Evolutionary Changes in the Masticatory Complex Following the Transition to Farming in the Southern...

Evolutionary Changes in the Masticatory ComplexFollowing the Transition to Farming in theSouthern Levant

R. Pinhasi,1* V. Eshed,2 and P. Shaw3

1Department of Archaeology, University College Cork, Cork, Ireland2Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel3School of Human and Life Sciences, Roehampton University, Holybourne Avenue, London,SW15 4JD, United Kingdom

KEY WORDS dental crown reduction; selective pressures; transition to agriculture; Levant

ABSTRACT A post-Pleistocene reduction trend in thedimensions of the masticatory complex followed the transi-tion to agricultural lifestyle in several world regions. Amajor limitation of previous studies is large temporal gapsbetween the analyzed skeletal populations, which do notallow the detection and analysis of a diachronic morpho-logical transition. In this work, we analyze a large numberof specimens from the southern Levant, where agriculturefirst emerged in situ and for which there is a good dia-chronic sequence of the shift from a hunting-gatheringway of life to a food producing, farming economy (12,000–7,000 uncalibrated bp). Changes in the masticatory com-plex are examined in the context of three prevailing dentalreduction models: the Probable Mutation Effect (Brace,1963; Brace and Mahler, 1971), Increasing Population

Density Effect (Macchiarelli and Bondioli, 1986) and Selec-tive Compromise Effect (SCE) (Calcagno, 1989). A series oflinear regressions of dimension vs. time and coefficients ofvariation for each dimension are analyzed. Our resultsindicate significant reduction in the buccolingual but notmesiodistal dental dimensions and in the ramus breadthand anterior height dimensions of the mandible but not inits overall size. These findings, taken together with lowcoefficients of variation for the buccolingual dimensions,suggest selective pressure resulting in reduction of specificdimensions. The observed trend is in partial accordancewith the SCE but differs from the trends observed in otherregions, and is therefore best explained as a region-specificvariant of the SCE. Am J Phys Anthropol 135:136–148,2008. VVC 2007 Wiley-Liss, Inc.

The Levant is the region in which some of the world’searliest farming communities first emerged. The transi-tion between foraging and food production economies inthe Levant was a major threshold in human prehistoryand involved profound changes in mobility, social organi-zation, subsistence, and technology (Henry, 1989; Kuijt,1994; Eshed et al., 2004a,b, 2006). In the southern Le-vant, the early Holocene Natufian culture (12,500–10,200, uncalibrated radiocarbon years before present;henceforth: ‘‘uncal bp’’) marks the onset of the transitionto a fully sedentary lifestyle with a subsistence base thatcontinues to rely on hunting, gathering, and foraging(Belfer-Cohen, 1991). It is generally divided into threemajor chronological phases: Early (11,700–11,300 uncalbp), Middle (recent) (11,300–10,500 uncal bp), and Final(late) (10,500–10,300 uncal bp) (Bocquentin et al., 2001;Valla et al., 2004; Fig. 1).The first agricultural communities in the Levant

emerged during the succeeding Pre-Pottery Neolithic Aperiod (PPNA, 10,000–9,200 uncal bp), with a subsist-ence base that combines reliance on cultivation ofdomestic cereals and legumes, the collection of wildseeds and fruits, and hunting (Bar-Yosef, 1989; Kuijt,1994). The PPNA displays architectural, technological,and artistic attributes that indicate cultural continuitywith their Natufian predecessors (Banning, 1998). Bythe middle of the following Pre-Pottery Neolithic B pe-riod (PPNB, 9,200–8,100 uncal bp) the subsistence baseshifted to include domestic cereals and a growing reli-ance on domesticated livestock (cattle, pigs, goats, andsheep). It marks the peak of the Pre-Pottery Neolithic

period in terms of cultural uniformity across a wide geo-graphic sphere of interaction, complex architecture, tech-nology, and art (Aurenche and Kozlowski, 1999). ThePre-Pottery Neolithic C (PPNC, 8,100–7,600 uncal bp)was a short transitional period, which is associated withthe gradual decline of the PPNB, possibly due to over-exploitation of resources (Galili et al., 2005). The PotteryNeolithic period (PN, 7,600–7,000 uncal bp) marks theend of a transformation from a hunter-gatherer socioeco-nomic system to a fully agricultural economy, the intro-duction of pottery, and the end of hunting (Orrelle andGopher, 2000).Pronounced reduction in jaw and tooth dimensions

was reported among Early Holocene populations fromEurope (Brace et al., 1987; y’Edynak, 1989; y’Edynakand Fleisch, 1983), North Africa (Chamla, 1980); Nubia(Greene, 1972; Carlson and van Gerven, 1977; vanGerven et al., 1977; Calcagno, 1986, 1989); and the NearEast (Dahlberg, 1960; Smith et al., 1984, 1986). Some of

Grant sponsors: Irene Levi-Sala CARE Foundation, National Geo-graphic Society, Israel Science Foundation.

*Correspondence to: Ron Pinhasi, Department of Archaeology,University College Cork, Cork, Ireland. E-mail: [email protected]

Received 7 February 2007; accepted 8 August 2007

DOI 10.1002/ajpa.20715Published online 28 November 2007 in Wiley InterScience

(www.interscience.wiley.com).

VVC 2007 WILEY-LISS, INC.

AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 135:136–148 (2008)

the observed reduction trends were addressed in the con-text of the transition from hunter-gatherer to a fullyNeolithic lifestyle (cf. Greene, 1972; Carlson and VanGerven, 1977; Armelagos et al., 1989; Calcagno, 1989;Larsen, 1995, 1997). These post-Pleistocene cranio- dentalchanges took place in a relatively short period in evolu-tionary terms (Hillson, 2005). The following models havebeen proposed to explain reduction trends in one or moreof the above mentioned regions:

a. The Probable Mutation Effect (PME) suggests that inthe absence of natural selection, mutations will be themain force acting towards a reduction of structuralsize and complexity of teeth and other organs. Thus,developmental processes, controlled by complexgenetic mechanisms, will be disrupted resulting in anincomplete or a simplified dental structure (Brace,1963; Brace and Mahler, 1971). Brace and Mahler(1971) hypothesized that the invention and use of pot-tery during the early Holocene and the subsequentchanges in food preparation techniques led to a relax-ation of selective forces on the masticatory apparatusand the onset of PME, which resulted in a consequentdecrease in tooth size.

b. Increasing Population Density Effect (IPDE) suggeststhat reduction in dental crown size was mainlyderived from changes in population densities associ-ated with the transition to a sedentary lifestyle. Thus,

the new post-Pleistocene environmental conditionswere associated with a new set of adaptive pressures.These triggered a selection for reduction in nutri-tional and metabolic requirements, which led to a cor-responding reduction in body size. Reduction in toothsize was therefore a byproduct of selection for smallerbody size (Macchiarelli and Bondioli, 1986).

c. Selective Compromise Effect (SCE) is a model thatwas introduced by Calcagno, based on his study ofreduction trends in post-Pleistocene Nubian popula-tions (1986, 1989). It proposes that larger morphologi-cally-complex crowns provide more surface area forcaries, which in turn can significantly affect the indi-vidual’s fitness. However, large crown area is essentialfor the mastication of abrasive foodstuff. In the caseof populations who undergo a subsistence shift fol-lowing the transition to agricultural economy, a selec-tive compromise must occur between a selection forsmaller teeth with less complex cusp pattern and thinenamel and a selection for bigger teeth with thickerenamel to counter occlusal wear. A central aspect ofthis model is the assumption that selection for smallerdentition is triggered by dental crowding and high prev-alence of cariogenic disease (cf. y’Edynak and Fleisch,1983; Calcagno and Gibson, 1988; y’Edynak, 1989),which is evident in Near Eastern and Nubian earlyHolocene archaeological populations (Dahlberg, 1960;Smith et al., 1984; Calcagno, 1986; Eshed et al., 2006).

