DMANISI HOMININS —1.8-MILLION-YEAR-OLD HOMO ERECTUS IN GEORGIA

DMANISI HOMININS

Is he Homo erectus or Homo georicus

The Dmanisi hominins refers to population of early hominins whose fossils were found at Dmanisi, Georgia. The fossils and stone tools found there range in age from 1.85 to 1.77 million years old, making them the earliest well-dated hominin fossils in Eurasia and the oldest undisputed hominin fossils found outside of Africa. The first of these fossils were unearthed in 1991 and big deal was made when the first skulls were unearthed in the late 1990s. Earlier fossils and artifacts have been found in Asia but they have not been as precisely dated and carefully excavated as the Dmanisi fossils Though the precise classification is still disputed, the Dmanisi fossils are highly significant for the insights they provide on early hominin migrations out of Africa. [Source: Wikipedia]

The Dmanisi fossils is the largest collection of “Homo erectus” bones ever found in one place and and the best preserved fossils of early Homo from a single site so early in time. They include over a hundred postcranial fossils and five famous well-preserved skulls, referred to as Dmanisi Skulls 1–5. The taxonomic classification of the Dmanisi hominins is somewhat unclear due to their small brain size, primitive skeletal features, and different morphologies of the five skulls. The most recently unearthed one revealed an individual with a long face and big teeth, but the smallest braincase of the five.

Some scientists say the Dmanisi fossils belong to “ Homo Erectus” . Others think they are closer to “Homo habilis”, the “H. erectus” predecessor. Many see them as a link between erectus and habilis. Yet others say they belonged to different species, “Homo ergaster” . Others still say they belong to a new species “Homo georgicus”.

The fossils were initially described Homo erectus or Homo ergaster (whether H. ergaster constitutes a separate species or subspecies of H. erectus is unresolved). The discovery of a massive jaw, D2600, in 2000 led researchers to hypothesize that more than one species of hominin was present at the Dmanisi site. In 2002, the jaw was designated as belonging to a new species Homo georgicus. Later analyses by a team of researchers concluded that all the skulls likely come from the same species and difference can be explained by age-related and sexual dimorphism. In 2006, the team said the Dmanisi hominins should be placed under Homo erectus taxon as Homo erectus georgicus or Homo erectus ergaster georgicus. The classification is still debated.

The Dmanisi finds have been indispensable to and changed scientists' understanding of early human evolution and migration patterns. Scientists believe early humans — likely Homo erectus — started migrating out of Africa around two million years ago. Ancient tools dated to around 2.1 million years have been discovered in modern-day China, but the Georgian sites are home to the oldest remains of early humans yet recovered outside Africa. Dmanisi would have been reachable from Africa through the Levantine corridor. Stone tools found at the site are like those found in Olduvai Gorge in Tanzania. [Source: Reuters]

Characteristics of the Dmanisi Hominins

Anatomically, the Dmanisi hominins display a wide range of traits — some related to homo erectus; others to modern humans; and other still harking back to pre-homo-erectus Homos and even Australopithecus. The length and morphology of the Dmanisi hominin legs were adapted to long-range walking and running. Their small body (145–166 centimeters; 4.8–5.4 feet) and brain size (545–775 cubic centimeters) were more comparable to H. habilis than to later H. erectus. The tallest individual was a bit shorter than other Homo erectus specimens. The tools found at the Dmanisi were less sophisticated than researchers had expected.

An article published in Nature in September 2007 said the Dmanisi fossils contained a surprising mix of primitive and modern traits: spines and lower back are similar to those in modern humans, which enabled them to walk fully upright and make long-distance treks, but arms that were more like those on australopithecines than people. The foot bones are thick suggesting that its owner was quite strong and spend a great deal of time walking around.

The skulls found at Dmanisi have straight brow ridges and nasal cavities like those of Homo erectus. But otherwise the skulls are small for erectus and rounded instead of angled at the back — traits associated with H. habilis. Morphological traits unifying all of the skulls, though the degree in which they are pronounced differ, include large brow ridges and faces.

