Dmanisi, GeorgiaEurope

The region of Kvemo Kartli is home to the town and excavation site of Dmanisi, Georgia, which is located approximately 96 kilometers southwest of the nation's capital of Tbilisi. In the past, Dmanisi grew as an important commercial town, a hub for trade routes along the Silk Road with bright and lively culture before ultimately being destroyed in war during the 14th century. Today, Dmanisi is home to approximately 2,600 people and holds ruins of medieval castles and cathedrals. In addition, Dmanisi holds a much more extensive history of humans than just ruins. It has been a site of archaeological interest since the 1930's and in the 1980's the site began systematic excavations.  The first fossil found at this site was a tooth belonging to a rhinoceros that lived in the Plio-Pleistocene era and has thus shown that this site withholds clues about the early Pleistocene. In 1991, a hominin mandible was found and since then, five nearly complete hominin skulls were found that date to be the oldest Homo fossils outside of Africa (Vekua & Lordkipanidze, 2010).

Surrounding the Dmanisi site, 1 km away are the Masavera and Pinezaori Rivers. This excavation site is characterized by deep river canyons and a promontory created by the two rivers (Gabunia et al., 2000). This area was also previously shaped by basaltic lava that flowed down into the river valleys. The resulting base of the promontory is made of volcanic sedimentary rock resulting in the Masavera Basalt. The Masavera Basalt was the primary indicator of aging based on Argon dating. This sediment has dated faunal findings and artifacts to as old as approximately 1.8 million years ago. Within all stratigraphic layers, stone tool and faunal fossils have been found. Paleobotanical evidence from pollen, phytoliths, and fossil fruits also indicates that Dmanisi previously held a diversity of habitats like mixed woodlands, savannahs, and grasslands (Hemmer et al. 2011, Blain et al. 2014). Further, this data has shown that Dmanisi has become more arid with time. The terrain in Dmanisi around 1.8 million years ago was characterized by more wet conditions, which has since then turned more arid and dry.

The medieval cellars of Dmanisi held a plethora of animals fossils, stone tools, human artifacts, and of course, hominin fossils.The hominin excavations were led by anthropologist David Lordkipanidze of the Georgian National Museum. These specimens are dated to be approximately 1.77 million years old and are thus some of the oldest hominin species to be found outside of Africa (Lordkipanidze et al., 2006). The five hominin skulls that Lordkipanidze’s team founded hold varying morphologies which call into question, to which hominin species do they belong? These specimens differ in cranial shape, cranial capacity, supraorbital torus prominence and more (Rightmire et al., 2018). They also vary in age and sex, which some experts argue is the reason for their differing characteristics. Do these specimen belong to one species or multiple taxa? This has been a topic of great debate among physical anthropologists. The fifth and most recently founded skull D4500 also nicknamed "Skull 5" holds a mosaic of traits that characterize different Homo species like H. erectus, H. habilis, and H. rudolfensis (Lordkipanidze et al., 2013). This specimen alone calls into question the origination of the Hominin lineage and dispersal from Africa, another topic of debate that the skulls from Dmanisi have provoked.

            Dmanisi also holds many stone tools and artifacts from the Upper Pliocene and Lower Pleistocene, the first of which were founded in 1982 by archaeologists led by Kopaliani. These tools greatly resemble Oldowan tools but are ultimately different in the makeup of their raw materials (Gibbons, 2016). Found within Dmanisi assemblage are flakes, cores, coretools, and hammerstones. These tools are dated to be approximately 1.85 million years old thus pushing back archaeological evidence for occupation back to 1.85 million years old (Ferring et. al., 2011). This indicates that there was colonization at Dmanisi dating to before the Dmanisi fossils found and thus was a significant area for colonization in the Eurasia region. This finding could also indicate that colonization at Dmanisi appeared before Homo erectus appears in the African fossil record.

The faunal assemblage found at Dmanisi is extremely diverse as a result of its variety of habitats. Remains of carnivores, reptiles, amphibians, rodents, and varying sizes of mammals were found at this site. Animal fossils were found to have cut marks on their bones indicating that the Dmanisi hominins were meat eaters and they used their stone tools to process meat from animals carcassses. Around 2000 vertebrate fossils were found at this site. The diverse fossil fauna found aids in creating a reconstruction of the life surrounding the found hominins which further illustrates the diverse habitats Dmanisi once held.

 Since the discovery of the five peculiar hominin specimens, excavations at Dmanisi have continued. The Dmanisi Research Team, led by Lordkipanidze, consists of physical anthropologists, archeologists, geologists, paleontologists, taphonomists, and palynologists.

