Dmanisi and dispersal

Gabunia, Leo; Antón, Susan C.; Lordkipanidze, David; Vekua, Abesalom; Justus, Antje; Swisher, Carl C.

doi:10.1002/evan.1030

Cited by 143 publications

(72 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…First, with an intraspecific scaling exponent of 0.25, body size would still have to be reduced to one-eighth of the average for Homo erectus (from 60 to 7.5 kg) to decrease mean cranial capacity from 664 to 400 cc. In fact, taking the smaller body mass of 50 kg estimated for the Dmanisi fossils (Gabunia et al, 2001), body size would have to be reduced to around 6 kg to reach a mean cranial capacity of 400 cc. Contrary to the impression that has been given, cranial capacities of the Dmanisi hominids are not unusually small, given their antiquity.…”

Section: Cranial Capacitymentioning

confidence: 99%

“…Doklá dal (1958), for example, reported on a 57-year-old microcephalic with a cranial capacity of 405 cc having a small mandible with weak development of the chin. Seckel syndrome consists of similar intrauterine and postnatal growth retardation and microcephaly, typically Data from Gabunia et al (2000Gabunia et al ( , 2001, Kappelman (1996), Rightmire et al (2006), Stanyon et al (1993), andVekua et al (2002).…”

Section: 4mentioning

confidence: 99%

See 1 more Smart Citation

Flores hominid: New species or microcephalic dwarf?

et al. 2006

View full text Add to dashboard Cite

The proposed new hominid ''Homo floresiensis'' is based on specimens from cave deposits on the Indonesian island Flores. The primary evidence, dated at $ 18,000 y, is a skull and partial skeleton of a very small but dentally adult individual (LB1). Incomplete specimens are attributed to eight additional individuals. Stone tools at the site are also attributed to H. floresiensis. The discoverers interpreted H. floresiensis as an insular dwarf derived from Homo erectus, but others see LB1 as a small-bodied microcephalic Homo sapiens. Study of virtual endocasts, including LB1 and a European microcephalic, purportedly excluded microcephaly, but reconsideration reveals several problems. The cranial capacity of LB1 ($ 400 cc) is smaller than in any other known hominid < 3.5 Ma and is far too small to derive from Homo erectus by normal dwarfing. By contrast, some associated tools were generated with a prepared-core technique previously unknown for H. erectus, including bladelets otherwise associated exclusively with H. sapiens. The single European microcephalic skull used in comparing virtual endocasts was particularly unsuitable. The specimen was a cast, not the original skull (traced to Stuttgart), from a 10-year-old child with massive pathology. Moreover, the calotte does not fit well with the rest of the cast, probably being a later addition of unknown history. Consideration of various forms of human microcephaly and of two adult specimens indicates that LB1 could well be a microcephalic Homo sapiens. This is the most likely explanation for the incongruous association of a small-brained recent hominid with advanced stone tools.

show abstract

Section: Cranial Capacitymentioning

confidence: 99%

Section: 4mentioning

confidence: 99%

Flores hominid: New species or microcephalic dwarf?

et al. 2006

View full text Add to dashboard Cite

show abstract

“…Similarly, as an effect of lingual tipping, interproximal contacts between incisors are preserved. During an individual's lifetime, the combined, accumulated effects of continuous eruption, mesial drift, and lingual tipping tend to result in an edge-to-edge bite in the front dentition (7) and in significant changes in mandibular morphology (13,20).The site of Dmanisi, Georgia, has yielded a crucial sample of early Pleistocene hominin fossils along with a rich vertebrate fauna and mode I (Oldowan) lithic implements (21,22). Site occupation began shortly after 1.85 Ma (million years ago) (23); the fossils are dated to 1.77 Ma (21,[23][24][25][26].…”

mentioning

confidence: 99%

“…The site of Dmanisi, Georgia, has yielded a crucial sample of early Pleistocene hominin fossils along with a rich vertebrate fauna and mode I (Oldowan) lithic implements (21,22). Site occupation began shortly after 1.85 Ma (million years ago) (23); the fossils are dated to 1.77 Ma (21,(23)(24)(25)(26).…”

mentioning

confidence: 99%

Tooth wear and dentoalveolar remodeling are key factors of morphological variation in the Dmanisi mandibles

