A recent study analyzing fossilized bones suggests Sahelanthropus tchadensis, an ape-like species from seven million years ago, may be the earliest human ancestor due to adaptations for bipedalism. Researchers identified a femoral tubercle and femur shape similar to hominins, indicating upright walking. However, some experts dispute whether S. tchadensis was a direct human ancestor, with the species possibly walking on two legs while also spending time in trees.