" Toumaï the Human Ancestor "


The hominid: What does he look like?


 
  • At present, only the cranium and the lower jaws are known, and no post-cranial remains (limbs, ribs, vertebra...) have been recovered. Therefore, further discoveries and analyses are necessary to make reliable inferences on the new hominid overall morphology.



  • Taking into consideration the skull alone, the new hominid is probably close to the size of a common chimpanzee (Pan troglodytes).



  • Toumaï doesn't look like a chimpanzee, neither a gorilla nor the more recent fossil hominids currently described.



  • Because limbs morphology is still unknown, it is not yet possible to infer reliably whether or not Toumaï was a habitual biped. Nevertheless, such adaptation could be acquired by Toumaï given the skull's basicranial and facial similarities to later true bipedal fossil hominids.

  • The cranium is characterized by a tall face with a weak sub-nasal prognathism, a thick supraorbital torus (=brow ridge - probably a male feature), and a long and narrow braincase. The cranial capacity (ca 350 cc) is similar to that of living chimpanzees. The dental arch is U-shaped with cheek teeth (molars, premolars) smaller than Australopithecine ones; the dental enamel is thicker than Chimpanzee but thinner than Australopithecine.



  • Canines don't project far above the other teeth as in Apes where the upper high crowned male canines hone against the third lower premolars.



  • Upper canines are small-sized, conical with an apical wear, less asymmetric than in Ardipithecus and quite distinct from Orrorin, which are more female-chimp-like.



  • On the lower canine, the wear surface is located above the distal tubercle implying a non-honing C-P3 complex (i.e. third lower premolar without honing facet), probably one of the first hominid feature.



  • Toumaï displays several distinctive features which clearly relate him to the human lineage: small canines with apical wear, non-honing C-P3 complex, enamel thickness of cheek teeth intermediate between Pan and Australopithecus, reduced sub-nasal prognathism, no canine diastema, thick and continuous brow ridge, long and narrow horizontally oriented basicranium.

 
 

The Toumaï discovery