Fig. 1. Map of the Natufian and Neolithic sites, by period.

137EVOLUTIONARY CHANGES IN THE MASTICATOR COMPLEX

American Journal of Physical Anthropology—DOI 10.1002/ajpa

The above models provide three different approaches tothe observed mandibular and dental reduction amongagricultural populations. The PME essentially suggestsmutation as the predominant mechanism that inducesmorphometric change and is hence a stochastic micro-evolutionary model. Both the IPDE and SCE modelsemphasize the role of selective pressures in the dentalreduction process. However, the IPDE model views den-tal reduction as a byproduct of selection for smaller bodysize following the decrease in nutrition and an increasein population densities during the Neolithic period(Machiarelli and Bondioli, 1986) while the SCE empha-sizes functional-based reduction in teeth dimensions asthe direct outcome of balancing selective pressures (Cal-cagno, 1989).

Each of the above models for post-Pleistocene dentalreduction is associated with a set of specific assumptionsand predictions (see also Christensen, 1998):

Model 1 (PME): All dental dimensions are reducedindicating a general decrease in size over time, vari-ation in all dimensions either increases or remainsconstant over time.

Model 2 (IPDE): Overall reduction in the main man-dibular and dental dimensions and a correspondingreduction in their metric variation. This conditionmust be associated with evidence of decrease inoverall health and a decrease in stature that beganfollowing a transition to sedentary lifestyle (cf. Mac-chiarelli and Bondioli, 1986).

Model 3 (SCE): Overall reduction in the main mandibu-lar dimensions and a corresponding reduction in allor a specific set of dental dimensions [i.e. total changein overall crown area, or a uniform trend of changein length or breadth dimensions that may potentiallyand differentially affect certain tooth groups (e.g. pos-terior dentition to reduce prevalence of caries)], andin their corresponding metric variation.

A major limitation of previous studies on post-Pleisto-cene dental and mandibular reduction trends was thattheir skeletal samples did not include representativespecimens from the period of transition. While Levantinejaw and dental reduction trends were previously studiedby Smith et al. (1984, 1986), their results were compro-mised by the limited sample size and combining speci-mens to groups that do not correspond to specificarchaeological phases and hence do not provide the suffi-cient resolution to address changes in the masticatorycomplex in relation to specific cultural changes. It there-fore remained unclear what sort of changes in the masti-catory complex occurred in this region. The availabilityof Natufian and Neolithic specimens that were recoveredduring the last 2 decades from excavations in Israeloffers a unique window into the study of morphologicalchange in human populations (Fig. 2). In this region,this process began with the transition to a fully seden-tary lifestyle (Natufian Period), followed by an increasein the reliance on cereals during the PPNA, the intro-duction of domestic livestock (Mid-PPNB) and eventuallythe introduction of pottery (PN). Hence, a major issue inthe Levantine diachronic sequence is whether the inten-sity and particular pattern of a process of dental and jawreduction occurred in a uniform manner across the totaltime span, or rather drastically changed in intensity andpattern following the transition between the Natufianand PPNA periods (hence representing a ‘‘punctual’’

rather than a continuous trend). Moreover it is of inter-est to examine whether the invention of pottery resultedin the intensification of existing reduction trends as sug-gested by the PME model.In this study we investigate the following:

1. The nature of the reduction trend: (a) which crowndimensions and mandibular dimensions are signifi-cantly reduced over time; and (b) is there any evi-dence to suggest that the trend intensified or reducedin magnitude during (i) the early Neolithic period(PPNA onwards) and/or (ii) the PN period.

2. Assuming that a significant reduction trend is ob-served, we investigate which of the above models bestfit our data by assessing the obtained results in con-junction with published reports on diachronic changesin the prevalence of dental pathologies (Eshed et al.,2006), stature (Smith et al., 1984), cranial dimensions(Pinhasi, 2004); and overall health (Smith et al., 1984).

Subsequently, we address the relationship between theobserved trend and those reported for other populationsthat underwent a similar cultural/economic transition toinspect whether some of its aspects are universal amongpost-Pleistocene populations that underwent a transitionto agricultural economy.

MATERIAL AND METHODS

We analyzed a total sample of 242 individuals (some ofwhich are represented by only few isolated teeth) fromfive archaeological periods (Table 1, Fig. 1). Only some ofthe archaeological phases from which the skeletons wererecovered are associated with radiocarbon dates for theirspecific layer/context. The rest were given an averageuncalibrated date in years before present (uncal bp) for

Fig. 2. A schematized chronology of the Natufian and Neo-lithic cultures of the Levant based on uncalibrated 14C dates,and associated skeletal samples utilized in this study.

138 R. PINHASI ET AL.


the period with which they are associated, based on theLevant Neolithic chronology published in Garfinkel (1999).The most commonly applied dental measurements are

the maximum length and breadth dimensions of thetooth crown, also known as the mesiodistal and buccolin-gual diameters, respectively. Buccolingual and mesiodistaldimensions were measured using the method of Moorrees(1957). All left-sided teeth were measured except whenmissing, worn, or poorly preserved. In such cases, theright side antimeres were used instead. Loose dentitionthat could be assigned to the correct anatomical positionwas also measured when associated archaeological docu-mentation indicated that it belongs to a single specimen.We excluded all mesiodistal dimensions when inter-prox-imal wear or pathology resulted in reduction of the over-

all crown length and buccolingual dimensions when oc-clusal wear or pathology reduced the overall crownheight below the point at which maximum breadthdimension appear to have been located (cf. Christenen,1998). Jaw dimensions were measured based on thestandard methodology specified in Brauer (1988).Specimens from the Department of Anatomy and An-

thropology, Tel-Aviv University, were measured by RPand VE. All other specimens were measured by RP. Dataconsistency was assessed by examining inter-observererror on a randomly selected subset of 22 Natufian speci-mens that was independently measured by RP and VE.A t-test for two independent samples on the two datasets showed that none of the means or standard devia-tions was significantly different at 99% confidence inter-

TABLE 1. Summary table of chronology, sites, and number of specimens

Site Na Period Date Lab no. References

Areq el Ahmar 2 Natufian (ancient) 11700 2 11300 BP RANGE Garfinkel, 1999Ein Mallahab 13 Natufian (ancient) 11700 2 11300 BP

11590 6 540RANGE

Ly-1660Belfer-Cohen, 1988;

Bocquentin et al.,2001; Valla et al., 2004

Ein Mallahab 9 Natufian (recent) 11300 2 10500 BP RANGE Belfer-Cohen, 1988;Bocquentin et al.,2001; Valla et al., 2004

Ein Mallahab 15 Natufian (final) 10500 2 10300 BP RANGE Bocquentin et al., 2001;Valla et al., 2004

Hayonim Cave 12 Natufian (ancient) 12010 6 180 OXA-743 Belfer-Cohen, 1988Hayonim Cave 7 Natufian

(recent 5 middle)11300 2 10500 BP RANGE Belfer-Cohen, 1988;

Bocquentin et al.,2001; Valla, 2004

Rakefetb 4 Natufian recentand final

10980 6 260 I-7032 Belfer-Cohen, 1988

Nahal Orenb 10 Natufian (middle) 11300 2 10500 BP RANGE Noy, 1989Nahal Orenb 6 Natufian (Late) 10490 6 430 SMU-9 Belfer-Cohen, 1988Hatoulab 7 PPNA 10030 6 140 GifA 91360 Lechevallier and Ronen,

