The dental developmental status of six East African juvenile fossil hominids

doi:10.1016/0047-2484(87)90076-5

Journal of Human Evolution

Volume 16, Issue 2, February 1987, Pages 197-213

https://doi.org/10.1016/0047-2484(87)90076-5 Get rights and content

Abstract

Radiographs of five juvenile fossil hominids from Koobi Fora, Kenya are described and presented together with measurements and observations made on the original speciments. Data are also presented for a single specimen from Olduvai Gorge, Tanzania. Four of these specimens are attributed to Paranthropus boisei (KNM ER 812, 1477 1820 and OH 30), and are all of remarkably similar dental developmental status. Conventional age estimates for these specimens of Paranthropus based on the first permanent molar, indicate an age at death of around 2·2 to 3 years. Perikymata counts on permanent lower central incisors of these specimens also indicate an age at death between 2·5 and 3 years. Two specimens attributed to early Homo (KNM ER 820 and 1507), are dentally more mature than specimens of Paranthropus boisei described here being closer to 5 years of age. Differences between the spacing and distribution of perikymata on the surfaces of incisor teeth are now apparent between Homo, Australopithecus. Paranthropus boisei and Paranthropus robustus: these are described in this paper. Details of the dental developmental patterns of these hominids are also discussed in the light of recent publications that have presented data about hominid eruption sequences and fossil hominid growth periods.

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M.C. Dean et al.

Age at death of the Neanderthal child from Devil's Tower Gibraltar and the implications for studies of general growth and development in Neanderthals

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(1986)

Cited by (73)

