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.

Australopithecus bahrelghazali

• 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.

Australopithecus deyiremada

• 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.

Australopithecus garhi

• 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.

Kenyanthopus platyops

• 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.