Questions of khoesan continuity: Dental affinities among the indigenous holocene peoples of South Africa

Questions of Khoesan Continuity: Dental AffinitiesAmong the Indigenous Holocene Peoples of SouthAfrica

Joel D. Irish*

Research Centre in Evolutionary Anthropology and Palaeoecology, School of Natural Sciences and Psychology,Liverpool John Moores University, Liverpool L3 3AF, UK

KEY WORDS dental anthropology; phenetic affinity; population history; Khoesan; SouthAfrica

ABSTRACT The present report follows up on thefindings of previous research, including recent bioarch-aeological study of well-dated Khoesan skeletal remains,that posits long term biological continuity among theindigenous peoples of South Africa after the Pleistocene.The Arizona State University Dental Anthropology Sys-tem was employed to record key crown, root, and intra-oral osseous nonmetric traits in six early-through-lateHolocene samples from the Cape coasts. Based on thesedata, phenetic affinities and an identification of traitsmost important in driving intersample variation weredetermined using principal components analysis and themean measure of divergence distance statistic. Toexpand biological affinity comparisons into more recenttimes, and thus preliminarily assess the dental impact

of disproportionate non-Khoesan gene flow into localpeoples, dental data from historic Khoekhoe and Sanwere also included. Results from the prehistoric compar-isons are supportive of population continuity, though asample from Matjes River Rockshelter exhibits signifi-cant, albeit slight, phenetic distance from other earlysamples. This and some insignificant regional divergenceamong these coastal samples may be related to environ-mental and cultural factors that drove low-level repro-ductive isolation. Finally, a close affinity of historic Santo all samples, and a significant difference of Khoekhoefrom most early samples is reflective of documented pop-ulation history following immigration of Bantu-speakersand, later, Europeans into South Africa. Am J PhysAnthropol 000:000–000, 2014. VC 2014 Wiley Periodicals, Inc.

Until a relatively recent reboot of bioarchaeologicalresearch on the indigenous Holocene inhabitants ofSouth Africa, the consensus peopling scenario could besummarized as follows. Terminal Pleistocene/Early Holo-cene peoples appeared phenotypically similar to themodern Khoesan, though of larger body size (Tobias,1966, 1972, 1974; Clark, 1970; Br€auer and Rosing,1989). It is from this “large” Khoesan ancestor that ante-cedents of modern San and Khoekhoe (Brothwell, 1963),perhaps among other sub-Saharan Africans (Tobias,1966, 1972, 1974), had developed by 12,000–10,000 BP1

(Tobias, 1966, 1972, 1974, 1985; Clark, 1970; Br€auer,1978; Inskeep, 1979; Nurse et al, 1985; Phillipson, 1985).Skeletal remains maintained to represent these “small”Khoesan were dated to 11,000 BP at Matjes River Rock-shelter (Clark, 1970; Br€auer, 1984), and about 10,000 BPat Border Cave and Tuinplaats (Inskeep, 1979). Finally,the Khoekhoe and San began to diverge 3,000–2,000years ago when the former turned to herding while thelatter maintained a foraging lifestyle (Parkington, 1981;Ehret, 1984; Denbow and Wilmsen, 1986).

Over the past several decades, as detailed elsewhere(Pfeiffer and Sealy, 2006; Stynder, 2006, 2007, 2009;Stynder et al., 2007), new fieldwork, reinterpretations ofthe archaeological record, wide-ranging radiocarbon dat-ing of many previously recovered skeletal remains, and

morphometric study of these newly contextualizedremains have yielded a much clearer picture of theregion’s Holocene population history. For starters, thisrenewed bioarchaeological focus suggests that the Termi-nal Pleistocene/Early Holocene South Africans werelikely of local late Pleistocene origin (Morris, 2002, 2003;Stynder et al., 2007)—in seeming opposition to the ideaof an older, more widespread ancestral population (Sut-ton, 1981; Ehret and Posnansky, 1982; Nurse et al,1985). It is also said that these people were the precur-sors of later South African Khoesan only (Morris, 2002,2003), not a source for all sub-Saharan populations asonce thought (Tobias, 1966, 1972, 1974, 1985; Clark,1970; Br€auer, 1978; Inskeep, 1979; Nurse et al, 1985;Phillipson, 1985). These ostensibly contradictory scenar-ios are actually reconcilable in light of recent geneticresearch (Schuster, 2010; Pickrell et al., 2012;

Grant sponsor: National Science Foundation; Grant number:BCS-0840674.

*Correspondence to: Prof. Joel D. Irish, Research Centre in Evo-lutionary Anthropology and Palaeoecology, School of Natural Scien-ces and Psychology, Liverpool John Moores University, ByromStreet, Liverpool, L3 3AF, United Kingdom.E-mail: [email protected]

Received 17 February 2014; accepted 21 April 2014

DOI: 10.1002/ajpa.22526Published online 00 Month 2014 in Wiley Online Library

(wileyonlinelibrary.com).

1All dates reported in this paper are uncalibrated, following stand-ard practice (Sealy and Pfeiffer, 2000; Stynder et al., 2007), to allow forconsistency with previous South African Late Stone Age archaeologi-cal studies.

� 2014 WILEY PERIODICALS, INC.

AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 00:00–00 (2014)

Schlebusch et al., 2012; Barbieri et al., 2013). That is, apopulation once spread throughout southern and easternAfrica is the likely ancient source from which TerminalPleistocene/Early Holocene South African ancestors ofthe local Khoesan (Morris, 2002, 2003; Stynder et al.,2007) and other sub-Saharan peoples are descended;however, this diversification event occurred earlier thanonce thought, i.e., >30,000 years ago (Pickrell et al.,2012; Schlebusch et al., 2012). The concept of “large” vs.“small” Khoesan skeletal remains is also sustained—although again with revised timing. A reduction in cra-nial (Stynder, 2006, 2007; Stynder et al., 2007) and bodysize (Sealy and Pfeiffer, 2000; Pfeiffer and Sealy, 2006) isdocumented, but it occurred more recently, i.e., >4,000BP, than 12,000–10,000 BP; moreover, a return to pre-4000 BP levels occurred by 2000 BP. Finally, the afore-mentioned initiation of differentiation between the Sanand Khoekhoe is supported to some extent as well,though the timing was again revised to when pastoral-ism was first introduced some 2,000 years ago (Deaconand Deacon, 1999; Collins and Burns, 2007; Stynder,2007, 2009; Stynder et al., 2007). And obvious intergroupskeletal and other variation is not apparent until his-toric times (e.g., Irish, 1993, 1997; Collins and Burns,2007).

