Contested Hominin Species

Contested Species

Many named species are debated, with specimens potentially belonging to variable Au. afarensis or Au. anamensis species.

Specimens are sometimes dated to times or found in places with gaps in the palaeoanthropological record.
These may represent chronospecies or Au. afarensis variants.
More discoveries may validate distinct species types.

Dated to within the time period of Au. afarensis (3.6 mya; Brunet et al. 1995).
First Australopithecine discovered in Chad, central Africa.
Holotype "Abel" may fall within the variation range of Au. afarensis (Lebatard et al. 2008).
If "Abel" is Au. afarensis, the geographic range of the species would be greatly extended.

Dated to 3.5 mya to 3.3 mya.
Based on fossil mandible bones discovered in 2011 in Woranso-Mille, Afar region of Ethiopia, by Yohannes Haile-Selassie (Haile-Selassie et al. 2019).
Au. deyiremada means “close relative” in the Afar language.
Smaller teeth with thicker enamel (potentially suggesting a harder diet).
Larger mandible and more projecting cheekbones, in contrast to Au. afarensis.
Evidence suggests more than one closely related hominin species occupied the same region at the same time (Haile-Selassie et al. 2015; Spoor 2015).
Alternative view: This species has been prematurely identified, more evidence is needed.
Variation may be due to slightly different niche occupations between populations over time.

Found in the Middle Awash region of Ethiopia.
Dated to 2.5 mya (younger than Au. afarensis).
Fills in a temporal gap between hominin finds in the region.
Anatomical differences: relatively large cranial capacity (450 cc), larger hind dentition than other gracile Australopithecines.
450 \text{ cc}
Longer hind limbs than Au. afarensis, but still able to move arboreally (Asfaw et al. 1999).
Not well documented or understood, based on only several fossil specimens.
Crude stone tools resembling Oldowan found in association with Au. garhi.
This is one of the earliest technologies found in direct association with a hominin.

Highly contested genus/species designation, "platyops" refers to its flatter-faced appearance.
Specimen KNM-WT 40000 from Lake Turkana in Kenya, discovered by Maeve Leakey in 1999.
Dated to between 3.5 mya and 3.2 mya.
Some suggest it is an Australopithecus, perhaps even Au. afarensis (small brain size).
Others place it in Homo (small dentition and flat-orthognathic face).
Discoverers argue it is ancestral to Homo, in particular to Homo ruldolfensis (Leakey et al. 2001).
Earliest tool finds from Lomekwi, Kenya, are temporally (3.3 mya) and geographically close to this specimen.