Homo georgicus

Homo georgicus is the name proposed to describe fossil human remains that have been found at the medieval town of Dmanisi, Georgia from 1991. The site has been of interest to archaeologists for many years and bones of extinct mammals had previously been recovered from the site. Mode I stone tools, similar to the Oldowan tradition of East Africa, and comprising flakes and flaked pebbles were discovered in 1984. The human remains include four partial human skulls and two lower jaws.

A basalt layer below the fossils has been dated to between 1.95-1.77 million years old by magnetic polarity considerations, which are normal. The material occurring with the fossils shows reversed polarity, dating it from 1.77 million to 790,000 years. The mammal bones do suggest the earlier date based on when certain species overlapped in time.

The skull known as D2700 has an extremely small braincase volume of 600cc, similar to that of Homo habilis and it has been suggested that it has a closer relationship to this species than it does to African Homo ergaster or Asian Homo erectus. If so, it would imply that humans of the habilis rather than the erectus grade were the first to leave Africa. However a recent description of a metatarsal shows a close fit with the derived Homo ergaster body plan rather than that of Homo habilis, which retained many australopithecine features.

References:

Cameron D & Groves C (2004): Bones, Stones and Molecules: “Out of Africa” and Human Origins, Elsevier Academic Press.

Scarre C (2005) (Ed): “The human past”, Thames & Hudson.

Abesalom Vekua, David Lordkipanidze, G. Philip Rightmire, Jordi Agusti, Reid Ferring, Givi Maisuradze, Alexander Mouskhelishvili, Medea Nioradze,
Marcia Ponce de Leon, Martha Tappen, Merab Tvalchrelidze, Christoph Zollikofer (2002): A New Skull of Early Homo from Dmanisi, Georgia, Science 297, 85 (2002).

© Christopher Seddon 2008

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Homo cepranensis

Homo cepranensis is the name proposed for a hominid skullcap found near the Italian town of Ceprano in 1994 by archaeologist Italo Biddittu. Unfortunately it was shattered by a bulldozer during highway construction immediately before its discovery. On the basis of regional correlations and a series of absolute dates, the age of the Ceprano hominid is estimated to range between 800,000 and 900,000 years.

It shares many features with skull caps of Homo erectus including a massive shelf-like brow ridge, extremely thick skull walls, sharply-angled occipital region and a small internal volume, estimated at 1057cc. Had it been discovered in eastern Asia, it might well have been assigned to H. erectus (Scarre (2005)).

Interpretation is difficult due to the lack of material. Manzi et al (2001) point out that affinity with the contemporary Homo antecessor might be expected but unfortunately among the nearly 80 fossil pieces that have been found so far, none is directly or adequately comparable with the Ceprano specimen, at least in terms of completeness (as for some temporal bone fragments) or age at death (as in the case of the juvenile frontal TD6-15). It is possible that further examples of H. antecessor will eventually be recovered, and that these will reveal affinities to H. cepranensis.

However Cameron & Groves (2004) have suggested that this species originated in Eurasia, with a later Eurasian Homo erectus population moving into Western Europe about one million years ago before eventually becoming extinct. Clarke (2000) claims the Ceprano specimen has affinities to the Olduvai hominid OH9 (1.2 million years old). OH9 and OH12 (700,000 years old) have been considered to represent “classic” (i.e. Eurasian) specimens of Homo erectus and may represent an expansion of this species back into Africa from Eurasia. On this picture, then, Homo cepranensis is seen as a representative of a European deme of Homo erectus that was associated with migrations “Into Africa”.

References:

A. Ascenzi, F. Mallegni, G. Manzi, A. G. Segre & E. Segre Naldini (2000): A re-appraisal of Ceprano calvaria affinities with Homo erectus, after the new reconstruction, Journal of Human Evolution (2000) 39, 443–450.

Cameron D & Groves C (2004): Bones, Stones and Molecules: “Out of Africa” and Human Origins, Elsevier Academic Press.

Clarke R.J (2000): A corrected reconstruction and interpretation of the Homo erectus calvaria from Ceprano, Italy, Journal of Human Evolution, Volume 39, Number 4, October 2000, pp. 433-442.