1994Jericho 11 PPNA 9551 6 63 BM-1327 Burleigh, 1983Abu Hureyrac,d 4 PPNB 8676 6 72 BM-1423 Burleigh et al., 1982Abu Hureyrad,e 6 PPNB 8330 6 100 Oxa-2168 Housley, 1994Abu Hureyraf 5 PPNB 8190 6 77 BM-1424 Burleigh et al., 1982Abu Hureyrad,g 3 PPNB 8490 6 100 OxA-878 Housley, 1994Abu Ghosh 22 PPNB 60 6 8895 RT-2453 Segal and Carmi, 2003Yiftahelb 6 PPNB 8870 6 90 Pta-4242 Garfinkel et al., 1987Bananab 7 PPNB 9200 2 8100 RANGE Hershkovits pers. com.Abu Madib 4 PPNB 9200 2 8100 RANGE Hershkovits pers. com.Nahal Betzetb 1 PPNB 8330 6 100 RT-1394 Carmi and Segal, 1992Nahal Oren

Neolithicb6 PPNB 9200 2 8100 RANGE Noy et al., 1973

Kefar Hahoreshb,h 28 PPNB 8650 6 50 RTT-3733.1 Goring-Morris et al.,2001

Jerichod 9 PPNB 8710 6 150 BM-253 Burleigh, 1983Bastai 3 PPNB 8155 6 50 GrN-14538 Muheisen. and Gebel,

1987Atlit Yamb 31 PPNC 7755BP 6 55 RT2495,93 Galili, 2004Lod (Neve Yaraq)b 3 PN 7050 6 100 RT-1642 Gopher and Blockman,

2004Tell Roim Westb 4 PN 7600 2 7000 RANGE Dani Nadel pers. com.Neve Yama 4 PN 6565 6 70 RT724 Wreschner, 1977

PA is the Period’s average date in uncalibrated years BP, entries for Neolithic specimens are from the chornological table publishedby Garfinkel (1999). Natfufian chronology is based on Valla et al., 2004; Bocquentin et al., 2001; Belfer-Cohen, 1988.a Based on number of specimens.b Department of anatomy and anthropology, Tel Aviv University, Israel.c Phase 6, Trench C.d Natural History Museum, London.e Phase 5, Trench E.f Trench B.g Trench D, Levels 68, Phase 4, Trench D.h Based on Minimum Number of Individuals-MNI.i Anatomy Centre University of Gottingen, Germany.



val. None of the specimens was sexed since a large partof the sample contained mandibles and crania withoutpostcranial remains. However, a previous study on theskeletal samples from the Natufian and Pre-Pottery peri-ods indicate a similar degree of sexual dimorphism acrossthe studied time interval (around 10%, Smith et al., 1984).Linear regressions of change in dimension over time

were calculated for (a) the total set; (b) the Natufian andPre-Pottery Neolithic specimens (excluding the PN set)to test reduction trends in the jaw and dentition. We an-alyzed 32 regressions of mesiodistal and buccolingualdimensions representing the complete adult dentitionand nine regressions of mandibular measurements rep-resenting the main dimension of the mandibular corpusand ramus. For each dimension studied, only regressionswith a statistically significant value for the regressionslope’s coefficient indicate a significant diachronic trend.These were then examined to assess the magnitude anddirection of the change over time. Additionally, scatterplots for all significant dimensions were visually exam-ined to support the linearity in the observed trends.We then analyzed whether the reduction trend has

changed in intensity following the transition from theEpipalaeolithic (Natufian) to the Neolithic (PPNA-PN)period. Analyses of Covariance (Ancova) were performedto detect any significant difference in the magnitude ofthe reduction trend for each dimension. The null hypoth-esis was that there is no significance difference in themagnitude of the slope for a given dimension. A signifi-cant P value (set at P \ 0.05) indicates that the regres-sion slopes for each period are different and that thenull hypothesis should be rejected.The Coefficient of Variation (CV) provide a standar-

dized way to compare the magnitude of morphologicalvariation in the dentition and other morphological struc-tures (Sokal and Braumann, 1980):

CV ¼ 100S

X

S, standard deviation and X, arithmetic mean.For small sample size, a correction factor should be

applied:

CVc ¼ CVð1þ ð1=4nÞÞ;

n, sample size (Plavcan and Cope, 2001).

Low CV values suggest that a given dimension is sub-ject to directional selection (Mayr, 1963; Leamy andBader, 1970). While there have been some cases wherethe amount of variation in the phenotype has increasedwith directional selection (Guthrie, 1963), the majority ofstudies indicate that directional selection is responsiblefor a reduction in phenotypic variability (Frayer, 1978).CVs were calculated for the data set to detect dia-

chronic changes in variability of mesiodistal vs. buccolin-gual dimensions for (1) the total dental set (2) upper andlower dentition, and (3) on the total set of dental dimen-sions by period, including the tripartite division of theNatufian (Fig. 2). The sum of the mesiodistal mandibulardimensions provides an estimate of the total length ofthe lower dental arch. We used multiple imputationssoftware Norm V2.02 (Schafer, 1999) to replace missingvalues for up to four teeth (but not from the same toothgroup) and then calculated the sum of half of the lowerarcade, multiplied by two to obtain an estimate of itsoverall length. The low number of specimens with nearlycomplete upper dentition did not allow the estimation ofa similar sum for the upper arcade. According to Sokaland Baunmann (1980), it is only possible to comparebetween two coefficients of variation from independentsamples by a conventional t-test when the distribution ofthe sample coefficients approaches normality. Since somedeviation from normality was noted in the case of bothparameters, we applied a robust nonparametric test(Wilcoxon for two related samples) to assess differencebetween the CVs of mesiodistal and buccolingual dimen-sions of the lower dental arcade.

RESULTS

Dental data

Table 2 provides results of the regression analyses ofchanges over in upper and lower mesiodistal and bucco-lingual dimensions (sample size, slope value, r2 value,and significance value). All the buccolingual dimensionsof both the upper and lower dentition, with the exceptionof upper second incisor and upper canine, were signifi-cantly reduced. The only mesiodistal dimensions thatwere significantly reduced are those of the second upperincisor and the lower canine. In total, 16 of the regres-sion slopes are significant at P \ 0.05; out of which

TABLE 2. Linear regressions of teeth dimensions over time for the total set of specimens

Upper N r2Slope mm/1000 years Sig. F Lower N r2

Slope(mm/1000 years) Sig. F

I1MD 77 0.043 0.100 Ns 0.9 I1MD 71 0.002 0.023 Ns 0.7I1BL 78 0.061 0.070 * 1.4 I1BL 72 0.254 0.177 ** 0.1I2MD 69 0.067 0.098 * 0.1 I2MD 89 0.004 20.027 Ns 0.2I2BL 70 0.010 0.039 Ns 1.5 I2BL 91 0.136 0.164 ** 1.1CMD 105 0.000 0.004 Ns 0.8 CMD 119 0.044 0.081 * 0.1CBL 106 0.036 0.091 Ns 3.4 CBL 120 0.099 0.158 ** 2.0P3MD 92 0.026 0.086 Ns 0.1 P3MD 128 0.024 0.026 Ns 0.6P3BL 91 0.181 0.228 ** 0.2 P3BL 129 0.249 0.234 ** 0.0P4MD 90 0.026 20.067 Ns 0.6 P4MD 125 0.002 20.021 Ns 0.8P4BL 90 0.152 0.191 ** 0.1 P4BL 122 0.082 0.125 ** 1.2M1MD 107 0.000 0.001 Ns 3.7 M1MD 148 0.010 0.054 Ns 0.5M1BL 107 0.122 0.185 ** 1.6 M1BL 151 0.144 0.171 ** 0.0M2MD 89 0.002 20.029 Ns 0.0 M2MD 150 0.015 0.061 Ns 0.6M2BL 88 0.112 0.217 ** 0.0 M2BL 151 0.075 0.151 ** 0.7M3MD 64 0.013 20.085 Ns 0.1 M3MD 107 0.007 0.050 Ns 0.0M3BL 63 0.150 0.260 ** 0.2 M3BL 104 0.068 0.145 ** 4.9*

