Overview

A debated australopith species based primarily on the remarkably complete skeleton StW 573 ("Little Foot"), discovered by Ronald Clarke beginning in 1994 in the Silberberg Grotto of Sterkfontein Cave, South Africa. The skeleton is ~90% complete—the most complete Australopithecus ever found—and dated to ~3.67 Ma by cosmogenic nuclide burial dating. The species name "prometheus" was originally coined by Raymond Dart in 1948 for Makapansgat fossils he believed were associated with fire (later disproven). Clarke revived the name in 2019 for StW 573 and allied Sterkfontein Member 2 specimens, arguing they differ from A. africanus in having a flatter, more prognathic face, larger anterior teeth, and a more ape-like grasping hallux. Critics maintain these specimens fall within A. africanus variation. If valid, A. prometheus would be a distinct, more primitive lineage contemporary with A. afarensis in East Africa.

Key Fossils

StW 573 (Little Foot)

Brain Anatomy

Endocast-Based Estimates

Brain region sizes are estimated from endocasts (internal skull casts), not direct brain observation. These are approximations with inherent uncertainty.
Frontal
–
Occipital
–
Cerebellar
–
RegionFunctional Implicationsvs. Modern Human
Frontal Relatively small frontal lobe proportions consistent with australopiths
Occipital Prominent lunate sulcus suggests ape-like visual cortex organization
Cerebellar Cerebellar size within australopith range

Tools & Technology

No Tool Associations

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

Diet

Herbivorous/omnivorous; C4 isotope signals suggest mixed C3-C4 diet

Phylogenetic Relationships

Related SpeciesRelationshipConfidenceNotes
Australopithecus afarensis Contemporary Strong Contemporary with A. afarensis in East Africa at ~3.67 Ma
Australopithecus africanus Sister taxon Weak Debated; Clarke argues distinct from A. africanus; critics see them as conspecific

Key Specimens

SpecimenNameSiteYearAge (MYA)CompletenessSignificance
StW 573 Little Foot Sterkfontein Member 2 1994 3.67 90.00% Most complete Australopithecus skeleton ever found; ~90% complete

Explore all specimens and measurements →

Life History

Estimated Lifespan~40 years
Age at Maturity~12.0 years
Dental DevelopmentDental development intermediate between apes and later hominins based on StW 573 dentition
ConfidenceInferred from phylogeny

Comparative Anatomy

Encephalization Quotient2.50
Intermembral Index85.0
LocomotionFacultative biped
Foramen MagnumIntermediate

Long curved phalanges; divergent hallux indicates arboreal climbing

Compare anatomy across species →

Dating Evidence

MethodDate (MYA)UncertaintyMaterialSite / Specimen
Cosmogenic nuclide 3.6700 ± 0.1600 Quartz pebbles from cave infill surrounding skeleton Sterkfontein Member 2 / StW 573

Scientific References

  1. Ronald J. Clarke (2019). "Australopithecus prometheus is a nomen nudum". Journal of Human Evolution 137:102655. DOI:10.1016/j.jhevol.2019.102655
  2. Darryl E. Granger, Ryan J. Gibbon, Kathleen Kuman, Ronald J. Clarke, Laurent Bruxelles, Marc W. Caffee (2015). "The Little Foot Australopithecus dated to 3.67 million years". Nature 522:85-88. DOI:10.1038/nature14268
  3. Ronald J. Clarke (1998). "First ever complete adult Australopithecus fossil found". South African Journal of Science 94:460-463