Cosmogenic nuclide dating of sahelanthropus tchadensis
Ape-like features include brain size, heavy brow ridge.
Its human-like features include forward position of the foramen magnum (visit (scroll down) to view image comparing placement of foramen magnum in chimps, humans, and Sahelanthropus), reduced prognathism, smaller canine teeth, and intermediate thickness of the premolar and molar enamel.
Some suggest that the specimen belongs to that of a female ape because it is likely to find canines worn at the tips in female apes.
Critics claim that without postcranial evidence it is premature to claim that Sahelanthropus is bipedal (Su 2013).
It is also important to keep in mind that new discoveries are made each year that refine what we know about human evolution.
What this means is that what you learn this quarter could change somewhat next year as new data is made available.
Its teeth are more ape-like so the determination of bipedality is central to attributing the fossils to that of a hominin.
The founding research team claims that features of the femur indicate that Orrorin was a biped and in the direct line to modern humans. Tim White, Gen Suwa, and Yohannes Haile Selassie discovered Ar.
Overall, the postcranial fragments are more ape-like; however, the toe bone mentioned previously is similar to the toe bones of Australopithecus afarensis, a species that had all the hallmarks of habitual bipedalism. Over 40% of the skeleton was recovered, which allowed the team to fully reconstruct the skeleton. afarensis have been found (60 individuals at least from Hadar alone!The binomial reflects where the fossils were found, the Tugen Hills region of Kenya. Using multiple dating techniques, including paleomagnetism and biochronology, the Tugen Hills fossils are dated to about 6.0 mya.Figure \(\Page Index\) - Orrorin tugenensis fossils Like Sahelanthropus, Orrorin has a mix of ape-like and human-like traits.In determining what fossil features denote a specimen is a hominin, many different characteristics are examined, including those related to bipedalism, about which you previously learned, and non-honing chewing.Apes have a canine-premolar honing complex, which means that there is a diastema between the lower canine lower third premolar where the upper canine fits when the jaws close (Larsen 2014).