Tag Archives: teeth

An Odontometric Investigation of Canary Islander Origins

An Odontometric Investigation of Canary Islander Origins 2004

Joel D. Irish* and Brian E. Hemphill** *Department of Anthropology, University of Alaska, Fairbanks, AK 99775.*Department of Sociology & Anthropology, California State University, Bakersfield, CA 93311

ABSTRACT Attempts by anthropologists to account for the peopling of the Canary Islands have led to theories that call for one, two, and even four immigration events. However, most agree the Canary Island Guanche are biologically closest to Berbers from Morocco and Algeria. Genetic contributions from Arabs, Romans, and Carthaginians have also been proposed. An earlier study by Irish using Penrose analysis of odontometric data in samples of Guanche, Shawia and Kabyle Berbers, and Bedouin Arabs supports many of these proposed genetic relationships. The present investigation expands upon this earlier work by adding samples of Carthaginians, Egyptians, and Nubians, and by using tooth size apportionment analysis, a more robust statistical approach for assessing inter-sample differences in the distribution, or allocation, of tooth size in the maxillary and mandibular dental arcades. The analysis yielded three components that account for >80% of the total variance. Cluster analysis and three-dimensional ordination of group component scores provide additional insight into Canary Island/North African relationships. Except for one early Nubian sample, the Guanche exhibit some measure of affinity to all others. However, they are most like Berbers and Carthaginians. These results suggest that Canary Islanders belong to a greater North African gene pool, yet show the closest affinities to Northwest Africans—which corroborates earlier dental and nondental findings.

Something published a  few years ago that I finally located the text for. The conclusion isn’t exactly a surprise; that Canary Islanders were part of the north African population as ADNA has shown that already. Its not surprising to see Lower Nubians also grouping with the North Africans for teeth, as this was true generally for mDNA and cranial shape, although it shows much more distance to the upper Nubian Soleb sample (18th Dynasty Pharonic Nubians, 1575-1380 BC). It says ‘The Soleb sample is characterized by the largest teeth of all samples, as well as broad buccolingual anterior tooth diameters and large mandibular molars relative to the  to the maxillary counterparts’ which I believe would make them more typical of sub Saharan  Africans (dentition is not my strong point).

The conlusion..

First, the Canary Island Guanche show closest dental affinities to Northwest Africans, relative to other samples of various ages. Second, the pattern of phenetic affinities possessed by the Guanche suggest that some degree of biological relatedness extends beyond the adjacent mainland to Nubians and Egyptians in Northeast Africa.

 The pdf also has on it ‘An Artificial Human Tooth from the Neolithic Cemetery at Gebel Ramlah, Egypt’ by Irish.

Bioarchaeological Analysis of Cultural Transition in the Southern Levant Using Dental Nonmetric Traits

Bioarchaeological Analysis of Cultural Transition in the Southern Levant Using Dental Nonmetric Traits

To many Near Eastern archaeologists, the Late Bronze Age-Early Iron Age transition in the southern Levant indicates the emergence of a new ethnicity. The question remains, however, whether changes in the material culture are the result of an invasion of foreigners, or instead arose from shifting cultural and technical practices by indigenous peoples. This study utilized dental morphological traits to assess phenetic relationships between the Late Bronze Age site of Dothan (1500-1100 BC) and the Iron Age II site of Lachish (Tell edDuweir, 701 BC). Information on 30 dental crown and root traits was collected for 4,412 teeth, representing 392 individuals from Lachish and a minimum of 121 individuals from Dothan, using the Arizona State University Dental Anthropology System. Seventeen traits from Dothan and Lachish were compared with dentitions from a Byzantine Jerusalem monastery, Iron Age Italy, a Natufian group (early agrarians from the Levant), and a Middle Kingdom Egyptian site using C.A.B. Smith’s mean measure of divergence statistic. The findings suggest that there are more similarities between Dothan and Lachish than either of them and other sites. This analysis indicates that the material culture changes were not the result of a foreign invasion. Rather, the Iron Age people of the southern Levant were related to their Bronze Age predecessors.

A study of teeth, with some interesting insights into other past papers on it..