Slope values are in mm per 1000 years, Sig. indicates significant slope values at * 5 P\ 0.05, and ** 5 P\ 0.01.



seven are of the upper dentition and nine of the lowerdentition and only two are of mesiodistal dimensions.Thirteen of the regression slopes show a reduction rategreater than 0.1 mm/1000 years (Table 2, bold ink); noneof which are of mesiodistal dimensions. These include allthe buccolingual dimensions of the lower dentition, andthe buccolingual dimensions of the posterior upper denti-tion (premolars and molars). Figure 3 illustrates some ofthe regression slopes for both significant (buccolingual)and nonsignificant (mesiodistal) dental dimensions. Theaverage slope value for the significant maxillary bucco-lingual dimensions is 0.19 and 0.17 mm/1000 years forthe mandibular dentition. The average slope value forthe buccolingual dimensions of the posterior maxillarydentition is 0.22 mm/1000 years and 0.16 for the poste-rior maxillary dentition. The average slope rate for theanterior buccolingual dimensions of the lower dentitionis 0.17 mm/1000 years. The average slope rate for thesignificant mesiodistal dimensions is 0.09 mm/1000 yearsand is therefore approximately half the rate of the aver-age reduction in buccolingual dimensions. Table 2 alsoprovides the results of the Ancova for each dimension.The only difference in slopes between the Natufian andNeolithic sets was for in the case of the buccolingualdimension of the lower third molar. Since P value wasset to (P \ 0.05) it was expected that at least one of the32 slopes will flag significant by chance. Hence the nullhypothesis, that there is no significant difference in theslope values of the Natufian vs. Neolithic sets, shouldnot be rejected.Table 3 provides the results of the regressions on the

same data set excluding all PN specimens (11 in total).The significance tests of the slopes yielded very similarresults. Three of the dimensions that were significantlyreduced in the previous analysis are nonsignificant inthe current test: the lower buccolingual dimension of thethird molar, the mesiodistal dimension of the upper sec-ond incisor, and the mesiodistal dimension of lower ca-nine. The latter were only significant at P \ 0.05 in thecase of the analysis of the total set. In the current analy-sis, 13 of the regression slopes are significant at P \0.05; out of which six are of the upper dentition andseven of the lower dentition and all are of buccolingualdimensions. Twelve of the regression slopes show areduction rate greater than 0.1 mm/1000 years (Table 3,bold ink). These include all the buccolingual dimensionsof the lower dentition with the exception of the lowerthird molar, and the buccolingual dimensions of theposterior upper dentition (premolars and molars). Ittherefore appears that the trend of significant reductionin the buccolingual dimensions of all dentition and thehigher rate of reduction for the posterior upper denti-tion and all the buccolingual dimensions of the lowerarcade is not an artifact of the inclusion of the PNgroup.Results of the analysis of CV by period for the upper

and lower dentition are provided in Tables 4 and 5,respectively. The nonparametric test on the total periodindicates a significant difference (P \ 0.01) between themesiodistal and buccolingual CVs. A significant differ-ence (P \ 0.01) was also detected when analyzing eachjaw dimensions separately. Paired tests for each period(except for PN due to small sample size) showed that dif-ferences are highly significant for the early/ancientNatufian period, and the late/final Natufian period, butnonsignificant for the middle/recent Natufian period andfor the PPNA, PPNB, and PPNC periods (Fig. 4).

The analysis of the sum of the mesiodistal mandibulardimensions was used to estimate whether there were anysignificant changes over time to the total length of thelower dental arch. Regression of the sum of the lowermesiodistal dimensions vs. time (in years bp) indicates nosignificant trend while a regression of the average lowerbuccolingual dimension per specimen over time shows astatistically significant reduction trend (P\ 0.01).

Mandibular data

The regressions of change in each of nine mandibulardimensions over time (in 1000 years) is provided in Table 6(sample sizes, slope values, r2 values, and significancevalues). It is evident that only the ramus breadth andanterior symphyseal height dimensions were signifi-cantly reduced over the time period (Table 6). Sinceramus height and breadth dimensions are significantlycorrelated (r 5 0.425, P \ 0.01, and n 5 72), the signifi-cant reduction in ramus breadth alone indicates a uni-directional change in the overall shape of the ramus asit becomes narrower without a corresponding change inheight.Figure 5 illustrates the regression slopes for the two

dimensions with a significant reduction trend (symphy-seal height—A, and ramus breadth—C), which contrastwith the no significant change in the dimension of themandibular length (Fig. 5B).The exclusion of the PN group (Table 7) did not

change the results but yielded a lower significance valuefor the slope of the ramus breadth dimension (P \ 0.05).The slope parameters indicate a slightly slower reduc-tion rate in ramus breadth dimension (0.55 mm/1000years) and for the symphyseal height dimension (0.795mm/1000 years).

DISCUSSION

Our statistical analysis indicates reduction mainly inthe buccolingual dimensions of the posterior upper denti-tion and both the anterior and posterior lower dentition.The reduction in dimension over time is significant for14 out of the 16 buccolingual dimensions and in only 2 ofthe 16 mesiodistal dimensions. The analysis of the man-dibular dimensions shows that only two dimensions outof the nine, the anterior symphyseal height and ramusbreadth, were significantly reduced. It therefore indi-cates a diachronic reduction trend that is nearly uniformacross the dentition and that is not associated with anoverall reduction of mandibular size, but rather withparticular changes in the corpus height at the mandibu-lar symphysis and a reduction in ramus breadth.The average slope value for the buccolingual dimen-

sions is 0.17 mm/1000 years, which is a greater figurethan the one reported by Brace et al. (1987) for Euro-pean Neolithic populations (0.049 mm/1000 years for theaverage maxillary buccolingual dimension and 0.041mm/1000 years for the average mandibular buccolingualdimension). Brace et al. (1987) report that the rate ofreduction in buccolingual dimensions in general and inmaxillary dentition in particular is accelerated amongpost-Pleistocene European populations when comparedwith the rates among Late Pleistocene populations. Cal-cagno (1989) in his study of diachronic dental trendsamong post-Pleistocene Nubian populations notes that‘‘length dimensions do not reduce with nearly the consis-tency nor magnitude as the breadth, and some even dis-



Fig. 3. Bivariate scatterplots of both significant (right column, A, C, E) and nonsignificant (left column, B, D,) regression slopesof change in dental dimensions over time (in uncalibrated radiocarbon years). [Color figure can be viewed in the online issue, whichis available at www.interscience.wiley.com.]



