HOMININS

Dmanisi is the most productive Lower Paleolithic site in the world, yielding a minimum of 5 individuals represented by over 60 cranial and post-cranial remains.  These individuals span different developmental stages (subadult, adult and old adult) and demonstrate the morphological diversity within the Dmanisi paleodeme [fig. below].

The hominin remains of Dmanisi share morphological similarities with early Homo in some traits related to small cranial capacity, as well as a more forward projecting face and U-shaped mandible.  The post-cranial hominin remains from Dmanisi constitute the best-preserved fossils for this period [fig. below].  These small bodied hominins were fully bipedal, but their upper limbs retain primitive features adapted to different movements, especially upward rotation of the arm.

One of the most remarkable of the Dmanisi hominin finds is the toothless cranium and mandible of an old adult [fig. to the left].  This individual lived several years without teeth before death. This person could eat only food that did not require heavy chewing, maybe using soft plants and soft animal parts such as marrow and brains, and perhaps relied on others in the social group for procuring and processing food. This edentulous (toothless) specimen raises interesting questions regarding social structure and subsistence strategies of early Homo. This is the earliest case of severe masticatory (chewing) impairment in the hominin fossil record.

The Dmanisi hominin fossils have raised several questions among scientists about hominin dispersals and evolution.  These finds suggest movement of hominins from Africa through the Levantine corridor to the Caucasus and finally to southern Asia and Far East, much earlier than previously thought.

The first mandible, D211, is missing both rami, but the U-shaped corpus is quite well preserved.  All 16 teeth are present and show a low degree of wear.  This mandible is probably associated with the skull D2282.

The specimen D2282 preserves much of the face and cranial vault but has undergone lateral and dorso-ventral post-mortem deformation. This individual is small, with an endocranial capacity of 650 to 660 cm³. It exhibits gracile muscle attachment areas and less well-developed cranial sutures.  The well-demarcated cranial sutures allow us to say that it was either an older subadult or young adult, and possibly a female. This skull is probably associated with the mandible D211.

Although the facial morphology is missing, the braincase of cranium D2280 is complete, and small in size like the rest of the Dmanisi hominins, with a endocranial capacity of 775cm3. This skull has a thickened brow ridge, a strong angular torus and deeply incised nuchal lines, and could be considered a male individual.

The mandible D2600 was found just above the Masavera basalt. This mandible is unusually large: the whole length is 126.9 mm, the corpus width is 92.4 mm and the height of the ascending ramus is 91 mm. The teeth are worn down to the roots, which are remarkably well-developed.  One peculiarity of this mandible is the double-rooted P3s.  The morphological differences and remarkably large size compared to the rest of the Dmanisi hominins, has led some scientists propose to separate it as new species - H. georgicus.  Alternatively, this could be a case of intrapopulational variation and/or a robust male of the same paleodeme. 

Skull D2700 with the associated mandible D2735 is a subadult, with partially erupted third molars. Some isolated teeth also fit the skull. Some damage can be observed on the orbital walls, the fragile elements of the interorbital region and the anterior part of the maxillae. The mastoid process is eroded and the zygomatic arches are broken. Otherwise, the specimen is complete and in very good condition. The cranial capacity is 600 cm³.

The edentulous skull D3444 and associated mandible D3900  has a cranial capacity of 650 cm³ is clearly an adult, displaying many of the features typical of males of the genus Homo: the glabellar region is broad and prominent, the supraorbital tori are projecting, the mastoid crests are strongly developed and the mastoid portion of the temporal bone is laterally inflated; lastly, the upper face is relatively broad and the cheeks are massive. The condition of the alveoli indicate that this individual lived several years after losing its teeth: the tooth sockets (alveolis) and alveolar arch is completely resorbed and atrophied. Hypotheses for the survival of this individual include the utilization of softer plants, extraction of the animal brain and marrow with stone tools, or assistance and care from other individuals.

Cranium D4500 associated with the D2600 mandible represents the fifth individual (referred as Skull 5) found at Dmanisi and is the world’s first completely preserved adult hominid skull from the early Pleistocene (1.77 million years ago). Skull 5 shows a combination of features hitherto unknown for early Homo. It has the smallest braincase of all Dmanisi individuals (546ccm), but the largest and most protruding face, and the biggest teeth. Hence it considerably expands the range of morphological variation seen at Dmanisi. Together with the four Dmanisi individuals found earlier, it provides first insights into patterns of variation in a paleopopulation (ancient population) of early Homo. The Skull 5 individual probably had a long and eventful life. Its big teeth are worn down to stumps, such that it suffered from tooth root infections. Its deformed right cheek bone testifies a badly healed fracture. The left mandibular joint is deformed as a consequence of a chronic arthritic inflammation.

D4167 is the complete right femur, which together with D3901 (first complete fossil hominin tibia) and D3481 (right patella) create the most complete lower limb of early Homo recovered so far [fig. to the left].

D4507 is the left adult humerus, D2680 and D2715 are the laft and right subadult humeri. Humeri in both iondividuals is different from modern humans, but similar to Plio-Pleistocene hominins [fig to the left]. 

Photographs from top to bottom: Georgian National Museum (collage), late Guram Bumbiashvili (D3444) and Lordkipanidze et al 2007 (postranial).