The first report on the Lachish skulls included a thorough examination of pathology, metrics, artifi-cial deformation, and epigenetic affinity. Utilizing craniometrics, Risdon (1939) concluded that the group was very similar to dynastic Egyptian material. In fact, he stated that the entire population was of foreign origin, representing descendants of a group derived primarily from Upper Egypt. This conclusion was subsequently supported by a craniometric study by Musgrave and Evans (1981). Keita (1988, p. 377) likewise examined the skulls metrically, omitting those that were either “artificially deformed, female, warped, split, [or] juvenile,” using only those measurements that he believed were consistent population discriminators. He concluded that the group was fairly heterogeneous, having close relationships to North African, Egyptian, and Nubian groups, thus lending support to an “Egypto-Nubian presence” (Keita, 1988, p. 388).

One of the first to oppose the idea of an Egyptian origin was Keith (1940), who felt that the Lachish inhabitants were markedly different from Egyptians, though his analysis was rather anecdotal. Others have since concurred, arguing that the people of Lachish were indigenous, closely related to pre-Middle Bronze Age skeletons in Palestine and the modernday Bedouin (Arensburg, 1973; Arensburg et al.1980; Smith, 1995). Arensburg (1982) further stated that although Egypt and Mesopotamia were very influential culturally, they made no biological contribution to the Levant at all. Giles (1953) conducted a craniometric examination of the Bronze Age skulls at
Lachish excavated after the initial study of Risdon (1939), and established that the crania were most likely from the same population as the Iron Age people studied by Risdon (1939). Berry and Berry (1972), utilizing nonmetric cranial features, likewise, found that the Lachish series was quite distinct from Egyptian collections dating to the Predynastic, Middle Kingdom, and Late Periods.

Other than the immediate observation that Egyptians seem to be very similar to their Levantine neighbours? It suggests that Keita’s methods are a bit questionable if these people are coming up as Nubian. I’ll have a look for the paper in question, ‘An analysis of crania from Tell-Duweir’. The overall conclusion of this paper is that ” The results of this dental morphology study indicate biological continuity in the Late Bronze-Early Iron Age transition in the southern Levant,” and not an Egyptian/Nubian origin for them. Which is supported by the DNA, no big population movements in that direction as far as I know.

Basques in an Indo-European sea: a perspective from tooth crown morphology.

Basques in an Indo-European sea: a perspective from tooth crown morphology.
G.R. Scott1, K.A. Hopkinson1, C. de la Rua2, A. Anta2. 1Department of Anthropology, University of  Nevada Reno, 2 Departamento de Genética, Antropología Física y Fisiología Animal, Universidad del Pais Vasco.

Basques represent one of the few non-Indo-European populations in Europe. Ruhlen proposed a distant  linguistic relationship between Basque and the Caucasian, Sino- Tibetan, and Na-Dene language families.  Dentally, the first
language family is distinctly European while populations of the latter two exhibit Sinodonty. Some authors suggest Basques are the descendents of Upper Paleolithic peoples of Western Europe. Genetically, they have a high frequency of the Rh allele (r) and a low frequency of blood group B. Such differences set the Basques apart from their neighbors, but they still group with Europeans in world genetic analyses, suggesting a common origin but one with some time depth.

Little is known of Basque tooth morphology and size. To partially remedy this situation, observations were made on 29 crown traits in modern Basque and Spanish samples. We did not find any noteworthy differences in crown trait frequencies between Basques and either Spaniards or Europeans in general. Basques exhibit no incisor winging and low frequencies of shoveling, double shoveling, 3-cusped upper second molars, cusp 5, and cusp 7. Compared to Europeans, they exhibit fewer cusp forms of Carabelli’s trait and a higher frequency of deflecting wrinkle. The frequencies of four-cusped lower molars mirror almost exactly the frequencies of European populations. In a world-wide analysis, Basques cluster with Europeans although they separate at a higher level in the dendrogram. This does not, however, preclude a linkage between Basques and
Upper Paleolithic groups who also exhibit the dental pattern that sets Europeans apart from other world populations.

From today’s pdf. Not my specialist area, but Maju will probably like it.

Who made the early Aurignacian? The dental evidence.

Who made the early Aurignacian? Evidence from isolated teeth.

Page 5

S.E. Bailey. Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology (Leipzig), Department of
Anthropology, New York University.

Neandertals and anatomically modern humans overlapped in Europe between 45- and 30,000 BP. Unfortunately, the human fossil record during this important time period is sparse. What is preserved is fragmentary and consists primarily of jaws and isolated teeth. This has led some to question whether we can determine if Neandertals or anatomically modern humans were responsible for the early Aurignacian. The goals of this study were, first, to investigate whether root lengths can help differentiate these two taxa; and second, to combine these data with tooth crown traits to assess the taxonomic affiliation of isolated teeth from two early Aurignacian sites (Brassempouy and La Ferrassie).