Discovery of the Dmanisi Hominins

Dmanisi location

Dmanisi is 80 kilometers (50 miles) from the Georgian capital of Tbilisi. The first hint of interesting things there was the discovery of 1.8 million year tools there in 1991. Bones from African species such as ostriches and short-neck giraffes were also found there at that time. As of 2005, more than 50 bones from four “Homo erectus” individuals had been found [Source: John Fischman, National Geographic, April 2005]

In 1997, a 1.7 million-year-old jaw bone of a teenager was found beneath the ruins of the medieval castle of Dmanisi. In 1999, two skulls and stone tools were found at Dmanisi. The tools were similar to tools found Homo erectus sites in Africa. The bones were found between layers of basalt and ash deposited by volcanic eruptions and dated by examining grains of magnetic material that recorded the direction of the earth’s magnetic fields around 1.78 million years ago when the magnetic poles of the earth changed from north to south.

In 2002, scientists found the 1.77-million-year-old cranium of a toothless “old man” near Dmanisi. The skull held a brain that was a quarter smaller than the other skulls found there and had an apelike brow and huge canine teeth. Scientists also found stone chopping and scraping tools similar to those found Homo habilis sites in Africa. The discoveries were made by a team led by the Georgian David Lordkipanidze, a paleoanthropologist and director at the Georgian State Museum.

Lifestyle of the 1.8-Million-Year-Old Hominin Fossils in Georgia

In the Early Pleistocene Period, when the Dmanisi hominins lived, the climate of Georgia was more humid and forested than it is today, and comparable to a Mediterranean climate of southern California. The Dmanisi fossil site was located near an ancient lake shore, surrounded by forests and grasslands and home to a diverse fauna of Pleistocene animals. The favourable climate at Dmanisi might have acted as a refuge for homiThe Dmanisi bones were found on a wooded plateau thought to be a hunting ground for a number of predators. The site was surrounded on three sides by water and deep gorges — ideal for trapping prey. Bones of predators such as saber-tooth tigers wolves and hyenas and prey including deer, ostriches, giraffes and horses were all found at the site.

Stone tools have been found near deer bones with cut marks made by the tools, the earliest evidence of carnivorous hominins outside of Africa, supporting a theory meat eating allowed early humans to survive in northern latitudes, where plant could not provide food in the winter as they can in Africa, and was key to the migration out of Africa. Scientists are not sure how the humans obtained the meat.

Paleoanthropologist Philip Rightmire told National Geographic: “The hominins probably did more scavenging than hunting. They had only crude stone tools, is it is likely they chased predators away from carcasses. Their tools — stones flakes made by knocking stones together — were not sophisticated or deadly enough for hunting.”

Dmanisi

Humans were as likely to be hunted as the hunters. Teeth marks appear on at on at least one of the Dmanisi hominin bones, suggest it may have been fed on by another creature. Piles of stones found with Dmanisi bones are thought to have been kept for defense against larger predators or drive large animals away from carcasses that used to kill smaller prey.

The “toothless” old man is thought to have been about 40. Not only are there no teeth but all the sockets are smooth, filled in by bone that grew over the spaces, suggesting he continued to live for several years after his teeth fell out. In harsh survival of the fittest terms it is surprising that such a helpless individual would be allowed live to such an old age. It seems likely that someone cared for him: preparing soft food for him since he was unable to chew meat. This is regarded as the first evidence of compassion, a characteristic key to being a modern human. Skeptics say he could have been a tough old geezer. Studies of primates and other animals show that individuals can survive many years without teeth.

1.8-million-Year-Old Human Tooth Found At a Georgian Site Different from Dmanisi

In September 2022, scientists announced they had found a 1.8-million-year-old tooth belonging to an early hominin species at a site different from Dmanisi. The tooth was discovered by a research student near the village of Orozmani, around 100 km (62 miles) southwest of Tbilisi, 20 kilometers from Dmanisi. [Source: Reuters. September 10, 2022]

Reuters reported: The latest discovery provides yet more evidence that Georgia was likely one of the first places early humans settled after migrating out of Africa, experts said. "Orozmani, together with Dmanisi, represents the centre of the oldest distribution of old humans - or early Homo - in the world outside Africa," the National Research Centre of Archaeology and Prehistory of Georgia said, announcing the discovery of the tooth.

