Flores Hominid: New Species orMicrocephalic Dwarf ?

ROBERT D. MARTIN,1* ANN M. MACLARNON,2 JAMES L. PHILLIPS,3

AND WILLIAM B. DOBYNS41Academic Affairs, Field Museum, Chicago, Illinois

2School of Human and Life Sciences, Roehampton University, London, United Kingdom3Department of Anthropology, University of Illinois at Chicago and the Field Museum,

Chicago, Illinois4Department of Human Genetics, University of Chicago, Chicago, Illinois

ABSTRACTThe proposed new hominid Homo oresiensis is based on specimens

from cave deposits on the Indonesian island Flores. The primary evi-dence, dated at 18,000 y, is a skull and partial skeleton of a very smallbut dentally adult individual (LB1). Incomplete specimens are attributedto eight additional individuals. Stone tools at the site are also attributedto H. oresiensis. The discoverers interpreted H. oresiensis as an insulardwarf derived from Homo erectus, but others see LB1 as a small-bodiedmicrocephalic Homo sapiens. Study of virtual endocasts, including LB1and a European microcephalic, purportedly excluded microcephaly, butreconsideration reveals several problems. The cranial capacity of LB1( 400 cc) is smaller than in any other known hominid < 3.5 Ma and isfar too small to derive from Homo erectus by normal dwarng. By con-trast, some associated tools were generated with a prepared-core tech-nique previously unknown for H. erectus, including bladelets otherwiseassociated exclusively with H. sapiens. The single European microce-phalic skull used in comparing virtual endocasts was particularly unsuit-able. The specimen was a cast, not the original skull (traced to Stuttgart),from a 10-year-old child with massive pathology. Moreover, the calottedoes not t well with the rest of the cast, probably being a later additionof unknown history. Consideration of various forms of human micro-cephaly and of two adult specimens indicates that LB1 could well be amicrocephalic Homo sapiens. This is the most likely explanation for the in-congruous association of a small-brained recent hominid with advancedstone tools. Anat Rec Part A, 288A:11231145, 2006. 2006Wiley-Liss, Inc.

Key words: brain size; cranial capacity; hominid evolution;Homo; microcephaly; stone tools; prepared core;Flores; insular dwarsm

Brown et al. (2004) recently recognized a new hominidspecies, Homo oresiensis, on the basis of skeletalremains recovered from the limestone cave of Liang Buaon the Indonesian island of Flores. In a companion pa-per, Morwood et al. (2004) reported on associated stonetools and faunal remains, providing dates bracketedbetween 38,000 and 18,000 years ago for the relevantsediments. The time depth for H. oresiensis and associ-ated stone artifacts was extended to 74,00095,000 yearsago by Morwood et al. (2005a). The primary specimen(LB1), from an uppermost level dated at about 18,000

years ago, is an associated skull and partial skeletonfrom a dentally adult individual. The most immediately

*Correspondence to: Dr. Robert Martin, The Field Museum Academic Affairs, 1400 S. Lake Shore Drive, Chicago, Illinois60605. Fax: 312-665-7806. E-mail: rdmartin@eldmuseum.org

Received 26 April 2006; Accepted 1 August 2006

DOI 10.1002/ar.a.20389Published online 9 October 2006 in Wiley InterScience(www.interscience.wiley.com).

2006 WILEY-LISS, INC.

THE ANATOMICAL RECORD PART A 288A:11231145 (2006)

striking feature of the LB1 skeleton is its small size.Maximum length of the femur is 280 mm, slightly lessthan the minimum value of 281 mm recorded for Aus-tralopithecus afarensis (AL-288-1) and equal to the mini-mal estimate for the Homo habilis skeleton (OH62). Tak-ing maximum femur length, stature of the LB1 skeletonwas estimated at 106 cm using formulae derived fromhuman pygmies (Jungers, 1988), and a body mass of16.028.7 kg was then inferred from this stature. (Forcomparative purposes below, a mid-range value of 23 kgis taken.) One key feature, which gives the visualimpression of primitive morphology in LB1, is the ab-sence of a chin in the mandible. An even more striking,and certainly unexpected, feature of the skull of themain specimen is its very small cranial capacity. Brownet al. (2004) reported a value of only 380 cc measuredwith mustard seed. Indeed, because of the small cranialheight associated with the small brain size of this indi-vidual, Brown et al. (2004) stated that their inferredstature of 106 cm was likely to be an overestimation. De-spite this very small cranial capacity, a follow-up studyof a virtual endocast derived from the LB1 skull con-cluded that the brain shows a number of similarities tothat of Homo and is closest to that of Homo erectus (Falket al., 2005a).In addition to the main skeleton LB1, fragments of

two other individuals were reported in the initial publi-cations. Brown et al. (2004) referred to Homo oresiensisan isolated mandibular premolar (left P3) dating back atleast 37.7 kyr and stated that additional evidence of asmall-bodied adult hominin is provided by an unassoci-ated left radius shaft, without the articular ends, froman older section of the deposit (7495 kyr). Morwoodet al. (2004) gave a body height estimate of about 1 mbased on that radius shaft. Additional elements of theLB1 skeleton and further remains attributed to six addi-tional individuals were subsequently reviewed by Mor-wood et al. (2005a). The only substantial new specimensreported are a second mandible (LB6) that resemblesthe LB1 mandible in lacking a chin and a second righttibia (LB8).The overall conclusion initially derived from all of the

skeletal material from an inferred total of nine individu-als is that Homo oresiensis was a dwarf form derivedfrom Homo erectus. Dwarng was interpreted as a resultof isolation on the island of Flores, paralleling knowncases of evolutionary dwarng in certain island-livingmammals (e.g., elephants). In fact, dwarf elephants (ge-nus Stegodon) are found in the same deposits, and itwas concluded that Homo oresiensis not only made thestone tools found in the deposits but also hunted juve-nile Stegodon and possibly even used re for cooking, inview of the presence of charred animal bones (Morwoodet al., 2005a). This scenario was reiterated in a popularaccount by Morwood et al. (2005b). Among other things,it has been suggested that the Flores hominid showsthat a large brain size is not a prerequisite for the pro-duction of advanced stone tools (Wong, 2005). Givensuch far-reaching interpretations, the nds have natu-rally attracted considerable attention.Because the Flores nds involve such a strikingly in-

congruous combination of a tiny-brained hominid withadvanced stone tools, it is surely advisable to give seri-ous consideration to alternative explanations (Henne-berg and Thorne, 2004; Jacob et al., 2006; Martin et al.,