Inherent in many of the preceding studies is a presump-tion of South African population continuity during muchof the Holocene (also Deacon and Deacon, 1999; Mitchell,2002), contra old arguments for migration and discontinu-ity in (Stynder et al., 2007). For example, the reason(s)has not been determined with certainty (Pfeiffer andSealy, 2006), but environmental and cultural factors mayaccount for skeletal size variation between the early(here, >4,000 BP) and middle Holocene (4,000–2,000 BP)(Sealy, 2006; Stynder et al., 2007); however, are otherexplanations possible? Similarly, diet and lifestyle differ-ences between foragers and the “new” late Holocene(<2,000 BP) pastoralists could contribute to possible inter-group variability. But beyond that, are any differencesbetween San and Khoekhoe, prior to historic incursionsby non-Khoesan groups, genetically driven? After all,among others, one well-accepted scenario is that someKhoesan emigrated, obtained herd animals on their ownor from outsiders, and after an extended period of timereturned to South Africa around 2000 BP as full-fledgedKhoekhoe pastoralists (Parkington, 1981; Ehret, 1984;Nurse et al., 1985; Denbow and Wilmsen, 1986; Wilson,1986; Excoffier et al, 1987, among others).

To date, re-analyses of post-Pleistocene Khoesan skele-tons have been dominated by post-cranial (Sealy andPfeiffer, 2000; Pfeiffer and Sealy, 2006; Sealy, 2006) andcraniometric study (Morris, 1992a, 2002, 2003; Stynder,2006). Of these, only Stynder (2009; et al., 2007) focusedon early through late Holocene phenetic affinities toaddress questions of population continuity or discontinu-ity; his findings support continuity. The present reportagain delves into population history, though by describ-ing and comparing highly heritable nonmetric dentaltraits among eight Khoesan samples. Five of the lattercomprise many of the specimens used above (Stynder,2006, 2009; et al., 2007), as well as teeth from fragmen-tary skulls that are unsuitable for craniometric study.They, and a sample from Matjes River Rockshelter, areused to answer the two questions stated above; both areadapted from Stynder et al. (2007) who, based onarchaeological evidence, identified two likely periods,i.e., about 4,000 BP and about 2,000 BP, when popula-

tion continuity may have occurred. The first, relating tovariation between “large” and “small” Khoesan isphrased here in the form of a null hypothesis: there isno significant difference between dental samples fromthe early and middle Holocene. The second, concerningpotential variation after the advent of herding is: thereis no significant difference between samples of late Holo-cene (<2,000 BP) mixed forager/pastoralists and early-to-middle Holocene (>2,000 BP) foragers. Both hypothe-ses are tested using the multivariate mean measure ofdivergence distance statistic (Sj�vold, 1977; Irish, 2010).If one or both can be rejected, then discontinuity frompopulation replacement or gene flow may have occurred.The final two samples, San and Khoekhoe, are includedto extend the study of Khoesan affinities into historictimes, and further quantify intergroup variation fromdifferential admixture with immigrant Bantu-speakersand Europeans (Mourant, 1983; Nurse et al., 1985; Irish,1993, 1997; Cavalli-Sforza et al., 1994; Cruciani et al.,2002; Stynder et al., 2007, Stynder, 2009). Of course, allinferences and findings are contingent upon the assump-tions that samples are representative of the populationsfrom which they derive and, of most importance, phe-netic similarity provides a reasonable estimate of geneticrelatedness (Scott et al., 1983; Larsen, 1997; Scott andTurner, 1997; Rightmire, 1999; Martinon-Torres et al.,2007). In sum, the intent is that these new analysescomplement those of previous researchers to help facili-tate an improved understanding of South Africa’s origi-nal peoples (e.g., Afolayan, 2000).

MATERIALS

The eight samples, with dentitions from 424 individu-als, have adequate provenience and size to attempt thestudy outlined above. Information concerning samplecomposition, the region of South Africa from which theywere recovered, group affiliation(s), time period (e.g.,>4,000, 4,000–>2,000, and <2,000 BP), and other char-acteristics are provided. Details can be found in thesources cited below. For quick reference, summary dataare listed in Table 1.

South African late Holocene West (SHLw)

Eighty-five sets of remains from the coastal regions ofthe Cape were originally identified to fit within the mostrecent of three key temporal periods noted above, i.e.,<2000 BP. However, to facilitate an additional level ofanalysis these specimens were divided along geographiclines. Following standard regional designations (Deaconand Lancaster, 1988; Pfeiffer and Sealy, 2006; Stynderet al., 2007), individuals recovered on the West andSouth-west coasts (SHLw) of the Western and NorthernCape provinces (Fig. 1) were separated from those alongthe South coast (SHLs below); the goal is to assesspotential intersample regional variation. Radiocarbondates are reported for 51 of 57 SHLw crania (Hausman,1980; Sealy and van der Merwe, 1988; Sealy, 1989; Mor-ris, 1992b, Personal Communication, 2012; Pfeiffer andSealy, 2006; Sealy, 2006; Stynder et al., 2007), while theother five have been identified as <2,000-years old basedon curation records. Dates range from 2011 6 30 to 2006 50 BP, with rough mean and median ages of 1240 BP.These individuals likely belonged to groups that prac-ticed foraging, pastoralism, or a combination of the two(Stynder et al., 2007; Stynder, 2009).

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American Journal of Physical Anthropology

South African late Holocene South (SHLs)

This second late Holocene sample (<2,000 BP) consistsof 28 individuals from the South coast in the Westernand Eastern Cape provinces (Fig. 1). Like SHLw, mostspecimens (n 5 21) were radiocarbon dated (Morris,1992b, Personal Communication, 2012; Morris et al.,2004; Sealy, 2006; Stynder et al., 2007), and the remain-ing seven can confidently be assigned a date of <2,000BP using museum records. The date range is 2,060 6 50to 207 6 25 BP, with an approximate mean of 1120 andmedian of 1300 BP. These individuals, like their westernlate Holocene counterparts, may have been foragers,pastoralists, or both (Stynder et al., 2007; Stynder,2009).

South African middle Holocene West (SHMw)

A total of 115 individuals from the coastal regions thatretain dentitions were originally identified to fit withinthis second key temporal period: 4,000 to >2,000 BP.However, to again allow a regional analysis, the samplewas subdivided spatially (after Stynder et al., 2007). Atotal of 73 individuals from the West and South-westcoasts of the Western and Northern Capes (Fig. 1) com-prise this sample (SHMw), of which 63 have absolutedates (de Villiers and Wilson, 1982, Sealy and van der

Merwe, 1988; Sealy, 1989; Morris, 1992b, Personal Com-munication, 2012; Stynder et al., 2007). Enough informa-tion is known about the other 11 to determine that theyfit within the requisite period. Dates cover a periodbetween 3850 6 80 and 2050 6 50 BP, with a roughmean age of 2,600 and median of 2,530 BP. With regardto subsistence strategy groups of this time were foragers,albeit of a more sedentary nature than before 4,000 BP(below) (Deacon, 1984; Sealy, 2006; Stynder et al., 2007).