 

Dmanisi is most famous for the five skulls found at the site. There has been controversy as to which species the Dmanisi remains belong to. It has been concluded that there are too many differences in the skull for the specimens to be Homo habilis (Henderson, 2015). Comparisons of the skulls and mandibles have been compared to other Homo erectus remains, and suggest that the Dmanisi remains belong to early Homo erectus (Henderson, 2015).

Specimen D2280 is remarkable because it provides an almost entirely complete braincase. This individual’s cranial capacity was 775 cc (Rightmire et al., 2006). The large nuchal crest and supraorbital tori indicate that it was likely male (Rightmire et al., 2006). This skull also shows keeling along the sagittal suture (Rightmire et al., 2006).

Specimen D2282 was a young adult (Rightmire et al., 2006). Its cranium is less complete, as the temporal and occipital have been damaged and distorted with time, and most of the orbital and zygomatic are missing (Rightmire et al., 2006). However, a mandible has been paired with this skull. The cheek teeth of this mandible are well worn and the mandible is missing the third molar on both sides (Rightmire et al., 2006).

 Specimen D3444 has a cranial capacity of roughly 625 cc (Lordkipanidze et al., 2006). Like the other specimens, it has a prominent sagittal keel (Lordkipanidze et al., 2006). The supraorbital torus was prominent (Lordkipanidze et al., 2006). This specimen is remarkable because of the mandible that has been paired with it. This individual was most likely advanced in age, as indicated by substantial tooth loss (Lordkipanidze et al., 2006).  

 Specimen D2700 is a young adult; its third molars are only partially erupted (Rightmire et al., 2006). Its cranial capacity is 600 cc, and it is more similar in size to specimen D2282, who was also an adolescent at the time of death (Rightmire et al., 2006). Like skull 2282, 2700 has pronounced supraorbital ridges and a large zygomatic arch (Henderson, 2015).

 Specimen D4500 is the most recent discovery at Dmanisi. Its cranial capacity is approximately 545 cc (Lordkipanidze et al., 2013). The nuchal crest and zygomatic arches of this skull are very robust (Lordkipanidze et al., 2013). These features, in addition to the prominent supraorbital tori and lambdoid hump, suggest that this individual was male (Lordkipanidze et al., 2013).

 There are postcranial remains from three individuals from the same stratigraphic placement, indicating that they were placed in the area around the same time (Lordkipanidze et al., 2007). It is difficult to tell which postcrania are from which of the five individuals.

 Part of an adult’s scapula was found, with an intact and cranially-oriented glenoid cavity (Lordkipanidze et al., 2007). This orientation of the glenoid cavity is likely a retention from the specimen’s ancestors, as it is typically used for swinging through trees with the arms upright as in the australopithecines. There are several incomplete clavicles that seem to be similar to anatomically modern Homo sapiens (Lordkipanidze et al., 2007). Humeri from two juveniles and one adult have also been found within the area; the shaft of the humeri is nearly straight and the lateral epicondyle is higher than the medial condyle, which is similar to australopithecines and apes (Lordkipanidze et al., 2007).

There are cervical, thoracic, and lumbar vertebrae remains present at Dmanisi. All of the vertebrae are wider transversally, similar to modern humans (Lordkipanidze et al., 2007).

The bones of the leg are some of the most complete early Homo specimens found to date. A complete right femur was found, with intact linea aspera, prominent greater trochanter, and bicondylar angle present (Lordkipanidze et al., 2007). The medullary canal is thin, similar to Homo erectus and smaller than modern humans (Lordkipanidze et al., 2007). A complete right patella was also found (Lordkipanidze et al., 2007). Dmanisi boasts the first complete hominin patella, which is robust compared to modern humans (Lordkipanidze et al., 2007).

While it is uncommon to find bones of the foot, Dmanisi has several foot bones well preserved. A left talus similar to modern humans was recovered, as well as several adult metatarsals, all of which fall within the range of variation for modern humans.

The evidence from Dmanisi has sparked a lively debate among anthropologists, mainly over which species the Dmanisi remains belong to. The skulls exhibit traits similar to both H. habilis and H. erectus. It has now been concluded that the specimens are all from the same species, and exhibit variation that falls within the norm for a species. The skulls are now believed to be early H. erectus specimens, and are some of the first H. erectus individuals who travelled out of Africa (Zorich, 2014).