play insignificant decreases.’’ Thus, our current resultsdo not stand in contrast to those reported by Brace et al.(1987) and Calcagno (1989), but rather indicate a parti-cularly pronounced reduction trend that mainly affectsthe buccolingual dimensions of the Levantine popula-tions.Lack of significance in 14 out of the 16 mesiodistal

dimensions taken together with no significant reductionin the mandibular size and estimated lower arch lengthsuggest that both the mandibular overall size dimen-sions and the overall dental arcade were not signifi-cantly reduced over time. The difference in the CVs formesiodistal vs. buccolingual dimensions suggest thatselective pressures acted on the buccolingual dimensionsand resulted in their overall reduction over time butthat these pressures did not act on the mesiodistal andoverall mandibular size dimensions. It therefore appearsthat in the southern Levant, dental reduction was notassociated with a reduction in overall jaw dimensions aswas reported in the case of Nubia (Calcagno, 1989) andSerbia (y’Edynak, 1989).Which of the above models best explain this pattern of

mandibular and dental reduction? The PME model canbe rejected as a possible mechanism behind the observedreduction trend since the data indicates a uniformchange in specific dimensions, which best fits a model ofdirectional selection rather than one that proposes theaccumulation of random mutations. Furthermore, theexclusion of PN specimens from the analysis of dentalreduction did not significantly alter the overall dental ormandibular reduction patterns. It therefore appears thatthe observed trend continues during the PN period andthat more than likely, the development of pottery in theLevant did not by itself mark a major shift in the dietaryhabits of Levantine populations (also cf. Gopher, 1998).Our results do not support the assumptions that

underlie the IPDE model. First, there is no reduction inthe overall size of the dentition but particularly in itsbuccolingual dimensions. Secondly, there is no significantreduction in overall mandibular size (no reduction inmandibular corpus length and breadth dimensions). Areport on average stature of males and females duringthe Natufian, PPNA, and PPNB periods in the southernLevant region (Smith et al., 1984) shows no significantdecrease in stature following the transition to agricul-ture. Craniometric analyses on Natufian and PPNB popu-

lations show no evidence for overall gracilisation anddecrease in all cranial dimensions following the transi-tion to agriculture (Pinhasi, 2004). Thirdly, the IPDEassumes that selection for smaller body size would onlyoccur in response to overall deterioration in the healthstatus of the early agricultural populations. While dete-rioration in health was indeed reported in the case ofmany world regions (cf. Larsen, 1995), it does not agreewith data for the southern Levant, which indicates noevidence for the deterioration in overall health followingthe transition (Smith et al., 1984). It therefore appearsthat the IPDE does not provide a satisfactory explana-tion for the observed Levantine trend.Our results are compatible with certain aspects of the

SCE model: evidence of selection for smaller buccolin-gual dimensions (low CV values) and a nearly uniformreduction trend in this dimension. However, there is nosignificant change over the span of this analysis in over-all mandibular length (Fig. 4) or in lower dental archdimensions (as estimated from the sum of the mesiodis-tal dimensions of the lower dentition). This contrast withsignificant reduction in ramus breadth and anteriorheight dimensions.The SCE model associates the reduction trends in den-

tal dimensions following the transition to agriculturewith changes in the prevalence rates of two pathologicalconditions: malocclusion and dental infections, which aremainly the outcome of an increase in the prevalenceof caries (Calcagno, 1989; Larsen, 1997; Christensen,1998). There is no published data on dental crowdingand malocclusion among the southern Levantine popula-tion. A recent study by Eshed et al. (2006) on the sameskeletal samples that were analyzed in this work reportsno significant differences in the prevalence of caries,periapical lesions, and antemortem tooth loss betweenthe Natufian and Neolithic populations. However, thestudy revealed a high prevalence of periodontal disease(PD) among the Natufians, which is significantly reducedduring the PPN periods. According to Eshed et al.,(2006) the differences in PD do not appear to be associ-ated with changes in overall oral hygiene or in diet butare most likely the outcome of physiological causes dueto the application of extensive occlusal forces in the mas-tication of abrasive food during the Natufian period.This observation is further supported by evidence of dif-ferences in wear pattern among the two populations: the

TABLE 3. Linear regressions of teeth dimensions over time for the total set excluding the Pottery Neolithic group

Upper N r2Slope

(mm/1000 years) Sig. Lower N r2 Sig.Slope

(mm/1000 years)

I1MD 73 0.036 0.096 Ns I1MD 64 0.002 Ns 20.026I1BL 74 0.100 0.093 ** I1BL 65 0.196 ** 0.165I2MD 64 0.023 0.061 Ns I2MD 82 0.024 Ns 20.072I2BL 65 0.014 0.048 Ns I2BL 84 0.081 ** 0.130CMD 99 0.002 20.019 Ns CMD 111 0.025 Ns 0.066CBL 100 0.025 0.082 Ns CBL 112 0.064 ** 0.134P3MD 88 0.025 0.091 Ns P3MD 119 0.003 Ns 0.028P3BL 87 0.122 0.198 ** P3BL 120 0.230 ** 0.244P4MD 86 0.038 20.085 Ns P4MD 119 0.004 Ns 20.037P4BL 86 0.121 0.183 ** P4BL 116 0.051 ** 0.104M1MD 102 0.008 20.066 Ns M1MD 140 0.002 Ns 0.025M1BL 102 0.101 0.181 ** M1BL 143 0.089 ** 0.137M2MD 84 0.004 20.004 Ns M2MD 142 0.016 Ns 0.068M2BL 84 0.097 0.219 ** M2BL 143 0.067 ** 0.148M3MD 62 0.007 20.064 Ns M3MD 100 0.003 Ns 0.011M3BL 61 0.107 0.207 ** M3BL 97 0.016 Ns 0.076

Slope values are in mm per 1000 years, Sig. indicates significant slope values at * 5 P\ 0.05, and ** 5 P\ 0.01.



TABLE

5.Tooth

mea

suremen

tsandcoefficien

tof

variation

ofthelower

den

tition

(all

periodsexcludingPN)

