John HawksDepartment of Anthropology,University of Utah,Salt Lake City, UT 84112,U.S.A. E-mail:john.hawks@anthro.utah.edu

Stephen OhPaleoanthropology Laboratory,Department of Anthropology,University of Michigan,Ann Arbor, MI 48109-1382,U.S.A.

Keith HunleyPaleoanthropology Laboratory,Department of Anthropology,University of Michigan,Ann Arbor, MI 48109-1382,U.S.A. E-mail:khunley@umich.edu

Seth DobsonDepartment of Anthropology,Washington University,St. Louis, MO 63130,U.S.A. E-mail:sddobson@artsci.wustl.edu

Graciela CabanaPaleoanthropology Laboratory,Department of Anthropology,University of Michigan,Ann Arbor, MI 48109-1382,U.S.A. E-mail:graciela@umich.edu

Praveen DayaluPaleoanthropology Laboratory,Department of Anthropology,University of Michigan,Ann Arbor, MI 48109-1382,U.S.A.

Milford H. WolpoffPaleoanthropology Laboratory,Department of Anthropology,University of Michigan,Ann Arbor, MI 48109-1382,U.S.A. E-mail:wolpoff@umich.edu

An Australasian test of the recent Africanorigin theory using the WLH-50 calvarium

This analysis investigates the ancestry of a single modern humanspecimen from Australia, WLH-50 (Thorne et al., in preparation;Webb, 1989). Evaluating its ancestry is important to our understand-ing of modern human origins in Australasia because the prevailingmodels of human origins make different predictions for the ancestryof this specimen, and others like it. Some authors believe in thevalidity of a complete replacement theory and propose that modernhumans in Australasia descended solely from earlier modern humanpopulations found in Late Pleistocene Africa and the Levant. Theseancestral modern populations are believed to have completelyreplaced other archaic human populations, including the Ngandonghominids of Indonesia. According to this recent African origin theory,the archaic humans from Indonesia are classified as Homo erectus, adifferent evolutionary species that could not have contributed to theancestry of modern Australasians. Therefore this theory of completereplacement makes clear predictions concerning the ancestry of thespecimen WLH-50. We tested these predictions using two methods:a discriminant analysis of metric data for three samples that arepotential ancestors of WLH-50 (Ngandong, Late PleistoceneAfricans, Levant hominids from Skhul and Qafzeh) and a pairwisedifference analysis of nonmetric data for individuals within thesesamples. The results of these procedures provide an unambiguousrefutation of a model of complete replacement within this region, andindicate that the Ngandong hominids or a population like them mayhave contributed significantly to the ancestry of WLH-50. We there-fore contend that Ngandong hominids should be classified within theevolutionary species, Homo sapiens. The Multiregional model ofhuman evolution has the expectation that Australasian ancestry is inall three of the potentially ancestral groups and best explains modernAustralasian origins.

� 2000 Academic Press

0047–2484/00/070001+22$35.00/0 � 2000 Academic Press

2 . ET AL.

1Even if the most recent Ngandong date estimate iscorrect (Swisher et al., 1996), and the oldest WLH-50estimate is correct (Caddie et al., 1987), Ngandong isolder than WLH-50, and the Indonesian site may beconsiderably older (Grun & Thorne, 1997).

Received 15 July 1998Revision received12 September 1998and accepted15 September 1999

Keywords: modern humanorigins, Australasia, recentAfrican origins,multiregional evolution,WLH-50, Ngandong.

Journal of Human Evolution (2000) 39, 1–22doi:10.1006/jhev.1999.0384Available online at http://www.idealibrary.com on

Introduction

Since its discovery in 1982, Willandra LakesHominid (WLH) 50, as reconstructed by A.Thorne, has figured prominently in discus-sions of modern human origins in Australiaand Indonesia (Thorne, 1984; Webb, 1989;Thorne & Wolpoff, 1992; Frayer et al.,1993, 1994; Stringer, 1998). Dated to some15–13 ka by gamma spectrometric U-seriesanalysis (Simpson & Grun, 1998), and toabout double that by ESR (on bone, byCaddie et al., 1987), the WLH-50 cal-varium appears on inspection to exhibitmany features that closely resemble earlierIndonesian hominids, including theNgandong fossils of Java [Thorne, cited inWong (1999); Thorne et al., in preparation;Wolpoff, 1999]. Those authors who supporta multiregional model of human evolutionview the similarities between the Ngandonghominids and WLH-50 as phylogenetic,meaning in this case that these specimensare members of the same evolutionaryspecies and share some features by virtue ofhaving come from the same region of theworld (Frayer et al., 1993, 1994). Ngandongis one of the probable ancestors of WLH-50,in this view,1 or the two may share a recentcommon ancestor. However, authors whosupport the recent African replacement

hypothesis of modern human origins inAustralasia have explained the seeminglyarchaic nature of WLH-50 differently, as aconsequence of either its size and relatedrobusticity or possibly pathology (Stringer,1998; Webb, 1990), but not as a resultof any significant ancestor–descendantrelationship with earlier Australasianpopulations. Despite these differences, bothinterpretations agree on one fundamental item;WLH-50 is a modern human (Thorne, 1984;Wolpoff, 1989, 1999; Stringer, 1998).

We therefore begin with the suppositionthat earlier Late Pleistocene Africans,Levantines (Near Eastern individuals fromSkhul and Qafzeh), and WLH-50 are mem-bers of the same species, Homo sapiens, andall represent modern humans or their im-mediate ancestors. There are two differentpredictions about the pattern of ancestry,and it is from these that we can develop atest for the African replacement model formodern human origins. The replacementmodel asserts:( 1) The earlier Late Pleistocene Africans

and Levantines are likely to be directancestors of WLH-50 by virtue of ageand geography.

( 2) The Ngandong hominids cannot bedirect ancestors of WLH-50, byvirtue of being in a different species,H. erectus (Rightmire, 1990), whosehabitation on Java may have persistedwell into the late Pleistocene (Swisheret al., 1996).

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Table 1 Specimens in the comparative samples

NgandongLate Pleistocene

Africans Levantines

1 Jebel Irhoud 1 Skhul 54* Jebel Irhoud 2 Skhul 95 Laetoli 18 Qafzeh 66 Omo 1* Qafzeh 99 Omo 2

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*Used only in the nonmetric analysis.

Materials and methods

Our fossil sample consists of the possiblePleistocene ancestors for WLH-50 from theLevant, Africa and Indonesia, as describedabove. Seventeen crania from the earlierpart of the Late Pleistocene were chosen forcomparison with WLH-50 (Table 1). Weassigned all fossils except for WLH-50 toone of three groups based on geography.These are the most complete crania fromthis time period in these regions and includethe specimens that preserve all or most ofthe areas that are observable on WLH-50.Fragmentary specimens and specimens toorecent to be potential ancestors of WLH-50were excluded from this study. The metricvariables were chosen to maximize thenumber of measurements we could replicatein all the crania. The incomplete conditionof WLH-50 limited us to 21 variables,mostly standardized chords and arcs, whichcould be accurately and repeatedlymeasured. All of them were present on allcrania, and no missing data were allowed forthe discriminant analysis.

