RESUMEN
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.
Asunto(s)
Evolución Biológica , Cara/anatomía & histología , Fósiles , Hominidae/anatomía & histología , Cráneo/anatomía & histología , Animales , Encéfalo/anatomía & histología , Dentición , Georgia (República) , Hominidae/crecimiento & desarrollo , Humanos , Tamaño de los Órganos , Filogeografía , Cráneo/crecimiento & desarrollo , Base del Cráneo/anatomía & histología , Base del Cráneo/crecimiento & desarrollo , Hueso Temporal/anatomía & histología , Hueso Temporal/crecimiento & desarrolloRESUMEN
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.
Asunto(s)
Hominidae , Animales , Antropología , Fósiles , Georgia (República) , Historia Antigua , Humanos , PaleontologíaRESUMEN
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.
Asunto(s)
Fósiles , Hominidae/anatomía & histología , Adolescente , Animales , Tamaño Corporal , Georgia (República) , Historia Antigua , Hominidae/clasificación , Hominidae/fisiología , Humanos , Huesos de la Pierna/anatomía & histología , Locomoción , EsqueletoRESUMEN
Newly discovered Homo remains, stone artifacts, and animal fossils from Dmanisi, Republic of Georgia, provide a basis for better understanding patterns of hominin evolution and behavior in Eurasia ca. 1.77 million years ago. Here we describe a fourth skull that is nearly complete, lacking all but one of its teeth at the time of death. Both the maxillae and the mandible exhibit extensive bone loss due to resorption. This individual is similar to others from the site but supplies information about variation in brain size and craniofacial anatomy within the Dmanisi paleodeme. Although this assemblage presents numerous primitive characters, the Dmanisi skulls are best accommodated within the species H. erectus. On anatomical grounds, it is argued that the relatively small-brained and lightly built Dmanisi hominins may be ancestral to African and Far Eastern branches of H. erectus showing more derived morphology.
Asunto(s)
Encéfalo/anatomía & histología , Hominidae/anatomía & histología , Cráneo/anatomía & histología , Adulto , Animales , Arqueología , Remodelación Ósea , Cefalometría , Fósiles , Hueso Frontal/anatomía & histología , Georgia (República) , Historia Antigua , Hominidae/clasificación , Humanos , Masculino , Mandíbula/anatomía & histología , Apófisis Mastoides/anatomía & histología , Maxilar/anatomía & histología , Hueso Occipital/anatomía & histología , Tamaño de los Órganos , Paleontología/métodos , Filogenia , Caracteres Sexuales , DienteRESUMEN
Evidence for ancient hominin occupation in Eurasia comes from Dmanisi in the Georgian Caucasus. Stratigraphic and sedimentological arguments, geochemical observations, paleomagnetic sampling and radiometric dates all point to the conclusion that bones and artifacts were deposited at this site during a brief interval following the close of the Olduvai Subchron (1.77 million years ago). In this report we present further descriptive and comparative studies of the D2280 braincase, the D2282 partial cranium, now linked with the D211 mandible, and the skull D2700/D2735. The crania have capacities ranging from 600 cm3 to 775 cm3. Supraorbital tori and other vault superstructures are only moderately developed. The braincase is expanded laterally in the mastoid region, but the occiput is rounded. The pattern of sagittal keeling is distinctive. D2700 displays a prominent midfacial profile and has a very short nasoalveolar clivus. Also, the M3 crowns are reduced in size. Although there is variation probably related to growth status and sex dimorphism, it is appropriate to group the Dmanisi hominins together. With the possible exception of the large D2600 mandible, the individuals are sampled from one paleodeme. This population resembles Homo habilis in brain volume and some aspects of craniofacial morphology, but many of these features can be interpreted as symplesiomorphies. Other discrete characters and measurements suggest that the Dmanisi skulls are best placed with H. erectus. There are numerous similarities to individuals from the Turkana Basin in Kenya, but a few features link Dmanisi to Sangiran in Java. Some traits expressed in the Dmanisi assemblage appear to be unique. Reconstructing the evolutionary relationships of these ancient populations of Africa and Eurasia is difficult, as the record is quite patchy, and determination of character polarities is not straightforward. Nevertheless, the evidence from anatomical analysis and measurements supports the hypothesis that Dmanisi is close to the stem from which H. erectus evolved.
Asunto(s)
Evolución Biológica , Fósiles , Hominidae/anatomía & histología , Cráneo/anatomía & histología , Animales , Antropología Física , Cefalometría , Dentición , Georgia (República) , HumanosRESUMEN
The site of Dmanisi in the Eurasian republic of Georgia has yielded striking hominin, faunal and archaeological material as evidence for the presence of early Homo outside Africa 1.77 million years ago, documenting an important episode in human evolution. Here we describe a beautifully preserved skull and jawbone from a Dmanisi hominin of this period who had lost all but one tooth several years before death. This specimen not only represents the earliest case of severe masticatory impairment in the hominin fossil record to be discovered so far, but also raises questions about alternative subsistence strategies in early Homo.
Asunto(s)
Fósiles , Hominidae/anatomía & histología , Cráneo/anatomía & histología , Pérdida de Diente/patología , Animales , Georgia (República) , Historia Antigua , Hominidae/fisiología , Mandíbula/anatomía & histología , Mandíbula/patología , Masticación/fisiología , Cráneo/patología , Diente/patología , Diente/fisiología , Pérdida de Diente/fisiopatologíaRESUMEN
Another hominid skull has been recovered at Dmanisi (Republic of Georgia) from the same strata in which hominid remains have been reported previously. The Dmanisi site dated to approximately 1.75 million years ago has now produced craniofacial portions of several hominid individuals, along with many well-preserved animal fossils and quantities of stone artifacts. Although there are certain anatomical differences among the Dmanisi specimens, the hominids do not clearly represent more than one taxon. We assign the new skull provisionally to Homo erectus (=ergaster). The Dmanisi specimens are the most primitive and small-brained fossils to be grouped with this species or any taxon linked unequivocally with genus Homo and also the ones most similar to the presumed habilis-like stem. We suggest that the ancestors of the Dmanisi population dispersed from Africa before the emergence of humans identified broadly with the H. erectus grade.