EarlyNatufian

Middle

Natufian

FinalNatufian

PPNA

PPNB

PPNC

NMea

nSD

CV

NMea

nSD

CV

NMea

nSD

CV

NMea

nSD

CV

NMea

nSD

CV

NMea

nSD

CV

LI1MD

35.30

1.01

19.09

115.65

1.50

26.57

85.18

0.49

9.40

55.65

0.42

7.39

23

5.53

0.27

4.85

65.34

0.59

11.09

LI1BL

46.77

0.37

5.52

116.44

0.52

8.04

86.31

0.47

7.49

56.17

0.29

4.67

23

6.11

0.43

7.07

65.92

0.39

6.63

LI2MD

76.05

0.57

9.39

115.78

1.05

18.19

75.96

0.77

12.91

66.04

0.49

8.06

30

6.18

0.41

6.66

10

5.99

0.38

6.35

LI2BL

76.95

0.42

6.01

116.48

0.78

12.06

76.82

0.81

11.94

76.38

0.39

6.09

30

6.50

0.45

6.93

116.39

0.35

5.43

LCMD

97.10

0.40

5.60

13

6.96

0.71

10.15

10

6.86

0.44

6.39

10

6.82

0.82

12.09

44

6.84

0.45

6.55

13

6.65

0.38

5.76

LCBL

98.61

0.50

5.84

13

7.93

0.88

11.05

10

7.71

0.69

8.95

117.63

0.72

9.47

44

7.80

0.55

7.11

13

7.65

0.51

6.64

LP3MD

97.17

0.64

8.99

13

6.66

0.59

8.89

13

6.74

0.38

5.65

10

6.94

0.41

5.97

43

6.95

0.50

7.21

17

6.76

0.42

6.15

LP3BL

98.63

0.51

5.87

13

8.42

0.65

7.70

13

8.27

0.41

4.99

117.75

0.43

5.55

43

7.89

0.53

6.67

17

7.63

0.61

7.96

LP4MD

87.13

0.71

9.95

12

6.62

0.37

5.62

13

6.68

0.67

9.97

116.92

0.35

5.09

44

7.05

0.46

6.55

16

6.99

0.45

6.48

LP4BL

88.88

0.41

4.67

12

8.48

0.77

9.07

12

8.49

0.46

5.41

118.12

0.50

6.15

42

8.34

0.54

6.44

16

8.24

0.54

6.53

LM1MD

810.99

1.24

11.31

15

11.10

0.71

6.39

15

10.84

0.89

8.19

15

10.96

0.65

5.90

51

10.99

0.63

5.78

20

10.78

0.80

7.44

LM1BL

811

.35

0.53

4.63

15

11.29

0.51

4.56

15

11.02

0.64

5.77

15

10.67

0.57

5.36

52

10.80

0.63

5.81

22

10.70

0.45

4.20

LM2MD

910.79

1.00

9.31

13

10.62

0.43

4.10

16

10.62

0.73

6.91

14

10.41

0.51

4.87

58

10.61

0.63

5.90

17

10.37

0.78

7.54

LM2BL

911

.16

0.55

4.90

13

10.89

0.70

6.39

16

10.75

0.67

6.25

14

10.20

0.65

6.35

58

10.53

0.81

7.67

18

10.25

0.49

4.75

LM3MD

810.60

0.77

7.24

10

10.52

0.42

3.96

16

10.55

0.75

7.13

911

.00

0.65

5.86

42

10.43

0.95

9.12

710.26

0.85

8.28

LM3BL

811

.11

1.04

9.37

10

10.20

0.36

3.54

16

10.46

0.74

7.12

910.43

0.46

4.43

39

10.27

0.66

6.43

710.53

1.08

10.30

TABLE

4.Too

thmea

suremen

tsandcoefficien

tof

variation

oftheupper

den

tition

(all

periodsexcludingPN)

EarlyNatufian

Middle

Natufian

FinalNatufian

PPNA

PPNB

PPNC

NMea

nSD

CV

NMea

nSD

CV

NMea

nSD

CV

NMea

nSD

CV

NMea

nSD

CV

NMea

nSD

CV

UI1MD

69.25

1.51

16.39

79.02

0.42

4.68

98.97

0.53

5.87

38.83

0.50

5.67

29

8.87

0.66

7.40

118.68

0.46

5.30

UI1BL

67.46

0.49

6.63

87.61

0.21

2.74

97.22

0.40

5.49

37.73

0.21

2.73

29

7.32

0.39

5.38

117.07

0.32

4.59

UI2MD

86.96

0.76

10.89

67.05

0.32

4.48

86.84

0.63

9.21

37.34

0.17

2.28

24

6.81

0.65

9.58

96.76

0.22

3.24

UI2BL

86.86

0.48

6.93

76.66

0.91

13.70

86.56

0.38

5.72

36.81

0.56

8.15

24

6.74

0.62

9.27

96.47

0.40

6.20

UCMD

10

7.87

0.34

4.26

10

7.14

0.78

10.92

15

7.25

0.65

8.91

47.50

0.40

5.35

39

7.73

0.49

6.30

10

7.54

0.51

6.72

UCBL

10

8.86

0.62

7.06

10

8.43

0.91

10.77

15

8.63

0.54

6.26

48.88

0.52

5.83

39

8.55

0.68

7.99

10

8.44

0.50

5.96

UP3MD

10

7.10

0.50

6.98

10

6.91

0.92

13.29

18

6.75

0.74

11.03

46.98

0.48

6.90

24

7.04

0.54

7.69

86.58

0.56

8.45

UP3BL

10

9.75

0.97

9.99

10

9.66

0.90

9.34

18

9.43

0.56

5.98

49.36

0.05

0.57

24

9.24

0.53

5.79

89.25

0.47

5.11

UP4MD

10

6.70

0.83

12.45

116.60

0.27

4.13

17

6.32

0.48

7.61

46.71

0.44

6.56

23

6.95

0.57

8.21

116.69

0.50

7.53

UP4BL

10

9.76

0.74

7.56

119.84

0.63

6.38

17

9.42

0.67

7.11

49.64

0.57

5.88

23

9.04

0.78

8.66

119.50

0.31

3.23

UM1MD

1110.74

0.68

6.29

13

9.87

1.73

17.48

15

10.16

1.19

11.69

49.99

0.72

7.25

35

10.70

0.74

6.89

14

10.33

0.93

9.01

UM1BL

1112.34

0.74

6.02

12

11.95

0.80

6.70

15

11.69

0.81

6.92

411

.40

0.42

3.68

36

11.60

0.73

6.31

14

11.47

0.54

4.68

UM2MD

12

9.84

1.11

11.29

12

9.83

0.78

7.89

119.05

0.91

10.03

49.06

0.57

6.32

30

9.98

0.97

9.76

89.64

0.99

10.25

UM2BL

12

12.10

1.52

12.59

12

11.92

0.64

5.35

1111

.87

1.09

9.22

411

.59

0.76

6.57

30

11.66

1.00

8.54

811

.51

0.97

8.45

UM3MD

79.20

1.02

11.14

99.43

0.70

7.44

78.71

1.11

12.70

38.78

1.27

14.51

21

9.22

1.08

11.72

89.64

1.46

15.14

UM3BL

711

.35

1.45

12.78

911

.26

0.80

7.08

711

.35

0.61

5.41

310.54

0.94

8.88

21

10.87

0.75

6.88

710.64

0.92

8.64



Natufians have evenly distributed flat wear, while thePPN populations have a more angled wear and the pres-ence of cupped wear on occlusal surfaces. Similarchanges in wear pattern following the transition to agri-culture were observed in Nubia (Smith, 1984), Japan(Kasai and Kawamura, 2001) and other regions and arebelieved to reflect a reduction in toughness of agricul-tural diets.Therefore there is evidence for change in wear follow-

ing change in mastication demands, which may be asso-ciated with the observed reduction pattern in some ofthe mandibular dimensions and in the buccolingualdimensions of most of the dentition. This fits well withthe ‘‘Masticatory-Functional Hypothesis’’ of Carlson andVan Gerven (1977), which suggests that a decrease inthe functional demands placed on the masticatory com-plex among early agriculturalists lead to correspondingalterations in the craniofacial complex. The change inthe size of the dentition is then viewed as a compensa-tory process following reduction in the anteroposteriorgrowth of the craniofacial complex. Since this study didnot involve the analysis of craniofacial dimensions, it isnot possible at this stage to ascertain whether the Le-vantine transition involved a similar trend. However,previous craniometric analyses on much smaller Levan-tine samples shows that the Natufian’s vault and cranio-facial architecture differ from the PPNB (Abu Hureyra)sample. The Natufians had long vaults and a high andnarrow facial morphology while the Abu Hureyra(PPNB) population had shorter and broader vaults, andshorter faces (Pinhasi, 2004). Hence, the Natufian-Neo-lithic change in craniofacial and vault morphology is notone of a simple reduction in overall size as predicted bythe IPDE model but rather suggests adaptation to a newset of selective pressures (some of which are more thanlikely relating to changes in diet).Lack of change in caries rate may be the outcome of

SCE whereas dental reduction is counter-balanced by anincreasingly cariogenic diet as was noted in a diachronic

study of changes in dental dimensions among prehistoricagricultural populations from the Valley of Oaxaca, Mex-ico (Christensen, 1998). In other words, lack of evidencefor an increase in caries is not by itself contra evidencefor selection for smaller dental dimensions but ratherthe outcome of SCE. In the case of the southern Levan-tine populations, selection for smaller crown surface areaonly affected the shortening of the buccolingual dimen-sions as a reduction in the mesiodistal dimension of crownswould have led to change in the overall length of the den-tal arcades and a corresponding reduction in mandibularand maxillary dimensions. Hence, the observed reductionin buccolingual dimension and the retention of overall longdental arches and robust mandibles can be viewed as partof the overall compensatory balancing process.The major limitation of the current study is its inabil-

ity to assess the full array of morphological, pathologicaland ontogenetic factors that may have been part of theobserved reduction pattern. For this reason, and to avoidtautology, we focused on the assessment of our data inrelation to three models that explain post-Pleistocenedental and mandibular reduction. Our results best fitwith the SCE model, which takes into account the syn-ergy between selection for smaller dentition, which arerelated to both changes in masticatory-functional de-mands and prevalence of oral pathology. However, ourresults show that the SCE need not involve evidence foroverall mandibular size reduction particularly when thedimensions that are being reduced are buccolingual. Infact, a reduction trend in buccolingual dimensions willachieve a reduction in the overall crown area (and hencea reduced surface, which may be affected by caries),while avoiding the shortening of the overall length of themandibular and maxillary dental arcades. The reductionin the latter will follow a corresponding reduction inoverall mandibular dimensions, which will then result ina masticatory apparatus that is no longer adapted forthe mastication of abrasive diet.

