Olduvai Hominid number 9 (OH 9), known as the Chellean Man, is a fossilized skull cap of an early hominin, found in LLK II, Olduvai Gorge by Louis S. B. Leakey in 1960.[1] It is believed to be ca. 1.4 million years old. Its cranial capacity is estimated at than 1067 cm3, the largest value among all known African Homo erectus specimens.[2] OH 9 is significant because the features it carried and its correlation to the species classification it resides in.
Leakey named it "Chellean Man", in reference to the Oldowan tools found at the site, which were then referred to by the now-obsolete name Chellean. Heberer (1963) provisionally named a new species Homo leakeyi based on the specimen in honor of Leakey,[3] but most subsequent workers have regarded it as Homo ergaster, or as Homo erectus (H. ergaster is sometimes regarded as a subspecies of H. erectus, H. erectus ergaster). Phillip Tobias provisionally named a new subspecies, H. erectus olduvaiensis, in 1968 based on the specimen, but this has not seen continued use.[4] To the extent that proponents of the use of H. ergaster define ergaster as a separate species (instead of an "African H. erectus") rather than a pure chronospecies, the assignment of OH 9 to H. erectus sensu stricto by Colin Groves supports subsuming H. ergaster into H. erectus.[5]
Because the name Homo leakeyi was proposed conditionally, it is not valid according to the rules established by the ICZN. Kretzoi (1984) created the replacement name Homo louisleakeyi, which is valid.[6]
Cranial bone thickness has been widely qualified for Homo erectus but rarely quantified.[7] It’s quite often that throughout craniums found, the thickness varies between those different hominids. Yet in OH 9, compared to other H. erectus, it had the biggest cranial capacity standing at 1,067 cc and one of the largest mid supra-orbital torus thickness of 18.5 mm also known as the brow ridge. OH 9 has a robust brow ridge that allows it to stand out among other H. erectus. The brow ridge made it difficult to determine whether this cranium should be classified as H. erectus or a different species. Cranial bone thickness is key when determining whether a specimen found is H. erectus. The pattern of bone thickness distribution observed in Asian H. erectus, P. paniscus, and possibly in the australopiths, early Homo or African H. ergaster/erectus analyzed appears to be a pleomorphic trait among hominids.[8] Since cranium thickness and the OH 9 cranium capacity is larger than any found, it explored the idea of different forms of H. erectus from different areas due to migration. By the 1980s, the growing numbers of H. erectus specimens, particularly in Africa, led to the realization that Asian Homo erectus (H. erectus sensu stricto), once thought so primitive, was in fact more derived than its African counter-parts,[9] which leads into the Out of Africa hypothesis of humans origins.
Cranial Featuresedit
The significant features of the OH 9 also consisted of the structure of the skull. O.H. 9 had a flatter frontal squama curving not as steep from a broader supratoral shelf. Also, OH 9 showed no sign of keeling in the midline,[10] which was often found in H. erectus especially with a protruding brow ridge. The occipital torus thickness also known as the occipital bun which is the back of the head was also fairly thick compared to most H. erectus with a thickness of 18.5 mm.[11] OH 9 being the largest cranium capacity, helped us learn the increase of brain growth in H. erectus. Which implied that major differences in the development of cognitive capabilities existed between H. erectus and anatomically modern humans.[12] These new traits like the robust brow ridge and skull thickness confirmed that H. erectus in different areas kept evolving. In the same site, the oldowan tools found could be assumed to have been used by this exact H. erectus. This allowed anthropologist to understand how advanced this unique H. erectus cognitive behavior truly was.
Referencesedit
^Leakey, Mary (1971). Olduvai Gorge Vol 3: Excavations in Beds I and II, 1960-1963. London: Cambridge University Press.
^Robert Jurmain, Lynn Kilgore, Wenda Trevathan, Essentials of Physical Anthropology (2008), p. 201
^Heberer, G. (1963). "Über einen neuen archantropinen Typus aus der Oldoway-Schlucht". Z. Morph. Anthropol. (in German) (53): 171–177.
^Harrison, Terry (1993). "Cladistic Concepts and the Species Problem in Hominoid Evolution". In William Kimbel and Lawrence Martin (ed.). Species, Species Concepts, and Primate Evolution. New York: Plenum Press. pp. 360–365.