Giorgi Bidzinashvili, the scientific leader of the dig team, said he considers the tooth belonged to a "cousin" of Zezva and Mzia, the names given to two near-complete 1.8-million-year-old fossilised skulls found at Dmanisi. "The implications, not just for this site, but for Georgia and the story of humans leaving Africa 1.8 million years ago are enormous," said British archaeology student Jack Peart, who first found the tooth at Orozmani. "It solidifies Georgia as a really important place for paleoanthropology and the human story in general," he told Reuters. The oldest Homo fossils anywhere in the world date to around 2.8 million years ago - a partial jaw discovered in modern-day Ethiopia.

Implications of the 1.8-Million-Year-Old Hominin Fossils in Georgia

The Dmanisi fossils raise many questions about the Out of Africa theory. They seem to suggest that a creature more primitive than the relatively big-brained Homo Erectus was the first to migrate out of Africa and that a large brain was not necessary to accomplish break from Africa. They also raise question about the role of big brain in both the evolution and migration of hominins. Lordkipanidze told Reuters, “these are the earliest humans found outside of Africa. This is the time when our genus spread outside of Africa. Their heads are primitives, Their legs are very human-like.”

20120202-Dmanisi_cranium_D2700_(A).jpg
Dmanisi craniumSome scientists think the hominin at Dmanisi were the precursors of “Homo erectus”. They theorize some members of this hominin group migrated further east and gave rise to Peking Man and Java Man and other erectus fossils found in Asia while another group doubled back to Africa and developing into a more slender verison of erectus — “Homo ergaster”.

The tools and the bodies of the Dmanisi hominins were much less well suited for traveling and hunting than those of fully developed homo erectus, which had long legs, were relatively tall and had hand axes and sharp-edged stone tools.

The well developed legs of the fossils found at Dmanisi raise the possibility that hominins could have migrated out of Africa, learned to walk upright in Eurasia and then them migrated back to Africa. Lordkipanidze has suggested that “Homo erectus” might have even evolved dn Eurasia. Other scientists have been struck the similarity between the Dmanisi hominins and the hobbits found in Indonesia (See Hobbits).

Dmanisi Fossils Show the Diversity of Homo Erectus

Zach Zorich wrote in Archaeology magazine: Five skulls found within a 100-square foot area at the site of Dmanisi — the last of which (above) was recovered in 2005 — illustrate the diversity of Homo erectus individuals. The findings might lead to a recategorization of hominin remains dating back 1.8 to 1.5 million years.[Source:Zach Zorich, Archaeology magazine, January-February 2014]

“The analysis by paleoanthropologists of a skull dated to 1.8 million years ago, found at the site of Dmanisi in Georgia, could result in the recategorization of ancient hominin species. The skull, originally excavated in 2005, is the fifth one to be found within a 100-square-foot area. Taken together, these five individuals, although highly variable in appearance, are believed to provide a snapshot of Homo erectus, the first human species to migrate out of Africa.

“The most recently discovered skull has a small brain case, roughly half the size of that of the average modern human, but a very large face. According to existing standards of classification, if those two parts of the skull had been found as fragments at separate sites, they may have been assigned to two different species, says Christoph Zollikofer, a paleoanthropologist at the University of Zurich. Now, he says, the fact that the five skulls differ widely shows that Homo erectus individuals were far more diverse in appearance than many scientists had thought.

“Based on the range of skull shapes and sizes from Dmanisi, Zollikofer believes that all Homo fossils that date to roughly 1.8 to 1.5 million years ago likely belonged to a single human species. All African fossils of that time period, he explains, variably attributed to Homo habilis, Homo rudolfensis, and Homo ergaster, should be considered part of the species Homo erectus.