South African middle Holocene South (SHMs)

The second Middle Holocene sample (4,000 to >2,000BP) consists of 42 dentitions in remains from the Southcoast in the Western and Eastern Capes (Fig. 1). Mostspecimens (n 5 28) were radiocarbon dated (Morris,1992b, Personal Communication, 2012; Sealy andPfeiffer, 2000; Sealy, 2006; Stynder et al., 2007); 14 werenot, but their ages can be approximated with some confi-dence to this 2,000-year period. Dates run from 3760 660 to 2145 6 40 BP, with an approximate mean of 2500and median of 2300 BP. As above, these foragers wouldhave led a more sedentary lifestyle than earlier groups(Deacon, 1984; Sealy, 2006; Stynder et al., 2007).

South African early Holocene (SHE)

This sample of early Holocene foragers (Deacon, 1984;Stynder et al., 2007), which dates to the third key tem-poral period of >4,000 BP, is too small to subdivide bygeographic region. Thirty-nine of the 40 individualshave radiocarbon dates ranging from 10,860 6 180 to3,980 6 60 BP (Hausman, 1980; Patrick, 1989; Sealy,1989; Morris, 1992b, Personal Communication, 2012;Sealy and Pfeiffer, 2000; Sealy, 2006; Stynder et al.,2007). A date for the fortieth specimen (i.e., Fish Hoek)has not been published, but is likely about 12,000 BP(Stynder et al., 2007). Overall, the mean date is 6400with a median of 5565 BP. Regarding spatial prove-nience, 32 sets of remains were recovered within a rela-tively confined area on the South coast of the Westernand Eastern Cape (Fig. 1); seventeen of these specimensare from Oakhurst Rockshelter (between 9120 6 90 and4100 6 60 BP). The other eight originated on the South-west coast in the Western Cape.

Matjes river rockshelter (MAT)

This coastal cave/rockshelter, which sits adjacent toPlettenberg Bay in the Eastern Cape (Fig. 1), was usedby Holocene foragers from >9,600 to <2,200 BP. Cura-tion issues associated with the site’s skeletal remains

Fig. 1. Approximate origin locations of the eight Khoesansamples used in the present study. The sample abbreviationsare defined in the text.

TABLE 1. The South African Holocene dental samples

Sample Region(s) of origin Ethnic/subsistence group Date BP No. Location

Late Holocene West (SHLw)a West to South-west coasts Forager/Pastoralist <2000 57 SAM, UCTb

Late Holocene South (SHLs) South coast Forager/Pastoralist <2000 28 SAM, UCTMid Holocene West (SHMw) West to South-west coasts Forager 4000–>2000 73 SAM, UCTMid Holocene South (SHMs) South coast Forager 4000–>2000 42 NMB, SAM, UCTEarly Holocene (SHE) West and South coasts Forager >4000 40 NMB, SAM, UCTMatjes River (MAT) Plettenberg Bay, South coast Forager 7400–2200 51 NMBKakamas (KAK) Uppington to Augrabies (interior) Khoekhoe 210–150 65 MMK, NMB, UCTRiet River (RRI) Koffiefontein to Douglas (interior) San 890–110 66 MMK, NMB

a Sample three-letter abbreviations used in all subsequent tables and most figures.b Curation at MMK 5 McGregor Memorial Museum, Kimberly, NMB 5 National Museum, Bloemfontein, SAM 5 Iziko (South Afri-can) Museum, Cape Town, UCT 5 University of Cape Town, Department of Human Biology.

KHOESAN DENTAL AFFINITIES 3


are well known—to the extent that even MNI is notagreed upon (Rightmire, 1978; Sealy, 2006; L’Abb�e et al.,2008). Fifty-one dental individuals were recorded. Ofthese, 36 have maxillary and mandibular dentitionsexhibiting matching catalog numbers that would, thoughnot always, imply they represent single individuals.Thirty-four other specimens make up the remaining 15“composite” individuals. Of the 70 cataloged specimens,22 do not have an absolute date; the rest are from strati-graphic layers with known dates: 19 from Layer B at3,600–2,200 BP, 20 in Layer C at 7,400–5,000 BP, threefrom the B/C boundary, and six from Layer D—with asingle date of 9,688 6 36 BP (Sealy et al., 2006). Overall,most remains in this sample may date between 7,400–2,200 BP.

Kakamas (KAK)

A majority of this Khoekhoe sample, which includes65 individuals, was excavated from a series of burialcairns in South Africa’s interior (Fig. 1), along the lowerOrange River in the Northern Cape (Dreyer and Meir-ing, 1937). Museum and other records establish thatthese “Kakamas burials” (Morris, 1992a, p 38) were orig-inally located, from east to west on the river’s course, inthe vicinities of Uppington, Louisvale, Kakamas, andAugrabies Falls. Radiocarbon dates for these graves,based on sampling of three skeletons, range between 2106 40 and 150 6 40 BP; overall, the remains are likelyfrom an early historic Khoekhoe group called the Eini-qua (Morris, 1992a).

Riet river (RRI)

Sixty-six dentitions were recorded for this San sample.Fifty-five are directly associated with what Morris(1992a, p 26) refers to as the “Riet River graves,” whichshare various attributes in their construction, location,and content. Like Kakamas, they too were located in theinterior, having been excavated along the shores of theriver between Koffiefontein and Jacobsdal in the westernFree State (Fig. 1). Radiocarbon dates from four of theseskeletons are 890 6 50, 390 6 50, 380 6 50, and 110 650 BP (Morris, 1992a). Another date, 410 6 50 (Morris,1992b), was obtained from a skull found near Douglasthat is included in this sample as well (see below). Arange of evidence (Morris, 1992a) suggests the individu-als were foragers, i.e., likely San (Stow, 1910; Hum-phreys, 1972), who atypically engaged in small scalecattle-herding; Morris (1992a) suggests this practicemay have resulted from contact with Iron Age Bantu-speakers. Although there is variation in grave pattern-ing, Humphreys (1972) reported enough cultural similar-ities to include burials as far west as Douglas within theRiet River sequence. Given these and dental similarities(data available from author), 11 crania from near Doug-las were also included to maximize sample size.