^Cela-Conde, Camilo; Ayala, Francisco (2007). Human Evolution: Trails from the Past. New York: Oxford University Press. p. 197.
^Groves, Colin P. (1999-12-01). "Nomenclature of African Plio-Pleistocene hominins". Journal of Human Evolution. 37 (6): 869–872. doi:10.1006/jhev.1999.0366. ISSN 0047-2484. PMID 10600324.
^Balzeau, Antoine (2013-06-01). "Thickened cranial vault and parasagittal keeling: Correlated traits and autapomorphies of Homo erectus?". Journal of Human Evolution. 64 (6): 631–644. doi:10.1016/j.jhevol.2013.02.005. ISSN 0047-2484. PMID 23541383.
^Balzeau, Antoine (2013-06-01). "Thickened cranial vault and parasagittal keeling: Correlated traits and autapomorphies of Homo erectus?". Journal of Human Evolution. 64 (6): 631–644. doi:10.1016/j.jhevol.2013.02.005. ISSN 0047-2484. PMID 23541383.
^Antón, Susan C. (2003). "Natural history of Homo erectus". American Journal of Physical Anthropology. 122 (S37): 126–170. doi:10.1002/ajpa.10399. ISSN 1096-8644. PMID 14666536.
^Rightmire, G. P. (1979). "Cranial remains of Homo erectus from Beds II and IV, Olduvai Gorge, Tanzania". American Journal of Physical Anthropology. 51 (1): 99–115. doi:10.1002/ajpa.1330510113. ISSN 1096-8644.
^Antón, Susan C. (2004-03-01). "The face of Olduvai Hominid 12". Journal of Human Evolution. 46 (3): 335–345. doi:10.1016/j.jhevol.2003.12.005. ISSN 0047-2484. PMID 14984787.
^Coqueugniot, H.; Hublin, J.-J.; Veillon, F.; Houët, F.; Jacob, T. (September 2004). "Early brain growth in Homo erectus and implications for cognitive ability". Nature. 431 (7006): 299–302. Bibcode:2004Natur.431..299C. doi:10.1038/nature02852. ISSN 1476-4687. PMID 15372030. S2CID 4428043.
External linksedit
Media related to OH 9 at Wikimedia Commons
April 13, 2024
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Olduvai Hominid number 9 OH 9 known as the Chellean Man is a fossilized skull cap of an early hominin found in LLK II Olduvai Gorge by Louis S B Leakey in 1960 1 It is believed to be ca 1 4 million years old Its cranial capacity is estimated at than 1067 cm3 the largest value among all known African Homo erectus specimens 2 OH 9 is significant because the features it carried and its correlation to the species classification it resides in Chellean manOH 9 replicaCatalog no OH 9Common nameChellean manSpeciesHomo erectus Homo erectus Homo louisleakeyiAge1 4 million yearsPlace discoveredOlduvai Gorge TanzaniaDate discovered2 December 1960Discovered byLouis S B Leakey Contents 1 Species Classification 2 Cranial Features 3 References 4 External linksSpecies Classification editLeakey named it Chellean Man in reference to the Oldowan tools found at the site which were then referred to by the now obsolete name Chellean Heberer 1963 provisionally named a new species Homo leakeyi based on the specimen in honor of Leakey 3 but most subsequent workers have regarded it as Homo ergaster or as Homo erectus H ergaster is sometimes regarded as a subspecies of H erectus H erectus ergaster Phillip Tobias provisionally named a new subspecies H erectus olduvaiensis in 1968 based on the specimen but this has not seen continued use 4 To the extent that proponents of the use of H ergaster define ergaster as a separate species instead of an African H erectus rather than a pure chronospecies the assignment of OH 9 to H erectus sensu stricto by Colin Groves supports subsuming H ergaster into H erectus 5 Because the name Homo leakeyi was proposed conditionally it is not valid according to the rules established by the ICZN Kretzoi 1984 created the replacement name Homo louisleakeyi which is valid 6 Cranial bone thickness has been widely qualified for Homo erectus but rarely quantified 7 It s quite often that throughout craniums found the thickness varies between those different hominids Yet in OH 9 compared to other H erectus it had the biggest cranial capacity standing at 1 067 cc and one of the largest mid supra orbital torus thickness of 18 5 mm also known as the brow ridge OH 9 has a robust brow ridge that allows it to stand out among other H erectus The brow ridge made it difficult to determine whether this cranium should