Overview

The earliest definite australopith, known from multiple sites in Kenya and Ethiopia. Combining ancestral (small brain, long jaw) and derived (thick enamel, bipedal tibia) features. The 2019 discovery of the MRD cranium from Woranso-Mille showed that Au. anamensis and Au. afarensis overlapped in time, challenging the anagenesis model of one species gradually transforming into the other.

Key Fossils

KNM-KP 29281 (tibia), MRD-VP-1/1 (cranium, 2019)

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.

Diet

Hard foods based on thick enamel; C3/C4 mixed diet from isotopes

Genetics & Ancient DNA

Genome Coverage%
DNA Source
Sequencing Year
mtDNA AvailableNo
Nuclear DNANo
Divergence Date (fossil calibrated)4.0 MYA

Au. anamensis: no DNA; used in comparative population genomics as fossil anchor.

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

Phylogenetic Relationships

Related SpeciesRelationshipConfidenceNotes
Australopithecus afarensis Proposed ancestor Strong Au. anamensis is the likely ancestor of Au. afarensis; MRD cranium shows some temporal overlap
Ardipithecus ramidus Proposed ancestor Moderate Ar. ramidus shows features intermediate between earlier hominins and australopiths

Key Specimens

SpecimenNameSiteYearAge (MYA)CompletenessSignificance
KNM-KP 29281 Kanapoi tibia — 1994 4.12 15.00% Earliest evidence of obligate bipedalism in A. anamensis

Explore all specimens and measurements →

Life History

Estimated Lifespan~28 years
Age at Maturity~10.5 years
Weaning Age~3.5 years
Interbirth Interval~4.5 years
Gestation~8.0 months
Dental DevelopmentMRD/DIK: faster than Homo
Brain GrowthSmall brain vs later hominins
Growth ComparisonApe-scaled developmental pace
ConfidenceEstimated from fossils

Comparative Anatomy

Encephalization Quotient2.55
Intermembral Index94.0
LocomotionObligate biped
Foramen MagnumAnterior
Precision GripRudimentary
Pelvic ShapeTall narrow
RobusticityModerate
Big ToePartially adducted
ThoraxFunnel shaped

Au. anamensis: Kanapoi tibia; earliest bipedal australopith.

Compare anatomy across species →

Fossil Occurrences

The Paleobiology Database records 2 fossil occurrence(s) attributed to Australopithecus anamensis. View on map →

Identified AsLocationFormationAge (MYA)
Australopithecus anamensis KE – 5.33 – 2.58
Australopithecus anamensis KE Kanapoi 5.33 – 3.60

Data from the Paleobiology Database (CC-BY).

Scientific References

  1. Haile-Selassie Y, Melillo SM, Vazzana A, et al. (2019). "A 3.8-million-year-old hominin cranium from Woranso-Mille, Ethiopia". Nature 573:214-219. DOI:10.1038/s41586-019-1513-8 (75 citations)
  2. Leakey MG, Feibel CS, McDougall I, Walker A (1995). "New four-million-year-old hominid species from Kanapoi and Allia Bay, Kenya". Nature 376:565-571