The Omo remains are a collection of hominin bones discovered between 1967 and 1974 at the Omo Kibish sites near the Omo River, in Omo National Park in south-western Ethiopia. The bones were recovered by a scientific team from the Kenya National Museums directed by Richard Leakey and others. The remains from Kamoya's Hominid Site (KHS) were called Omo I and those from Paul I. Abell's Hominid Site (PHS) were called Omo II.
Fossils
The bones found include two partial skulls, four jaws, a legbone, approximately two hundred teeth, and several other fossilized parts. Both of the specimens, Omo I and Omo II, are classified as anatomically modern humans (Homo sapiens), but they differ from each other in morphological traits. The Omo I fossils indicate more modern traits, while studies of the postcranial remains of Omo II indicate an overall modern human morphology with some primitive features. The fossils were found in a layer of tuff, between a lower, older geologic layer named Member I and a higher, newer layer dubbed Member III. The Omo I and Omo II hominin fossils were taken from similar stratigraphic levels above Member I.
Because of the very limited fauna and the few stone artifacts that were found at the sites when the original Omo remains were discovered, the provenance and estimated age of the Kibish hominids are uncertain. In 2008, new bone remains were discovered from Awoke's Hominid Site (AHS). The AHS fossil's tibia and fibula were unearthed from Member I, the same layer from which the other Omo remains derive.
Dating and implications
About 30 years after the original finds, a detailed stratigraphic analysis of the area surrounding the fossils was conducted. The Member I layer was argon-dated to 195,000 years ago, and the (higher layer) Member III was dated to 105,000 years ago. Numerous recent lithic records verify the tool technology from Members I and III to the Middle Stone Age.
The lower layer, Member I, (below the fossils) is considerably older than the 160,000-year-old Herto remains designated as Homo sapiens idaltu. The rainy conditions at that time—which are known from isotopic ages on the Kibish Formation corresponding to the ages of Mediterranean sapropels—suggest increased flow of the Nile River and, therefore, increased flow of the Omo River. But the climates changed such that, after 185,000 years ago conditions were so dry as to not allow speleothems to grow in the caverns in the Levantine land-bridge region, the vital inroad for migration to Eurasia.
Parts of the fossils are the earliest to have been classified by Leakey as Homo sapiens. In 2004, the geological layers around the fossils were dated, with the age of the "Kibish hominids" estimated at 195±5 ka [thousand years ago]. For some time, these were the oldest known fossils classified as H. sapiens (the Florisbad Skull is older, but its classification as H. sapiens was then disputed). With the dating of the Jebel Irhoud 1–5 to before 250 ka (315 ± 34 ka, and 286±32 ka) in 2017, as well as the classification of the Florisbad Skull as H. sapiens, this is no longer the case.
In 2022, a study by Vidal et al. found an earlier age for the Omo fossils than previously reported, revising the date assigned to them as, a minimum date of approximately 233,000 years old.
See also
- List of fossil sites (with link directory)
- List of human fossils
- Recent African origin of modern humans
Notes
- This article quotes historic texts that use the terms 'hominid' and 'hominin' with meanings that may be different from their modern usages. This is because several revisions in classifying the great apes have caused the use of the term "hominid" to vary over time. Its original meaning referred only to humans (Homo) and their closest relatives. That restrictive usage has been largely assumed by the term "hominin", which comprises all members of the human clade after the split from the chimpanzees (Pan). The modern meaning of the term "hominid" refers to all the great apes, including humans. Usage still varies, however, and some scientists and laypersons still use the term in the original restrictive sense; the scholarly literature generally will show the traditional usage until around the end of the 20th century. For further information, see Hominini (at "hominins") and Hominidae (at discussion of the terms "hominid" and "hominin" in the lede section).
In this article, hominid is italicized when the traditional term is necessary to keep as-is—as in a quotation, or a record, or a title, etc.
References
- Fossil Reanalysis Pushes Back Origin of Homo sapiens. Scientific American 2005-02-17. Retrieved 2005-08-22.[Retrieved 2011-08-27]
- Fleagle, Jg; Assefa, Z; Brown, Fh; Shea, Jj (Sep 2008). "Paleoanthropology of the Kibish Formation, southern Ethiopia: Introduction". Journal of Human Evolution. 55 (3): 360–365. doi:10.1016/j.jhevol.2008.05.007. ISSN 0047-2484. PMID 18617219.
- Mcdougall, Ian; Brown, FH; Fleagle, JG (2005). "Stratigraphic placement and age of modern humans from Kibish, Ethiopia" (PDF). Nature. 433 (7027): 733–736. Bibcode:2005Natur.433..733M. doi:10.1038/nature03258. PMID 15716951. S2CID 1454595.
