Homo sapiens idaltu

Homo sapiens idaltu
Temporal range: Pleistocene (Lower Paleolithic), 0.16 Ma
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Homo sapiens idaltu skull
Scientific classification
Kingdom:Animalia
Phylum:Chordata
Class:Mammalia
Order:Primates
Suborder:Haplorhini
Infraorder:Simiiformes
Family:Hominidae
Subfamily:Homininae
Tribe:Hominini
Genus:Homo
Species: H. sapiens
Subspecies: H. s. idaltu
Trinomial name
Homo sapiens idaltu
White et al., 2003

Homo sapiens idaltu (Afar: Idaltu; "elder" or "first born"[1]), also called Herto Man,[1] is the name given to a number of hominin fossils found in 1997 in Herto Bouri, Ethiopia. They date to around 160,000 years ago.[2]

Paleoanthropologists determined that the skeletal finds belong to an extinct subspecies of Homo sapiens which lived in Pleistocene Africa since the fossils possess some archaic cranial traits that are uncommon among anatomically modern humans. They also generally lack the derived features of classic Neanderthals. Homo sapiens idaltu are morphologically similar to both archaic African fossils and subsequent anatomically modern humans of the Late Pleistocene.

Because of their early dating and unique physical characteristics, they were believed to represent the immediate ancestors of anatomically modern humans, as suggested by the Out-of-Africa theory.[1][3] The oldest anatomically modern human fossils (315,000 years old) discovered at Jebel Irhoud, Morocco, have since been dated to nearly twice the age of the Herto fossils.

Discovery

The fossilized remains of Homo sapiens idaltu were discovered at Herto Bouri near the Middle Awash site of Ethiopia's Afar Triangle in 1997 by Tim White, but were first unveiled in 2003.[1] Herto Bouri is a region of Ethiopia under volcanic layers. According to radioisotope dating, the layers are between 154,000 and 160,000 years old. Three well preserved crania are accounted for, the best preserved being from an adult male (BOU-VP-16/1) having a brain capacity of 1,450 cm3 (88 cu in). The other crania include another partial adult male and a six-year-old child.[1][4]

Morphology and taxonomy

The Omo fossils differ from those of chronologically later forms of early Homo sapiens, such as Cro-Magnon specimens found in Europe and other parts of the world. Their morphology has features that show resemblances to more primitive African fossils, such as huge and robust skulls, yet have a globular shape of the brain-case and the facial features typical of H. sapiens.[1][5]

Anthropologist Chris Stringer argued in a 2003 article in the journal Nature that "the skulls may not be distinctive enough to warrant a new subspecies name".[6][7]

Location of discovery

Despite the archaic features, these specimens were argued to represent the direct ancestors of modern Homo sapiens sapiens which, according to the "recent African origin (RAO)" or "out of Africa" model, developed shortly after this period (Khoisan mitochondrial divergence dated not later than 110,000 BCE) in Eastern Africa. "The many morphological features shared by the Herto crania and AMHS, to the exclusion of penecontemporaneous Neanderthals, provide additional fossil data excluding Neanderthals from a significant contribution to the ancestry of modern humans."[1]

A 2005 potassium-argon dating of volcanic tuff associated with the Omo remains showed them to date from around 195,000 years ago. At the time of the dating, this made these fossils the earliest known remains of anatomically modern humans, older than the idaltu specimens.[8] Fossils excavated at the Jebel Irhoud site in Morocco have since been dated to an earlier period, around 315,000 years ago.[9]

In 2013, comparative craniometric analysis of the Herto Homo idaltu skull with ancient and recent crania from other parts of Africa found that the specimen was morphologically closest to the Pleistocene Rabat fossil and Early Holocene Kef Oum Touiza skeleton. Herto and the prehistoric fossils were also distinct from crania belonging to modern Afroasiatic-speaking populations from the Horn of Africa and Dynastic Egypt, which instead possessed Middle Eastern affinities. This suggests that the Afroasiatic-speaking groups settled in the area during a later epoch, having possibly arrived from the Middle East.[10]

See also

References

  1. 1 2 3 4 5 6 7 White, Tim D.; Asfaw, B.; DeGusta, D.; Gilbert, H.; Richards, G. D.; Suwa, G.; Howell, F. C. (2003), "Pleistocene Homo sapiens from Middle Awash, Ethiopia", Nature, 423 (6491): 742–747, Bibcode:2003Natur.423..742W, doi:10.1038/nature01669, PMID 12802332
  2. ↑ "160,000-year-old fossilized skulls uncovered in Ethiopia are oldest anatomically modern humans". UC Berkeley. June 11, 2003. Retrieved June 7, 2016.
  3. ↑ "Meet the Contenders for Earliest Modern Human". Smithsonian. January 11, 2012. Retrieved June 8, 2016.
  4. ↑ White, TD; Asfaw, B; DeGusta, D; et al. (June 2003). "Pleistocene Homo sapiens from Middle Awash, Ethiopia". Nature. 423 (6941): 742–7. Bibcode:2003Natur.423..742W. doi:10.1038/nature01669. PMID 12802332. Retrieved June 7, 2016.
  5. ↑ "HOMO SAPIENS IDALTU". Bradshaw foundation. Retrieved June 7, 2016.
  6. ↑ Stringer, Chris (June 12, 2003). "Human evolution: Out of Ethiopia". Nature. 423 (6941): 693–695. Bibcode:2003Natur.423..692S. doi:10.1038/423692a. PMID 12802315. Retrieved June 7, 2016.
  7. ↑ "Herto skulls (Homo sapiens idaltu)". talkorigins org. Retrieved June 7, 2016.
  8. ↑ McDougall, I.; Brown, F. H.; Fleagle, J. G. (2005), "Stratigraphic placement and age of modern humans from Kibish, Ethiopia", Nature, 433 (7027): 733–736, Bibcode:2005Natur.433..733M, doi:10.1038/nature03258, PMID 15716951
  9. ↑ Callaway, Ewan (7 June 2017). "Oldest Homo sapiens fossil claim rewrites our species' history". Nature. doi:10.1038/nature.2017.22114. Retrieved 5 July 2017.
  10. ↑ Terrazas Mata, A. Serrano Sánchez, C. and Benavente, M. (2013). "The Late Peopling of Africa According to Craniometric Data. A Comparison of Genetic and Linguistic Models" (PDF). Human Evolution (1–2): 1–12. Retrieved 17 March 2017.
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