G. Manzi, F. Mallegni, and A. Ascenzi (2001): A cranium for the earliest Europeans: Phylogenetic position of the hominid from Ceprano, Italy, PNAS August 14, 2001 vol. 98 no. 17 10013.

Scarre C (2005) (Ed): “The human past”, Thames & Hudson.

© Christopher Seddon 2008

Homo antecessor

Homo antecessor (“Pioneer Man”) is the name given to an extinct human species known from just two sites in the Atapuerca Hills of Northern Spain – Gran Dolina and Sima del Elefante. The remains were discovered by Eudald Carbonell, Juan Luis Arsuaga and J. M. Bermúdez de Castro.

The initial discoveries were made at the Gran Dolina Cave, Layer TD6 between 1994 and 1995. The find comprised over 90 bone fragments including 18 skull fragments, 4 partial jaws, 14 teeth, 16 vertebrae, 16 ribs, 20 bones from the hands and feet, 2 wrist bones, 3 collar bones, 2 lower arm bones, a thigh bone and 2 knee-caps from a minimum of 6 individuals, all of whom were aged between 3 and 18 when they died. Around 200 flaked stone artefacts were also found. Palaeomagnetic considerations date the find to at least 700,000 years old; electron spin resonance dates the fossils and artefacts to between 857,000 and 780,000 years old; bones of extinct rodent species support this age; the excavators conservatively date the find to 800,000 years old.

However in 2007 a fragment of a mandible and an isolated lower left fourth premolar from the same individual were recovered from the TE9 layer at the nearby Sima del Elefante site. These have also been assigned to Homo antecessor and dating based on palaeomagnetism, biostratigraphy and cosmogenic nuclides suggests an age of 1.2–1.1 million years.

The tools found at the Gran Dolina are simple Mode 1 (Oldowan) technology, with no evidence of Acheulian hand-axes or cleavers characteristic of later African Homo ergaster or H. heidelbergensis.

One of the most significant features of the Gran Dolina TD6 find is that around 25% of the bones show signs of human-caused damage including chop and cut marks, peeling where bones have been broken and bent, and percussion marks where bones have been splintered for marrow extraction. All of which adds up to a compelling case for cannibalism. The extent of the damage suggests this was of a dietary rather than ritual nature, suggesting in turn nutritional stress.

Bermúdez de Castro and his colleagues argue against the currently popular view that hominids such as Mauer, Vertesszollos, Bilzingsleben, Arago, and Petralona, together with Bodo, Broken Hill 1, and Dali (among other middle Pleistocene fossils not considered to be H. erectus) belong to a single species, Homo heidelbergensis, that was ancestral to both modern humans and the Neanderthals. They argue that European middle Pleistocene fossils are ancestral only to the Neanderthals and that the Mauer mandible, the holotype for Homo heidelbergensis, shows clear derived Neanderthal traits, such as a large retromolar space, whereas teeth shape and morphology are indistinguishable from those of Neanderthals. They conclude that other than a European chronospecies, H. heidelbergensis should be rejected.

Dental and cranial features suggest Homo antecessor is close to Homo ergaster. While Homo antecessor has similarities to Homo heidelbergensis (i.e. proto-Neanderthals), it has more traits in common with modern humans than does Homo heidelbergensis, being for example relatively gracile, most similar to H. ergaster and modern humans but unlike H. heidelbergensis or the Neanderthals. On this picture, Homo antecessor evolved from Homo ergaster in Africa then spread via the Middle East to Europe where it evolved (via Homo heidelbergensis) into the Neanderthals. In Africa Homo antecessor evolved into Homo sapiens via such fossils as the Bodo and Kabwe skulls. The species Homo rhodesiensis or Homo helmei would have to be revived for these presumptive H. antecessor/H. sapiens transitional types, with H. heidelbergensis being a solely European transitional type between H. antecessor and the Neanderthals.

Neither this view nor Homo antecessor as a species is widely accepted. Many believe that H. antecessor is an ofshoot of Homo ergaster and that it died off without issue, possibly during the glacial periods of 800,000-600,000 years ago. Clearly further evidence is needed, from Africa in particular.