2006; Richards, 2006). One possibility is that the indi-vidual represented by the main skeleton LB1 sufferedsome kind of pathology, exhibiting a form of microce-phaly. For the time being, only a single skull is knownfor Homo oresiensis and that skull happens to have avery small cranial capacity. In this sense, it is undoubt-edly microcephalic, i.e., small-headed (see also Richards,2006). It is important to note at once that small brainsize and small body size are to some extent separableissues. It is perfectly possible that Flores was inhabitedby a small-bodied hominid species between 100,000 and18,000 years ago. It is well established that human bodysize tends to decrease with decreasing latitude, accompa-nied by increasing average annual temperature, and isparticularly small in warm, humid climates at low lati-tudes (Roberts, 1953; Ruff, 1994; Katzmarzyk and Leonard,1998). Furthermore, a skeleton from an adult humanpygmoid with an estimated age of about 30 years anda height of only 146 cm has been reported from the sepa-rate cave site of Liang Toge on Flores (Verhoeven, 1958;Jacob, 1967). Richards (2006) provides an extensive dis-cussion of reduced stature in various modern humanpygmy populations. LB1 could be a pathological, tiny-brained individual from such a population of very shortstature.Rejection of the possibility of pathological microce-

phaly in LB1 by Brown et al. (2004) was seemingly sup-ported by a subsequent publication by Falk et al.(2005a), which compared virtual endocasts of LB1, mod-ern human, Homo erectus, chimpanzee, and a Europeanmicrocephalic. It was concluded that the endocast ofLB1 was distinctly different from the single microce-phalic included in that comparison. Later on, however, astudy of 19 human microcephalic skulls revealed consid-erable variation in external brain morphology, with theendocast of one individual seemingly showing overallsimilarity to that of LB1 (Weber et al., 2005), althoughthat conclusion was questioned (Falk et al., 2005a).

CRANIAL CAPACITY

As Brown et al. (2004) themselves noted, the value of380 cc they reported for the cranial capacity of LB1 iscomparable to the lowest values recorded for Australopi-thecus and lies well within the range for great apes(e.g., chimpanzees). In fact, the volume of the virtualendocast subsequently reported for LB1 by Falk et al.(2005a) is appreciably larger, at 417 cc. The discrepancyof 37 cc between these two reported values for cranialcapacity, almost 10%, is disconcertingly large. Neverthe-less, even the higher value of 417 cc is strikingly smallin comparison to all other known hominids. The initiallyreported value (380 cc) is smaller than in any otherknown undoubted hominid apart from two individualAustralopithecus afarensis (343 cc in AL 333-105; 375 ccin AL 162-28), although the higher value of 417 cc alsoexceeds that reported for more recent Paranthropusaethiopicus (410 cc for WT 17000). In fact, the volume ofa computer-generated endocast of LB1 has since beenreported to be 400 cc (Holloway et al., 2006), and thatvalue (close to the mean of the two previously reportedvalues) will be taken for purposes of further discussionhere. Accordingly, it is necessary to go back about 3.5million years (my) to nd a hominid cranial capacity assmall as that of the Flores hominid (Fig. 1). All values

1124 MARTIN ET AL.

reported for the Flores hominid (380417 cc) are alsosmaller than in most gorillas and fall well within therange for common chimpanzees (Fig. 2). Hence, it isunquestionable that brain size in the LB1 skeleton ofHomo oresiensis, dating back only 18,000 years, wastiny by any standard.At rst sight, it might be thought that the diminutive

cranial capacity of LB1 could be attributable to evolu-tionary dwarsm, as suggested by Brown et al. (2004),although Argue et al. (2006) note that insular dwarsmis unknown for Homo to date. However, it is well estab-lished that reduction of body size within a mammal spe-cies (including Homo sapiens) is usually associated withonly moderate reduction in brain size. Whereas theexponent value for scaling of brain mass size to bodymass in comprehensive interspecic comparisons acrossplacental mammals is close to 0.75 (Martin, 1981; Mar-tin et al., 2005), there is a progressive decline withdecreasing taxonomic rank and the value for intraspe-cic scaling among adults of a single species is typicallyabout 0.25 (Martin and Harvey, 1985; Kruska, 2005).One of the best-documented cases is that of the domesticdog, with an exponent value of 0.27 determined for 26breeds covering a 21-fold range of body sizes generatedby articial selection (Bronson, 1979). In fact, in modernhumans and other primates examined, the exponentvalue is generally lower than 0.25 and approaches zeroif males and females are considered separately (Martinand Harvey, 1985). Even with an intraspecic scalingexponent value of 0.25, halving of body mass would onlybe expected to result in reduction of brain mass to 84%of its original value. In modern human pygmies, for

example, cranial capacity is not greatly different fromthat in populations of larger body size. Falk et al.(2005a) note that human pygmy skulls typically havecranial capacities exceeding 1,000 cc (compared to aworldwide mean value for all modern humans of 1,349cc) (Beals et al., 1984). The adult female pygmy skullused in their comparison in fact had a cranial capacityof 1,249 cc, while modern Rampasasa pygmies on Floreshave an average cranial capacity of 1,270 cc (Jacobet al., 2006), similar to the value of 1,204 cc reported byJacob (1967) for the Flores pygmoid described by Ver-hoeven (1958).Brown et al. (2004) explicitly suggested that Homo

oresiensis was derived from Homo erectus through aprocess of insular dwarng (see also Morwood et al.,2005b), although Morwood et al. (2005a) state that H.oresiensis is not just an allometrically scaled-down ver-sion of H. erectus. Examination of this proposal is com-plicated by considerable divergence in the denition ofHomo erectus. Here, a very broad view with no geo-graphical restriction will be taken, as this effectivelycovers all options for comparison. In one general surveyusing such a broad denition (Stanyon et al., 1993),mean cranial capacity for 28 Homo erectus was 991 cc(range, 7271,251 cc). If brain size scales to body sizewith an exponent value of 0.25, the body size of Homoerectus would have to be reduced to one-eighth of theoriginal value for a cranial capacity of 400 cc to beincluded at the lower end of the range. In fact, for a cra-nial capacity of 400 cc to correspond to the mean valueof dwarfed Homo erectus, body size would have to bereduced to 1/32 of its original value (Martin et al., 2006).

