early 2000s, with initial analyses focusing on its skull. Two decades later, studies on other parts of that discovery—its forearms, or ulnae, and thigh bone, or femur—were reported. This prompted debate over whether the species was bipedal or not, leaving open the question on its status: Is Sahelanthropus a hominin (a human ancestor)?

Crania, ulnae, and femora of (left to right): a chimpanzee, Sahelanthropus, and Australopithecus.

Image courtesy of Scott Williams/NYU and Jason Heaton/University of Alabama Birmingham.

In the Science Advances study, the scientists took a closer look at the ulnae and femur using two primary methods: a multi-fold trait comparison with the same bones of living and fossil species and 3D geometric morphometrics—a standard method for analyzing shapes in greater detail in order to illuminate areas of particular interest. Among the compared fossil species was Australopithecus—an early human ancestor, well-known through the discovery of the “Lucy” skeleton in the early 1970s, who lived an estimated four to two million years ago.

The analysis revealed three features that point to bipedalism in Sahelanthropus:

The presence of a femoral tubercle, which provides attachment for the iliofemoral ligament linking the pelvis to the femur and has so far been identified only in hominins
A natural twist, specifically within the range of hominins, in the femur—or femoral antetorsion—that helps legs to point forward, thereby aiding walking
The presence, drawn from the 3D analysis, of gluteal, or butt, muscles similar to those in early hominins that keep hips stable and aid in standing, walking, and running

The latter two traits—femoral antetorsion and gluteal complex—had previously been identified by other scientists; the Science Advances study affirmed their presence.

The authors also found that Sahelanthropus had a relatively long femur relative to its ulna—additional evidence of bipedalism. The researchers note that apes have long arms and short legs, whereas hominins have relatively long legs. And while Sahelanthropus had much shorter legs than do modern humans, these were distinct from apes and approached Australopithecus in relative femur length, suggesting another adaptation to bipedalism.

Our analysis of these fossils offers direct evident that Sahelanthropus tchadensis could walk on two legs, demonstrating that bipedalism evolved early in our lineage and from an ancestor that looked most similar to today’s chimpanzees and bonobos.

Associate Professor Scott A. Williams.

The paper’s other authors were Xue Wang and Jordan Guerra, both NYU doctoral students, Isabella Araiza, an NYU graduate student at the time of the study and now a doctoral candidate at the University of Washington, Marc Meyer, an anthropology professor at Chaffey College, and Jeffery Spear, an NYU graduate student at the time of the study and now a researcher at the University of Chicago.

Publication:
Scott A. Williams et al.
Earliest evidence of hominin bipedalism in Sahelanthropus tchadensis.
Sci. Adv. 12, eadv0130(2026). DOI:10.1126/sciadv.adv0130

Once again, the fossil record is behaving exactly as evolutionary theory predicts and in precisely the way creationist dogma insists it cannot. An early hominin appears close to the expected time of the human–chimpanzee divergence, shows a mosaic of primitive and derived traits, and exhibits clear anatomical evidence of a key transitional adaptation — in this case, bipedalism. This is not an anomaly or a “just-so story”; it is the routine outcome of careful scientific investigation.

For creationism, however, Sahelanthropus tchadensis is profoundly inconvenient. It exists millions of years before their imagined Creation Week, displays traits that cannot be dismissed as either fully ape or fully human, and fits seamlessly into an ever-growing sequence of hominin fossils documenting gradual change over deep time. To accept it would require abandoning the comforting fiction of instant, perfect creation — something ideology simply does not allow.

As the evidence continues to accumulate, the claim that there are no transitional fossils becomes increasingly untenable. What remains is not a scientific controversy, but a refusal to engage honestly with reality. And as 2026 is already demonstrating, reality is not waiting for creationism to catch up.

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