Margvelashvili

Zollikofer

Lordkipanidze

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

View full text Add to dashboard Cite

The Plio-Pleistocene hominin sample from Dmanisi (Georgia), dated to 1.77 million years ago, is unique in offering detailed insights into patterns of morphological variation within a paleodeme of early Homo. Cranial and dentoalveolar morphologies exhibit a high degree of diversity, but the causes of variation are still relatively unexplored. Here we show that wear-related dentoalveolar remodeling is one of the principal mechanisms causing mandibular shape variation in fossil Homo and in modern human huntergatherer populations. We identify a consistent pattern of mandibular morphological alteration, suggesting that dental wear and compensatory remodeling mechanisms remained fairly constant throughout the evolution of the genus Homo. With increasing occlusal and interproximal tooth wear, the teeth continue to erupt, the posterior dentition tends to drift in a mesial direction, and the front teeth become more upright. The resulting changes in dentognathic size and shape are substantial and need to be taken into account in comparative taxonomic analyses of isolated hominin mandibles. Our data further show that excessive tooth wear eventually leads to a breakdown of the normal remodeling mechanisms, resulting in dentognathic pathologies, tooth loss, and loss of masticatory function. Complete breakdown of dentognathic homeostasis, however, is unlikely to have limited the life span of early Homo because this effect was likely mediated by the preparation of soft foods.aging | compensatory mechanisms | toothpick | local periodontitis | early Pleistocene Homo A lthough patterns of dental micro-and macrowear and wearrelated pathologies are amply documented in the hominin fossil record (1-5), processes of in vivo dentoalveolar remodeling (3, 6, 7) and their potential influence on dentognathic morphology are only beginning to be studied in fossil hominins (8). In modern human hunter-gatherer populations, remodeling of dentoalveolar hard tissue is triggered mainly by dental wear, aging, pathologies, and trauma. Wear-related remodeling can be understood as a mechanism of in vivo modification that maintains masticatory function (3,7,(9)(10)(11)(12)(13)(14). Three main processes are typically identified (Fig. 1): i) Wear-induced reduction of dental crown height leads to alterations in masticatory biomechanics. This triggers alveolar bone remodeling, yielding dislocation of dental structures and eventual continuous eruption of all teeth. As an effect, occlusal contact between upper and lower teeth is maintained (15-17), and the position and orientation of the occlusal plane relative to the temporomandibular joints (TMJs) is held approximately constant, thus preventing the "wear-out" (18) of the TMJs. ii) The reduction of mesiodistal crown dimensions through interproximal dental wear triggers alveolar bone remodeling in the mesiodistal direction. This leads to mesial drift of the postcanine dentition and shortening of the dental arcade (19).iii) In the anterior dentition, remodeling induced by interproximal wear results in increas...

show abstract

“…and Georgian specimens from Gabunia et al (2000Gabunia et al ( , 2001. Data for late H. erectus are from McHenry (1994a).…”

mentioning

confidence: 99%

The Energetics of Encephalization in Early Hominids

Snodgrass

Leonard

Robertson

2009

The Evolution of Hominin Diets

View full text Add to dashboard Cite

Bioenergetics, the study of the use and transfer of energy, can provide important insights into the ecology and evolution of early hominids. Despite a relatively large brain with high metabolic demands, contemporary humans and other primates have resting metabolic rates (RMRs) that are similar to those of other mammals. As a result, a comparatively large proportion of their resting energy budget is spent on brain metabolism among humans (~20-25%) and other primates (~8-10%) compared to other mammals (~3-5%). To understand this shift in energy budget, Aiello and Wheeler's Expensive Tissue Hypothesis (ETH) posits a metabolic trade-off-a reduction in gut size with brain size increase-to explain this phenomenon. Here, we explore the interrelationships between brain size, body size, diet, and body composition using comparative data for humans, non-human primates, and other mammals. Among living primates, the relative proportion of energy allocated to brain metabolism is positively correlated with dietary quality. Contemporary humans fall at the positive end of this relationship, having both a high quality diet and a large brain. Thus, high costs associated with the large human brain are supported, in part, by energy-rich diets. Although contemporary humans display relatively small guts, primates as a group have gut sizes that are similar to non-primate mammals. In contrast, humans and other primates have significantly less skeletal muscle for their size compared to other mammals. These comparative analyses suggest that alterations in diet quality and body composition were necessary conditions for overcoming the constraints on encephalization. Fossil evidence indicates that brain expansion with the emergence of Homo erectus at about 1.8 million years ago was likely associated with important changes in diet, body composition, and body size.

show abstract

Dmanisi and dispersal

Cited by 143 publications

References 48 publications

Flores hominid: New species or microcephalic dwarf?

Flores hominid: New species or microcephalic dwarf?

Tooth wear and dentoalveolar remodeling are key factors of morphological variation in the Dmanisi mandibles

The Energetics of Encephalization in Early Hominids

Contact Info

Product

Resources

About