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For decades now, there has been a tenacious argument on who the first bipedal hominid was. There are a few contenders, dating to around 6.5-7 mya, While there has been a great deal of controversy, new analysis may shed light on who the first biped in our family stream was.
In 2001, a very interesting near complete, but very distorted cranium was found in the the Djurab Desert in norther Chad by a Franco-Chadian team, a year later, a team led by Michel Brunet described the skull, claiming that by the placement of the foramen magnum (the opening in the skull where the spinal spine passes through) proved that Toumaï, as the fossil would soon be known, was bipedal.
However, many anthropologists did not see this as clearly as Brunet thought they would. Many argued that the foramen magnum was pushed too far posteriorly, or towards the back of the skull, and that it would not have supported a bipedal gate. But many agreed that it would. A major problem with this, is that with the massive age of the skull, (7 mya) it had been crushed and distorted by geologic forces, and could only be reconstructed using computer programs to place the features back into their proper place, or at least what we believe is proper.
While the skull does support that this possible hominin was bipedal, there are associated post cranial remains that some researchers have determined show that sahelanthropus was indeed not a biped, that the possible associated femur that was found, would not support a upright walking pattern. So where does Toumaï stand? No pun intended! Was this species bipedal or not? While we may never know, a new paper published in Nature today, gives a great deal of more information.
“A research team, involving researchers from the CNRS, the University of Poitiers1 and their Chadian partners, examined three limb bones from the oldest human representative currently identified, Sahelanthropus tchadensis. Published in Nature on August 24, 2022, this study* reinforces the idea of bipedalism being acquired very early in our history, at a time still associated with the ability to move on four limbs in trees.
At 7 million years old, Sahelanthropus tchadensis is considered the oldest representative species of humanity. Its description dates back to 2001 when the Franco-Chadian Paleoanthropological Mission (MPFT) discovered the remains of several individuals at Toros-Menalla in the Djurab Desert (Chad), including a very well-preserved cranium. This cranium, and in particular the orientation and anterior position of the occipital foramen where the vertebral column is inserted, indicates a mode of locomotion on two legs, suggesting that it was capable of bipedalism 2.” (1)
Along with the skull of Toumaï, there were other post cranial remains that were found, and while there is no way to be sure that they were associated with the skull, the researchers are almost positive that they belong to the same species, as no other large ape has been found in the area dating to that time. “The femur and ulnae were subjected to a battery of measurements and analyses, concerning both their external morphology, and their internal structures using microtomography imaging: biometric measurements, geometric morphometrics, biomechanical indicators, etc. These data were compared to those of a relatively large sample of extant and fossil apes: chimpanzees, gorillas, orangutans, Miocene apes, and members of the human group (Orrorin, Ardipithecus, australopithecines, ancient Homo, Homo sapiens).” (1)
According to more than twenty comparisons of habitual bipedalism, based on observation and comparison of characteristics, the researchers from CNRS, University of Poitiers have concluded based on their findings that sahelanthropus was not only capable of walking upright terrestrially, or on the ground, but arboreally, or in the trees as well. It seems that the possible first hominin was capable as well as very adept at locomotion through the canopies as well as the floors of ground.
Of course, we will never know for sure who the first obliged biped was, but the research continues to point in the same direction. That Sahelanthropus tchadensis was the first bipedal hominin. Will this result stand the test of time? Only more research and fossil discoveries will tell, but for now I think it is safe to say Toumaï was the first obligate bipedal hominin.
As for me? Well, I have always been on the side of Toumaï being the first biped, having a 3D print of his skull, and seeing the features myself, it is clear to me at least where the spine would enter the skull, and to me, it is in a more upright position and not posteriorly, enough at least, to support quadrupedal locomotion. I think it would be too stressful on the skeleton to do that, bipedal locomotion seems to be the best way for that skeleton to move around. Of course, I am open to changing my mind, Ororin tugenensis is also a good client for the first biped, dating to around 6.5 million years ago, but I just think that Toumaï takes the cake. We will have to see, but for now, I think we have our answer.
Paper: Daver, G., Guy, F., Mackaye, H.T. et al. Postcranial evidence of late Miocene hominin bipedalism in Chad. Nature (2022). https://doi.org/10.1038/s41586-022-04901-z
- Received31 August 2020
- Accepted24 May 2022
- Published24 August 2022