The Plio-Pleistocene site of Dmanisi, Georgia, has yielded a rich fossil and archaeological record documenting an early presence of the genus Homo outside Africa. Although the craniomandibular morphology of early Homo is well known as a result of finds from Dmanisi and African localities, data about its postcranial morphology are still relatively scarce. Here we describe newly excavated postcranial material from Dmanisi comprising a partial skeleton of an adolescent individual, associated with skull D2700/D2735, and the remains from three adult individuals. This material shows that the postcranial anatomy of the Dmanisi hominins has a surprising mosaic of primitive and derived features. The primitive features include a small body size, a low encephalization quotient and absence of humeral torsion; the derived features include modern-human-like body proportions and lower limb morphology indicative of the capability for long-distance travel. Thus, the earliest known hominins to have lived outside of Africa in the temperate zones of Eurasia did not yet display the full set of derived skeletal features.

The site of Dmanisi, Georgia, has yielded an impressive sample of hominid cranial and postcranial remains, documenting the presence of Homo outside Africa around 1.8 million years ago. Here we report on a new cranium from Dmanisi (D4500) that, together with its mandible (D2600), represents the world's first completely preserved adult hominid skull from the early Pleistocene. D4500/D2600 combines a small braincase (546 cubic centimeters) with a large prognathic face and exhibits close morphological affinities with the earliest known Homo fossils from Africa. The Dmanisi sample, which now comprises five crania, provides direct evidence for wide morphological variation within and among early Homo paleodemes. This implies the existence of a single evolving lineage of early Homo, with phylogeographic continuity across continents.

Archaeological excavations at the site of Dmanisi in the Republic of Georgia have uncovered two partial early Pleistocene hominid crania. The new fossils consist of a relatively complete cranium and a second relatively complete calvaria from the same site and stratigraphic unit that yielded a hominid mandible in 1991. In contrast with the uncertain taxonomic affinity of the mandible, the new fossils are comparable in size and morphology with Homo ergaster from Koobi Fora, Kenya. Paleontological, archaeological, geochronological, and paleomagnetic data from Dmanisi all indicate an earliest Pleistocene age of about 1.7 million years ago, supporting correlation of the new specimens with the Koobi Fora fossils. The Dmanisi fossils, in contrast with Pleistocene hominids from Western Europe and Eastern Asia, show clear African affinity and may represent the species that first migrated out of Africa.

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The early Pleistocene colonization of temperate Eurasia by Homo erectus was not only a significant biogeographic event but also a major evolutionary threshold. Dmanisi's rich collection of hominin fossils, revealing a population that was small-brained with both primitive and derived skeletal traits, has been dated to the earliest Upper Matuyama chron (ca. 1.77 Ma). Here we present archaeological and geologic evidence that push back Dmanisi's first occupations to shortly after 1.85 Ma and document repeated use of the site over the last half of the Olduvai subchron, 1.85-1.78 Ma. These discoveries show that the southern Caucasus was occupied repeatedly before Dmanisi's hominin fossil assemblage accumulated, strengthening the probability that this was part of a core area for the colonization of Eurasia. The secure age for Dmanisi's first occupations reveals that Eurasia was probably occupied before Homo erectus appears in the East African fossil record.Lower Paleolithic | paleoanthropology I n recent years, paleoanthropologists have intensified the search for evidence for one of the most significant events in human evolution: the dispersal of early Homo from Africa to Eurasia. That Homo erectus was the first hominin to leave Africa and colonize Eurasia has been accepted by paleoanthropologists for over a century. However, models that linked the first African exodus to increases in stature, encephalization, and technological advances (1-3) have been challenged by discoveries at Dmanisi (4). Dmanisi is located in the southern Georgian Caucasus (41°20'10"N and 44°20'38"E), 55 km southwest of Tbilisi (Fig. 1). The prehistoric excavations at Dmanisi have been concentrated in the central part of a promontory that stands above the confluence of the Masavera and Pinasauri rivers. Lower Pleistocene deposits are preserved below the Medieval ruins and above the 1.85-Ma Masavera Basalt (Fig. 1). Those excavations yielded numerous exceptionally preserved hominin fossils. Stratigraphic studies revealed that that all of those hominin fossils are from sediments of stratum B, dated to ca. 1.77 Ma, based on 40 Ar/ 39 Ar dates, paleomagnetism, and paleontologic constraints (4, 5). In the main excavations, no artifacts or fossils have been found in the older stratum A deposits, which conformably overlie the Masavera Basalt. Dmanisi's rich collection of hominin fossils reveals a population with short stature and cranial capacities of only 600-775 cc (4-9). Artifact assemblages are all indicative of a Mode I technology, with no bifacial tools (10). Recently completed testing in the M5 sector of Dmanisi has yielded in situ artifacts and faunal remains from the older stratum A deposits, pushing back Dmanisi's occupational history into the upper Olduvai subchron. These findings indicate that African and Eurasian theaters for the evolution of early humans had been established even earlier than thought previously, with implications for the age of dispersals not only within Eurasia but also between Eurasia and Africa. This article describes t...