 "Sahelanthropus" is described by Brunet as the earliest representative of the human lineage and this is endorsed by the Smithsonian Institution in its description of the species, which states that it has two key human characteristics, small canine teeth and walking upright on two legs.However, some researchers doubt whether "Sahelanthropus" is a hominim and argue that fossils in Ethiopia and Kenya are better candidates.The placement of this species as a human ancestor but not a chimpanzee ancestor, as suggested by the original 2002 publication by Brunet et al., the facial features of the "Toumaï" cranium bring into doubt the status of "Australopithecus" whose thickened brow ridges were reported to be similar to those of some later fossil hominins (notably "Homo erectus"), and where the brow ridge morphology of "Sahelanthropus" differs from that observed in all australopithecines, most fossil hominins and extant humans.