References:

J. M. Bermudez de Castro, J. L. Arsuaga, E. Carbonell, A. Rosas, I. Martınez, M. Mosquera (1997): A Hominid from the Lower Pleistocene of Atapuerca, Spain: Possible Ancestor to Neandertals and Modern Humans, Science Vol. 276 30 May 1997.

Cameron D & Groves C (2004): Bones, Stones and Molecules: “Out of Africa” and Human Origins, Elsevier Academic Press.

Eudald Carbonell, Jose M. Bermudez de Castro, Josep M. Pares, Alfredo Perez-Gonzalez, Gloria Cuenca-Bescos, Andreu Olle, Marina Mosquera, Rosa Huguet, Jan van der Made, Antonio Rosas, Robert Sala, Josep Vallverdu, Nuria Garcıa, Darryl E. Granger, Marıa Martinon-Torres, Xose P. Rodrıguez, Greg M. Stock, Josep M. Verges, Ethel Allue, Francesc Burjachs, Isabel Caceres, Antoni Canals, Alfonso Benito, Carlos Dıez, Marina Lozano, Ana Mateos, Marta Navazo, Jesus Rodrıguez, Jordi Rosell & Juan L. Arsuaga (2008): The first hominin of Europe, Nature Vol 452 27 March 2008.

Scarre C (2005) (Ed): “The human past”, Thames & Hudson.

© Christopher Seddon 2008

The Bodo cranium (Homo heidelbergensis)

The Bodo cranium was recovered in 1976 from an outcrop of Middle Pleistocene sediments at Bodo in the Middle Awash valley, Ethiopia. It is one of the most complete African skulls from this period yet recovered. It was found in deposits containing Acheulian tools that were dated by the argon-40/argon-39 method to between 670,000 and 600,000 years old. It possesses many features characteristic of Homo ergaster, such as a low braincase, broad and robust facial skeleton, relatively thick bones, a forehead with a central bulge and a massive brow ridge.

Its cranial capacity, however, has been estimated at 1300cc, close to that of a modern human and considerably greater than that of Homo ergaster. It has variously been classed as archaic Homo sapiens, Homo sapiens c.f. rhodesiensis, but is now generally classed as Homo heidelbergensis.

The cranium has cut-marks suggesting intentional de-fleshing by a human with a stone tool. These may imply cannibalism, mortuary practice for ritual purposes, or both. However, the skull lacks the cranial base, meaning that brain removal through the foramen magnum cannot be clearly established, and unequivocal evidence for cannibalism is therefore lacking.

References:

Scarre C (2005) (Ed): “The human past”, Thames & Hudson.

White T (1986) Cut Marks on the Bodo Cranium: A Case of Prehistoric
Defleshing, American Journal of Physical Anthropology 69503-509 (1986).

© Christopher Seddon 2008

The Herto remains (Homo sapiens idaltu)

The Herto remains are a find of early anatomically modern human remains from Herto, Middle Awash in the Afar Triangle, Ethiopia. The find comprises of three well-preserved crania plus fragmentary remains. The crania were discovered in 1997 by a team lead by Dr. Tim White but the find was not described until 2003. Two of the crania belong to adult males; the third belongs to a six-year-old child. The cranial capacity of the best-preserved adult cranium, known as BOU-VP-16/1, is 1450cc – at the high end of the modern human range.

Deposits dated by the argon-40/argon-39 method to 154,000 years old and 160,000 years old provided constraints on the age of the Herto remains. At the time, they were the earliest examples known of modern Homo sapiens. Crucially they pre-date the “classic” Neanderthals, ruling out the possibility that modern humans are descended from the latter.

Although the finds are close enough to present-day humans to be considered the same species, they retain some primitive morphological features from earlier human species such as Homo heidelbergensis. The braincases are longer and the brow ridges are more pronounced than those of later humans. For this reason, White erected a new subspecies for them, Homo sapiens idaltu (idaltu means elder or first-born in the Afar language).

Stone tools found with the fossils suggest a transitional phase between the Acheulian hand-axe and Middle Stone Age (MSA) flake technologies. Such assemblages are traditionally classified as final Acheulian.

The Herto people occupied the margin of a freshwater lake, and archaeological evidence indicates butchery of large mammal carcasses, particularly hippopotamus. Whether they hunted or simply scavenged these animals is not known.