Four measurements of WLH-50 requireda reconstruction of the glabella region,

The complete replacement hypothesisrequires that there is a unique relationshipbetween early modern humans, representedby the earlier Late Pleistocene AfricansLevantines, and WLH-50, to the exclusionof more archaic hominids from Ngandong.

We propose to test this complete replace-ment hypothesis by demonstrating that oneor both of the above assertions must beincorrect. A recent African replacementexplanation of modern human origins inAustralasia is incorrect if it could be shownin a comparison of WLH-50 to earlier LatePleistocene Africans, Levantines, and theNgandong people that the closest relation-ships are to Ngandong. This is becausecomplete replacement predicts unique re-lationships between WLH-50 and the latePleistocene Africans and individuals fromSkhul/Qafzeh to the exclusion of Ngandong.Multiregional evolution, in contrast, viewsall three of these groups as potentialancestors for WLH-50.

We have chosen two procedures toexamine the relationship of WLH-50 tothe African, Levantine, and Indonesiansamples:( 1) A discriminant analysis of metric data

which differentiates the Africans,Levantine, and Ngandong hominidsinto three groups and can be used toassess the group affinity of WLH-50,and

( 2) a pairwise difference analysis usingnon-metric data, comparing WLH-50with the individuals in these threesamples.

The prediction of the replacement model isthat WLH-50 will sort with the Africans orLevantines in both tests, since it must beuniquely descended from these groups. Ifthese procedures find that WLH-50 clusterswith Ngandong rather than with Africansor Levantines, then it must follow thatWLH-50 shares no special relationship withLate Pleistocene hominids from Africaand the Levant that would exclude the

Ngandong hominids from its ancestry. Inthis case, replacement would be refuted as amodel for the ancestry of Australasia, andthe Ngandong hominids must be acceptedas H. sapiens.

4 . ET AL.

which was accomplished by molding clay tofollow the existing supraorbital contour seenin superior and facial views. It was assumedthat there was no depression at glabella. Fewlater Pleistocene Australians (e.g., KowSwamp and Coobool Creek samples) have aglabellar depression. Therefore all measure-ments involving glabella represent maxi-mum values. The measurements (Table 2)are consistent with measurements publishedby Stringer (1998) and Brown (1998).2 Forexample, our cranial length, which includesthe reconstructed glabella, is 212·2 mmwhile Stringer’s value is 211·0 mm andBrown’s is 212 mm. Most of the other com-parisons are quite close; only one of themeasurements we present is significantly

different from Stringer’s, as addressedbelow.

All other measurements of fossil craniawere taken on the original specimens by oneof us (MHW), with a small number ofexceptions. A combination of published andcast measurements were used for LaetoliHominid 18 (Magori & Day, 1983), andOmo 2 (Day & Stringer, 1991). We checkedboth for the accuracy of casts in the Paleo-anthropology Laboratory at the Universityof Michigan and at the National Museumsof Kenya, and for equivalent measurementdefinitions with all published sources.

The nonmetric observations on the com-parative samples (see Table 4) were made bypairs of observers on casts. We used onlyvariables that could be unambiguously andrepeatedly scored on the high quality rep-licas available to us. Our 16 nonmetrictraits represent an exhaustive list of allcharacteristics that could be scored onWLH-50. We avoided duplicating featuresthat seemed to reflect the consequences ofthe same anatomical variation. The workwas done on consecutive days to insure thesame criteria were applied to all specimens.In our scoring system, the presence of a traitwas scored as a one (1), and absence as zero.Some of these traits may reflect robustness,and for all such traits the more robustcondition was scored as one.

2This reference is a web page and differs somewhatfrom a regular journal reference (Poumay, 1998), notonly because there has been no peer review of itscontent, but also since a web page can be modified atany time without record of the changes. For instance,the address of the Brown web page we cite here, andsome of its content, changed between submitting thispaper in 1998 and reviewing the final manuscript in1999. Stringer (1998) quotes from the 1998 site insupport of his analysis and assumptions, and weaddress here some of the issues raised in the web sitetext as well as reproduce a view of the WLH-50 vaultfrom the cite, with Brown’s permission. As it happens,no substantial differences in the points discussed occuron the 1999 site, but this may not be true in the future.

Table 2 Comparison of selected measurementsby different authors* for WLH-50

WLH-50 Measurement(in mm)

Stringer(1998)value

Brown(1998)value

Thisstudy

Biasterionic breadth 123 127 123Biauricular breadth 138 138Biparietal breadth 142 139 142Bregma-asterion 151 151 150Bregma-lambda 127 130 129Thickness at bregma 17 17Central parietal thickness 14 16Cranial length 211 212 212Maximum cranial breadth 151 150Maximum frontal breadth 117 124

*The comparisons are limited to measurements pub-lished by these authors and do not include the full set of21 measurements used for analysis in this paper.

Discriminant function analysisOur first approach emphasized the ability ofmetric data to discriminate the membersof geographic groups. Discriminant functionanalysis allows the investigators to examineor predict group membership for samples ofunknown group affinities by using multiplevariables taken for a set of cases with knowngroup affinities. It is a robust techniquewhose use is most valid when the specimento be discriminated is a member of one ofthe groups defining the function. Discrimi-nant functions are commonly used for

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Table 3(a) Unstandardized discriminant func-tion coefficients for the five variables chosen inthe stepwise function to separate the three groups

Variable(mm)

Discriminantfunction 1

Discriminantfunction 2

Cranial length 0·396 �0·075Glabella-bregma 0·318 0·207Bregma-asterion arc �0·721 0·021Central parietal thickness 0·988 0·190Medial supraorbital height �0·508 0·039(Constant) 2·368 �13·541

Calculations are based on the Wilks’ Lambda stat-istic, and the functions are normalized around theorigin. These values reflect the absolute importanceof the independent variables in contributing todiscrimination. See Figure 2 for the results.

Table 3(b) Standardized discriminant functioncoefficients

Measurement Function 1 Function 2

Maximum cranial length 3·437 �0·649Medial supraorbital height �1·512 0·117Central parietal thickness 2·416 0·464Glabella-bregma 1·600 1·042Bregma-asterion arc �4·631 0·137

These values reflect the relative importance of theindependent variables in contributing to discrimination.

Table 3(c) Total structure coefficients for allindependent variables

Measurement Function 1 Function 2

Maximum cranial length* 0·245041 0·137516Medial supraorbital

torus height*0·165216 0·052964

Bregma-asterion arc* �0·82218 0·38818Glabella-bregma* 0·147245 0·825686Central parietal thickness* 0·333043 0·533806Glabella-inion 0·271686 0·230179Glabella-lambda �0·1479 0·201619Bisupramastoid breadth 0·739836 0·122409Biparietal breadth 0·237524 0·267109Biasterionic breadth 0·626238 0·168729Minimum frontal breadth 0·39857 �0·12133Bifrontotemporale breadth �0·06242 0·084195Maximum frontal breadth 0·152752 0·265026Nuchal torus height 0·482174 �0·1689Lateral supraorbital

torus height0·557043 �0·11858

Central supraorbitaltorus height

0·190555 0·427552

Lambda-inion �0·35891 0·018806Lambda-asterion �0·72614 �0·07127Inion-asterion 0·600948 �0·0112Bregma-lambda �0·6142 �0·19288Bregma-asterion �0·59628 0·245766

These indicate the correlations of each independentvariable to the discriminant functions.