Fig. 1. Cranial capacities recorded for 118 fossil hominids plottedagainst time, extending back almost 3.5 Ma (data from Stanyon et al.,1993). The arrow indicates the highly incongruous value (red circle)reported for Homo oresiensis at only 18,000 years ago. The recently

reported values for the four Dmanisi skulls (magenta circles) fall wellwithin the range for hominids dated at around 1.7 mya and t the gen-eral trend, in striking contrast to the value for H. oresiensis.

1125FLORES HOMINID

In other words, an original body size of 60 kg for Homoerectus (Kappelman, 1996) would have to be reduced tojust 2 kg for the mean cranial capacity to be reducedfrom 991 cc to an average value of 420 cc. A more recent

survey of cranial capacity in broadly dened Homo erec-tus, with an increased sample size of 38 (Krantz, 1995),reported a higher mean value of 1,045 cc (range, 7801,360 cc). This would correspond to an even greater body

Fig. 2. Histograms showing cranial capacities for African greatapes (Gorilla gorilla; n 48; Pan troglodytes; n 95) and various fos-sil hominids (Australopithecus spp., n 10; Paranthropus spp., n 8;Homo habilis, n 7; Homo erectus, n 28; archaic Homo, n 17;Homo neanderthalensis, n 22; Homo sapiens, n 26). Data for the

African great apes are taken from the records of Adolph Schultz (An-thropological Institute, University of Zurich); data for fossil hominidsare from Stanyon et al. (1993). The pink vertical bar indicates therange covered by the reported values for Homo oresiensis (380417 cc).

mass reduction required to attain the cranial capacity ofLB1 in a dwarf form.It could be argued that some individuals included in

the broadly dened taxon Homo erectus have quitesmall brains, and that the cranial capacity reported forHomo oresiensis would be more likely to result fromdwarng of such small-brained individuals. A case inpoint is provided by four skulls from the Dmanisideposits in Georgia, dated at about 1.7 mya. Althoughthese specimens have in fact been referred to the taxonHomo ergaster, for geographical reasons they could con-ceivably be relevant to the origin of the Flores hominid.The four skulls from Dmanisi have a mean cranialcapacity of only 664 cc (range, 600775 cc) (Gabuniaet al., 2000; Vekua et al., 2002; Rightmire et al., 2006).It has been suggested that the Flores hominiddescended from such a small-brained population, butthis proposal is also unconvincing. First, with an intra-specic scaling exponent of 0.25, body size would stillhave to be reduced to one-eighth of the average forHomo erectus (from 60 to 7.5 kg) to decrease mean cra-nial capacity from 664 to 400 cc. In fact, taking thesmaller body mass of 50 kg estimated for the Dmanisifossils (Gabunia et al., 2001), body size would have tobe reduced to around 6 kg to reach a mean cranialcapacity of 400 cc. Contrary to the impression that hasbeen given, cranial capacities of the Dmanisi hominidsare not unusually small, given their antiquity. The fourvalues recorded fall within the range previously foundfor hominids at 1.7 mya (Fig. 1). Indeed, the antiquityof the Dmanisi hominids renders any direct comparisonwith the Flores hominid inappropriate because cranialcapacity shows a general trend to increase over timewithin the broadly dened taxon Homo erectus andamong hominids generally. Taking the sample of 28 val-ues for Homo erectus given by Stanyon et al. (1993), atrend line indicates that average cranial capacityincreased by about 200 cc over the period covered. AsHomo oresiensis is only 18,000 years old and has beenidentied as a remarkably late-surviving evolutionarydwarf form of Homo erectus, it seems more likely thatdwarng would have taken place from a relativelylarge-brained late representative. It should also benoted that in one of the cranial comparisons conductedby Argue et al. (2006), including a single skull fromDmanisi (D2280), there was no indication of any mor-phometric afnity with the LB1 skull.In both temporal and geographical terms, the repre-

sentatives of the taxon Homo erectus that are closest tothe Flores hominid are the Ngandong specimens fromthe Solo River in Java. Dating of those specimens hasbeen subject to much uncertainty. They were originallythought to date back around 200,000 years or more.However, preliminary radiometric dating indicated anage of 50,000100,000 years (Bartstra et al., 1988), andsubsequent dating using a combination of radiometricmeasurement and electron spin resonance yielded aneven younger age of 27,00053,000 years (Swisher et al.,1996). Hence, the Ngandong specimens may possibly beonly 9,00035,000 years older than the LB1 skeleton.The average cranial capacity for six skulls from Ngan-dong is 1,149 cc (Stanyon et al., 1993), almost threetimes larger than that of the Flores hominid.This all leads to the conclusion that it is simply unre-

alistic to explain the tiny cranial capacity of 380417 cc

recorded for Homo oresiensis as an outcome of evolu-tionary dwarsm affecting an insular population of late-surviving Homo erectus (Martin et al., 2006).Several instances of evolutionary dwarsm in mam-

malian lineages are known from the fossil record as wellas from recent species, ranging from squirrels and slothsto hippopotami and mammoths. Pleistocene dwarf ele-phants, for example, are known from a number of Medi-terranean islands. The presumed ancestral mainlandspecies, Elephas antiquus (Caloi et al., 1996), had an av-erage estimated body mass of 10,00015,000 kg, whilethe comparatively tiny island dwarf form, E. falconeri,from Malta-Sicily, had an estimated mass of only 100 kg(Roth, 1992). The difference in brain size between thesetwo species was much less marked than the hundred-fold difference in body size. The cranial capacity of E.antiquus was approximately 9,000 cc, whereas that of E.falconeri was 1,800 cc (Accordi and Palombo, 1971). Theslope of the line joining these two sets of values corre-sponds to an exponent value of 0.320.35, much closer tothe typical intraspecic scaling value of 0.25 than to theinterspecic scaling value of about 0.75 for mammalsgenerally. Brain size dwarng in elephants thereforeresembles the scaling pattern determined across widebody size ranges for domestic dogs (scaling exponent 0.27) (Bronson, 1979), sheep (0.29) (Bronson, 1979), horses(0.25) (Bronson, 1979), and wild boar (0.24) (Kruska,1970). The time taken for the dwarng of Mediterraneanelephants is unknown, but could be up to several hun-dred thousand years (Ambrosetti, 1968; Caloi et al.,1996; Lister, 1996). However, the dwarng process canoccur very quickly. This is shown by the case of red deeron the island of Jersey, which became dwarfed to aboutone-sixth of their original size (estimated body mass ofabout 36 kg for dwarf adult males compared with about200 kg for the ancestral mainland species) over a periodof 600011,000 years (Lister, 1996).A special case explicitly invoked by Brown et al.