The less-intact adult cranium (BOU-VP-16/2) bears cut-marks made with stone tools. Some of these are deep cut-marks typical of de-fleshing, but more abundant are more superficial marks showing a repetitive scraping motion, a pattern that is not seen on faunal remains processed for food, or in instances of cannibalism.

The child’s skull exhibits cut-marks made by a very sharp stone flake deep in its base. The rear part of the cranial base was broken away, and the broken edges polished. The sides of the skull show a deep polish that may have formed from repeated handling of the skull after it was de-fleshed.

All of this implies some form of ancient mortuary practice. Ethnographic evidence from several cultures documents the post-mortem manipulation and preservation of human remains as part of mortuary practices. For example, some New Guinean crania show cut-marks, decoration and polishing reminiscent of traces seen on the Herto people.

This suggests the Herto people may have had complex belief systems; a feature considered to be one of the hallmarks of modern human behaviour.

References:

Clark JD, Beyene Y, WoldeGabriel G, Hartk WK, Renne PR, Gilbert H, Defleurq A, Suwa G, Katoh S, Ludwig KR, Boisserie J-R, Asfawkk B & White TD (2003): Stratigraphic, chronological and behavioural contexts of Pleistocene Homo sapiens from Middle Awash, Ethiopia, Nature Vol 423 12 June 2003.

White TD, Asfaw B, DeGusta D, Gilbert H, Richards GD, Suwa G & Howell FC (2003): Pleistocene Homo sapiens from Middle Awash, Ethiopia, Nature Vol 423 12 June 2003.

© Christopher Seddon 2008

Omo remains (Homo sapiens)

The Omo I (Kibish) and Omo II (Kibish) remains are currently the oldest-known fossils of anatomically-modern humans (Homo sapiens). They were recovered by Richard Leakey in 1967 from the base of Member I of the Kibish Formation near the Omo River in south-western Ethiopia. Both Omo I and Omo II comprise a braincase and some postcranial material. Omo I fully modern in appearance; Omo II is slightly more primitive with a long, low cranium. However both are believed to be about the same age.

Originally believed to be around 130,000 years old, the Omo remains have recently been assigned a date of 195,000 +/- 5,000 years old, based on argon-40/argon-39 dating of volcanic tuffs (ash) found within Member I at levels. This makes them substantially older than the Herto remains discovered in 1997, previously thought to be the earliest-known fossil remains of modern humans. What is curious is that the 156,000 year old Herto remains, despite being around 40,000 years more recent than the Omo remains, retain more primitive features and were originally assigned their own subspecies, Homo sapiens idaltu.

Reference:

McDougall I, Brown FH & Fleagle JG (2005): Stratigraphic placement and
age of modern humans from Kibish, Ethiopia, Nature 734 Vol 433 17 Feb 2005.

© Christopher Seddon 2008

The Florisbad skull (Homo helmei)

Florisbad 1 is a hominin fossil recovered by Prof. T.F. Dreyer from the depths of a warm lithium spring deposit in the Orange Free State, South Africa, in 1932. The skull consists of frontal and parietal pieces and an incomplete right side of the face (Conroy, 1997). In 1996 a direct date was obtained for the skull using electron spin resonance dating on two small samples of enamel removed from the only tooth to be found with the skull. These yielded a date of 259,000 +/- 35,000 years (Grun et al 1996).

The skull was originally classified as Homo helmei by Dreyer to mark its distinctiveness from other fossil Homo sapiens. It is now generally either described as “archaic Homo sapiens” or assigned to Homo heidelbergensis, but it may be an intermediate form between H. heidelbergensis and H. sapiens, in which case retention of the Homo helmei classification would be appropriate.

References:

Conroy G (1997): “Reconstructing Human Origins: A Modern Synthesis”, W.W. Norton & Co. Inc, New York, NY & London.

Grün, R., Brink, J.S., Spooner, N.A., Taylor, L., Stringer, C.B., Franciscus, R.B. & Murray, A. (1996): Direct dating of the Florisbad hominid. Nature 382: 500–501.

Lewin, R and Foley, R 2004: Principles of Human Evolution (2nd edition), Blackwell Science Ltd.

© Christopher Seddon 2008