The Dmanisi site is located around 85 km southwest of Tbilisi, about 1 km above the Masavera and Pinezaouri Rivers on top of an erosional spur of the Masavera Basalt. The rivers cut canyonlike gorges in basaltic lava, resulting in the formation of the elongated cape. The plateau is about 90 m above the river surface. Over 8000 Oldowan tools have been recovered from all stratigraphic layers until now and the stone tools are manufactured from about 40 to 50 different raw materials (Henderson).

Archeological excavations in Dmanisi began in 1936 directed by L. Muskhelishvili. Archeologist Vakhtang Japaridze visited Dmanisi again in 1960 until his death in 1993. The expedition was then led by J. Kopaliani, and in 1982 the archeologists came across pits cut in compact sandy clay. After cleaning these pits, numerous bones of fossilized animals were found (Vekua and Lordkipanidze 159). While large amounts of fossil material were being gathered, stone tools were also found with bones. The stone tools and fossil animals were confirmed to be from the Upper Pliocene to the Lower Pleistocene.

The Dmanisi stone industry is identical with the Olduvai industry that was discovered in Africa. Artifacts such as rare choppers, chopping tools, scrappers, and flakes were made entirely from local basalt sources using Oldowan technology. These artifacts are similar to the pre-Acheulean assemblages of Easy Africa from 2.4 Ma (Gibbons 959). They all have simple core-flake technologies, but the number of raw materials used is what makes Dmanisi stand out from other sites.

The alluvium is divided into two stratigraphic units, Unit A and Unit B. Unit A is thick basaltic sand that measures up to 50cm. Unit B is brown sand and has concentrated pebble to small cobble colluvial. Stone tools are found in both Unit A and Unit B cavities, but most of them sit in Unit B and are stratigraphically higher than the hominoid remains (Gabunia, et al 160). The majority of the certain artifacts are flakes and represent late stages in the reduction process. Most of the core tools are unifacially worked and spheroids and subspheroids are absent. There were also no handaxes or cleavers found, but there were two possible hammerstones reported. Due to the size classes, tool types and the absence of many hammerstones or small flakes, it is argued that Unit B of Dmanisi could not be a knapping site. It is suggested that the raw materials were selected elsewhere, and the finished products were brought back to their site.

The tools found at Dmanisi are differentiated into two different categories. There are manuports, tools that are unmodified, which include broken cobbles, cobble fragments, and cobbles with single flake scars. There are also tools that have been strategically modified for a specific purpose, including cores, choppers, and flake tools (Henderson). Although these tools are simple, they somehow enabled these hominins to possibly eat meat, which allowed them to survive in new habitats where they couldn’t distinguish between toxic and edible plants.

In addition to the fossil hominin skull found at the Dmanisi excavation site, approximately 2000 identifiable vertebrate fossils were discovered alongside them as well.  The paleo-landscape of the area surrounding the site represented diversity, as it encompassed open grasslands, a forested valley floor, and a tree savannah.  The surrounding area provided habitats for carnivores to thrive in, as well as reptiles, amphibians, and other small and large mammals.   

Amphibian and Reptile remains: at least six taxa have been found at this location, that are comprised of a green toad, Greek tortoise, green lizard, four-lined snake, colubrid, and water snake.  All of these taxa aren’t extinct, hence they can contribute greatly to a recreation of the paleo-landscape. These remains were recovered from the B1 level of the excavation site, and a total of 118 elements were recovered.  We can learn a lot from the presence of these taxa, as they can be sources of information regarding temperature and precipitation, as they are all ectothermic vertebrates.  They are good indicators of the climate at the time, as they are unable to persist in environments without sufficient precipitation.  

Mammals: Dmanisi was home to a variety of small and large mammals.  The small mammals were mostly comprised of gerbils and hamsters.  These small mammals are typical for this sort of climate, as they are well-adjusted to thrive in warm, arid climates, such as Dmanisi’s.  On the larger side, Dmanisi’s faunal assemblage is mostly comprised by that of Deer.  Mammoths, archaic rhinos, archaic zebra, and other dry-adapted bovids also inhabited these areas (Mammuthus meridionalis, Stephanorhinus etruscus, Equus stenonis, Ursus etruscus, Megantereon cultridens, Pachycrocuta perrieri), but not in large numbers.  The mosaic of habitats and paleo-environments that surrounded Dmanisi have facilitated this rich faunal assemblage around the fossil site.

Carnivores: Recent morphological analysis have shown that elements from a nearly complete cat foreleg fossil has been retrieved from the Dmanisi excavation site, indicating that a prime source of food may have been present for the early hominin.  Acinonyx pardinensis, a stoutly built archaic cheetah likely traversed the open grasslands in and around Dmanisi, and likely served as a prime candidate for early hominin hunting and scavenging and food source.