Root lengths were measured from the lingual aspect of permanent teeth of Neandertals (maximum n=15) and Upper Paleolithic modern humans (maximum n=10). The student’s t-test showed that the mean root lengths of I1, I2, C’, I1, I2, C, P3, P4 and M2 were significantly longer in Neandertals than in Upper Paleolithic moderns (p<0.05), with no overlap in the ranges of I1, I1, C’, and P4. At Brassempouy, the root lengths of the two I1s, C’ and M2 fall more than three standard deviations below the Neandertal mean. Likewise, the single I1 from Le Ferrassie possesses a root that is too short to be considered Neandertal. Additionally, the tooth crowns at both Brassempouy and La Ferrassie lack any diagnostically Neandertal traits. Thus, the preponderance of dental evidence suggests that anatomically modern humans, not Neandertals, are associated with these early Aurignacian sites.

And also by the same author… 

Who made the Early Aurignacian? A Reconsideration of the Brassempouy Dental Remains

The dental human remains from the early Aurignacian layers of Brassempouy (Landes) have been recently described by Henry-Gambier et al. (2004). We provide a critical re-assessment of the features that have led these authors to conclude that the taxonomic status of these fossils is uncertain. Although the works of one of us (S.B.) have been partly used and cited by Henry-Gambier et al. (2004), we disagree with the conclusions that have been drawn from them. In our view and based on the available evidence, the early Aurignacian dental remains from Brassempouy are unambiguously modern in their anatomy. They indeed provide further evidence that the makers of the ancient Aurignacian were early anatomically modern Europeans.

 The second link contains a more complete article.I’ll refrain from mentioning that if the remains are so similar at times that they can only be categorised as one or the other with difficulty.. surely this would suggest some overlap between the two genetically as well as physically.

Gradual Change in Human Tooth Size

Gradual Change in Human Tooth Size in the Late Pleistocene and Post- Pleistocene,

by C. Loring Brace, Karen R. Rosenberg and Kevin D. Hunt © 1987 Society for the Study of Evolution.

Starting with the onset of the last glaciation approximately 100,000 years ago and continuing to the end of the Late Pleistocene approximately 10,000 years ago, human tooth size began to reduce at a rate of 1% every 2,000 years. Both the mesial-distal and the buccal-lingual dimensions of mandibular and maxillary teeth were undergoing the same rate of reduction. From the beginning of the Post-Pleistocene until the present, the overall rate of dental reduction doubled, becoming approximately 1% per thousand years. Buccal-lingual dimensions are now reducing twice as fast as mesial-distal dimensions, and maxillary teeth are reducing at an even more rapid rate than mandibular teeth. Late Pleistocene rates are comparable in Europe and the Middle East. The Post-Pleistocene rates are also the same for Europe, the Middle East, China, Japan, and Southeast Asia. It is suggested that the cookery at the beginning of the Late Pleistocene allowed the earlier changes to occur. The use of pottery within the last 10,000 years further reduced the amount of selection that had previously maintained usable tooth substance. Reduction then occurred as a consequence of the Probable Mutation Effect .

I wonder if this is the reason for the reduction of prognathism observed in Eurasia; smaller teeth need don’t require as much jaw.

Unfortunately, I can’t track down the full text.

The evolution of non-metric dental variation in Europe

The evolution of non-metric dental variation in Europe
Shara E. Bailey

 The potential for dental morphology to answer questions about human evolution in the Middle to Late Pleistocene has only recently begun to be appreciated. Non-metric dental traits provide useful information for taxonomic diagnosis as well as for assessing biological relationships among living and ancient populations. This study uses dental morphology to assess temporal change in Europe. Homo erectus serves as the presumptive primitive condition for later humans and change over time is assessed by calculating estimates of divergence between groups based on the mean measure of divergence multivariate statistic. The samples include Homo erectus (n = 12), early modern humans from Africa and West Asia (n = 12), early Neandertals (n = 16), late Neandertals (n = 20), Upper Paleolithic Europeans (n = 28) and contemporary Europeans (n = 47). The results show a marked disruption in continuity from early modern to later modern humans when Neandertals are incorporated into the temporal sequence. If Neandertals are left out of the sequence the change in divergence values conforms to expectations for gradual evolution toward the modern human condition (e.g., distance values get progressively smaller through time). At minimum this should set to rest any idea that modern Europeans evolved directly from Neandertal ancestors. Late Neandertals are somewhat less ‘specialized’ than early Neandertals; the implications of this finding are discussed.