*Included in discriminant functions.

identification in forensic anthropology (e.g.,Gill & Rhine, 1990).

We reasoned that if we could determinea discriminant function that accurately dis-tinguished the three groups, it could bevalidly applied to WLH-50 because eachgroup is a potential ancestor of this speci-men. With regard to these samples, thecompeting modern human origins hypoth-eses for Australasia disagree only about thepotential of a Ngandong ancestry, which thereplacement hypothesis holds to be zero.The discriminant function we calculated isuniquely determined to distinguish the threegroups on the basis of measurements knownfor all of their members. Therefore, theexpectation of the replacement hypothesisis that WLH-50 should sort with either the

Africans or Levantines, since only these twogroups may contain the ancestors of thisspecimen. If replacement is true, WLH-50should not sort with the Indonesians.

We began by finding whether a functioncould be calculated from our set of 21measurements that would accurately andunambiguously distinguish the three com-parative samples. Using SPSS version 8.0,we calculated a stepwise discriminant func-tion using the Wilkes–Lambda statistic. Theadvantage of this commonly used test stat-istic is that at each step it maximizes thecohesiveness within each group withoutaffecting the separation between groups(Klecka, 1980). Our discriminant analysisemployed the 21 metric variables [Table3(c)] that could be found on the 15 fossilcrania, which are in three groups (Table 1).

6 . ET AL.

A stepwise function, as we used, examinesthe relationships of all the metric variables togroup memberships and chooses those vari-ables that are best able to discrminate thegroups. The function that was calculated[Table 3(a)] correctly classified everymember of the three groups using fivemeasurements. These classifications ofknown specimens were without exceptionrobust to crossvalidation using the otherknown specimens, confirming the utility ofthis set of measurements for determininggeographic origin.

We then applied the function to WLH-50.Because this discriminant analysis is basedon the geographic associations of fossils, ingroups that are potentially ancestral toWLH-50, it provides a test of the replace-ment hypothesis with little Type 1 error. IfWLH-50 discriminates with an Indonesiansample, and not with an African or NearEastern sample, then it provides a strongrefutation of the replacement hypothesis.We do not contend that this procedureprovides a means of estimating the pro-portion of relationship among WLH-50 andthe three comparative groups—it certainlydoes not. However, even given the smallsample sizes available for this analysis, itwould be very surprising for WLH-50 to beclassified with the Indonesian sample if thereplacement hypothesis were true.

Pairwise difference analysisIf our first approach emphasized discrimi-nation, our second emphasized cohesiveness.We addressed the relationship of individualsin a way that ignored group assignments, todetermine if there were patterns of featuresthat could link specimens to their geo-graphic origins. For this, we calculated thepairwise differences between WLH-50 andthe 17 other specimens (Table 1) usingnon-metric traits (Table 4). We were able toinclude more individuals in this analysisbecause it is tolerant of missing data, as longas the missing data are randomly distributed

as is true for these groups of specimens(Kruskal–Wallis test, chi square=0·126,P=0·939). In cases where a trait could notbe scored on a specimen, we scored the traitas missing for that individual, and treated itas no difference in all comparisons involvingthat individual.

Of the 16 nonmetric variables used inthe final analysis, six were correlated withcranial capacity (Kolmogorov–Smirnovtest), which provides a proxy for cranial sizethat is not based on any of the measure-ments in our analysis. In each instancewhere the presence of a nonmetric featurewas correlated with cranial capacity, thespecimens that possessed the feature hadsmaller cranial capacities than those thatlacked the feature. For example, specimensthat possessed a mastoid crest were morelikely to have smaller cranial capacities thanthose that lacked this feature. These rela-tions are no doubt due to the fact thatNgandong is the most robust segment of oursample, and has the smallest mean cranialcapacity. However, this association did nothold within groups. There were no signifi-cant within-group associations of cranialsize and presence of nonmetric traits in oursamples (Africans: P=0·527; Levantines:P=0·901; Ngandong: P=0·580; Mann–Whitney test). Comparing the African andLevantine samples alone, there is a positivecorrelation, indicating that any correlationbetween cranial size and presence of non-metric features must depend strongly on thegeographic locations of the groups beingcompared (Figure 1). These non-metrictrait comparisons should therefore beexcellent indicators of geographic affinitiesamong these samples.

Pairwise difference analysis is commonlyapplied to DNA sequence data to deriveinformation about past population demogra-phy (Rogers, 1995). It has also been appliedto sequence data to investigate the closenessof relationship that a single ancient individ-ual has to samples of living humans from

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Nonmetric features

1. Transversely extensive nuchal torus—This feature is scored as present (1) ifa distinct nuchal torus defined by superior and supreme nuchal lines extendstransversely across the entire occipital bone.

2. Sulcus dividing the medial and lateral elements of the supraorbitaltorus/superciliary arches—This feature is scored as present (1) if a clearsulcus can be identified that divides the supraorbital torus or superciliary arches,whatever the case may be, into medial and lateral elements.

3. Frontal sagittal keel—A thickening along the midline of the frontal boneanterior to bregma. The feature is scored as present (1) if it can be visually andtacitly identified. It need not extend along the entire length of the frontal bone.

4. Parietal sagittal keel—A thickening along the sagittal suture. This feature isscored as present (1) as long as it can be identified anywhere along the suture.

5. Superior margin of the orbit—Scored as either blunt (1) or sharp (0). If themargin is blunt then the supraorbital surface grades evenly into the inferiorsurface of the frontal bone.

6. Suprainiac fossa—An elliptic depression on the occiput above the superiornuchal line. Scored as present (1) or absent (0).

7. Temporal line forms a ridge—This feature is scored as present (1) if thetemporal lines form a ridge along the frontal bone, posterior to the post-orbitalconstriction.

8. Projecting inion—This feature is scored as present (1) if the nuchal torus/lineprojects posteriorly at the most inferior midline point along the superior nuchallines.

9. Pre-bregmatic eminence—This feature is scored as present (1) if a distincteminence can be visually identified anterior to bregma when viewing thespecimen in Frankfurt Horizontal. If the frontal bone and the parietals form aneven curve in Frankfurt Horizontal then the feature is scored as absent (0).

10. Angular torus—This feature is scored as present (1) if the posterior temporalismuscle attachment forms a raised and thickened ridge at its furthest backwardextent.

11. Post-lambdoidal eminence—This feature is scored as present (1) if a distinctposteriorly projecting eminence can be visually identified immediately posteriorto lambda when viewed in Frankfurt Horizontal. The scores for this feature arethe same as those for the ‘‘raised lambdoidal suture’’ Brown (1998) mentions onhis web page, and we believe the different observations record fundamentally thesame feature.