be classified as H erectus or a different species Cranial bone thickness is key when determining whether a specimen found is H erectus The pattern of bone thickness distribution observed in Asian H erectus P paniscus and possibly in the australopiths early Homo or African H ergaster erectus analyzed appears to be a pleomorphic trait among hominids 8 Since cranium thickness and the OH 9 cranium capacity is larger than any found it explored the idea of different forms of H erectus from different areas due to migration By the 1980s the growing numbers of H erectus specimens particularly in Africa led to the realization that Asian Homo erectus H erectus sensu stricto once thought so primitive was in fact more derived than its African counter parts 9 which leads into the Out of Africa hypothesis of humans origins Cranial Features editThe significant features of the OH 9 also consisted of the structure of the skull O H 9 had a flatter frontal squama curving not as steep from a broader supratoral shelf Also OH 9 showed no sign of keeling in the midline 10 which was often found in H erectus especially with a protruding brow ridge The occipital torus thickness also known as the occipital bun which is the back of the head was also fairly thick compared to most H erectus with a thickness of 18 5 mm 11 OH 9 being the largest cranium capacity helped us learn the increase of brain growth in H erectus Which implied that major differences in the development of cognitive capabilities existed between H erectus and anatomically modern humans 12 These new traits like the robust brow ridge and skull thickness confirmed that H erectus in different areas kept evolving In the same site the oldowan tools found could be assumed to have been used by this exact H erectus This allowed anthropologist to understand how advanced this unique H erectus cognitive behavior truly was References edit Leakey Mary 1971 Olduvai Gorge Vol 3 Excavations in Beds I and II 1960 1963 London Cambridge University Press Robert Jurmain Lynn Kilgore Wenda Trevathan Essentials of Physical Anthropology 2008 p 201 Heberer G 1963 Uber einen neuen archantropinen Typus aus der Oldoway Schlucht Z Morph Anthropol in German 53 171 177 Harrison Terry 1993 Cladistic Concepts and the Species Problem in Hominoid Evolution In William Kimbel and Lawrence Martin ed Species Species Concepts and Primate Evolution New York Plenum Press pp 360 365 Cela Conde Camilo Ayala Francisco 2007 Human Evolution Trails from the Past New York Oxford University Press p 197 Groves Colin P 1999 12 01 Nomenclature of African Plio Pleistocene hominins Journal of Human Evolution 37 6 869 872 doi 10 1006 jhev 1999 0366 ISSN 0047 2484 PMID 10600324 Balzeau Antoine 2013 06 01 Thickened cranial vault and parasagittal keeling Correlated traits and autapomorphies of Homo erectus Journal of Human Evolution 64 6 631 644 doi 10 1016 j jhevol 2013 02 005 ISSN 0047 2484 PMID 23541383 Balzeau Antoine 2013 06 01 Thickened cranial vault and parasagittal keeling Correlated traits and autapomorphies of Homo erectus Journal of Human Evolution 64 6 631 644 doi 10 1016 j jhevol 2013 02 005 ISSN 0047 2484 PMID 23541383 Anton Susan C 2003 Natural history of Homo erectus American Journal of Physical Anthropology 122 S37 126 170 doi 10 1002 ajpa 10399 ISSN 1096 8644 PMID 14666536 Rightmire G P 1979 Cranial remains of Homo erectus from Beds II and IV Olduvai Gorge Tanzania American Journal of Physical Anthropology 51 1 99 115 doi 10 1002 ajpa 1330510113 ISSN 1096 8644 Anton Susan C 2004 03 01 The face of Olduvai Hominid 12 Journal of Human Evolution 46 3 335 345 doi 10 1016 j jhevol 2003 12 005 ISSN 0047 2484 PMID 14984787 Coqueugniot H Hublin J J Veillon F Houet F Jacob T September 2004 Early brain growth in Homo erectus and implications for cognitive ability Nature 431 7006 299 302 Bibcode 2004Natur 431 299C doi 10 1038 nature02852 ISSN 1476 4687 PMID 15372030 S2CID 4428043 External links edit nbsp Media related to OH 9 at Wikimedia Commons Retrieved from https en wikipedia org w index php title Chellean Man amp oldid 1189327135, wikipedia, wiki, book, books, library,