- Ian McDougall, Francis H Brown, John G Fleagle Sapropels and the age of hominins Omo I and II, Kibish, Ethiopia. Journal of Human Evolution (2008) Volume: 55, Issue: 3, Pages: 409–20 PubMed: 18602675 Copyright © 2012 Mendeley Ltd. All rights reserved. doi:10.1016/j.jhevol.2008.05.012 [Retrieved 2012-01-02]
- Stringer, C. (2016). "The origin and evolution of Homo sapiens". Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences. 371 (1698): 20150237. doi:10.1098/rstb.2015.0237. PMC 4920294. PMID 27298468.
- Pearson, Om; Fleagle, Jg; Grine, Fe; Royer, Df (Sep 2008). "Further new hominin fossils from the Kibish Formation, southwestern Ethiopia". Journal of Human Evolution. 55 (3): 444–7. doi:10.1016/j.jhevol.2008.05.013. ISSN 0047-2484. PMID 18691739.
- Vaks, Anton; Bar-Matthews, Miryam; Ayalon, Avner; Matthews, Alan; Halicz, Ludwik; Frumkin, Amos (2007). "Desert speleothems reveal climatic window for African exodus of early modern humans" (PDF). Geology. 35 (9): 831. Bibcode:2007Geo....35..831V. doi:10.1130/G23794A.1. Archived from the original (PDF) on 2011-07-21.
- "Oldest known human fossil outside Africa discovered in Israel". the Guardian. January 25, 2018.
- David Richter; et al. (8 June 2017). "The age of the hominin fossils from Jebel Irhoud, Morocco, and the origins of the Middle Stone Age". Nature. 546 (7657): 293–296. Bibcode:2017Natur.546..293R. doi:10.1038/nature22335. PMID 28593967. S2CID 205255853. Retrieved 8 June 2017. Smith TM, Tafforeau P, Reid DJ, et al. (April 2007). "Earliest evidence of modern human life history in North African early Homo sapiens". Proceedings of the National Academy of Sciences of the United States of America. 104 (15): 6128–33. Bibcode:2007PNAS..104.6128S. doi:10.1073/pnas.0700747104. PMC 1828706. PMID 17372199. 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.
- Vidal, Celine M.; Lane, Christine S.; Asfawrossen, Asrat; et al. (Jan 2022). "Age of the oldest known Homo sapiens from eastern Africa". Nature. 601 (7894): 579–583. Bibcode:2022Natur.601..579V. doi:10.1038/s41586-021-04275-8. PMC 8791829. PMID 35022610.
External links
- Analysis of the Huerto remains Archived 2015-12-08 at the Wayback Machine
The Omo remains are a collection of hominin bones discovered between 1967 and 1974 at the Omo Kibish sites near the Omo River in Omo National Park in south western Ethiopia The bones were recovered by a scientific team from the Kenya National Museums directed by Richard Leakey and others The remains from Kamoya s Hominid Site KHS were called Omo I and those from Paul I Abell s Hominid Site PHS were called Omo II Reproduction of the head of the Omo hominin in the Musee des Civilisations Noires de Dakar Senegal FossilsThe bones found include two partial skulls four jaws a legbone approximately two hundred teeth and several other fossilized parts Both of the specimens Omo I and Omo II are classified as anatomically modern humans Homo sapiens but they differ from each other in morphological traits The Omo I fossils indicate more modern traits while studies of the postcranial remains of Omo II indicate an overall modern human morphology with some primitive features The fossils were found in a layer of tuff between a lower older geologic layer named Member I and a higher newer layer dubbed Member III The Omo I and Omo II hominin fossils were taken from similar stratigraphic levels above Member I Because of the very limited fauna and the few stone artifacts that were found at the sites when the original Omo remains were discovered the provenance and estimated age of the Kibish hominids are uncertain In 2008 new bone remains were discovered from Awoke s Hominid Site AHS The AHS fossil s tibia and fibula were unearthed from Member I the same layer from which the other Omo remains derive Dating and implicationsAbout 30 years after the original finds a detailed stratigraphic analysis of the area surrounding the fossils was conducted The Member I layer was argon dated to 195 000 years ago and the higher layer Member III was dated to 105 000 years ago Numerous recent lithic records verify the tool technology from Members I and III to the Middle Stone Age The lower layer Member I below the fossils is considerably older than the 160 000 year old Herto remains designated as Homo sapiens idaltu The rainy conditions at that time which are known from isotopic ages on the Kibish Formation corresponding to the ages of Mediterranean sapropels suggest increased flow of the Nile River and therefore increased flow of the Omo River But the climates changed such that after 185 000 years ago conditions were so dry as to not allow speleothems to grow in the caverns in the