How Erectus Fossils from Georgia Have Changed Views of Human Evolution

Fossils found in Dmanisi, Georgia and dated to 1.8 million years ago suggests that half a dozen species of early human ancestor were actually all Homo erectus. Ian Sample wrote in The Guardian: “The spectacular fossilised skull of an ancient human ancestor that died nearly two million years ago has forced scientists to rethink the story of early human evolution. Anthropologists unearthed the skull at a site in Dmanisi, a small town in southern Georgia, where other remains of human ancestors, simple stone tools and long-extinct animals have been dated to 1.8 million years old. Experts believe the skull is one of the most important fossil finds to date, but it has proved as controversial as it is stunning. Analysis of the skull and other remains at Dmanisi suggests that scientists have been too ready to name separate species of human ancestors in Africa. Many of those species may now have to be wiped from the textbooks. [Source: Ian Sample, The Guardian, October 17, 2013]

skull from Dmanisi, Georgia

“The latest fossil is the only intact skull ever found of a human ancestor that lived in the early Pleistocene, when our predecessors first walked out of Africa. The skull adds to a haul of bones recovered from Dmanisi that belong to five individuals, most likely an elderly male, two other adult males, a young female and a juvenile of unknown sex. The site was a busy watering hole that human ancestors shared with giant extinct cheetahs, sabre-toothed cats and other beasts. The remains of the individuals were found in collapsed dens where carnivores had apparently dragged the carcasses to eat. They are thought to have died within a few hundred years of one another. "Nobody has ever seen such a well-preserved skull from this period," said Christoph Zollikofer, a professor at Zurich University's Anthropological Institute, who worked on the remains. "This is the first complete skull of an adult early Homo. They simply did not exist before," he said. Homo is the genus of great apes that emerged around 2.4 million years ago and includes modern humans. |=|

“Other researchers said the fossil was an extraordinary discovery. "The significance is difficult to overstate. It is stunning in its completeness. This is going to be one of the real classics in paleoanthropology," said Tim White, an expert on human evolution at the University of California, Berkeley. But while the skull itself is spectacular, it is the implications of the discovery that have caused scientists in the field to draw breath. Over decades excavating sites in Africa, researchers have named half a dozen different species of early human ancestor, but most, if not all, are now on shaky ground.

“The remains at Dmanisi are thought to be early forms of Homo erectus The Dmanisi fossils show that H erectus migrated as far as Asia soon after arising in Africa. The latest skull discovered in Dmanisi belonged to an adult male and was the largest of the haul. It had a long face and big, chunky teeth. But at just under 550 cubic centimetres, it also had the smallest braincase of all the individuals found at the site. The dimensions were so strange that one scientist at the site joked that they should leave it in the ground. The odd dimensions of the fossil prompted the team to look at normal skull variation, both in modern humans and chimps, to see how they compared. They found that while the Dmanisi skulls looked different to one another, the variations were no greater than those seen among modern people and among chimps.” The fossil is described in an October 2013 issue of Science.” |=|

Dmanisi Hominid Archaeological Site: Tentative UNESCO World Heritage Site

Dmanisi Hominid Archaeological Site: is on the UNESCO Tentative List. A Tentative List is an inventory of properties which each State Party intends to consider for nomination as a World Heritage Site. According to an unofficial text submitted by the State Party (the representative of the Georgian government) to UNESCO: “Recent excavations of Dmanisi have revealed an extraordinary record of the earliest hominid dispersal beyond Africa (1,75 million years ago). Several hominid individuals along with abundant well-preserved remains of fossil animals and stone artefacts have been found. The Dmanisi specimens are the most primitive and small-brained humans found outside of Africa to be attributed to Homo erectus sensu lato, and they are the closest to the presumed Homo habilis-like stream. It is widely recognized that Dmanisi discoveries have changed scientist's knowledge concerning the migration of homo from Africa to the European continent. [Source: UNESCO World Heritage Site website =]