CONCLUSIONS

In this study, we analyzed diachronic trends in themasticatory apparatus of late hunters and early farmersfrom the southern Levant region. Temporal trends ofchange in dental and mandibular dimensions wereexamined using a series of linear regressions. Our re-sults indicate a pronounced reduction trend that mainlyaffected the buccolingual dimensions of the upper andlower dentition. In total, 16 of the regression slopes are

Fig. 4. Differences in CV values for mesiodistal and bucco-lingual dimensions of the dentition, by period.

TABLE 6. Linear regressions of mandibular dimensions overtime for the total set of specimens

Variable N r2Slope

(mm/1000 years) Sig. F

RAMH 78 0.017 0.405 Ns 3.0MAXL 82 0.001 0.047 Ns 0.3RAMB 100 0.097 0.649 ** 0.0GONB 65 0.004 0.572 Ns 2.2CONDB 48 0.047 1.244 Ns 0.0ANTH 88 0.125 0.850 ** 0.2HM2_M1 109 0.001 0.056 Ns 1.0ANTHIC 97 0.011 1.049 Ns 0.9M2THIC 111 0.014 20.167 Ns 1.0

Slope values are in mm per 1000 years, Sig. indicates significantslope values at * 5 P\ 0.05, and ** 5 P\ 0.01.



significant; out of which seven are of the upper dentitionand nine of the lower dentition and only two are ofmesiodistal dimensions. The trend affected both Naturianand Neolithic populations and hence appears to havestarted prior to the period of initial crop domestication(PPNA). The average reduction rate (slope value) for thesignificant buccolingual dimensions and significant mesio-distal dimensions is 0.17 mm/1000 years. Interestingly,the reduction in the buccolingual dimensions of the lowerdentition was not accompanied by a corresponding reduc-tion in the overall dimensions of the mandible. Only theanterior symphyseal height and the ramus breadth weresignificantly reduced over time. Analysis of covarianceindicate that selection most likely acted only on the buc-colingual dimensions resulting in overall decrease incrown area but no overall decrease in dental arch length.

Fig. 5. Bivariate scatterplots of both significant (right column, A, C) and nonsignificant (left column, B) regression slopes ofchange in mandibular dimensions over time (in uncalibrated radiocarbon years). [Color figure can be viewed in the online issue,which is available at www.interscience.wiley.com.].

TABLE 7. Linear regressions of mandibular dimensionsover time for the total set of specimens excluding the

Pottery Neolithic group

Variable N r2Slope

(mm/1000 years) Sig.

RAMH 75 0.005 0.242 NsMAXL 77 0.033 20.979 NsRAMB 95 0.060 0.550 *GONB 61 0.031 0.883 NsCONDB 45 0.038 1.23 NsANTH 83 0.092 0.795 **HM2_M1 103 0.001 20.052 NsANTHIC 92 0.012 1.23 NsM2THIC 105 0.019 20.022 Ns

Slope values are in mm per 1000 years, Sig. indicates significantslope values at * 5 P\ 0.05, and ** 5 P\ 0.01.



Our results best fit with the ‘‘Masticatory-FunctionalHypothesis’’ of Carlson and Van Gerven (1977), which ispart of the SCE model (Calcagno, 1989). It suggests thatselective compromise may have affected the dental andmandibular dimensions of the southern Levantine post-Pleistocene population in a manner that is not similar toother post-Pleistocene trends (as it did not involve areduction in mandibular size). The fact that our studyfocused on the earliest farming communities in theregion during a relatively short period of time in evolu-tionary terms, suggests that we may have discerned theinitial phase of a complex evolutionary process andhence account for the difference between our results andthose reported from the above-discussed studies. Futureresearch will involve the assessment of wear patternsin relation to changes in craniofacial and masticatorycomplex and dental crowding to shed more light on thisprocess and its universalities.

ACKNOWLEDGMENTS

We thank Prof. Dani Nadel from Haifa University forhis kind permission to study some of the unpublishedPN material from the site of Tel Roim West (TRW),Israel. Prof. Nigel Goring-Morris from the Hebrew Uni-versity in Jerusalem gave permission to study some ofthe unpublished PPNB specimens from the site of KfarHaHoresh, Israel. We also thank Simon Mays for read-ing and editing the manuscript and the anonymousreferees for their helpful comments.

LITERATURE CITED

Armelagos GJ, Van Gerven DP, Goodman AH, Calcagno JM.1989. Post-Pleistocene facial reduction, biomechanics andselection against morphologically complex teeth: a rejoinder toMacchiarelli and Bondioli. Hum Evol 4:1–7.

Aurenche O, Kozlowski SK. 1999. La naissance du neolithiqueau proche orient. Paris: Editions errance.

Banning EB. 1998. The Neolithic period: triumphs of architec-ture, agriculture, and art. Near East Archaeol 61:188–237.

Bar-Yosef O. 1989. The PPNA in the Levant—an overview. Pale-orient 15:57–63.

Belfer-Cohen A. 1988. The Natufian settlement at Hayonim cave:a hunter-gatherer band, on the threshold of agriculture.Unpublished Ph.D. dissertation, Hebrew University, Jerusalem.

Belfer-Cohen A. 1991. The Natufian in the Levant. Ann RevAnthopol 20:167–186.

Bocquentin F, Sellier P, Murail P. 2001. La population natou-fienne de Mallaha (Eynan, Israel): denombrement, age audeces et recrutement funeraire. Paleorient 27:89–106.

Brace CL. 1963. Structural reduction in evolution. Am Nat97:185–195.

Brace CL, Mahler PE. 1971. Early Holocene changes in thehuman dentition. Am J Phys Anthropol 34:191–204.

Brace CL, Rosenberg KR, Hunt KD. 1987. Gradual change inhuman tooth size in the late Pleistocene and early Holocene.Evolution 41:705–720.

Brauer G. 1988. Osteometrie. In: Knusmann R, editor. Anthro-pologie: handbuch der vergleichenden biologie des menschen,Vol. 1. Stuttgart: Gustav Fische. p 160–231.

Burleigh R. 1983. Additional radiocarbon dates for Jericho (withan assessment of all the dates obtained). In: Kenyon K, HollandTA, editors. Excavations at Jericho, Vol 5: The pottery phasesof the Tell and other finds. London: Duckworth. p 760–765.

Burleigh R, Matthews K, Ambers J. 1982. British Museum nat-ural radiocarbon measurements XIV. Radiocarbon 24:229–261.

Calcagno JM. 1986. Dental reduction in early Holocene Nubia.Am J Phys Anthropol 70:349–363.

Calcagno JM. 1989. Mechanisms of human dental reduction: acase study from post-Pleistocene Nubia. Lawrence: Universityof Kansas Publications in Anthropology. p 18.