Levantine land bridge region the vital inroad for migration to Eurasia Parts of the fossils are the earliest to have been classified by Leakey as Homo sapiens In 2004 the geological layers around the fossils were dated with the age of the Kibish hominids estimated at 195 5 ka thousand years ago For some time these were the oldest known fossils classified as H sapiens the Florisbad Skull is older but its classification as H sapiens was then disputed With the dating of the Jebel Irhoud 1 5 to before 250 ka 315 34 ka and 286 32 ka in 2017 as well as the classification of the Florisbad Skull as H sapiens this is no longer the case In 2022 a study by Vidal et al found an earlier age for the Omo fossils than previously reported revising the date assigned to them as a minimum date of approximately 233 000 years old See alsoList of fossil sites with link directory List of human fossils Recent African origin of modern humansNotesThis article quotes historic texts that use the terms hominid and hominin with meanings that may be different from their modern usages This is because several revisions in classifying the great apes have caused the use of the term hominid to vary over time Its original meaning referred only to humans Homo and their closest relatives That restrictive usage has been largely assumed by the term hominin which comprises all members of the human clade after the split from the chimpanzees Pan The modern meaning of the term hominid refers to all the great apes including humans Usage still varies however and some scientists and laypersons still use the term in the original restrictive sense the scholarly literature generally will show the traditional usage until around the end of the 20th century For further information see Hominini at hominins and Hominidae at discussion of the terms hominid and hominin in the lede section In this article hominid is italicized when the traditional term is necessary to keep as is as in a quotation or a record or a title etc ReferencesFossil Reanalysis Pushes Back Origin ofHomo sapiens Scientific American 2005 02 17 Retrieved 2005 08 22 Retrieved 2011 08 27 Fleagle Jg Assefa Z Brown Fh Shea Jj Sep 2008 Paleoanthropology of the Kibish Formation southern Ethiopia Introduction Journal of Human Evolution 55 3 360 365 doi 10 1016 j jhevol 2008 05 007 ISSN 0047 2484 PMID 18617219 Mcdougall Ian Brown FH Fleagle JG 2005 Stratigraphic placement and age of modern humans from Kibish Ethiopia PDF Nature 433 7027 733 736 Bibcode 2005Natur 433 733M doi 10 1038 nature03258 PMID 15716951 S2CID 1454595 Ian McDougall Francis H Brown John G Fleagle Sapropels and the age of hominins Omo I and II Kibish Ethiopia Journal of Human Evolution 2008 Volume 55 Issue 3 Pages 409 20 PubMed 18602675 Copyright c 2012 Mendeley Ltd All rights reserved doi 10 1016 j jhevol 2008 05 012 Retrieved 2012 01 02 Stringer C 2016 The origin and evolution of Homo sapiens Philosophical Transactions of the Royal Society of London Series B Biological Sciences 371 1698 20150237 doi 10 1098 rstb 2015 0237 PMC 4920294 PMID 27298468 Pearson Om Fleagle Jg Grine Fe Royer Df Sep 2008 Further new hominin fossils from the Kibish Formation southwestern Ethiopia Journal of Human Evolution 55 3 444 7 doi 10 1016 j jhevol 2008 05 013 ISSN 0047 2484 PMID 18691739 Vaks Anton Bar Matthews Miryam Ayalon Avner Matthews Alan Halicz Ludwik Frumkin Amos 2007 Desert speleothems reveal climatic window for African exodus of early modern humans PDF Geology 35 9 831 Bibcode 2007Geo 35 831V doi 10 1130 G23794A 1 Archived from the original PDF on 2011 07 21 Oldest known human fossil outside Africa discovered in Israel the Guardian January 25 2018 David Richter et al 8 June 2017 The age of the hominin fossils from Jebel Irhoud Morocco and the origins of the Middle Stone Age Nature 546 7657 293 296 Bibcode 2017Natur 546 293R doi 10 1038 nature22335 PMID 28593967 S2CID 205255853 Retrieved 8 June 2017 Smith TM Tafforeau P Reid DJ et al April 2007 Earliest evidence of modern human life history in North African early Homo sapiens Proceedings of the National Academy of Sciences of the United States of America 104 15 6128 33 Bibcode 2007PNAS 104 6128S doi 10 1073 pnas 0700747104 PMC 1828706 PMID 17372199 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 Vidal Celine M Lane Christine S Asfawrossen Asrat et al Jan 2022 Age of the oldest known Homo sapiens from eastern Africa Nature 601 7894 579 583 Bibcode 2022Natur 601 579V doi 10 1038 s41586 021 04275 8 PMC 8791829 PMID 35022610 External linksAnalysis of the Huerto remains Archived 2015 12 08 at the Wayback Machine 4 48 1 27 N 35 58 1 45 E 4 8003528 N 35 9670694 E 4 8003528 35 9670694