Retzius periodicity in the Late Miocene hominoid Lufengpithecus lufengensis from Southwest China: Implications for dental development and life history
2023, Journal of Human Evolution
Making meaning from fragmentary fossils: Early Homo in the Early to early Middle Pleistocene
2023, Journal of Human Evolution
In celebration of the 50th anniversary of the Journal of Human Evolution, we re-evaluate the fossil record for early Homo (principally Homo erectus, Homo habilis, and Homo rudolfensis) from early diversification and dispersal in the Early Pleistocene to the ultimate demise of H. erectus in the early Middle Pleistocene. The mid-1990s marked an important historical turning point in our understanding of early Homo with the redating of key H. erectus localities, the discovery of small H. erectus in Asia, and the recovery of an even earlier presence of early Homo in Africa. As such, we compare our understanding of early Homo before and after this time and discuss how the order of fossil discovery and a focus on anchor specimens has shaped, and in many ways biased, our interpretations of early Homo species and the fossils allocated to them. Fragmentary specimens may counter conventional wisdom but are often overlooked in broad narratives. We recognize at least three different cranial and two or three pelvic morphotypes of early Homo. Just one postcranial morph aligns with any certainty to a cranial species, highlighting the importance of explicitly identifying how we link specimens together and to species; we offer two ways of visualizing these connections. Chronologically and morphologically H. erectus is a member of early Homo, not a temporally more recent species necessarily evolved from either H. habilis or H. rudolfensis. Nonetheless, an ancestral–descendant notion of their evolution influences expectations around the anatomy of missing elements, especially the foot. Weak support for long-held notions of postcranial modernity in H. erectus raises the possibility of alternative drivers of dispersal. New observations suggest that the dearth of faces in later H. erectus may mask taxonomic diversity in Asia and suggest various later mid-Pleistocene populations could derive from either Asia or Africa. Future advances will rest on the development of nuanced ways to affiliate fossils, greater transparency of implicit assumptions, and attention to detailed life history information for comparative collections; all critical pursuits for future research given the great potential they have to enrich our evolutionary reconstructions for the next fifty years and beyond.
An updated analysis of hominin phylogeny with an emphasis on re-evaluating the phylogenetic relationships of Australopithecus sediba
2023, Journal of Human Evolution
The discovery and description of Australopithecus sediba has reignited the debate over the evolutionary history of the australopiths and the genus Homo. It has been suggested that A. sediba may be an ancestor of Homo because it possesses a mosaic of derived Homo-like and primitive australopith-like traits. However, an alternative hypothesis proposes that the majority of the purported Homo-like craniodental characters can be attributed to the juvenile status of the type specimen, MH1. We conducted an independent character assessment of the craniodental morphology of A. sediba, with particular emphasis on evaluating whether the ontogenetic status of MH1 may have affected its purported Homo-like characteristics. In doing so, we have also expanded fossil hypodigms to incorporate the new Australopithecus anamensis cranium from Woranso-Mille (MRD-VP-1/1), as well as recently described Paranthropus robustus cranial remains from Drimolen (DNH 7, DNH 155). Morphological character data were analyzed using both standard parsimony and Bayesian techniques. In addition, we conducted a series of Bayesian analyses constrained to evaluate the hypothesis that Australopithecus africanus and A. sediba are sister taxa. Based on the results of the parsimony and Bayesian analyses, we could not reject the hypothesis that A. sediba shares its closest phylogenetic affinities with the genus Homo. Therefore, based on currently available craniodental evidence, we conclude that A. sediba is plausibly the terminal end of a lineage that shared a common ancestor with the earliest representatives of Homo. We caution, however, that the discovery of new A. sediba fossils preserving adult cranial morphology or the inclusion of postcranial characters may ultimately necessitate a re-evaluation of this hypothesis.
Patterns of permanent incisor, canine and molar development in modern humans, great apes and early fossil hominins
2022, Archives of Oral Biology
Citation Excerpt :
Clearly, gingival emergence can never be observed in fossils or in museum specimens and mixing observations about radiographic stages of development with assumptions about gingival emergence has generally been regarded as less than satisfactory. Observations about the stages of dental development or tooth eruption status made using the same definitions and on large enough samples of modern humans and great apes have not always been readily available for comparison (Beynon & Dean, 1991; Broom & Robinson, 1951; Conroy, 1988; Dean & Liversidge, 2015; Dean, 1985, 1987; Dean et al., 1993; Garn & Lewis, 1963; Garn et al., 1957; Grine, 1987; Kelley & Schwartz, 2012; Kuykendall & Conroy, 1996; Mann et al., 1990; Moggi-Cecchi et al., 1998; Smith, 1986, 1994a, 1994b; Wallace, 1977). The aim of this study was to combine radiographic data for a large sample of modern humans with comparable data collected from existing radiographs of once free-living great ape specimens of Pan, Gorilla and Pongo.
The objectives of this study were to quantify the variation in coincident stages of incisor, canine and molar eruption and tooth formation in modern humans and great apes and then to ask if any early fossil hominins showed a dental development pattern beyond the human range and/or clearly typical of great apes.
Four stages of eruption and 18 stages of tooth development were defined and then scored for each developing tooth on radiographs of 159 once-free-living subadult great apes and on orthopantomographs of 4091 dental patients aged 1–23 years. From original observations, and from published images of eleven early fossil hominins, we then scored formation stages of permanent incisors when M1 was at root formation stage R¼-R½ and R¾-RC.
Incisor and canine eruption/development was delayed in great apes relative to molar development when compared with humans but there was overlap in almost all anterior tooth stages observed. Molar crown initiation was generally advanced in great apes and delayed in humans but again, we observed overlap in all stages in both samples. Only two fossil hominin specimens (L.H.–3 from Laetoli, Tanzania and KNM-KP 34725 from Kanapoi, Kenya) showed delayed incisor development relative to M1 beyond any individuals observed in the human sample.
For certain tooth types, the distribution of formation stages in our samples showed evidence of generally advanced or delayed development between taxa. However, it would rarely if ever be possible to allocate an individual to one taxon or another on this basis.
'Virtual anthropology' and radiographic imaging in the Forensic Medical Sciences
2016, Egyptian Journal of Forensic Sciences
Technological advancements in forensic imaging have had tremendous flow-on benefits to the professional practice of forensic anthropology, not only in respect of case-work analyses, but in facilitating empirical research that has validated and/or improved existing, and introduced novel, methods into the discipline. Some of the pioneering practical examples of radiographic imaging being applied in the forensic analysis of human skeletal remains date to the initial introduction of radiography in the late 19th and early 20th centuries. Subsequent modern applications have developed concurrent to the use of computed tomography in the forensic morgue for autopsy procedures by pathologists; virtopsy (as it is now termed) represents a powerful non-invasive supplement/alternative to traditional autopsy practices where dissection may not be allowable due to religious objection (amongst other reasons). The present review considers a brief history of skeletal radiographic imaging and the specific modalities typically employed. Forensic applications of ‘virtual anthropology’ are then discussed, as are applications of the latter in DVI and other case-work scenarios. Throughout the review we emphasise the research importance of virtual modelling and conclude with some thoughts for future directions.
Genetic comparisons yield insight into the evolution of enamel thickness during human evolution
2014, Journal of Human Evolution
Citation Excerpt :
Thick enamel distinguishes modern humans from chimpanzees and gorillas and has long been a central feature in discussions of the origins and evolution of humans (Molnar and Gantt, 1977; Martin, 1983; Martin, 1985; Grine and Martin, 1988; Schwartz, 2000; Teaford and Ungar, 2000; Ungar et al., 2006; Teaford, 2007). Teeth are frequently preserved in the fossil record and enamel thickness has measurable links to tooth function and development, conferring a strong potential for variation in enamel thickness to provide insights into the inter-relations among dietary adaptation, phylogeny, behavioral ecology, and life history during human evolution (Dean, 1985, 1987; Smith, 1991, 1993, 1994; Smith and Tompkins, 1995; Dean, 2000; Dean, 2006; Lacruz et al., 2008; Dean and Smith, 2009; Guatelli-Steinberg, 2009; Dean, 2010; Schwartz, 2012). Our interest in the thick enamel phenotype of humans stems from our efforts to uncover the genetic basis for the origin of diet-related traits in humans (Haygood et al., 2007; Babbitt et al., 2011; Fedrigo et al., 2011; Pfefferle et al., 2011).
Enamel thickness varies substantially among extant hominoids and is a key trait with significance for interpreting dietary adaptation, life history trajectory, and phylogenetic relationships. There is a strong link in humans between enamel formation and mutations in the exons of the four genes that code for the enamel matrix proteins and the associated protease. The evolution of thick enamel in humans may have included changes in the regulation of these genes during tooth development. The cis-regulatory region in the 5′ flank (upstream non-coding region) of MMP20, which codes for enamelysin, the predominant protease active during enamel secretion, has previously been shown to be under strong positive selection in the lineages leading to both humans and chimpanzees. Here we examine evidence for positive selection in the 5′ flank and 3′ flank of AMELX, AMBN, ENAM, and MMP20. We contrast the human sequence changes with other hominoids (chimpanzees, gorillas, orangutans, gibbons) and rhesus macaques (outgroup), a sample comprising a range of enamel thickness. We find no evidence for positive selection in the protein-coding regions of any of these genes. In contrast, we find strong evidence for positive selection in the 5′ flank region of MMP20 and ENAM along the lineage leading to humans, and in both the 5′ flank and 3′ flank regions of MMP20 along the lineage leading to chimpanzees. We also identify putative transcription factor binding sites overlapping some of the species-specific nucleotide sites and we refine which sections of the up- and downstream putative regulatory regions are most likely to harbor important changes. These non-coding changes and their potential for differential regulation by transcription factors known to regulate tooth development may offer insight into the mechanisms that allow for rapid evolutionary changes in enamel thickness across closely-related species, and contribute to our understanding of the enamel phenotype in hominoids.