A close up of Neanderthal teeth from Krapina, showing a high degree of shovelling. According to an observation by Coon, the teeth of the Grimaldi boy were quite similar to the teeth from Krapina in some respects.

One previous study of teeth concluded…

Crummett (1994) examined the first of these two hypotheses by investigating temporal change in incisor morphology. Her results found no morphological trajectory from the Neandertal to the modern condition in Western Europe (with the caveat that data for Upper Paleolithic samples were unavailable). However, she felt that a better case for gradual evolution could be made for Central Europe. This is because she observed a trajectory of change from the incisor form observed in Neandertals to that observed in Upper Paleolithic (Dolní Věstonice) and recent Central Europeans.

A chart of the frequency of dental traits in Neanderthals. There’s more detailed information on the pdf

And another showing the mean distances between sampled groups..

Although the conclusion of this publication was that there was no evidence of significant interbreeding (which is probably correct) it doesn’t make a comment on lowlevels of interbreeding. This is probably because the low (5% or less) level suggested by a couple of DNA studies wouldn’t make a noticeable impact on the appearance of the UP European samples.

The affinity of the dental remains from Obi-Rakhmat Grotto

The affinity of the dental remains from Obi-Rakhmat Grotto, Uzbekistan

 9 July 2007Accepted 19 March 2008

A human partial maxillary dentition and a fragmentary cranium were recovered from Obi-Rakhmat Grotto in northeastern Uzbekistan in 2003. Initial descriptions of this single juvenile (OR-1) froma Middle Paleolithic archaeological context have emphasized its mosaic morphological pattern; the dentition appears archaic, while certain morphological aspects of the cranial fragments may be more ambiguous. The present study provides a systematic and comparative analysis of the dental morphology and morphometrics of OR-1 to provide a more refined appraisal of its phenetic affinity vis á vis Neandertals and modern humans. Two analyses were performed. The first uses 28 non-metric dental traits scored from Neandertals, Upper Paleolithic, and Middle Paleolithic modern humans to assess the posterior probability of group membership for the Obi-Rakhmat individual. The second is a morpho-metric analysis of the first upper molar of OR-1. The results of both analyses suggest the dentition of OR-1is essentially Neandertal.


Study of teeth from Wadi Halfa

Dentition of a mesolithic population from Wadi Halfa, Sudan

The dentition of a Mesolithic population (8,000-11,000 years old) from Wadi Halfa, Sudan, can be characterized as morphologically complex, massive and relatively free from pathology except that associated with extreme wear.
Maxillary incisors show shoveling. All of the maxillary molars show some development of the hypocone. Supernumerary cusps appear frequently. Almost one-half of the second lower molars observed show distally located third cusps. Over one-half of the maxillary third molars show an extra cusp. A high percentage of mandibular molars show six cusps.
Overall the teeth from this population compare favorably in size with those of an Australian aborigine tribe and are slightly larger than the teeth of the Neanderthaloids from Skhl.
The teeth show wear of a degree greater than that found in present day Eskimo or Australian aborigine groups.
This data may be interpreted as indicating that this Mesolithic group was subjected to rigorous selective pressures favoring large and/or morphologically complex teeth. This pressure was apparently intensive wear, presumably caused by the inclusion of large amounts of grit in the diet through the eating of vegetable food macerated on coarse grinding stones.

It seems they needed really strong teeth to cope with the grit in the grain. These people were grinding and eating wild wheat up until about 6,000 BC.

Neanderthal teeth growth rate studies

Neanderthal Teeth Grew No Faster Than Comparable Modern Humans’
ScienceDaily (Sep. 20, 2005) —

COLUMBUS , Ohio – Recent research suggested that ancient Neanderthals might have had an accelerated childhood compared to that of modern humans but that seems flawed, based on a new assessment by researchers from Ohio State University and the University of Newcastle .

They found that the rate of tooth growth present in the Neanderthal fossils they examined was comparable to that of three different populations of modern humans.

And since the rate of tooth growth has become a more-accepted tool for estimating the length of childhood among hominids, the finding is the latest evidence suggesting that Neanderthals may not have been as different from modern humans as some researchers have thought.