The faunal assemblage in paleo-Pleistocene Dmanisi was quite diverse, and had provided many options for early Homo species to use as food resources.  

The site of Dmanisi is within the Kevemo Kartli region of Georgia.  It is located about 90 kilometers southwest of Tbilisi, and about 1 kilometer above the junction of the Masavera and Pinezaouri rivers.  It is also upon an erosional spur of the Masavera Basalt, and 80 meters above present-day water levels.  “The canyons of the Masavera and Pinezaouri Rivers and archaeological excavation pits in the overlying sediments expose about 80 m of Masavera Basalt, which fills a paleo valley overlain by about 2.6 m of fossiliferous, volcaniclastic alluvium” (Gabunia et al., 2000).  The excavations conducted by the search team consisted of 1-m gridded sites and test pits, which were excavated all the way down to the surface of the underlying basalt.  The total excavation encompassed an area of approximately 150 square meters.  By the time of this study (2000), over 2000 identifiable vertebrate fossils have been discovered at this site, as well as over 1000 stone artifacts were recovered.  Historically, it was a defensible position during medieval times, and that is evidenced by the abundance of collapsed masonry structures at the site.

The Dmanisi deposits are adjudicated to be placed within the latest Pliocene, and this consideration was made based off Argon dating on the Masavera Basalt that lies beneath the fossil-bearing sediments.  The result of the Argon dating was the placement of the Masavera Basalt at around 1.8 million years ago (Ma).  The site itself is at an incline of 69º, and the fossil-bearing sediments are at an incline of 58º.  There are two divisions of stratigraphy within the Dmanisi site, designated as A and B, and are observed in this way due to their differences in “lithology and erosional and pedologic boundaries” (Gabunia et al., 2000).  The lowest unit, A1, was composed primarily of glass, and loamy sand, and was up to 50 cm thick, and has shown little to no evidence of erosion.  A2, our second layer, has an erosional surface at its upper boundary, creating a contact point between A2 and B1 that is an abrupt erosional surface.  B1 is mostly loamy sand and concentrated pebbles.  B2 is a thick loamy sand.  Archaeological excavations at Dmanisi in the late 90s produced two crania that are believed to belong to hominids, one being the D2280, and the other being the D2282.  These two skulls were found from the same “stratigraphic level and excavation pit” as a hominid mandible discovered in the early 90s.  The relative proximity between these findings is suggestive of the fact that maybe these populations were possibly living in communities.

Located in the Masavera River Valley of Southeast Georgia, Dmanisi stands as the oldest Early Paleolithic site discovered out of Africa. This site is located between the Masavera and Pinezauri Rivers and contains many volcanistic and marine rocks which suggests lava flow and the deposits of many faunal remains. Given the location and analyses of floral and faunal remains, the evidence suggests that during the hominin presence at Dmanisi, the climate was warm and dry.

The flora and fauna, which is based off of amphibian and reptile remains, suggests the prevalence of arid environments, which can appear similar to the present-day Mediterranean climate. Evidence also shows an important water stress suggesting a period of increased aridity simultaneous with human occupations of Dmanisi. While appearing to have a Mediterranean type climate, the Dmanisi had an estimated mean annual temperature (MAT) of 13.1° ± 2.4° C, and a mean annual precipitation (MAP) of 635mm, ± 191 mm, thus had a high atmospheric temperature range. Seasons in Dmanisi were not very distinct except between summer and winter. The summers were hot and the winters were cold, with a possible average winter temperature of around 2.7°C or 36.9°F. The precipitation was scarce and the precipitation distribution was extremely irregular, with a particularly dry summer. Archaeobotanical records, which include measurements of pollen, phytoliths and fossil fruits, indicate a well grassed environment, also suggesting that the Dmanisi hominins occupied a relatively open environment consisting of steppe forests, which are largely characterized by a dry and temperate or arid climate and grasslands.

The paleoecological results are consistent with the water stress index which indicates the presence of dry and temperate conditions and local open vegetation. The analyses of flora and the identification of most of the plants give evidence that the Dmanisi flora had short biological cycles, such as annual or biannual, which confirms their pioneer-like behavior in the sunny and arid conditions.

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Ferring, R., O. Oms, J. Agusti, et al. (2011). Earliest Human Occupations at Dmanisi (Georgian Caucasus) Dated to 1.85-1.78 Ma. Proceedings of the National Academy of Sciences 108(26): 10432–10436

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