(2004), Brown and Morwood (2004), and Argue et al.(2006) to account for the remarkably small cranialcapacity of LB1 is a report on unexpectedly small brainsize in a dwarfed insular bovid by Kohler and Moya`-Sola`(2004). It was found that six chronologically successivespecies of the extinct genus Myotragus found in Plioceneand Pleistocene deposits of Majorca had relatively smallbrains compared to other living and fossil bovids.Because the inferred sister genus (the Pliocene rupica-prine Gallogoral) resembles the other bovids in its rela-tive brain size, it was concluded that a marked decreasein relative brain size (by about 50%) had taken place fol-lowing the isolation of Myotragus on Majorca by 5.2mya. Despite the apparent parallels to the case of theFlores hominid, however, there are crucial differences.Most importantly, investigation of relative brain size inMyotragus was initiated because of the strikingly smallsize of the orbits, suggesting marked reduction in size ofthe eyes. No such reduction in orbit size has been sug-gested for the Flores hominid, and there is indeed noevidence thereof. Furthermore, the time scale concernedis one or two orders of magnitude greater and involves adistinction at the generic level (between Myotragus andother bovids) rather than at the intraspecic level (ifLB1 is interpreted as a dwarfed Homo erectus). In fact,a comparative study of a short DNA sequence extractedfrom Myotragus (Lalueza-Fox et al., 2002) indicates that

1127FLORES HOMINID

this genus is not closely related to rupicaprines after all(hence ruling out Gallogoral as the sister genus) and ismost closely related to Ovis, which was not included inthe comparative sample studied by Kohler and Moya`-Sola` (2004). The ancestry of Myotragus is at presentundetermined, so we have no direct information aboutrelative brain size at the outset. Inferred reduction inrelative brain size in Myotragus thus has little or norelevance to the tiny brain of the Flores hominid.

STONE TOOLS

Some scholars believe that the archaeological historyof the Island of Flores begins during the Lower Pleisto-cene/Middle Pleistocene transition, based on equivocalevidence from the site of Mata Menge (dated to ca.800,000 BP). At that site, 14 stone tools out of a total of54 artifacts were identied originally (Morwood et al.,1998, 1999), while an additional 507 artifacts were foundin recent excavations (Brumm et al., 2006). The objectsconcerned were found in river gravels in associationwith a Stegodon, although there is some questionwhether all of them are actually artifacts, rather thanaccidents of nature.Brumm et al. (2006) suggest that there are similar-

ities, and apparent technological continuity betweenthe akes produced at Mata Mange and Liang Bua, thesite where remains of H. oresiensis was recovered.There are, however, real questions concerning the asso-ciation of the artifacts with the ssion track datesbecause Brumm et al. (2006) mention hydraulic trans-portation and size sorting. Furthermore, the suggestionthat there is cultural continuity over a period of almost800,000 years is quite surprising and represents a viewof lithic technology that is at odds with our understand-ing of production and use of stone tools. Because akeswere produced at Mata Menge does not mean they rep-resent a tradition (see Clarke, 1968). Instead, theymay be just akes, as one would nd in any assemblageat any time and anywhere in prehistory. Additionally,the few cores from Mata Menge are not of types everfound with an Acheulean or Mousterian assemblage, butare recorded from the Upper Paleolithic period onward.Further, Brumm et al. (2006: Fig. 4) consider the rela-tionship between two perforators found at Liang Buaand several pieces they claim are the same type fromMata Menge. In this instance, we have to consider thefact that perforators have never been recovered fromAcheulean or Mousterian sites on any continent wherethese technocomplexes have been found. If the akesand tools from Mate Menge do indeed have any relation-ship with those recovered at Liang Bua, it is far morelikely that that they are from the same time period (ca.18,000 BP) and must have been transported either bythe movement of Homo sapiens or by water.The presumption of Morwood and colleagues is that

the maker of the Mate Menge implements was Homoerectus, remains of which had been found on the islandof Java early in the 20th century, but never on Flores.Although artifacts of Middle Pleistocene age are attrib-uted to fossil hominid nds on Java (Bartstra, 1992;Keates and Bartstra, 2000), the exact association isequivocal (Corvinus, 2004), and there is some questionof whether some are artifacts at all, whether on Java orFlores. Thus, stone artifact production earlier than

30,000 or so on Flores, and therefore the presence ofHomo erectus, is not conrmed.The belief stated by Morwood and colleagues is that

Homo erectus remained isolated on Flores for the re-mainder of the Pleistocene. It is proposed that, alongwith other mammals, Homo erectus became progres-sively smaller, until dwarf mammals and giant reptiles(e.g., Komodo dragons) were the main animal species onFlores ca. 18,000 BP (but see Allen, 1991). Morwoodet al. (2004) also hypothesize that their supposed dwarfform of Homo erectus developed hunting practicesto-gether with evolved artifactsthat replicate artifact assem-blages (and, presumably, hunting patterns) of modernHomo sapiens in other parts of Indonesia (e.g., EastTimor) (OConnor et al., 2002). This leads on to a partic-ularly incongruous feature of the proposed interpreta-tion of the recently discovered Flores material fromLiang Bua cave: All of the stone tools (n 32) reportedfrom the level of section VII containing the LB1 skeletonby Morwood et al. (2004), as well as those describedfrom section IV (which are even more advanced thanthose in section VII), clearly belong to types that areconsistently associated with Homo sapiens and have notpreviously been associated with H. erectus or any otherearly hominid. The artifact assemblage clearly involveda tradition using the prepared-core technique, which isconned to Homo neanderthalensis and Homo sapiens.Furthermore, the explicitly noted presence of bladeletsis a hallmark of Homo sapiens, found in Africa, Asia,Europe, and after ca. 40,000 BP. Yet Morwood et al.(2004) concluded that H. oresiensis made the associ-ated stone artifacts.In fact, two anomalous features of the section VII