METHODS

Dental trait recording

Each dentition was inspected for the presence of >125nonredundant discrete crown, root, and osseous oraltraits. By nonredundant, it is meant that in the case ofbilateral expression, both antimeres were recorded and,allowing for asymmetry, the side with the greatestexpression was counted (Turner and Scott, 1977). Alter-nate approaches, e.g., left side only, etc., are possible

(see discussion in Irish, 2005), but the aim is to identifythe trait’s maximum genetic potential in each individual(Turner, 1985; Turner et al., 1991). Thirty-six of thesetraits (see list in Table 2) used by the author in priorAfrican dental studies (Irish, 1993, 1997, 2005, 2006,etc.) were employed for the following quantitative analy-ses. All except UI1 midline diastema (Irish, 1993) arepart of the Arizona State University Dental Anthropol-ogy System (ASUDAS) (Turner et al., 1991; Scott andTurner, 1997). Reasons for selecting these traits aremany (Irish, 1993, 1988, 2005, 2006); in brief they canbe observed despite slight to moderate attrition (or areunaffected by it with root and osseous traits), have mini-mal inter- and intra-observer error rates in recording,are simple to identify, and represent all morphogeneticfields; however, of greater importance, they have a veryhigh genetic component in expression (Scott, 1973;Larsen, 1997; Scott and Turner, 1997; Rightmire, 1999;Martinon-Torres et al., 2007) and are evolutionarily con-servative—making them excellent markers for biodis-tance analyses (Larsen, 1997). Another benefit is thegeneral absence of sexual dimorphism (Scott 1973, 1980;Smith and Shegev, 1988; Bermudez de Castro, 1989;Hanihara, 1992; Irish, 1993), which allows pooling of thesexes for maximum sample sizes. Turner et al. (1991)and Scott and Turner (1997) provide a full description ofthe ASUDAS.

Quantitative analyses

The first step in analysis was to dichotomize all of therank-scale ASUDAS traits into categories of present orabsent. Trait dichotomization is based on their appraisedmorphological thresholds (Haeussler et al., 1988), asevaluated by Scott (1973), Nichol (1990), and othersusing a standard procedure (Turner, 1985, 1987; Irish,1993). This step facilitates tabulation of trait frequenciesand is required before data are compared using themean measure of divergence statistic (MMD) (Berry andBerry, 1967; Sj�vold, 1973, 1977; Green and Suchey,1976; Harris and Sj�vold, 2004; Irish, 2010).

The second step is, by using the MMD, to identifyintersample dental phenetic affinities. This statisticmeasures dissimilarity between sample pairs; low valuesare indicative of similarity and vice versa. The formulacontains the Freeman and Tukey angular transforma-tion to correct for low (<0.05) or high (>0.95) trait fre-quencies and small sample sizes (n � 10) (Sj�vold, 1973,1977; Green and Suchey, 1976). To determine if samplesdiffer significantly, each MMD value is compared to itsstandard deviation (SD). If the MMD > 2 X SD, then thenull hypothesis of P1 5 P2 (where P 5 sample popula-tion) is rejected at the 0.025 level. The MMD and stand-ard deviation formulae, rationale for determiningsignificance, and other methodological details are pre-sented in Sj�vold (1977) and Irish (2010).

Beyond its effective application in prior studies, someof which are cited here, the MMD is used because itholds several advantages over other distance measures,including its handling of missing data (Irish, 2010). Thatsaid, careful trait editing, a key step when using anydistance statistic, is of particular importance with theMMD. To begin with, traits having minimal or no“contributory information” can be deleted (Harris andSj�vold, 2004, p 91). Oftentimes invariant traits areobvious. Otherwise, those that are least likely or, con-versely, most liable to drive inter-sample variation can

4 J.D. IRISH


TABLE 2. Dental trait percentages (%) and number of individuals scored (n) for the eight South African Holocene samples

Samplea SHLw SHLs SHMw SHMs SHE MAT KAK RRI

Traitb

1) Winging UI1 % 0.00 5.00 10.34 3.33 4.00 3.23 5.41 7.14(15ASU 1) n 45 20 58 30 25 31 37 42

2) Labial curvature UI1 % 64.71 66.67 61.76 50.00 80.00 88.89 60.00 54.84(15ASU 2–4) n 17 9 34 24 15 18 30 31

3) Palatine torus % 26.53 8.33 16.13 19.35 3.85 6.67 2.04 7.69(15ASU 2–3) n 49 24 62 31 26 30 49 52

4) Shoveling UI1 % 0.00 33.33 9.52 5.56 22.22 44.44 14.81 16.00(15ASU 2–6) n 9 6 21 18 9 9 27 25

5) Double shoveling UI1 % 0.00 0.00 2.94 0.00 0.00 0.00 0.00 0.00(15ASU 2–6) n 22 9 34 25 13 16 34 30

6) Interruption groove UI2 % 0.00 16.67 3.45 0.00 0.00 0.00 8.00 3.70(15ASU 1) n 17 6 29 14 10 14 25 27

7) Tuberculum dentale UI2 % 25.00 20.00 36.00 7.69 22.22 21.43 19.23 42.31(15ASU 2–6) n 12 5 25 13 9 14 26 26

8) Bushman canine UC % 33.33 66.67 33.33 40.00 55.56 53.33 20.00 33.33(15ASU 1–3) n 9 3 24 15 9 15 30 27

9) Distal accessory ridge UC % 0.00 0.00 26.09 9.09 0.00 23.08 9.09 18.18(15ASU 2–5) n 7 1 23 11 3 13 22 22

10) Hypocone UM2 % 97.56 100.00 94.34 93.75 91.67 100.00 93.18 95.35(15ASU 3–5) n 41 15 53 32 24 27 44 43

11) Cusp 5 UM1 % 35.29 11.11 46.43 31.58 28.57 52.17 5.88 20.83(15ASU 2–5) n 17 9 28 19 14 23 34 24

12) Carabelli’s trait UM1 % 44.44 25.00 31.03 21.05 18.18 32.00 18.75 15.00(15ASU 2–7) n 18 8 29 19 11 25 32 20

13) Parastyle UM3 % 3.03 0.00 0.00 0.00 0.00 0.00 0.00 2.86(15ASU 1–5) n 33 12 29 18 18 17 43 35

14) Enamel extension UM1 % 0.00 0.00 0.00 2.78 0.00 0.00 0.00 0.00(15ASU 1–3) n 39 15 58 36 26 24 42 53

15) Root number UP1 % 45.45 72.22 15.22 33.33 33.33 56.67 52.78 43.33(15ASU 21) n 44 18 46 30 27 30 36 30

16) Root number UM2 % 66.67 88.89 53.85 66.67 78.95 81.82 65.52 83.33(15ASU 31) n 21 18 26 18 19 22 29 18

17) Peg-reduced UI2 % 2.22 0.00 6.45 5.26 17.24 14.63 3.51 0.00(15ASU P or R) n 45 23 62 38 29 41 57 57