The study by Debbie Guatelli-Steinberg, assistant professor of anthropology at Ohio State , appeared in the current issue of the Proceedings of the National Academy of Sciences. Donald J. Reid, lecturer in oral biology at the University of Newcastle , Thomas A. Bishop, associate professor of statistics, and Clark Larsen, professor and chair of anthropology, both at Ohio State , were co-authors in the study.

“Based on our study of the enamel of these Neanderthal teeth and other modern ones, we can’t support the claim that Neanderthals grew up more quickly than do modern humans,” she said.

Key to this conclusion are microscopic lines on the outside of teeth that mark the incremental growth of enamel on a young tooth. Like tree rings that can gauge the age of a redwood, these striations – called perikymata – record new growth on the surface of the tooth.

Researchers know from earlier work that these markings are present in all forming teeth, signifying six to 12 days of growth. By multiplying that interval by the number of perikymata on a tooth’s surface, researchers can gauge how long it took for the tooth to mature. And that gives them an indication of the length of an individual’s childhood.

Neanderthals, Homo neanderthalensis, were the dominant hominid inhabiting most of what is now Europe and western Asia . Remains have been found as far south as Iraq and as far north as Great Britain . Fossil skulls reveal the distinctively prominent brows and missing chins that set them apart from later humans.

They thrived from about 150,000 to 30,000 years ago until their lineage failed for as-yet unknown reasons. Most researchers have argued that their life in extremely harsh, Ice Age-like environments, coupled with their limited technological skills, ultimately led to their demise.

In a study published last year in the journal Nature, other researchers contended that Neanderthal teeth took 15 percent less time to reach maturity than those in later Homo sapiens, suggesting to them that a Neanderthal childhood would be shorter than our own.

But Guatelli-Steinberg’s team wanted a broader comparison and therefore compared the teeth from Neanderthals to those of three modern populations – people currently living in Newcastle-upon-Tyne , U.K. ; indigenous people from southern Africa, and Inuit from Alaska dating from 500 B.C. until the present.

“We chose these three groups since they would provide a good cross-section of various populations from different regions of the world,” she said. “We feel that they give us some insights into the variation that exists within modern humans.”

For the study, the researchers used precise dental impressions Guatelli-Steinberg and Larsen made of 55 teeth believed to come from 30 Neanderthal individuals. These were compared to 65 teeth from 17 Inuit, 134 teeth from 114 southern Africans and 115 teeth from as many Newcastle residents. In all cases, the researchers tallied the number of perikymata on the enamel surface of the teeth.

Guatelli-Steinberg said that the results showed that the enamel formation times for the Neanderthals fell easily within the range of time shown by teeth from the three modern populations – a conclusion that did not support a shorter childhood for the Neanderthals.

Enticing though it may be, these new findings haven’t convinced the researchers that a Neanderthal childhood was equal to a modern human’s.

“The missing key bit of data to show that would be evidence for when the first molar tooth erupted in the Neanderthals, and we simple have no evidence of when that occurred,” she said.

The length of time is important, the researchers say, because unlike all other primates, humans have an extended period of childhood growth, during which brain matures both in size and through experiences. Some earlier hominids matured far more quickly than modern humans.

“The question is when exactly did that pattern of development evolve in the growth of humans,” she said.

Support for this research came from a grant from the Leakey Foundation and from the College of Social and Behavioral Sciences at Ohio State .

However, this is contradicted by a later study

Neanderthal Children Grew Up Fast
ScienceDaily (Dec. 5, 2007) — An international European research collaboration led by scientists at the Max Planck Institute for Evolutionary Anthropology reports evidence for a rapid developmental pattern in a 100,000 year old Belgian Neanderthal (Homo neanderthalensis).

A new report details how the team used growth lines both inside and on the surfaces of the child’s teeth to reconstruct tooth formation time and its’ age at death.

Scientists found differences in the duration of tooth growth in the Neanderthal when compared to modern humans, with the former showing shorter times in most cases. This faster growth resulted in a more advanced pattern of dental development than in fossil and living members of our own species (Homo sapiens).

The Scladina juvenile, which appears to be developmentally similar to a 10-12 year old human, was estimated to be in fact about 8 years old at death. This pattern of development appears to be intermediate between early members of our genus (e.g., Homo erectus) and living people, suggesting that the characteristically slow development and long childhood is a recent condition unique to our own species.

Neanderthal life history, or the timing of developmental and reproductive events, has been under great debate during the past few decades. Across primates, tooth development, specifically the age of molar eruption, is related to other developmental landmarks such as weaning and first reproduction.