assemblage are evident in Figure 5 of Morwood et al.(2004): 5g is a Levallois core (not a burin core for pro-ducing microblades; the small bladelet-like removals arefeatures of the core preparation); and 5c, the bipolarcore, like the Levallois core, produced akes, not bladeor bladelet blanks. In other words, the blanks in theassemblage are blades and bladelets, while the cores cor-respond to production of akes. The most likely interpre-tation is that these blade and bladelet blanks, althoughfound near the cores, are not actually associated withthem. For section IV, stratigraphically partially abovethe section VII material and located toward the centerof the cave, the authors mention the nding of thou-sands of artifacts, up to 5,500 per cubic meter, mainlyakes produced from radial cores (i.e., Levallois). How-ever, they also mention a more formal component . . .including . . . blades and microblades, thus reinforcingthe interpretation that there are at least two sets ofassemblages in the cave, both seemingly associated withtheir hominid.It is inherently unlikely that the reported complex of

Upper Paleolithic blanks and tools would have beendeveloped independently by an unusually small-braineddwarf evolutionary descendant of H. erectus. Any alter-native explanation invoking secondary acquisition byHomo oresiensis of tools or tool-making techniquesfrom Homo sapiens would raise a host of additionalunanswered questions. The normal expectation would bethat any hominid dated at 18,000 years ago associatedwith tools typical of Homo sapiens would be a memberof that species. The anomalies in the archaeological datamost likely indicate the presence of fully modern compe-

1128 MARTIN ET AL.

tent Homo sapiens utilizing the Liang Bua cave manytimes after their arrival on Flores.

SKULL IN HUMAN MICROCEPHALICS

Given that the brain size is so unusually small in theLB1 hominid despite its remarkable young geologicalage (Fig. 1), the possibility of a pathological disorder,specically some form of microcephaly, must be consid-ered (Henneberg and Thorne, 2004; Jacob et al., 2006;Martin et al., 2006; Richards, 2006). This possibility wasmentioned briey in the original report (Brown et al.,2004), but then rejected. The main authors of the origi-nal reports on the LB1 skeleton also defended this posi-tion in dismissing the proposal by Henneberg andThorne (2004) that LB1 might be a pathological speci-men (Brown and Morwood, 2004). That proposal was ex-plicitly addressed in a subsequent paper comparing avirtual endocast of the LB1 skull with endocasts froman adult female chimpanzee, an adult female H. erectus(specimen ZKD XI from Zhoukoudian), a modern humanfemale, and a single European microcephalic (Falket al., 2005a). The origin of the European microcephalicskull was not otherwise described, but the authorsreported that its shape conforms to features of its corre-sponding skull that typify primary microcephaly (micro-cephalia vera): small cranial vault relative to face, slop-ing forehead, and pointed vertex.On closer examination, the single microcephalic skull

of unstated provenance taken by Falk et al. (2005a) fortheir comparison has proved to be an inappropriatechoice for several reasons (Martin et al., 2006; Richards,2006). The published account provides no details of theskull that was investigated. It was particularly importantto establish whether the skull concerned was that of anadult as in the case of LB1 or derived from an immatureindividual suffering from a pronounced pathology result-ing in early death. Another cause for concern is that thecranial capacity of this microcephalic skull, which is notexplicitly stated by the authors, is exceedingly small.Although its remarkably small size is not obvious fromthe illustrations provided by Falk et al. (2005a), whichwere all scaled to a standardized volume (rather thanscaled in proportion), it is evident from the diminutivelinear dimensions provided in the accompanying table.In response to our enquiry, Falk reported that the

microcephalic specimen examined had been obtainedfrom the collections of the American Museum of NaturalHistory (AMNH) in New York. Falk also noted that thespecimens skull shape typies that associated withmicrocephalia vera and stated that the specimen hadanomalous teeth. For that reason, the specimens age atdeath was not estimated, although it was believed to bea juvenile. In fact, it is simply impossible to take anysingle skull as typical of true microcephalics. The termprimary microcephaly (microcephalia vera) is a generaldescriptor applied to individuals that have an unusuallysmall brain size at birth, recently dened as 3 stand-ard deviations at birth (Dobyns, 2002) or 4 standarddeviations at older ages (Woods et al., 2005), reectingimpairment of brain development attributable to a greatvariety of syndromes (Gilbert et al., 2005). As noted byMochida and Walsh (2001), the condition is clearly ge-netically and clinically heterogeneous. The key point isthat the microcephalic skull examined by Falk et al.

(2005a) was used for a comparison with adult represen-tatives of all other taxa despite the fact that it wasthought to come from an immature individual. Althoughbrain size reaches adult dimensions early in develop-ment (typically 67 years in normally developinghumans), early death of the microcephalic individualstudied renders direct comparison with the adult LB1inappropriate.Direct measurement of the cranial capacity of the

AMNH specimen using glass beads yielded a cranialcapacity of only 260 cc (K. Mowbray, personal communi-cation). Hence, the apparent brain size of this specimenwas remarkably small not only in comparison to that ofLB1 (about 65% of the value) but also in comparison tothe usual range of modern human microcephalics. Infact, the published images of the microcephalic endocastin the supplementary data provided by Falk et al.(2005a) also exhibit several unusual features that arenot seen in humans with the more common forms ofmicrocephaly. Few gyral indentations are apparent incomparison to all of the other endocasts, and the frontalpole is pointed. The cerebellum is small, although it isnot as drastically reduced as the cerebrum. Also, boththe occipital lobes and the cerebellum appear to hangdown further and at a sharper angle than observed inmost hominid brains. Finally, the foramen magnum isseemingly greatly enlarged, a defect known to be associ-ated with cerebellar malformations. These rare anoma-lies, combined with the extremely small cranial volume,suggest that the individual suffered from a severe brainmalformation and not isolated or primary microcephaly.Examination of the microcephalic skull studied by