“Dmanisi is located about 85 km south-west of Tbilisi buried below the ruins of the medieval town of Dmanisi, in the Mashavera River Valley, which drains the Javakheti volcanic chain to the west of the site. The site is situated on a promontory elevated about 80 m above the confluence of the Mashavera and Pinezaouri River valleys. Just prior to the occupations at Dmanisi, the Mashavera Valley was filled by 80-100 m of mafic lavas that formed the Mashavera Basalt. This basalt dammed the Pinezaouri Valley, forming a lake ca. 1 km long immediately south of the site.=

1.8 million-year-old tools from Dmanisi

“The hominid and artefact-bearing deposits (up to 3 m thick) directly cover the original surface of basalt layer (Mashavera basalt) and are magnetically normal, dated ca. 1.8±0.01 Ma and correlated with Olduvai subchron. No evidence of erosion and minimal weathering of its surface suggest that the basalt was quickly buried by volcanic ash and fossiliferous sediments. Presently two main stratigraphic units are distinguished in the exposed sections: Stratum A): bearing vast majority of the faunal materials and all hominid remains - consisting of pyroclastic silt and fine sand with weak pedogenic structure and pedogenic carbonates in the upper part; and Stratum B) with highest densities of stone artefacts but poorer with fossils - consisting of weathered volcanic silts and sands, with dark grey ash in the middle of the unit and prominent basal grey ash. =

“These two layers are separated by calcareous horizon that has halted further diagenetic damage and compaction in stratum A thus allowing remarkable fossil preservation. The structure and thickness of calcareous horizon is variable in different locations and is posing questions concerning sedimentation process that need to be clarified. Central geographic location, dramatic biodiversity, and the extremely dynamic geologic evolution of the Caucasus region on the Neogene-Quaternary boundary, permits to generate not only new geologic information, but also new protocols for expanding stratigraphic studies and archaeological site surveys by teams working in the important adjacent regions of the Levant, south-eastern Europe, and south-central Asia. =

“Dmanisi archaeological material is well dated by science-based methods to about 1.75 million years ago. The Lower Palaeolithic site has the fascinating and unusual context of being located underneath the medieval ruins of an ancient town and fortress frequently visited by tourists. In fact, the Palaeolithic excavations have all been conducted from within the walls of ancient structures. From point of view of the early palaeontology, the site has been known since 1983 when fossilized bones of extinct animals were found by medieval archaeologists in the walls of household pits of the Dmanisi medieval town. Immediately, it was clear that we were dealing with late-middle Villafranchian fauna, of approximately 1.8-1.7 million years in age. Then in 1984, with the discovery of primitive stone tools, a new page started not only in the history of the site excavations, but of one of the major events in human evolution: the peopling of the northern latitudes and eventually the entire globe. Dmanisi is the key to deciphering Homo's origins and for tracing the earliest Pleistocene hominid migrations. Dmanisi have an iconic position in the discovery and demonstration of human evolution. =

Recent excavations of Dmanisi have revealed an extraordinary record of the earliest hominid dispersal beyond Africa. Several hominid individuals (4 skulls, 3 of them with maxillas, 4 mandibles, 16 isolated teeth and 24 post-cranial elements), along with abundant well-preserved remains of fossil animals and stone artefacts have been found. In 2003-04 field season another new hominid mandible, with fascinating pathologies having implications for the evolution of human disease and also social behaviour has been discovered. It was also found a new tibia and talus (ankle) bone, which will allow accurate estimations of body size, body proportions and locomotory behaviour. This is the richest and most complete collection of indisputable early Homo remains outside of Africa with good stratigraphic context, now well dated to about 1.75 million years ago. At Dmanisi, there is also clear potential to define and compare records of serial occupations in single locality.” = Image Sources: Wikimedia Commons

Text Sources: National Geographic, New York Times, Washington Post, Los Angeles Times, Smithsonian magazine, Nature, Scientific American. Live Science, Discover magazine, Discovery News, Times of London, Natural History magazine, Archaeology magazine, The New Yorker, Time, Newsweek, BBC, The Guardian, Reuters, AP, AFP and various books and other publications.

Last updated April 2024