12. Linea obliquus—This feature is scored as strongly developed (1) if there is aclear line or ridge extending inferiorly and anteriorly from the lateral portion ofthe nuchal line/torus.

13. Lateral frontal trigone—A backward-facing triangular development at thelateral-most portion of the supraorbital torus (see Figure 6). The apex is createdwhen a prominent temporal ridge meets a clear line on the anterior portion ofthe supraorbital torus.

14. Mastoid crest—This feature is scored as present (1) if a distinct bony crest canbe identified that extends inferiorly and slightly anteriorly from the top of themastoid process towards the tip of the mastoid process.

15. Supramastoid crest—This feature is scored as present (1) if a distinct bonycrest can be identified that curves posteriorly and slightly superiorly from theroot of the zygomatic arch on the temporal bone above the mastoid process.

16. Coronal keel—A thickening of raised bone extending transversely from bregmaalong the coronal suture.

Table 4

different regions of the world (Krings et al.,1997). In these genetic analyses, the numberof nucleotide differences between all poss-ible pairs of individual DNA sequences are

counted, and the results are presented as thefrequency distribution of the number ofdifferences. The assumptions are that eachdifference represents a mutation and that

8 . ET AL.

3A trait, say, scored with four character states couldcontribute as much to a pairwise difference analysis asthree traits scored as present or absent. We realize thatour non-metric characters are not formally equal toeach other in complexity or heritability, but contendthat our approach to scoring makes them as comparableas possible.

Figure 1. Robustness and cranial size. The relationship between presence of non-metric traits, presentedhere as the sum of their scores for each individual (following Lahr & Wright, 1996, Figure 10) and cranialsize as measured by cranial capacity. The sum of the nonmetric scores is a measure of robustness becauseeach was scored as a ‘‘0’’ or ‘‘1’’, and whenever robustness characterized the difference, the more robustcondition was scored as ‘‘1’’. The geographic affinities of the groups being compared provide the mainsource of variation.

individuals who share fewer pairwise differ-ences are more closely related because fewermutations separate them. A similar assump-tion underlies all phenetic clustering tech-niques, where similarity is assumed to reflectrelationship. Such procedures consider indi-viduals who cluster more closely to be moreclosely related to each other.

We use pairwise analysis here for a similarpurpose, to examine the relationship ofWLH-50 to the individuals in our compara-tive samples, based on the 16 nonmetrictraits described in Table 4. Our nonmetrictraits were scored as presence or absence, sothat the differences could be validly com-bined without weighing one more thananother.3 We calculated pairwise differencesin nonmetric traits between WLH-50 and allspecimens in the comparative samples ofAfricans, Levantines and Indonesians. Thechance of a Type 1 error is high with this testonly if WLH-50 is more similar in size to the

Ngandong sample and if the traits that arecorrelated with cranial size do not reflectgeographic differences. Both these con-ditions may be rejected, as discussed below.If WLH-50 is exclusively related to Africansand Levantines, then the probability of itlooking more like the Ngandong samplethan these other two samples should beeffectively zero.

It may be claimed that because the analy-sis is a phenetic procedure, it is insufficientto test the relationships of this set of speci-mens because it does not take into accountthe polarity of the character states whenjudging the level of similarity between speci-mens. However, determinations of characterpolarity cannot be made using geographicgroupings, but must instead be made usingassumed phylogenetic groups. The identi-fication of an appropriate outgroup forpolarity assignments is not a problem, butthe definition of traits within the phylo-genetic groups assumed by the replacementhypothesis introduces an unacceptableamount of homoplasy for cladistic analysis.In particular, since replacement assumesthat Africans and Levantines are part of asingle species, and Ngandong a separate

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species, then only traits uniquely presenteither in Ngandong or in the group ofAfricans together with Levantines could beconsidered as synapomorphies, if they werepresent in WLH-50. However, there areonly eight such traits in our nonmetric data.Of these eight character states that areuniquely in one sample, five are polymor-phic within their samples, and only three areshared with WLH-50 (all three are sharedbetween WLH-50 and Ngandong). Such adegree of homoplasy may itself suggest theconspecificity of the specimens involved, butwe question the validity of this wholeapproach.

Another cladistic alternative is to considereach specimen as an individual operationaltaxonomic unit (OTU). However, besidescompounding the problem of homoplasy,this would require that we treat individualsas nonreticulating evolutionary units. Butwe know that some of these specimens belongto the same species, and that many of thetraits are both polymorphic within samplesand polygenic in inheritance. In these cir-cumstances, it is more than likely for indi-viduals to inherit the genes for a trait, evenif the trait itself is absent in one or bothparents. Therefore the traits do not conformto the cladistic assumption that descent withmodification is the process generating theirvariation.

For these reasons, a phenetic procedure ispreferred. The pairwise difference analysiswould refute a replacement hypothesisif WLH-50 is found to be more similarto Ngandong fossils than to Africans orLevantines. It remains unexplained howsuch a pattern of similarities could evolve bychance.

Results

Discriminant function analysisThe discriminant function analysis resultedin two functions that together assigned allknown specimens correctly into their orig-

inally assigned group. These functions, asdetermined by stepwise analysis, are basedon five of the original 21 variables [Table3(a–b)]. The first discriminant functionaccounts for 99·1% of the among-groupvariance, and is highly significant (P<0·001,Wilks’ Lambda test). The second discrimi-nant function accounts for the remaining0·9% of the among-group variance, but isinsignificant (P=0·192, Wilks’ Lambdatest). These variables sort WLH-50 with theNgandong group to the exclusion of eitherthe African or Levantine group (Figure 2).For the first discriminant function, thesquared Mahalanobis distance fromWLH-50 to the Ngandong centroid is18·15, while the distance to the next closestgroup centroid, Africans, is 74·48.

Including the second discriminant func-tion, though it is insignificant, tends to pullWLH-50 away from all of the groups some-what. The high score on this discriminantfunction for WLH-50 appears to reflectprincipally the long glabella–bregma dis-tance for this specimen, which, though itexceeds every other specimen in the analy-sis, is most similar to the value for the largestAfrican specimens. For both functions takentogether, the squared Mahalanobis distancefrom WLH-50 to the Ngandong centroid is42·5, while that to the centroid of the nextclosest group, Africans, is 91·7. Based onthese data, classification of WLH-50 issignificant at the 0·001 level.

Pairwise difference analysisFigure 3 shows significant differencesamong the groups for pairwise differencesfrom WLH-50. Six of the seven Ngandongcrania are closer to WLH-50 than any otherspecimens, and the seventh is only separatedfrom the others by one specimen (Skhul 9).WLH-50 is unequivocally closer to thespecimens from Ngandong than to any othergroup in its nonmetric traits. On the averageit possesses fewer differences from the

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Figure 2. Discriminant function scores. The horizontal axis accounts for 99·1% of the among-groupvariance. Classification of WLH-50 is significant at the 0·05 level.

Figure 3. Pairwise comparison of WLH-50 to Indonesian, African and Levantine specimens. Meanpairwise differences between Ngandong and African, and Ngandong and Levantine groups are statisticallysignificant at the 0·05 level (Wilcoxon–Mann–Whitney Test). The distribution of differences forNgandong differs from the others (P�0·01, sign test).