18) Odontome P1-P2 % 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00(15ASU 1) n 40 13 42 26 21 36 50 38

19) Congenital absence UM3 % 0.00 12.00 10.77 11.43 6.45 5.88 1.69 6.78(15ASU 2) n 52 25 65 35 31 34 59 59

20) Midline diastema UI1 % 4.08 15.00 6.45 8.57 17.86 12.50 7.50 5.88(10.5 mm) n 49 20 62 35 28 32 40 51

21) Lingual cusp LP2 % 82.14 66.67 96.97 80.00 92.86 58.33 79.31 76.67(15ASU 2–9) n 28 6 33 15 14 24 29 30

22) Anterior fovea LM1 % 60.00 100.00 68.00 76.47 75.00 71.43 50.00 68.42(15ASU 2–4) n 10 4 25 17 8 21 14 19

23) Mandibular torus % 0.00 0.00 1.79 3.13 0.00 4.44 0.00 1.89(15ASU 2–3) n 48 18 56 32 28 45 51 53

24) Groove pattern LM2 % 78.05 66.67 76.00 82.76 59.09 64.52 76.74 65.91(15ASU Y) n 41 15 50 29 22 31 43 44

25) Rocker jaw % 6.38 11.11 3.51 16.13 0.00 2.27 6.00 5.77(15ASU 1–2) n 47 18 57 31 26 44 50 52

26) Cusp number LM1 % 0.00 0.00 0.00 8.33 0.00 6.90 9.09 8.33(15ASU 61) n 27 9 38 24 13 29 33 24

27) Cusp number LM2 % 94.44 100.00 97.92 100.00 100.00 96.43 82.93 96.55(15ASU 51) n 36 12 48 27 17 28 41 29

28) Deflecting wrinkle LM1 % 13.33 33.33 23.08 21.05 11.11 20.00 13.64 32.00(15ASU 2–3) n 15 3 26 19 9 20 22 25

29) C1-C2 crest LM1 % 0.00 0.00 3.45 0.00 0.00 0.00 0.00 0.00(15ASU 1) n 14 4 29 18 10 22 24 24

30) Protostylid LM1 % 7.14 0.00 7.41 25.00 9.09 6.06 0.00 11.76(15ASU 1–6) n 14 5 27 20 11 33 37 17

31) Cusp 7 LM1 % 13.89 30.00 11.63 34.62 30.00 28.13 12.20 20.51(15ASU 2–4) n 36 10 43 26 20 32 41 39

32) Tome’s root LP1 % 14.29 5.88 2.17 4.17 23.53 23.08 3.03 5.71(15ASU 3–5) n 42 17 46 24 17 39 33 35

33) Root number LC % 0.00 0.00 2.04 0.00 0.00 0.00 0.00 0.00(15ASU 21) n 40 18 49 26 21 38 39 34

34) Root number LM1 % 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00(15ASU 31) n 31 11 28 16 14 28 38 26

35) Root number LM2 % 88.24 85.71 90.91 90.00 71.43 100.00 89.19 80.95



be identified quantitatively; in earlier studies correspon-dence analysis (Irish, 2005, 2006) and principal compo-nents analysis (PCA) (Irish and Guatelli-Steinberg,2003) were used for this purpose. In the present studytrait percentages were compared with PCA. Next, it isrecommended that intersample distances be based on asmany traits as possible; however, these traits should notbe highly correlated with one another, as differentialweighting of the underlying dimensions may renderresults inaccurate (Sj�vold, 1977). Between-trait correla-tion was assessed by submitting the rank-scale ASUDASdata to the Kendall’s tau-b correlation coefficient.

The third step in analysis involves presentation of theintersample variation. In addition to MMD distance mat-rices, an effective and largely unbiased way to illustratesample affinities is multidimensional scaling (MDS)(Kruskal and Wish, 1978). Interval-level MDS in SPSS20.0 Procedure Alscal was used to produce three-dimensional spatial representations of the samples.

RESULTS

Table 2 presents the percentages of individualsexpressing each trait and the total number scored. TheASUDAS presence/absence dichotomies are parentheti-cally listed under each trait name. Very small samplesizes adversely impact a number of traits; the SHLsand, to a lesser degree, SHE samples are particularlyaffected (e.g., distal accessory ridge UC). Needless to say,such data likely do not adequately characterize the pop-ulation from which they come, so should be interpretedwith caution and addressed during the trait editingprocess.

Missing and other data issues aside, a full 36-traitMMD comparison was conducted to move beyond quali-tative inspection of individual trait frequencies and gainan initial impression of inter-sample affinities. Theresulting distance matrix is provided in Table 3. Despite

notable variation among several individual traits acrosssamples (Table 2), including shoveling UI1 (range of 0–44%), root number UP1 (15–72%), and protostylid LM1(0–25%), overall dental homogeneity is evident as justthree sample pairs are significantly different at the0.025 alpha level (KAK/MAT, KAK/SHMw, and MAT/SHMw).

The MMD has been shown to be a very robust statis-tic, in that even problematic traits (numerous missingdata, highly correlated, invariant) can yield plausibleresults (see Irish, 2010). Nonetheless, trait editing wasundertaken as described.

First, all patently noncontributory traits were deleted,including: double shoveling UI1 (0–3% across samples),hypocone UM2 (92–100%), parastyle UM3 (0–3%),enamel extension UM1 (0–3%), odontome P1-P2 (0%),C1-C2 crest LM1 (0–3%), root number LC (0–2%), androot number LM1 (0%). This initial round of editingreduced the number of traits to 28. Second, these per-cent data were submitted to PCA to identify additional,largely non-contributory traits in seven of the eight sam-ples; SHLs was excluded from this phase of editing afterdetermining that its very small sample sizes and non-representative frequencies for some traits artificiallyinflated several of the resultant loadings.

Six components with eigenvalues >2.0 were obtainedthat account for 100% of the total variance. However,inspection of the accompanying scree plot (not shown)suggests that the first three components accounting for65% of the variance are most important; unrotated load-ings for these components are listed in Table 4. Traitswith strongly positive or negative values (>j0.5j) drivemost of the intersample variation, as illustrated in agraph of group component scores (Fig. 2). For Comp 1,very strong (>0.7) positive loadings for labial curvatureUI1, shoveling UI1, Bushman canine, peg-reduced UI2,midline diastema UI1, anterior fovea LM1, cusp 7 LM1,and Tome’s root LP2 are most responsible for pushing

TABLE 2. Continued

Samplea SHLw SHLs SHMw SHMs SHE MAT KAK RRI

(15ASU 21) n 34 14 33 20 14 29 37 2136) Torsomolar angle LM3 % 13.64 6.25 2.17 4.76 3.85 7.41 2.17 9.76

(15ASU 1) n 44 16 46 21 26 27 46 41

a SHLw 5 South African Late Holocene (West), SHLs 5 South African Late Holocene (South), SHMw 5 South African Middle Holo-cene (West), SHMs 5 South African Middle Holocene (South), SHE 5 South African Early Holocene, MAT 5 Matjes River Rock-shelter, KAK 5 Kakamas, RRI 5 Riet River (see text for sample details).b ASU rank-scale trait breakpoints from Irish (1993, 1997, 1998a, b, 2005, 2006) and Scott and Turner (1997).