Falk et al. (2005a), housed in the collections of theAMNH (Fig. 5), revealed the surprising fact that it isnot an original specimen but a plaster-based cast. Itbears the accession number 2792a and is contained in abox bearing an inscription indicating that it came fromCannstatt, Germany. However, the catalogue entrystates Casts of microcephalus skull from Plattenhardtand fragments from Cannstatt, Germany (Wurtemberg).The cast itself bears the inscription Plattenhardt.Tausch mit Stuttgart 1907 (Plattenhardt. Exchangewith Stuttgart 1907). Available records provide no fur-ther information concerning this specimen, other thanthe fact that it was included in a large collection pur-chased from Felix von Luschan by the AMNH in 1924.The teeth on the cast (eight in the upper jaws and ninein the mandible) are highly unusual. They are small,widely separated, and peg-like, with apparent signs ofheavy wear on the crowns. It is indeed virtually impossi-ble to determine a reliable age from the cast of this indi-vidual using standard dental criteria. One reasonableinterpretation would be that only one molar is present,on the right side of the lower jaw, and that this is theskull of a child.Further enquiries revealed that the original skull from

which the AMNH cast had been made almost a centuryago is in fact still included in the collection of the Staat-liches Museum fur Naturkunde, Stuttgart (Dr. ElmarHeizmann, personal communication; Fig. 3). The skullhas two accession numbers: 5297 (former registrationsystem) and 25523 (new registration system). Usingstandard criteria, the age of this individual at death wasestimated to be 1213 years (Dr. Doris Morike, personalcommunication).

1129FLORES HOMINID

A remarkable feature of the AMNH cast 2792a isthat the calotte (a separate element) is cream-colored,whereas the rest of the cranium and the mandible aredark brown (Fig. 3), suggesting that the latter partswere varnished at some time. Furthermore, the calottedoes not t properly onto the rest of the skull and theprole of the cut line deviates in several respectsbetween the two. Whereas sutures are clearly apparenton the calotte, their continuation cannot be traced downinto the lower part of the cranium. These disparities,taken together, raised the distinct possibility that thecalotte was not in fact part of the original cast and hadbeen manufactured subsequently. In order to check this,small samples were taken from the two separate partsof the cranium and subjected to chemical analysis usingan inductively coupled plasma-mass spectrometer (ICP-MS) in the Department of Anthropology at the Field Mu-seum in Chicago. It emerged that there are strikingchemical differences between the two parts (Table 1).The level of calcium, effectively serving as a control, isvirtually identical in the two samples, but there aremajor differences in other elements. The level of lead isapproximately 50 times higher in the lower part of theskull (compatible with the interpretation that there hadbeen previous treatment with a lead-based varnish),whereas the calotte shows markedly higher levels ofmanganese (2.73), barium (3.53), lanthium (14.63), andcerium (14.43). By contrast, tina major component inthe elemental proleis three times higher in the lowerpart of the skull cast than in the calotte. Other notabledifferences in that part of the cast are seen in boron(53), sodium (2.73), and potassium (2.43). These majordifferences in elemental composition demonstrate beyondreasonable doubt that the calotte was created from a dif-ferent batch of plaster and has a questionable connec-tion with the rest of the cast. This would directly con-

cern any impressions of gyri on the dorsal surface of thevirtual endocast generated from this specimen by Falket al. (2005a). The dangers of studying a cast instead ofthe original skull are further illustrated by the fact thatthe cross-sectional area of the foramen magnum is infact about 17% greater in the AMNH cast than in theoriginal skull. This increase exaggerates the markedpathological appearance of the foramen magnum and ad-jacent features of the endocast. Furthermore, there arediscrepancies between the cast and the original skullwith respect to volumetric measurements. Measurementby one of us (R.D.M.) of the cranial capacities of theoriginal skull and the AMNH cast, using ne lead shot,yielded values of 269 and 268 cc, respectively. Althoughthese values are almost identical, the volume of the ven-tral part of the cranial cavity is larger in the originalskull than in the AMNH cast (139 vs. 130 cc), whereasthe volume of the calotte is smaller (130 vs. 138 cc).It was also discovered that the Stuttgart skull was

included in an early discussion of human primary micro-cephaly by Vogt (1867). That survey covered 10 skullsfrom Germany in considerable detail, including descrip-tions of endocasts for 9 of them, and also incorporatedinformation from 19 other cases. Only 6 of the overallsample of 29 cases (i.e., 21%) involved adult individualsaged 21 years or more. In a more extensive review con-ducted much later by Hofman (1984), the proportion ofadult individuals aged 21 years or more was higher (31out of 68; i.e., 46%; Fig. 4), but it is nevertheless clearthat many microcephalics represented in collections andsurveys died before reaching adulthood. On the otherhand, survival into adulthood is not uncommon, andHofmans survey included one woman with a height of1.34 m who survived to the age of 74 with a brain massof only 277 g. The average cranial capacity reported fornine of the skulls examined by Vogt was 410 cc (393 cc

Fig. 3. Comparison of the original microcephalic skull in Stuttgart (left; Staatliches Museum fur Natur-kunde, 5297/25523) with the cast held in the collections of the American Museum of Natural History, NewYork (right; AMNH No. 2792a). Note the clear difference in coloration of the calotte compared to the restof the skull in the AMNH cast.

1130 MARTIN ET AL.

for the four adult individuals aged 21 years or above).Comparable gures are indicated by the sample exam-ined by Hofman (1984) (Fig. 5), with a mean brain massof 421 g for adult females (n 16) and a mean of 433 gfor adult males (n 17). All of these values match wellwith the observation from clinical experience that thebrain volume of human primary microcephalics is about400 cc, an estimate consistent with typical adult headcircumferences of 4045 cm in living human cases per-sonally examined by one of us (W.B.D.). The full range

TABLE 1. Results from chemical analysis of the two parts (calotte and remaining cranium) of thecast of a microcephalic skull (AMNH 2792a). (Results generated using an inductively coupled

plasma-mass spectrometer (ICP-MS) by Laure Dussubieux and P. Ryan Williams.)