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Ngandong group (3·7 pairwise differences)than from either the African (9·3) orLevantine (7·25) groups. The Ngandongmean pairwise difference from WLH-50 issignificantly lower than both the Africanmean and the Levantine mean differences(Wilcoxon–Mann–Whitney test). WLH-50is most different from the Africans. How-ever, the difference between the Africanand Levantine samples in the number ofpairwise differences from WLH-50 is notsignificant.

Figure 4. Ngandong 1 (left) compared with WLH-50 (center, cast) and Qafzeh 9 (right, cast), shownin lateral view to the same scale. The fundamental question this paper addresses is which two arealike and which one is different? According to Stringer’s analysis (1998) the most similar pair isWLH-50 and Qafzeh 9. His illustration of WLH-50, said to support this, is not part of a comparisonwith other specimens, and is presented tilted more forward than our best estimate of FrankfurtHorizontal, accentuating the forehead height. We believe our comparison and the comparison inFigure 5 provide a different answer.

Discussion

The results of both our analyses seem tounambiguously refute the replacementtheory. There is no evidence suggestingWLH-50 can be grouped with either LatePleistocene Africans or Levantines, to theexclusion of the Ngandong sample. To thecontrary, WLH-50 is metrically and mor-phologically more like the Ngandong samplethan it is like hominids from the other tworegions. We might expect these findings ifWLH-50 is a descendant of all three groups,whether or not the influence of Ngandongwas stronger than the other two as the data

suggest. The results involve two differentanalyses of many different variables, and arenot possible if the Levant and Africansamples are uniquely ancestral to WLH-50while Ngandong, or some other sample likeit, is not.

The concordance of both metric and non-metric analyses is important, because thesetwo sources of evidence address morpho-logical relationships in different ways. Themetric analysis considers both the size andthe shape of the crania under consideration,while the nonmetric analysis considers somefactors that are independent of size or shapeand allows comparisons of individual speci-mens. For the nonmetrics that do showsome relationship to cranial size, this rela-tionship depends on the populations beingcompared, and may be positively related,negatively related, or unrelated betweensamples of recent populations. This linkageto geography makes them appropriate testsof geographic affinities.

Yet Brown (1998) and Stringer (1998)reach different conclusions about the pos-ition of WLH-50, and it is worthwhile exam-ining why these authors have accepted whatvisual inspection so readily rejects (Figures 4and 5).

12 . ET AL.

Figure 5. Posterior view of Ngandong 5 (left), WLH-50 (center), and Qafzeh 9. The central figure,WLH-50, is reproduced from Brown (1998), with his permission, and the other two are casts. Allthree are oriented in the Frankfurt Horizontal and are shown to the same scale. Once again thequestion is which two are the same, and which stands out as being different? We do not believe thatWLH-50 and Qafzeh 9 are the most similar, as the replacement hypothesis would claim.

Different anatomy reportedBrown’s anatomical observations do notalways conform to our own, and we believethe differences are significant. In particularBrown makes two key points that areincorrect.

He asserts

‘‘there is certainly no backward extension ofthe supraorbital region at the outer cornerof the orbit, along with the temporal line,forming a knob-like trigone.’’

This feature, named the frontal trigone byWeidenreich (1951), is common in andvirtually unique to the Ngandong sample(Figure 6), and its absence in WLH-50would be significant.

But while the outer corners of the lateraltorus with the temporal lines are missing onboth sides (the WLH-50 supraorbitalbreadth in Table 5 is Brown’s estimate),the angled edge between the anterior andsuperior surfaces of the lateral torus can beseen. On the left side, where the lateral torusis better preserved, as this edge is tracedlaterally to the break it progresses in a pos-terior and superior direction. The surface ofthe lateral torus forms part of a triangularprominence in this position, with the medialedge of the structure as described above

and with its apex oriented in the supero-posterior direction. The tip of the temporalline can just be seen: it is preserved on thebit of lateral edge remaining. In specimenslacking a frontal trigone, this edge passeslaterally and inferiorly as it rounds the outercorner of the torus, and there is no promi-nence in this position. The WLH-50anatomy is not complete, but the existingportion is clearly the medial edge of a smallfrontal trigone.

Second, Brown claims that

‘‘although the inion region was undoubtedlylarge, what is preserved does not resemble thepronounced inferiorly pointing triangle presentat Ngandong.’’

Again, we differ with this assessment. Theposterior of the vault is badly eroded and nocortical bone remains. Yet it is possible tosee the outline of a nuchal torus that extendsacross the entire occipital bone, with itsinferior edge defined by the prominentsuperior nuchal line and in many places itssuperior edge defined by the supremenuchal line (Figure 5). Even though thesupreme line cannot always be seen becauseof the erosion, the supratoral sulcus crossesthe entire occipital bone, from one angulartorus (on the temporal, paralleling the

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lambdoidal suture) to the other. We do notknow how far posteriorly the nuchal torusextended because the bone surface is gone,but the presence of a supratoral sulcus andthe existing anatomy suggest there was sig-nificant rearward projection. The inferiorborder of the torus outlines a prominent,downward-facing tuberculum linearum thatfollows the contour of the bone, and anoccipital crest can be seen inferior to it, fora short distance until the broken base isencountered. Taking the erosion and miss-ing bone surface into account, it would befair to say there is no other region in theanatomy of WLH-50 that more closelyresembles the Ngandong condition.

Apart from these points, Brown doesnot think WLH-50 is representative of latePleistocene Australians and presumablybelieves its anatomy does not address theirancestry in any event. We discuss thisfurther below.

Figure 6. Right lateral supraorbital region of Ngandong9 showing the frontal trigone (after Weidenreich,1951).

Different methodologies: addressing the relationof size and robustnessStringer (1998) demonstrated that WLH-50is a modern human cranium, and weaccepted this as we had concluded thesame. However, for the replacementhypothesis to be correct, modern humansas a group including WLH-50, Africans,and Levantines must exclude Ngandong.

Stringer’s analysis asserts this. It makesWLH-50 out to be more like the Qafzehsample than any other group, includingliving Native Australians, and least likeNgandong. Here we cannot concur (Figures4 and 5). It may be that differences betweenthis study and our own stem from a dis-crepancy in data. Stringer’s maximumfrontal breadth measurement for WLH-50 (117 mm) is incorrect and probably is theminimum frontal breadth of the specimen.Instead, our maximum frontal breadthmeasurement (124 mm), taken on thecoronal suture, is a conservative value forthis variable.