TABLE 3. MMD distance matrix for 36 traits among the eight South African Holocene samples

Samplesa SHLw SHLs SHMw SHMs SHE MAT KAK RRI

Late Holocene West 0.000Late Holocene South 0.000 0.000Mid Holocene West 0.012 0.019 0.000Mid Holocene South 0.000 0.000 0.019 0.000Early Holocene 0.000 0.000 0.000 0.000 0.000Matjes River 0.044 0.000 0.070 0.033 0.000 0.000

Kakamas 0.018 0.000 0.054 0.032 0.017 0.073 0.000

Riet River 0.001 0.000 0.015 0.000 0.000 0.029 0.000 0.000

a See Table 1 and text for sample details.Underlined values indicate significant difference at 0.025 level.

6 J.D. IRISH


samples with high percents of these traits toward thepositive end of the x-axis (e.g., MAT, SHE). Similarly,very strong negative loadings (>20.7) for interruption

groove UI2 and Y-groove pattern LM2 occur at a highrate in samples near the other end of the x-axis (e.g.,KAK). Key traits were also identified along the y- (Comp2) and z-axes (Comp 3). As a result, tuberculum dentaleUI2, lingual cusp LP2, and root number LM2 weredeleted. Subsequent varimax rotation, which maximizesdifferences between large and small loadings, served toreinforce these trait choices; it yielded seven componentswith eigenvalues >1.0 that account for 100% of the totalvariance (again not shown). Third, several remainingtrait-pairs were found to be highly correlated by Ken-dall’s tau-b: Bushman canine/distal accessory ridge UC(sb 5 0.717), cusp 5 UM1/Carabelli’s UM1 (sb 5 0.704)and mandibular torus/rocker jaw (sb 5 0.738). Thus, inconjunction with their relatively low loadings (Table 4)and very small sample sizes (Table 2), distal accessoryridge UC, cusp 5 UM1, and mandibular torus weredropped. In the end 22 traits, denoted by asterisks inTable 4, were used for the final MMD comparison.

The 22-trait MMD distance matrix for all eight sam-ples is presented in Table 5. Overall homogeneity isagain indicated. However, the greater emphasis ondivergence, after deleting invariant and other largelynoncontributory traits, did increase the number of signif-icant differences from three to seven pairs. That is, KAKand MAT are now more distinct—from one another andthree other samples each. The MDS solution provides agood representation of the MMD matrix; Kruskal’s stressformula 1 value is 0.071 and the r2 is 0.941. The configu-ration (Fig. 3) shares some patterning with the PCAgraph (Fig. 2), including relative positions of KAK, RRI,SHMw, and MAT; yet phenetic similitude of all latethrough early Holocene samples is evident, though withsome variation along geographic lines. Divergence ofMAT and, particularly, KAK is clear—especially whenthe spikes are reoriented toward the MDS sample cent-roid (Fig. 4).

DISCUSSION

Hypothesis testing

Based on the 36- and, notably, 22-trait MMD compari-sons (Tables 3 and 5) between early Holocene SHE andmiddle Holocene samples SHMw (MMD 5 0.019) andSHMs (0.009), the first of two South African Holocenepeopling hypotheses to be tested cannot be rejected.Given that these distances did not reach the 0.025 alphalevel, the null hypothesis stands—there is no significantdifference between dental samples from the early(>4,000 BP) and middle Holocene (<4,000–2,000 BP). Afew notable differences in individual trait frequencies(Table 2) are evident across these three samples, e.g.,shoveling UI1, protostylid LM1, Tome’s root LP1, butthey are of insufficient influence to affect overall phe-netic similarity. As such, despite observable, yet slight,size and shape variation of “large” and “small” Khoesanskeletons between periods, particularly from about 4,000to 3,,000 BP (Sealy, 2006; Stynder et al., 2007), the den-tal phenetic findings are supportive of biological continu-ity, in agreement with Stynder et al. (2007) and others.Cranial and post-cranial differences, which are moreplastic than the highly conserved secondary dental mor-phological traits, are indeed likely to have been largelydriven by cultural and environmental factors (Pfeifferand Sealy, 2006; Stynder et al., 2007). In support, theaforementioned skeletal reduction was of relatively shortduration before a return to pre-4,000 BP levels about

Fig. 2. Three-dimensional scatterplot of the first three com-ponents among seven of the eight Khoesan samples for 28 den-tal traits. Accounts for 65% of the total variance (29.47% on x-axis, 19.73% on y-axis, and 15.8% on z-axis). Methodologicaldetails and the sample abbreviations are defined in the text.

TABLE 4. Component loadings, eigenvalues, and varianceexplained for seven South African Holocene samples

Trait Number Comp 1 Comp 2 Comp 3

1* 20.273 0.233 0.7552* 0.807 20.453 20.0593* 20.297 0.541 20.7264* 0.737 20.328 0.4746* 20.694 20.426 0.5567 20.180 20.086 0.3528* 0.979 0.159 20.0999 20.004 0.293 0.69511 0.526 0.431 20.19412* 20.029 20.011 20.70915* 0.134 20.653 20.00416* 0.644 20.287 0.22317* 0.878 20.135 0.01319* 0.200 0.843 0.42420* 0.840 20.170 0.12521 20.313 0.217 20.17622* 0.700 0.685 0.05423 0.416 0.508 0.36924* 20.736 0.388 20.31625* 20.423 0.604 20.15326* 20.173 20.021 0.56727* 0.584 0.720 20.14628* 20.150 0.504 0.59930* 0.128 0.862 20.10531* 0.722 0.401 0.01932* 0.877 20.354 20.31135 20.111 0.120 0.05636* 0.033 20.070 20.533Eigenvalue 8.252 5.524 4.428Variance (%) 29.471 19.729 15.816Total Variance 29.471 49.200 65.016

a The 22 final traits used for MMD analysis after editing (seeTable 2)Boldface numbers indicate “strong” loadings (i.e., > j.5j)



2,000 years ago. It is reasonable to assume that, basedon archaeological and isotopic evidence, increased popu-lation size, greater sedentism, and dietary stress after4,000 BP are instead responsible (Deacon, 1984; Pfeifferand Sealy, 2006; Sealy, 2006; Stynder et al., 2007).