Calcagno JM, Gibson KR. 1988. Human dental reduction: natu-ral selection or the probable mutation effect. Am J PhysAnthropol 77:505–517.

Carlson DS, Van Gerven DP. 1977. Masticatory function andearly Holocene evolution in Nubia. Am J Phys Anthropol46:495–506.

Chamla MC. 1980. Etude des variations metriques des cou-ronnes dentaires du Nord-Africains de l’Epipaleolithique al’Epoque Actuelle. L’Anthropologie 84:254–271.

Christensen AF. 1998. Odontometric microevolution in the Val-ley of Oaxaca, Mexico. J Hum Evol 34:333–360.

Dahlberg AA. 1960. The dentition of the first agriculturists(Jarmo, Iraq). Am J Phys Anthropol 18:243–256.

Eshed V, Gopher A, Gage TB, Hershkovitz I. 2004a. Has thetransition to agriculture reshaped the demographic structureof prehistoric populations? new evidence from the Levant. AmJ Phys Anthropol 124:315–329.

Eshed V, Gopher A, Galili E, Hershkovitz I. 2004b. Muscoloske-letal stress markers (MSM) in Natufian hunter-gatherers andNeolithic farmers in the Levant: the upper limb. Am J PhysAnthropol 123:303–315.

Eshed V, Gopher A, Hershkovitz I. 2006. Tooth wear and dentalpathology at the advent of agriculture: new evidence from theLevant. Am J Phys Anthropol 130:145–59.

Galili E. 2004. Submerged settlements of the ninth to seventhmillennia BP off the Carmel Coast. Ph.D. thesis, Tel Aviv Uni-versity.

Galili E, Eshed V, Gopher A, Hershkovitz I. 2005. Burial prac-tices at the submerged Pre-Pottery Neolithic C site of Atlit-Yam, Northern Coast of Israel. BASOR 339:1–19.

Garfinkel Y. 1999. Radiometric dates from the eighth millen-nium B.P. Israel. BASOR 315:1–13.

Garfinkel Y, Carmi I, Vogel JC. 1987. Dating of horsebean andlentil seeds from the Pre-Pottery Neolithic B village of Yifta-hel. Isr Explor J 37:40–42.

Gopher A. 1998. Early pottery-bearing groups in Israel—thePottery Neolithic period. In: Levy TE, editor. The archaeologyof society in the Holy Land. London: Leicester UniversityPress. p 205–221.

Gopher A, Blockman N. 2004. Excavations at Lod (NeveYaraq)and the Lodian culture of the Pottery Neolithic period. Atiqot47:1–50.

Goring-Morris AN, Boaretto E, Weiner S. 2001. Radiometricdating of the PPNB mortuary site of Kfar HaHoresh, LowerGalili, Israel: problems and preliminary results. J Isr Soc31:213–217.

Greene DL. 1972. Dental anthropology of early Egypt and Nubia.J Hum Evol 1:315–324.

Guthrie RD. 1963. Variability in characters undergoing rapidevolution, an analysis of Microtus molars. Evolution 19:214–233.

Henry DO. 1989. From foraging to agriculture: the Levant atthe end of the Ice Age. Philadelphia: University of Pennsylva-nia Press.

Hillson S. 2005. Dental anthropology, 2nd ed. Cambridge: Cam-bridge University Press.

Housely RA. 1994. Eastern Mediterranean chronologies: TheOxford AMS contribution. Radiocarbon 36:55–73.

Kasai K, Kawamura A. 2001. Correlation between buccolingualinclination and wear of mandibular teeth in ancient. ArchOral Biol 46:269–273.

Kujit I. 1994. Pre-Pottery Neolithic A settlement variability: evi-dence for sociopolitical developments in the Southern Levant.J Med Archaeol 7:41–68.

Larsen CS. 1995. Biological changes in human populations withagriculture. Ann Rev Anthropol 24:185–213.

Larsen CS. 1997. Bioarchaeolgy. Cambridge: Cambridge Univer-sity Press.

Leamy JL, Bader RS. 1970. Stabilizing selection for odonto-metric traits in Peromyscus leucopus. Am Midl Nat 84:521–536.



Macchiarelli R, Bondioli L. 1986. Early Holocene reductions inhuman dental structure: a reappraisal in terms of increasingpopulation density. Hum Evol 1:405–417.

Mayr E. 1963. Animal species and evolution. London: BelknapPress.

Moorees CFA. 1957. The Aleut dentition correlative study ofdental characteristics in an Eskimoid people. Cambridge: Har-vard University Press.

Muheisen M, Gebel HG. 1987. Report on the first two seasons ofexcavations at Basta (1986–1987). Annu Dep Antiq Jordan31:548–554.

Noy T. 1989. Some aspects of Natufian mortuary behaviour atNahal Oren. BAR Int Ser 508:53–58.

Noy T, Legge AJ, Higges ES. 1973. Recent excavations at NahalOren, Israel. Proceedings of the Prehistoric Society 39:25–99.

Orrelle E, Gopher A. 2000. The Pottery Neolithic period. In:Kuijt I, editor. Life in Neolithic farming communities: socialorganization, identity and differentiation. New York: KluwerAcademic. p 295–308.

Pinhasi R. 2004. A new model for the spread of the first farmersin Europe. Doc Praehist 30:1–76.

Plavcan JM, Cope D. 2001. Metric variation and species recogni-tion in the fossil record. Evol Anthropol 10:204–222.

Schafer JL. 1999. NORM: multiple imputation of incompletemultivariate data under a normal model, version 2. Softwarefor Windows 95/98/NT, available at http://www.stat.psu.edu/�jls/misoftwa.html.

Segal D, Carmi I. 2003. Radiocarbon dating. In: Khalaily H,Marder O, editors. The Neolithic site of Abu Ghosh: the 1995excavations. Tel-Aviv: Israel Antiquities Reports No. 19.

Smith BH. 1984. Patterns of molar wear in hunter-gatherersand agriculturalists. Am J Phys Anthropol 63:39–56.

Smith P, Bar-Yosef O, Sillen A. 1984. Archaeological and skele-tal evidence for dietary change during the late Pleistocene/early Holocene in the Levant. In: Cohen MN, Armelagos GJ,editors. Paleopathology at the origins of agriculture. New York:Academic Press. p 101–136.

Smith P, Wax Y, Adler F, Silberman U, Heinic G. 1986. Post-Pleistocene changes in tooth root and jaw relationships. Am JPhys Anthropol 70:339–348.

Sokal RR, Braumann CA. 1980. Significance tests for coeffi-cients of variation and variability profiles. Syst Zool 29:50–66.

Valla FR, Khalaily H, Valladas H, Tisnerat-Laborde N, SamuelianN, Bocquentin F, Rabinovich R, Bridault A, Le Dosseur G,Rosen A, Dubreuil L, Bar-Yosef D, Belfer-Cohen A. 2004. Lesfouilles de Mallaha en 2000 et 2001: 3eme rapport preliminaire.J Isr Prehist Soc 34:49–184.

Van Gerven DP, Armelagos GJ, Rohr A. 1977. Continuity andchange in cranial morphology of three Nubian archaeologicalpopulations. Man 12:270–277.

Wreschner E. 1977. Neve Yam. A submerged late-Neolithic set-tlement near Mount Carmel. Eretz Israel 13:260–271.

y’Edynak G. 1989. Yugoslav Mesolithic dental reduction. Am JPhys Anthropol 78:17–36.

y’Edynak G, Fleisch S. 1983. Microevolution and biologicaladaptability in the transition from food-collecting to food pro-ducing in the Iron Gates of Yugoslavia. J Hum Evol 12:279–296.



Evolutionary Changes in the Masticatory Complex Following the Transition to Farming in the Southern...

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