Isotope Calotte Skull Isotope Calotte Skull Isotope Calotte Skull

Li7 115 346 Ni60 2732 2667 Nd146 800 88Be9 4 6 Cu65 43161 35435 Sm147 108 27B11 3418 16959 Zn66 18741 8617 Eu153 94 37Na23 311505 833007 Rb85 1196 2402 Gd157 117 33Mg24 237809 518235 Sr88 1726897 1453091 Tb159 76 24Al27 31002 104554 Y89 4740 943 Dy163 110 24Si29 20895 20447 Zr90 1130 770 Ho165 81 10P31 4340 10108 Nb93 35 31 Er166 59 11Cl35

of postnatal head circumferences in human microce-phalics lies between 4 and 12 SD (Woods et al.,2005).The skull in the collection of the Staatliches Museum

fur Naturkunde in Stuttgart is undoubtedly that of anindividual named Jakob Moegele from the village ofPlattenhardt, who died at the age of 10 years and1 month. Vogt (1867) recorded the cranial capacity ofthat individual as 272 cc, the smallest value determinedin his survey. Interestingly, 3 of the 10 individual skullsexamined by Vogt came from closely related individuals;in addition to the skull of Jakob Moegele, he also exam-ined that of his brother Johann Georg Moegele (whodied at 5 years of age) and that of his cousin JohannMoegele (who died at 15 years of age). Jakob Moegelewas the 8th of 11 children born in a single family. Inaddition to his elder brother Johann Georg (the 6thchild), the 2nd child (also named Jakob) and the 11thchild (Barbara) were likewise microcephalic, giving atotal of 4 microcephalic individuals among the 11 sib-lings. Even more intriguingly, a total of seven microce-phalic children were born to four couples (two of themunrelated to the two Moegele families) in the village ofPlattenhardt within the space of a few years. Thisaroused sufcient attention for a special report to becommissioned from the court physician (Vogt, 1867).The extreme pathological nature of Jakob Moegeles

skull is clearly revealed by CT scans. Both the endocra-nial cavity and the virtual endocast (which has a calcu-lated volume of 268 cc) show the unusual shape of thebrain, with both the occipital lobes and the cerebellum

hanging down conspicuously (Fig. 6). The teeth, aptlydescribed as mushroom-like by Vogt (1867), are highlyunusual in shape and position, and the developingreplacement teeth that would be expected in a 10-year-old child are completely lacking in both upper and lowerjaws (Fig. 7).In contrast to the aberrant skull of Jakob Moegele,

microcephalic skulls and endocasts that are much closerin morphology to the Flores LB1 specimen most cer-tainly do exist. One hemiskull of a dentally adult malemicrocephalic that is held in the collections at the Hunt-erian Museum in London (RCSHM/Osteo 95.1) is quitesimilar in size and external appearance (Fig. 8). Themuseum catalogue indicates that this specimen camefrom India, and it is described in a note by Shortt (1874)in which he states that the individual concerned was 5ft. 6 in. tall and weighed 89 lb (40.3 kg). Further infor-mation is provided in a review of 19 microcephalic skullsby Humphry (1895), who included an illustration of theHunterian skull (his Fig. 1 of skull 1) conrming its ori-gin in India. Doubling of the endocranial volume meas-ured from the Hunterian hemiskull yields a cranialcapacity of 432 cc, very close to the value recorded forLB1. The anthropological collections of the Field Mu-seum in Chicago also include plaster casts of a dentallyadult human microcephalic skull (accession numberA219679) and an accompanying endocast (accessionnumber A219680). The catalogue entry indicates thatthe skull and endocast (Fig. 9) are from a microcephalicidiot from Basutoland (now Lesotho). The specimenswere acquired as part of the Marshall Field Archaeologi-

Fig. 6. Virtual reconstructions from CT scans of the right hemiskull and endocast of the Stuttgartmicrocephalic specimen. Note the highly unusual dentition and the downward-hanging occipital lobesand cerebellum. Images prepared by Jonathan Brown.

1132 MARTIN ET AL.

cal Expedition to Western Europe in 19271928 andentered the collections in 1931. A label attached to theendocast indicates that it was produced in England byR.F. Damon, but no further information is available inthe museum records. In fact, plaster casts of the skulland mandible of this same individual are present in thecollections of the American Museum of Natural Historyin New York (accession number 99.1 2601 A,B), andanother endocast is held in the Hunterian Museum of

the Royal College of Surgeons, London (RCSHM D684.4).A literature search revealed that this case had been re-ported by Dru-Drury (19191921), who stated that theindividual concerned was a 32-year-old woman withsevere mental retardation. She reportedly had the bodysize of a 12-year-old child and a body mass of only 60 lb(27.2 kg). The cause of death was recorded as tuberculo-sis. An endocast from this individual was later includedand illustrated in a discussion of four microcephalics by

Fig. 7. Maximum intensity projection derived from CT scans of the left upper and lower jaws of theStuttgart microcephalic, revealing the aberrant structure of the teeth and the complete absence of devel-oping replacement teeth. (Image prepared by Jonathan Brown.)

Fig. 8. Comparison between a hemiskull of an adult male human microcephalic from the collectionthe Hunterian Museum in London (RCSHM/Osteo 95.1) and the LB1 skull (after Brown et al., 2004), bothdrawn to scale. Drawing by Jill Seagard.

1133FLORES HOMINID

Weidenreich (1941), who noted the presence of the skullcast in the AMNH collection. Weidenreich (1941: p. 396)stated that the form and proportions of the brain . . . asmuch as can be dened from the endocast, fail to showany appreciable differences when compared with the nor-mal human brain. Yet the volume of the Lesotho microce-phalic endocast is even smaller than that of the Hunter-ian specimen, amounting to only 335 cc. Both of theseendocasts, illustrated in Figure 10, have a relatively nor-mal external appearance, lacking the evident pathologiesshown by the brains of some human microcephalics suchas that of Jakob Moegele. The only really obvious macro-scopic anomaly in both cases is the extremely small size.