Concerning the second hypothesis, that there is no sig-nificant difference between samples of late Holocene(<2,000 BP) mixed forager/pastoralists and early-to-middle Holocene (>2,000 BP) foragers, it too cannot berejected. The 22-trait distances (Table 5) between lateHolocene west (SHLw) and three of four early-to-middleHolocene samples, SHMw, SHMs, and SHE, are low andinsignificant (MMDs 5 0.009–0.035); it does differ signif-icantly at the 0.025 level from Matjes River (MAT),though the intersample value is not especially high(0.068). No distances between late Holocene south(SHLs) and all four of the early-to-middle Holocene sam-ples differ significantly (0.000–0.067). If early Khoekhoepastoralists after 2,000 BP differed phenotypically fromthe San, due to potential extra-regional genetic influence(above), then it might be expected that SHLw andSHLs—which likely comprise remains of foragers andherders (though is difficult to differentiate individually)(Sealy and Pfeiffer, 2000; Stynder, 2009)—exhibit greaterdental heterogeneity than the earlier samples. Such het-erogeneity should in turn increase the phenetic distan-

ces relative to earlier, presumably more homogeneousforager samples. Yet an increase is not evident. Interest-ingly, slightly greater “inter-individual” cranial variationin late Holocene South Africa was reported (Stynder,2009, p. 804). It was said that small scale immigrationcould be a contributing factor, but overall variation wasdeemed minimal enough that other variables, includingdietary stress and culturally-induced reproductive isola-tion from local San, were more likely involved (Stynder,2009).

With specific regard to the early-middle HoloceneMAT sample, its significant though relatively small dis-tance from SHLw (and other samples) could be an arti-fact of its composition, including the >7,000-year rangeof these remains. It is also the second most divergent ofsamples after KAK. Perhaps the MAT sample is not“representative.” However, the site’s inhabitants wereshown to have diachronic diet consistency (Sealy andPfeiffer, 2000), which could speak to temporal continuityand sample viability. Under this assumption, the phe-netic divergence is real and another answer is needed.Specifically, stable isotopic differences between skeletalremains at Matjes River Rockshelter and those just 14km to the east imply a “clear economic separation”(Sealy and Pfeiffer, 2000; Sealy, 2006, p. 569). The rea-son, according to Sealy (2006, p 580), is that by about

Fig. 3. Three-dimensional MDS of 22-trait MMD distancesamong the eight Khoesan samples. ethodological details and thesample abbreviations are defined in the text.

Fig. 4. Same three-dimensional MDS of 22-trait MMD dis-tances as Figure 3, except spikes are oriented toward the cent-roid of the eight samples. The sample abbreviations are definedin the text.

TABLE 5. MMD distance matrix for 22 traits among the eight South African Holocene samples

Samplesa SHLw SHLs SHMw SHMs SHE MAT KAK RRI

Late Holocene West 0.000Late Holocene South 0.072 0.000Mid Holocene West 0.018 0.067 0.000Mid Holocene South 0.009 0.011 0.001 0.000Early Holocene 0.035 0.000 0.019 0.009 0.000Matjes River 0.068 0.000 0.091 0.066 0.000 0.000

Kakamas 0.040 0.061 0.046 0.071 0.061 0.072 0.000

Riet River 0.022 0.000 0.020 0.000 0.002 0.030 0.009 0.000

a See Table 1 and text for sample details.Underlined values indicate significant difference at 0.025 level.

8 J.D. IRISH


4500 BP, South shore foraging groups occupied geo-graphically demarcated, mutually exclusive territories.In this particular case, a large estuary “too deep andwide to wade across” separated the territories (Sealy,2006, p. 580). Economic separation could parallel somesmall, though observable, measure of genetic separation.In any event, MAT is characterized by slightly greatercrown and root complexity than all others, includinghaving the highest occurrences of labial curvature UI1,shoveling UI1, cusp 5 UM1, and root number LM2. Withexceptions, these and some other mass-additive, high-frequency traits in the sample are ubiquitous in sub-Saharan Africans (Irish, 1993, 1997; Irish and Guatelli-Steinberg, 2003)—a pattern known as “Afridonty” (Irish,2013, p 288). “Ultra-Afridonty” in MAT and, to a lesserextent the other non-Khoekhoe samples, may parallel“ultra-African” genetic, skeletal, and anthropometrictraits that originally prompted some workers to charac-terize San as the closest living descendants of the Termi-nal Pleistocene/Early Holocene ancestors (Tobias, 1966,1972; Mourant, 1983; Nurse et al, 1985). Concerningother MMD distances, MAT is indistinguishable fromthe early Holocene (SHE) sample, and does not signifi-cantly differ from the late Holocene south sample(SHLs); all were recovered from the South coast, whichmay be suggestive of regional variation.

General indications

Of the quantitatively identified inter-sample trends,three stand out based on values in the two MMD matri-ces and, in particular, MDS illustrations (Figs. 3 and 4):1) an apparent west-south dichotomy of samples, 2) thedivergence of KAK, and 3) the affinity of RRI to all othersamples. Each trend is interpreted below.

First, a clear separation (Fig. 3), irrespective of age, isseen between samples from the western Cape (SHLw,SHMw) and those wholly (SHLs, SHMs, and MAT) orprimarily (SHE) from the South shore. In fact, MDSplotting of all samples roughly emulates geographiclocales (Fig. 1); unfortunately, the regional-level prove-nience of many specimens precludes calculation of MMDand spatial distance correlation. According to Pfeifferand Sealy (2006), there are some questions regardingthe extent to which peoples from the two regions inter-acted, and previous researchers generally treated themas distinct. Some support for geographic separation maybe gleaned from craniometric findings, where differentialsize and shape, albeit minor, have been reported amongearly through late Holocene crania between the South-west and South coasts (Stynder et al., 2007). Assumingthe division between dental samples is real, i.e., genetic,then presumed inter-region reproductive isolation mayhave been driven, as above, by environmental and/orcultural factors. For example, if Sealy’s (2006) idea ofcoastal territories can account for some measure ofinter-group variation on the South coast, then suchgenetic variation may be increased on an interregionallevel. Four biomes ranging from desert-like to forest,along with differences in terrain and resources, existbetween the West and South-East coasts (Rutherfordand Westfall, 1986; Pfeiffer and Sealy, 2006). A potentialindicator of cultural variation may be seen in the mortu-ary practices between regions. In the west, at least dur-ing the late Holocene, individuals were buried inisolated graves within sand dunes or rock shelters,whereas multiple burials in rock shelters were the

norms on the South coast (e.g., Matjes River) (Right-mire, 1978; Pfeiffer and Sealy, 2006; Stynder, 2009).And, of course, Dutch settlers reported population differ-ences along regional and even geographic lines (Inskeep,1979); such boundaries likely existed well before Euro-pean contact.