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Journal of Human Evolution

Abstract

References (24)

Growth layers and incremental markings in hard tissues; a review of the literature and some preliminary observations about enamel structure in Paranthropus boisei

J. hum. Evol

Replication technique for studying microstructure in fossil enamel

Scanning Microscopy

Variation in enamel thickness and structure in East African hominids

Am. J. phys. Anthrop

Relationships between perikymata counts and crown formation times in the human permanent dentition

J. dent. Res

Patterns of molar crown formation in East African fossil hominids

Nature

Estimation of age at death of young human skeletal remains from incremental lines within dental enamel

Re-evaluation of the age at death of immature fossil hominids

Nature

The biological application of teeth in archaeology

New hominids from East Turkana Kenya

Am. J. phys. Anthrop

The eruption pattern of the incisors and the first permanent molars in Australopithecus (Paranthropus) robustus

Am. J. phys. Anthrop

Developing pongid dentition and its use for ageing crania in comparative cross-sectional growth studies

Folia primal

Age at death of the Neanderthal child from Devil's Tower Gibraltar and the implications for studies of general growth and development in Neanderthals

Am. J. phys. Anthrop

Cited by (73)

Retzius periodicity in the Late Miocene hominoid Lufengpithecus lufengensis from Southwest China: Implications for dental development and life history

Making meaning from fragmentary fossils: Early Homo in the Early to early Middle Pleistocene

An updated analysis of hominin phylogeny with an emphasis on re-evaluating the phylogenetic relationships of Australopithecus sediba

Patterns of permanent incisor, canine and molar development in modern humans, great apes and early fossil hominins

'Virtual anthropology' and radiographic imaging in the Forensic Medical Sciences

Genetic comparisons yield insight into the evolution of enamel thickness during human evolution