Orrorin tugenensis is the name given to a fossil hominin from 6 million years ago. the femur of this species has a long neck characteristic of bipedal species. if an intact skull of this species were located, you would expect to find

There are various morphological differences between bipeds and quadrupeds. There is one obvious difference that can be seen in the skull. The opening in the base of the skull to receive the spinal cord is called the foramen magnum. In quadrupeds, the foramen magnum is situated more towards the back of the skull, whereas in bipeds, the foramen magnum is more or less in the middle of the base of the skull, indicating a more upright position of the head on top of the body.