A fourth hominin skull from Dmanisi, Georgia

Lordkipanidze, David; Vekua, Abesalom; Ferring, Reid; Rightmire, G. Philip; Zollikofer, Christoph P.E.; León, Marcia S. Ponce de; Agustı́, Jordi; Kiladze, Gocha; Mouskhelishvili, Alexander; Nioradzé, Médéa; Tappen, Martha

doi:10.1002/ar.a.20379

Cited by 96 publications

(64 citation statements)

References 32 publications

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“…Mandible D3900, which is associated with the edentulous cranium D3444 (28), represents an elderly individual. Its alveolar process is almost completely atrophied, indicating massive tooth loss several years antemortem (28,45). The only tooth still in place premortem (but lost postmortem) was the left canine (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…variation (25,(27)(28)(29)(30)(31). Here we focus on in vivo dentognathic remodeling as a potential mechanism contributing to the remarkable dentognathic variation in Dmanisi and differentiate normal remodeling processes from pathologic alterations.…”

Section: Significancementioning

confidence: 99%

“…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]. The Dmanisi hominin sample comprises five individuals that document dentognathic development from adolescence to old age, thus providing a unique opportunity to study wear-related dentognathic variation in a sample that comes from a single point in space and geological time (26)(27)(28)(29). Various hypotheses have been proposed to explain the high degree of variation seen in the Dmanisi mandibles, ranging from intrataxon sexual dimorphism to intertaxon…”

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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.

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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...

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Section: Resultsmentioning

confidence: 99%

Section: Significancementioning

confidence: 99%

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confidence: 99%

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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.

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“…Data for six cranial vault variables were collected from the literature for LB1 (11), a worldwide sample of 2,524 adult recent modern humans (17), and for 30 fossil hominin crania (11,(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)) (see Materials and Methods and supporting information (SI) Table S1). Univariate comparisons of size-adjusted shape variables between LB1 and the modern human sample yield mixed results: LB1 does not differ significantly from the modern comparative sample in size-adjusted cranial length (GOLЈ), maximum cranial breadth (XCBЈ), or cranial base length (BNLЈ) (see Materials and Methods), whereas it does differ significantly in size-adjusted cranial height (BBHЈ), maxillary prognathism (BPLЈ), and biasterionic breadth (ASBЈ) (t tests, ␣ ϭ 0.05).…”

Section: Resultsmentioning

confidence: 99%

The Homo floresiensis cranium (LB1): Size, scaling, and early Homo affinities

Gordon

Nevell

Wood

2008

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

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The skeletal remains of a diminutive small-brained hominin found in Late Pleistocene cave deposits on the island of Flores, Indonesia were assigned to a new species, Homo floresiensis [Brown P, et al. A dramatically different interpretation is that this material belongs not to a novel hominin taxon but to a population of small-bodied modern humans affected, or unaffected, by microcephaly. The debate has primarily focused on the size and shape of the endocranial cavity of the type specimen, LB1, with less attention being paid to the morphological evidence provided by the rest of the LB1 cranium and postcranium, and no study thus far has addressed the problem of how scaling would affect shape comparisons between a diminutive cranium like LB1 and the much larger crania of modern humans. We show that whether or not the effects of its small cranial size are accounted for, the external cranial morphology of the LB1 cranium cannot be accommodated within a large global sample of normal modern human crania. Instead, the shape of LB1, which is shown by multivariate analysis to differ significantly from that of modern humans, is similar to that of Homo erectus sensu lato, and, to a lesser extent, Homo habilis. Our results are consistent with hypotheses that suggest the Liang Bua specimens represent a diminutive population closely related to either early H. erectus s. l. from East Africa and/or Dmanisi or to H. habilis.allometry ͉ hominin phylogeny

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“…1.75 Ma (millions of years ago) (Gabunia et al, 2000;Lordkipanidze et al, 2005Lordkipanidze et al, , 2006Rightmire et al, 2006;Lordkipanidze et al, 2007Lordkipanidze et al, , 2013; but see Bermúdez de Castro et al, 2014), followed shortly afterward by the oldest from Sangiran, Java, Indonesia that are dated to ca. 1.5e1.6 Ma (Larick et al, 2001;Bettis et al, 2009;Zaim et al, 2011).…”

Section: Introductionmentioning

confidence: 99%