However, a more significant differencebetween our study and Stringer’s is themethod of analysis. Much of this differencecomes from his attempts to eliminate sizeand its influences. The issue is whetherrobustness is a function of size, as Lahr &Wright (1996), Brown (1989) and othershave suggested. This question surely hasdifferent answers at different levels of analy-sis. For instance, within populations there isusually a clear relation between size androbustness because males are on averageand in particular larger and more robustthan females. It is quite possible that this isthe fundamental relationship that Lahr &Wright (1996) show in their analysis.Between populations, on the other hand, therelationship could be just the opposite; thisdepends on which populations are com-pared. We examined the influence of size onthe rubustness between our comparativesamples. We chose endocranial capacity toestimate cranial size because it is not basedon any particular measurement used in ouranalysis. This helps to avoid spurious cor-relations that result from using differentmeasurements of the same thing as inde-pendent and dependent variables (Solow,1966), such as cranial length and brow ridgeprojection, or cranial breadth and parietalthickness. Ngandong is the smallest of ourgroups, but the most robust (Figure 1). A

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similar relation can be found in otherpopulation comparisons; the populationwith larger crania is not always the morerobust one.

Nevertheless, like many other investi-gators Stringer (1998) attempts to eliminatesize from his analyses and consider only theshape-related components of metric vari-ables (presumably, what is left after size is‘‘eliminated’’). There are two problems withsuch an approach. First, it is fairly clear thatstandard procedures for removing the effectsof size correlation do not accomplish theirgoal. A principal component analysis, whichStringer uses, rotates the intercorrelationmatrix for the data. It typically produces onegeneral factor and a series of bipolar factorsin which each variable tends to have a highcoefficient (loading) for one axis, while eachfactor has low or zero coefficients for someof the variables. The analysis is thereforeused to reveal structure in the intercorre-lation matrix. The first principal componentof a craniometric analysis, the general factor,is traditionally assumed to represent overallsize in craniometric analyses. In Stringer’sanalysis the first component reveals thearchaic samples to be closest to WLH-50(Ngandong and his ‘‘archaic Africans’’), butthis result is discarded because it is believedto be due to size.

Indeed the first component may accountfor many of the correlations of variables withoverall cranial size. However size is multi-dimensional in its effects of craniometricdata, effects that may be linear on somevariables, nonlinear on others, and areusually interactive. Pearson and colleagues(1998:655–656) note:

‘‘if a researcher wishes to investigate between-group differences, failing to consider the firstprincipal component may be inadvisable. Infact, the first component usually capturessize as well as between-group differencesthat mark some of the largest or smallest-sized OTUs (i.e., shape that is correlated withsize).’’

Some of the craniometric variables con-tribute to size more than others, and manyintercorrelations accounted for in the firstprincipal component may have nothing todo with size. Thus it is far from clear whatsize means when it is defined as the generalfactor. Again citing the Pearson et al.(1998:656) discussion of the first principalcomponent, its

‘‘aspects of between-group differences are thuscorrelated with size, but they may not neces-sarily result from allometry. Arguably, suchdifferences should not be discarded after beingsummarily ascribed to size.’’

Furthermore, standardizing variables forsize with specimen means as Stringer does(the division of all elements in each row bythe mean for the row), and then performinga principal components analysis, accountsfor size only if different variables are iso-metrically related, which is not likely forcraniometric data. It is not that these pro-ducers do not produce results (components,coefficients, and patterns) because theydo, as they must. The question is whetherthese results can possibly be interpreted inany biologically (evolutionary) meaningfulframework.

Second, there is no a priori reason to thinkthat size is unimportant in all tests involvinghow fossils are related. To the contrary,there is some reason to believe that size playsa role in the relationships we are testing(Figure 1), because if we use endocranialvolume, the Ngandong sample is thesmallest of the three comparative groupswhile, as many have pointed out (seebelow), WLH-50 is a large cranium in manyrespects. This makes a test that rejects thereplacement hypothesis if the closest relationof WLH-50 is with Ngandong a conservativetest. It follows that both the size and shapeof WLH-50 are of interest. The size ques-tion must be considered in reference to thehypothesis being tested, it may be importantto eliminate size for some, but invalid forothers.

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Use of the discriminant function analysisto address the combined questions of differ-ence between the samples and similarity ofWLH-50 does not require us to interpretcorrelations between variables in terms ofsize or shape. Instead, the analysis producesa discriminant function that maximizesgroup cohesion, including the variables thatcan best sort specimens according to groupmembership. We have shown that the result-ing variables are those that are associatedwith geography in the comparative sample.This is why the discriminant functionapproach is comparable with a visual inspec-tion while the various manipulations ofprincipal components analysis are not.

The non-metric analysis has the advan-tage of allowing us to examine some charac-teristics of the crania that are independent oftheir size. It might be claimed that certainnonmetric features reflect a pattern ofgreater muscle attachments on more robustcrania, and that this robusticity is related tosize. However, our data show no evidencethat this suggestion is true in general. Ourdata show that some of the largest crania arethe least robust. Using cranial capacity as aproxy for cranial size, none of the nonmetricfeatures that we examined show significantassociations with size within geographicregions. Instead, the features seem to beassociated with the geographic regionsthemselves. As such, they outline regionalpatterns of robusticity, and may be usefulindicators of the geographic affinities of thegroups.

Comparison of WLH-50 with other large Late Pleistocene and HoloceneAustralian crania

WLH-50Coobool

50·5Coobool

50·76 Cossack

Cranial length 212 207 211 221Biparietal breadth 142 144 145 145Supraorbital breadth 131 122 129

All measurements are in millimeters.

Table 5

Representation issuesSetting these questions of data error andappropriate analyses aside, there are twodifferent reasons why various authors havesuggested WLH-50 may not reflect normalvariation in Late Pleistocene Australians.If WLH-50 can be distinguished fromPleistocene Australian natives for reasons ofanatomy or pathology, it may not be a validtest of the replacement theory for livingindigenous Australians.

The first issue is about whether thevault is unusually large and thereby un-representative. Brown (1998) asserts that

‘‘the extremely large size of WLH-50 should beof some concern to those who argue that thisskeleton is in some manner representative of‘Late Pleistocene’ Australians.’’

He suggests that an unusual size forWLH-50 could create the elements ofrobustness whose manifestations cause it toappear similar to Ngandong. As we dis-cussed above, if there was such a size differ-ence, its consequences may well be expectedto differ from this assertion, but in anyevent, some of the Australian crania dated tothe terminal Late Pleistocene or Holocenefrom Coobool Crossing (that Brown himselfstudied, 1989), as well as others such asCossack (Freedman & Lofgren, 1979), areas large as WLH-50, or for some dimensionseven larger (Table 5, using publishedmeasurements).

In fact, there are many anatomicalsimilarities linking WLH-50 not only withNgandong, but with later Pleistocene

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Figure 7. Posterior view of Coobool Crossing 50.76. This large cranium (Table 5) has a posterior contourvery similar to WLH-50, with the greatest breadth across the supramastoid region at the cranial base. If thegamma spectrometric data is correct (Simpson & Grun, 1998), these two specimens may be penecon-temporary, but in any event the anatomy of WLH-50 is not unique among Late Pleistocene/Holocenenative Australians.