Second, KAK is the most divergent of all Khoesansamples. With regard to individual traits, these historicKhoekhoe pastoralists are characterized by slightly lesscrown complexity than all others, including much lowerfrequencies of Bushman canine, cusp 5 UM1, and ante-rior fovea LM1. Such dental patterning is somewhatremindful of Bantu-speaking groups (Irish, 1993). Basedon both 36- and 22-trait MMDs, KAK is most akin to thetemporally and regionally proximate San from RietRiver (RRI), and next closest to late Holocene SHLw andSHLs. It is significantly different from the remaining sixsamples—all of which date to >2,000 BP. Given the pop-ulation history of the Khoekhoe (above), these affinitiesare plausible.

Following the (re)appearance of pastoralist Khoekhoein South Africa some 2,000 years ago—after obtaininglivestock (on their own or from Nilo-Saharan- and/orAfroasiatic-speaking groups) locally or from outside theregion (Nurse et al., 1985; Excoffier et al., 1987; Deaconand Decon, 1999; G€uldemann, 2008))—local geneticexchange occurred, mainly San into Khoekhoe (Parking-ton, 1981; Nurse et al., 1985). Nevertheless, thesegroups lived mostly apart. Khoekhoe originally tendedtheir livestock on the West to South coasts, while Sanforaged farther inland. These economic and regional dif-ferences are substantiated by archaeological evidenceand 16th and 17th century Dutch observations (Inskeep,1979; Elphick, 1985; Collins and Burns, 2007). San andKhoekhoe maintained a measure of spatial, cultural,and hence genetic distinctiveness for the past 2,000years (Wilson, 1986). Thus, any phenotypic variationbetween groups likely resulted from genetic drift (Hier-naux, 1975), adaptation to different environments and/ordiet (Parkington, 1981; Nurse et al, 1985), other culturalfactors (Holden and Mace, 2003) and, of note, greaterKhoekhoe admixture with late arriving “Bantu” andEuropeans (Hiernaux, 1975; Mourant, 1983; Nurseet al., 1985; Morris, 1986; Cavalli-Sforza et al., 1994)including the specific Einiqua individuals comprising theKAK sample (Morris, 1992a).

Third, unlike KAK, the historic Riet River (RRI) Sansample is noticeable for its phenetic similarity to allothers—from contemporary Khoekhoe (KAK) to earlyHolocene (SHE) samples. With the exception of tubercu-lum dentale UI2 and Carabelli’s trait UM1, its trait fre-quencies are intermediate to those of all other samples,as indicated by low nonsignificant MMD distances and acentral location in both MDS diagrams. The affinity ofRRI to KAK likely relates to San and Khoekhoe admix-ture, in general, and perhaps direct contact betweenindividuals from these two particular samples (above).The affinity of RRI to the other, more ancient samplesmay be attributed to genetic isolation from non-Khoesanpeoples. That is, the San encountered later Bantu andDutch immigrants; and ethnohistoric and genetic evi-dence indicates some admixture occurred (Tobias, 1972,Nurse et al., 1985). However, compared to the Khoekhoe,San interacted little with these newcomers (Hiernaux,1975; Nurse et al., 1985), as substantiated by serologicaland other genetic study (Mourant, 1983; Nurse et al.,1985; Cavalli-Sforza et al., 1994; Cruciani et al., 2002).



In reality, the Bantu, and especially the Dutch, did moreto eradicate the San than to assimilate them (Parking-ton, 1981; July, 1992).

CONCLUSIONS

In sum, determinations of: 1) trait occurrence, 2) themost influential traits, and 3) intersample phenetic dis-tances provide a comprehensive dental description tohelp further define the Khoesan peoples of South Africa.Based on analyses of six prehistoric samples, overalltemporal and spatial homogeneity of early-through-lateHolocene peoples is suggested, in agreement with previ-ous archaeological and, more recent, bioarchaeologicalfindings. For the most part, these six samples are char-acterized by similar expressions of complex, mass-additive crown and root traits previously shown to occur,though to a lesser degree, in all sub-Saharan popula-tions. As such, the variation reported in cranial andpost-cranial size before and after about 4000 BP isindeed likely to have been related to cultural and envi-ronmental phenomena that would affect growth, ratherthan population replacement or substantial gene flow.As noted, these phenomena are thought to includeincreased population size, sedentism, and dietary stress.Likewise, with one exception, no dental samples olderthan 2000 BP were found to differ significantly fromthose after that time. Thus, in agreement with other evi-dence, the introduction of pastoralism and other culture-related factors by 2000 BP was not, apparently, accom-panied by noticeable extra-region genetic influence. Theone sample exception, i.e., Matjes River Rockshelter, wasreported elsewhere to have a different stable isotopic sig-nature than nearby groups, perhaps relating to anhypothesized concept of geographically demarcated,mutually exclusive territories. As suggested here, suchdemarcation, or other unspecified cultural and environ-mental variables, may have prompted low-level repro-ductive isolation to explain the dental divergence.Perhaps the obvious MDS division between early-to-lateHolocene samples from the western and southern Capecoasts is related to such an explanation as well, thoughat an inter-regional level. Finally, the historic Riet RiverSan sample appears similar to all others, while that ofthe Kakamas Khoekhoe is distant. The results are con-cordant at a broad level with known population history,in that the San interacted little with immigrant Bantu-and European groups relative to the Khoekhoe. Futuredental comparisons of these various groups will provideadditional detail. Beyond this relatively recent occur-rence, the indigenous peoples of South Africa, the Khoe-san, reveal notable homogeneity and a high level ofphenetic and, hence, population continuity throughoutthe Holocene.

ACKNOWLEDGMENTS

The author thanks the following individuals for grant-ing access to the skeletal collections curated at theirrespective institutions: James S. Brink and Sharon Holtfrom the National Museum in Bloemfontein, David Mor-ris at the McGregor Museum in Kimberly, Sven Ouzmanof the Iziko South African Museum in Cape Town, andAlan Morris in the Department of Human Biology, Uni-versity of Cape Town. Many other wonderful folks atthese places helped out as well. Lastly, the author isespecially indebted to Alan Morris for answering all ofthe many questions about sample composition, and for

ably playing the part of tour guide (along with his wifeLiz) during the time there.

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Questions of khoesan continuity: Dental affinities among the indigenous holocene peoples of South Africa