Scientists have previously found evidence to both support and refute the idea that Neanderthals grew up differently than our own species. In this new study, researchers used information from the inside of a molar tooth, coupled with data from micro-computed tomography (micro-CT), as well as evidence of developmental stress on the outsides of tooth crowns and roots.

This yields the first chronology, or time sequence, for Neanderthal tooth growth, which differs from living humans. The Scladina Neanderthal grew teeth over a shorter period of time, and has more teeth erupted (present in the mouth), than similarly-aged fossil or living humans (Homo sapiens).

This suggests that other aspects of physical development were likely more rapidly achieved as well, implying significant differences in the behaviour or social organization of these ancient humans.

Journal reference: Tanya M. Smith, Michel Toussaint, Donald J. Reid, Anthony J. Olejniczak, Jean-Jacques Hublin, Rapid Dental Development in a Middle Paleolithic Belgian Neanderthal, Proceedings of the National Academy of Sciences USA December 2007


Another news item noted grooves in the teeth that seem to have been caused by cleaning their teeth with sharp little sticks

Neanderthal man cleaned his teeth, experts find

– Two molar teeth of around 63,400 years old show that Neanderthal predecessors of humans may have been dental hygiene fans, the Web site of newspaper El Pais reported on Tuesday.

The teeth have “grooves formed by the passage of a pointed object, which confirms the use of a small stick for cleaning the mouth,” Palaeontology Professor Juan Luis Asuarga told reporters, presenting an archaeological find in Madrid.

The fossils, unearthed in Pinilla del Valle, are the first human examples found in the Madrid region in 25 years, the regional government’s culture department said.

Neanderthals were predecessors of modern humans who inhabited much of Europe, North Africa and parts of Asia from about 125,000 to 30,000 years ago.

“There are two (teeth), perfectly preserved, in which the wear and tear of a human of about 30 years old is perceptible,” a government statement said.

© Thomson Reuters 2008 All rights reserved


How Neanderthal teeth grew.

Neanderthal teeth.

Scientists from the United Kingdom, France and Italy have studied teeth from Neanderthals with X-rays from the European Synchrotron Radiation Facility (ESRF). They found that the dental development of Neanderthals is very similar to modern humans. Their results are published in Nature this week.

 Neanderthals first appeared in Europe approximately 200,000 years ago and became extinct about 25,000 years ago. These predecessors of modern humans have always been considered genetically closer to us than any other members of the genus Homo. It has even been suggested that Neanderthals achieved adulthood faster than modern humans do today.

 A research team from the United Kingdom, France and Italy has recently shed new light on this theory by studying this species’ teeth. Teeth express genetic differences found between individuals and different populations more efficiently than any other tissues preserved in the fossil record. Studies with teeth can identify a timescale on the entire period of dental development that occurs from before birth until adulthood.

  Three-dimensional virtual reconstruction of the deciduous and permanent Neanderthal molars. Both enamel and dentin are rendered in transparency to show the pulp chamber and the root canals. Credits: Luca Bondiolli and Arnaud Mazurier.

 Scientists used the ESRF X-rays to study the enamel dentine junction of a deciduous and a permanent Neanderthal molar tooth (approximately 130,000 years old) that was found on a site in France. The technique used to image the teeth is high-resolution tomography at ID17. The researchers noticed that the samples showed more complex folding of the enamel dentine junction than their modern human counterparts. Some of the unique surface morphologies of Neanderthal molars clearly showed a deep embryological origin and are likely to have been functionally significant.

 Thin ground sections of the same Neanderthal molars revealed that the crowns and roots did not grow faster than those of modern humans. The permanent molar tooth studied had completed its root growth at about 8.7 years of age, which is typical of many modern human children today.

 Almost all deciduous teeth contained an accentuated birth line, or neonatal line that results from the changing physiology and stress of birth. The Neanderthal deciduous also showed a neonatal line with evidence of the usual perinatal physiological stress but with no signs of additional postnatal stress.

 Among anthropoid primates there is a close relationship between brain growth and tooth eruption. Scientists predicted that the first permanent molar eruption in this Neanderthal (6.8 years) fits a dental development schedule similar to those found in modern humans.

 The next step in the research is to find out whether Neanderthal teeth from sites dated to more recent times will reveal evidence of the demographic pressures that overcame the Neanderthals as they approached extinction.
Macchiarelli et al., How Neanderthal molar teeth grew, Nature online, 22 November 2006