Australians as well. Coobool Creek 50.76,like WLH-50 and the Ngandong specimens(and many other Pleistocene hominids),has its greatest cranial breadth across thecranial base, and the greatest parietalbreadth low on the bone, near asterion(Figure 7). Some Late Pleistocene andHolocene Australians like this specimen andothers (Coobool Creek 50.35, Kow Swamp1, etc.) have a true, unbroken supraorbitaltorus (Figure 8). These observationsshow that some kind of link with Ngandongwould be a credible interpretation of LakePleistocene Australian variation, even ifWLH-50 had never been found. They alsoshow that the anatomy of WLH-50 is notunexpected in a Late Pleistocene Australiancranium.

These relationships were recognized adecade before WLH-50 was discovered,when a nonmetric study of recent crania byLarnach & Macintosh (1974) compared anumber of Australian and New Guineacrania with Europeans and Africans, scoringthem for the 18 characters that Weidenreich(1951) claimed were unique in theNgandong hominids. Six of these wereabsent in all modern samples, but nine ofthe 12 other features were found to attaintheir highest frequencies in the Australianand New Guinea natives. These frequenciesare fairly low, but there are similar findingsof a greatly reduced percentage of verycommon Neandertal features found in livingEuropeans (Frayer, 1993), and combined,these observations from different geographic

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Figure 8. An unbroken, true, supraorbital torus and wide interorbital area are not uncommon in LatePleistocene and Holocene Australians and may be found in recent Native Australians such as cranium3596 from Euston, shown here. This geographic distribution demonstrates that the features are regionaland cannot be used as markers of ‘‘evolutionary status’’ because by observation and definition no livinghuman group can be more ‘‘advanced’’ than another.

areas may provide an accurate reflection ofthe magnitude of Holocene skeletal change.

The second issue is about the possibilityof pathology, and its potential influence onthe size and shape of the cranium. Therehave been attempts to explain the unusuallythick vault of WLH-50 as an adaptiveresponse to some sort of chronic anemia ora related pathology (Brown, 1989, 1992;Webb, 1990; Pardoe, 1993), and this has

been used to invalidate comparisons withthe cranium because its form could bealtered, albeit in unknown and unspecifiedways. Webb suggests that the intracranialbone structure of WLH-50, which is markedby the presence of thin inner and outercortical tables contrasted by thick diploic orcancellous tissue in between, is an adap-tation brought on by the need for hemato-poietic reinforcement. The proposed anemic

18 . ET AL.

condition which created this need is perhapsclosely related to, or a precursor to, moderngenetically derived hemoglobinopathies,such as sickle cell anemia or thalassemia.The conditional tone of Webb’s assertion isdue to the fact that WLH-50 does notdisplay skeletal changes conforming to thoseobserved in recent populations sufferingfrom genetically determined anemias(Webb, 1990; Armelagos, personal com-munication). WLH-50 lacks any overtexpression of symmetrical hyperostosis,cribia orbitalia, or localized bossing of theparietal or frontal squamae, which are themain paleopathological indicators of chronicanemia.

Webb states that the Late PleistoceneSinga calvarium from the Sudan is the onlyother known example, either archaic ormodern, of such unusual cranial thickening.But in their analysis of the Singa craniumStringer et al. (1985) conclude with aprognosis similar to ours:

‘‘with the exception of the diploic thickening,the Singa skull did not exhibit any of the otherradiographic criteria associated with bonechanges in anemia. There was also no sign ofporotic hyperostosis. On the basis of theseresults there is little to support the hypothesisthat anemia was responsible for the unusualshape and diploic thickening seen in the Singaskull.’’

Stringer (1998) went on to use Singa’scranial measurements as part of his archaicAfrican sample, and we follow him inincluding this specimen in our sample.Furthermore, if WLH-50 and Singa arefound to share a similar pathological con-dition that results in thickened cancellousbone, this condition could not account forthe anatomical similarities of WLH-50 andNgandong because the anatomy of Singa isthe most different from WLH-50 of anycomparable specimen (Figure 3).

If diploic thickening of WLH-50 were theresult of chronic anemia, the hemoglobin-opathy responsible would have to be unlike

any known today or throughout paleoepide-miological history. For this reason, a patho-logical explanation of the vault thickening inWLH-50 is tentative at best. Other expla-nations for the morphology include a com-bination of advanced age (cranial thicknessincreases with age) and normal populationvariation, in this case similarity to the wideranges of variation in Australian fossil homi-nid samples such as Coobool Creek (Miller,1991). Webb (1989) notes that variation inseveral features among the Willandra homi-nids exceeds that of other fossil samplessuch as Ngandong and Zhoukoudian. But ineach of these samples the form of the vari-ation is limited to a distinct pattern; forinstance, the frontal trigone at Ngandong, orthe large percentage of diploic bone in rela-tion to total cranial thickness at Willandra,73% for WLH-50, which is the same asMungo 3 and less than several otherWillandra specimens (data from Webb,1989, Table 3).

PlesiomorphyA final issue concerning the analysis is thepossibility that one might view the simi-larities between WLH-50 and Ngandong asplesiomorphic. Though we use a noncladis-tic approach, it remains possible that any ofthe similarities between WLH-50 and theNgandong sample might be thought of asprimitive retentions from a distant commonancestor. If this were true, then our testsmight reject a unique ancestor–descendentrelationship between WLH-50 and LatePleistocene Africans and Levantines purelyon the basis of a more distant relationshipwith Late Pleistocene Indonesian hominids.

Since we considered Late Pleistocenesamples that are potentially ancestral toWLH-50, by virtue of the hypotheses weexamine and their age relative to this speci-men, we can view the issue of plesiomorphywithout recourse to a more distant out-group. Simply put, for a feature that tends tolink WLH-50 with the Ngandong to be a

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plesiomorphic retention, it must be presentin the putative African and Levantine ances-tors of WLH-50. But while some featureslinking WLH-50 to Ngandong are polymor-phic in the Africans and Levantines, othersare not. There are three nonmetric featuresin our data that are present in WLH-50 andthe Ngandong sample and absent in theother samples. These are a transverselyextensive nuchal torus, a projecting inion,and a lateral frontal trigone. For these traitsto be plesiomorphic, they must have existedat an as-yet-undetected frequency in theAfrican or Levantine ancestors of WLH-50.In contrast, there is no character state thatis present in WLH-50 and Africans orLevantines and absent from the Ngandongsample. It might therefore be easier to makean argument of plesiomorphy in the otherdirection, though this is not our aim.

Alternatively, it is possible that the fea-tures uniquely shared by Ngandong andWLH-50, other features that are rare in theAfrican and Levantine samples but frequentin Ngandong and present in WLH-50, anddetailed set of metric similarities betweenNgandong and WLH-50, reflect parallelevolution. Though we find it difficult toimagine a scenario in which this set of simi-larities between early and late specimens inIndonesia and Australia could evolve bychance, other workers may find justificationfor this alternative. However, since the cri-terion guiding phylogenetic systematics isparsimony, it would seem necessary to con-sider the least refuted hypothesis as the mostparsimonious alternative. In this case, themost parsimonious explanation for the simi-larities among these groups is surely theconspecificity of all the specimens involved.A reticulating evolutionary relationship canexplain both the presence of shared traitsbetween WLH-50 and Ngandong and thefact that WLH-50 and Late PleistoceneAfricans and Levantines are modernhumans. Since there is no reason to rejectsuch a hypothesis and no reason to accept an

alternative to it, as our analysis shows, weshould consider all these specimens to bemembers of a single reticulating species.The implications of this hypothesis arediscussed in the following section.

