Overview

Potentially the oldest known hominin, represented by a nearly complete cranium nicknamed "Toumai." The anteriorly positioned foramen magnum suggests possible bipedal posture, but the small brain size and ape-like features have led some researchers to argue it may be a stem ape rather than a hominin. The discovery in Chad, far from the East African Rift, challenged ideas about early hominin geography.

Key Fossils

TM 266-01-060-1 (nearly complete cranium "Toumai")

Brain Anatomy

No Cranial Data Available

No cranial remains or endocasts have been recovered for this species, so brain morphology cannot be directly assessed.

Tools & Technology

No Tool Associations

No stone tools have been directly associated with this species in the archaeological record.

Social Organization

Group Size15–30 individuals
MethodDunbar neocortex
StructureMulti male multi female
Sexual Dimorphism1.35x (male/female body mass)

Sahelanthropus: inference extremely limited; small-brained hominin likely similar to apes in group size.

Genetics & Ancient DNA

Genome Coverage%
DNA Source
Sequencing Year
mtDNA AvailableNo
Nuclear DNANo
Divergence Date (fossil calibrated)7.0 MYA

No ancient DNA; Sahelanthropus age ~7–6 Ma (geochronology) used as temporal anchor for comparative rows.

Molecular clock data from TimeTree 5 (Kumar et al. 2022).

Key Specimens

SpecimenNameSiteYearAge (MYA)CompletenessSignificance
TM 266-01-060-1 Toumai — 2001 7.20 40.00% Oldest widely accepted hominin cranium

Explore all specimens and measurements →

Comparative Anatomy

Encephalization Quotient3.40
Intermembral Index98.0
LocomotionFacultative biped
Foramen MagnumIntermediate
Precision GripAbsent
Pelvic ShapeTall narrow
RobusticityModerate
Big ToeAbducted
ThoraxFunnel shaped

Sahelanthropus: foramen magnum position debated for bipedality.

Compare anatomy across species →

Fossil Occurrences

The Paleobiology Database records 1 fossil occurrence(s) attributed to Sahelanthropus tchadensis. View on map →

Identified AsLocationFormationAge (MYA)
Sahelanthropus tchadensis n. gen. n. sp. TD – 7.25 – 5.33

Data from the Paleobiology Database (CC-BY).

Scientific References

  1. Zollikofer CPE, Ponce de Leon MS, Lieberman DE, et al. (2005). "Virtual cranial reconstruction of Sahelanthropus tchadensis". Nature 434:755-759. DOI:10.1038/nature03397 (258 citations)
  2. Brunet M, Guy F, Pilbeam D, et al. (2002). "A new hominid from the Upper Miocene of Chad, Central Africa". Nature 418:145-151. DOI:10.1038/nature00879 (790 citations)