4Polygenism seems to be the hypothesis a number ofauthors try to disprove when they address multiregionalevolution (cf. Tishkoff et al., 1996; Chu et al., 1998;Cavalli-Sforza, 1998). Multiregionalism is persistently,and incorrectly, described as multiple origins (seeWolpoff & Caspari, 1997).

Significance for Ngandong

If total replacement is the wrong explanationfor the morphology of recent humans in thisregion of the world, what are the impli-cations for Ngandong? Our analysis showsthere are significant similarities betweenWLH-50 and Ngandong, but there areample differences as well and we do notclaim, or believe, that WLH-50 could beconsidered part of the Ngandong sample(Thorne et al., in preparation; Webb, 1989).Moreover, these similarities do not implythat Ngandong is the sole ancestor of NativeAustralians. An explanation like that is simi-lar to Haeckel’s or Coon’s polygenism andrequires unjustified belief in the power ofparallel evolution4 (Wolpoff & Caspari,1997). On the other hand, the multiregionalinterpretation that Ngandong is among theancestors of Native Australians fits well withthe several hypotheses of multiple origins forNative Australians developed over the years(Birdsell, 1967; Macintosh, 1963; Thorne,1977). It is compatible with the contentionthat Ngandong is an intermediate betweenthe earlier Kabuh Indonesians and NativeAustralians in the sense that, as Weidenreich(1943) put it,

‘‘at least one line leads from Pithecanthropusand Homo soloensis to the Australian abor-igines of today. This does not mean . . . all theAustralians of today can be traced back toPithecanthropus or that they are the soledescendants of the Pithecanthropus–Homo solo-ensis line’’ (pp. 249–250).

20 . ET AL.

5This could be in the sense of a last commonancestor, or in the sense of an older common ancestor,some of whose Javan descendants were Australiancolonizers.

Table 6 Brain volumes in cubic centimetres

Female average Male average

Indonesian Kabu 875 (n=5) 1032 (n=2)Indonesian Ngandong 1093 (n=2) 1177 (n=4)Native Australian 1119 (n=22) 1239 (n=51)

However, in the recent redating ofNgandong (Swisher et al., 1996), it wasclaimed that Ngandong cannot be such anintermediate because

‘‘Homo erectus from Ngandong overlaps in timewith Homo sapiens from Australia.’’

There is a problem here, because even ifthere was such an overlap, Ngandong couldreflect a transitional anatomy for two differ-ent reasons: (1) as a direct ancestor of somePleistocene Australians,5 or (2) as a mutualdescendent of a common ancestor withNative Australians. Both could be correct,but if either is correct Ngandong cannot be‘‘Homo erectus’’, according to a definition ofspecies that relies on branching. Radio-metric dates cannot invalidate the anatomi-cal interpretation that Ngandong is (or isrelated to) an Australian ancestor, unlessone is willing to accept the premise of poly-genism and assume that the Australianswere a unique human line that becameisolated from the rest of the world onceAustralia was colon ized. Otherwise,Indonesia could have continued to contrib-ute colonists descended from Ngandong.

The possibility that Ngandong can be inthe middle of the Late Pleistocene, and be‘‘Homo erectus’’ and be among the ancestorsof Native Australians is rendered implaus-ible by the dates. To be valid, this wouldhave to mean that ‘‘Homo erectus’’ in thisregion became H. sapiens later than in otherparts of the world—a contradictory andbiologically invalid interpretation that isunacceptable. To circumvent it, there arethose who admit to the resemblances, butargue that they lack taxonomic significancebecause they are ‘‘plesiomorphic’’ sinceNgandong, which the Australians resemble,is ‘‘Homo erectus’’. If so, the argument con-tinues, the resemblances cannot describeregional continuity because relationships

should not be based on plesiomorphicfeatures.

But this whole line of argument is fal-lacious because it follows from the assump-tion that the human groups comparedevolved independently. Without making thisassumption, as we noted above the phylo-genetic descriptions like apomorphy andplesiomorphy can not validly apply. More-over, how can common anatomy in recentNative Austalians be more plesiomorphicthan different anatomy in other recenthuman populations, as would have to followfrom this argument, without interpreting thedifference to mean that some human popu-lations differ from others because they havemore genes from an extinct primitive humanspecies? The weight of the data suggests thatthe problem, and its solution, lie in thetaxonomy.

Ngandong differs from its Kabuh ances-tors and approaches the anatomy of LatePleistocene H. sapiens elsewhere in manyways. For instance, it has significantsupraorbital torus reduction (comparing likesexes, the torus is smaller than the Kabuhspecimens, and a depression over the noseresults in its distinct separation into rightand left sides). The frontal bone is markedlybroader, especially across the frontal lobes(behind the orbits, where the postorbitalconstriction is less). The articular eminencefor the mandible is projecting and welldefined. The occipital plane of the occipitalbone is markedly expanded while the nuchalmuscle attachment area is decreased bysome 30%. But most importantly the rela-tionship can be seen in brain size (Table 6).

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The Ngandong sample has a brain size con-siderably expanded over the Kabuh homi-nids, not just within the Native AboriginalAustralian range but closely approaching themean.

These common changes would have to beexplained by parallelism if ‘‘Homo erectus’’persisted on Java while H. sapiens was evolv-ing the same way in other places. One com-plex parallelism is possible but combinedthese pose a statistical improbability.

We do not believe any of this is correct.WLH-50 and other Australian Late Pleis-tocene fossils are modern humans, and theclear implication of their links to Ngandongis that these older Indonesians are H. sapiensas well.

Conclusion

The WLH-50 calvarium is vitally importantto the understanding of modern human ori-gins in Australasia (Thorne et al., in prep-aration; Webb, 1989). We used it in a testof the complete replacement model in theregion, which predicts that Late PleistoceneAfricans and Levantines are direct ancestorsof WLH-50, while the Ngandong hominidscannot be. Two distinct procedures, a dis-criminant analysis of metric data for thegroups and a pairwise difference analysis ofnonmetric data for individuals, were used totest this model. Both tests clearly refutedcomplete replacement in Australasia. Inaddition, both methods yielded statisticallysignificant results, which seemingly indicatethat similarities between the Ngandongfossils and WLH-50, a modern human, arephylogenetic.

Given their geographic and temporal dis-tribution, the Ngandong hominids weremost probably one of the ancestors of WLH-50, as would be predicted under a multi-regional model of human evolution. Thesefindings call into question prior classificationof the Ngandong hominids as a separateevolutionary species, H. erectus, and indicate

that they should be included within thespecies H. sapiens.

Acknowledgements

We thank Alan Thorne, Research Schoolof Pacific and Asian Studies, ANU, forgraciously sharing his observations andinsights with us, and for allowing one of us(M.H.W.) to study the original WLH-50specimen. We are grateful to the curators ofthe fossil hominid remains in our compara-tive samples for allowing their study.

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