A recent comparative study of virtual endocasts from19 human microcephalics by Weber et al. (2005), with anaverage volume of 404 cc, has emphasized the consider-able range of variability in brain shape that exists. Theauthors of that study singled out one particular endocastthat appeared to be quite similar to that of the Floreshominid LB1, although this interpretation was ques-tioned by Falk et al. (2005b) on the grounds that thedegree of similarity was decreased if the two endocastswere oriented in the same way. Unfortunately, Weberet al. (2005) did not provide identifying information forthe specimens examined and did not state which individ-uals were adults.

Fig. 9. Plaster casts of a dentally adult human microcephalic skull from Lesotho and an accompanyingendocast in the collections of the Field Museum, Chicago (accession numbers A219679 and A219680,respectively). (Photographs by John Weinstein).

Fig. 10. Drawings of (right) an endocast from the hemiskull of the human microcephalic from India inthe collections of the Hunterian Museum (RCSHM/Osteo 95.1) and (left) of the left side of a human micro-cephalic endocast from Lesotho in the collections of the Field Museum, Chicago (accession numberA219680). Illustrations by Jill Seagard.

1134 MARTIN ET AL.

In order to avoid disagreement about endocast orienta-tion and description (Falk et al., 2005b, 2006) and toachieve direct comparability with the results reported byFalk et al. (2005a), we repeated some of their multivari-ate analyses, expanding their sample by adding an endo-cast produced from the Hunterian microcephalic skullfrom India, and an endocast from the same museum ofthe Lesotho specimen. We also included a new endocastproduced from the original Stuttgart microcephalic skull[corresponding to the virtual endocast from the AMNHskull cast used by Falk et al. (2005a)]. Two principalcomponent analyses were carried out on the same sets ofindices as those used by Falk et al. (2005a). The rst setcomprised six indexes (ve being used in the analysis)derived from four external endocast dimensions: length,breadth, height, and frontal breadth. The eight indexesin the second set were derived from six measurements ofthe base of the endocasts (Table 2). In a minor departurefrom Falk et al. (2005a), to enhance clarity of data pre-sentation we opted for two-dimensional plots of the rstand second principal components (PC1 and PC2) ratherthan three-dimensional plots including PC3. Most of theinformation is contained in PC1 and PC2 (Table 3), andthree-dimensional plots (which are difcult to interpreton the printed page) do not reveal any major differences.In a plot of PC1 against PC2 for the external endocastindices (Fig. 11a), the distribution of specimens includedin the original analysis by Falk et al. (2005a) is verysimilar to that shown in their Figure 2A and corre-sponds to descriptions in their text. In Figure 11a, theendocast prepared directly from the original skull of theStuttgart microcephalic, newly included here, falls closeto the virtual endocast derived by Falk et al. (2005a)from the AMNH skull cast. The approximate matchingconrms general agreement between our measurements;the minor separation between the points may reectmeasurement deviations and/or distortion in the virtualendocast derived from the poor-quality AMNH skullcast. The other new specimens included in Figure 11a,the Hunterian and Lesotho microcephalic endocasts, fall

close together and are not far removed from LB1. Allthree of these specimens are clearly separate both fromthe Stuttgart/AMNH microcephalic endocasts and fromnormal modern humans. Insofar as the complexity ofbrain shape can be captured by such simple indices, thisdemonstrates that LB1 is not clearly distinct from allmodern human microcephalics and more closely resem-bles the two new specimens included here than the moreseverely pathological single specimen studied by Falket al. (2005a).In a plot of PC2 against PC1 for the basal endocast

indices (Fig. 11b), the specimens included in the analy-ses of Falk et al. (2005a) are again distributed very simi-larly, corresponding to their Figure 2C and to thedescriptions in their text. Falk et al. did not include theAMNH microcephalic endocast in this analysis. Figure11b includes all three microcephalic endocasts in oursample: the Hunterian, Lesotho, and Stuttgart speci-mens. They are scattered very widely across the plot,with the Hunterian microcephalic falling closest toWT17000, Gorilla and Pan, the Lesotho microcephaliclocated very close to Sts 5, and the Stuttgart microce-phalic closest to modern humans. (It was necessary toestimate basal measurements involving the olfactorybulbs for the Hunterian specimen because the impres-sion on the skull from these structures is not clear.Analysis without this specimen yields a very similar dis-tribution for the remaining specimens.) Intriguingly, asin the original plot published by Falk et al. (2005a), LB1lies very close to Homo sapiens in Figure 11b. The over-all conclusion that can be drawn from analyses of theseindices is that modern human microcephalics are clearlyvery variable, and that specimen choice would greatlyinuence any analysis based on a limited sample. Figure11b suggests that such principal component analyses ofbasal endocast indices are not useful for determiningwhether or not LB1 could be a modern human microce-phalic. Analyses of external endocast indices are poten-tially more useful, and the results presented here sup-port the conclusion of Weber et al. (2005) and Martin

TABLE 2. Endocast measurements and derived indices (following Falk et al., 2005a) for the 3 new specimensincluded here (Hunterian, Lesotho and Stuttgart microcephalics)

(a) External endocast data

New specimen

Measurements (mm) Indices

[1] Length [2] Breadth [3] Height [4] Frontal breadth 2/1 3/1 4/1 (4-2)/1 3/2

Hunterian m/c(RCSHM/Osteo 95.1)

107.10 85.80 77.70 59.20 .80 .73 .55 .25 .91

Stuttgart m/c(SMN 5297 or 25523)

88.00 84.40 64.80 63.40 .96 .74 .72 .24 .77

Lesotho m/c(RCSHM D684.4)

108.00 84.00 71.00 65.00 .78 .66 .60 .18 .85

(b) Basal endocast data

Newspecimen

Measurements (mm) Indices

[1]bat-bat

[2]mat-mat

[3]mbat-rof(tan)

[4]cob-

rof(tan)

[5]rob-

rof(tan)

[6]rof(tan)-bpc(tan) 1/6 2/6 3/6 4/6 5/6 (3-4)/6 (4-5)/6 (6-3)/6

Hunterian m/c 41.00 70.20 35.90 21.20 11.40 108.80 .38 .65 .33 .19 .10 .14 .09 .67Stuttgart m/c 59.80 68.40 25.30 22.90 8.30 96.70 .62 .71 .26 .24 .09 .02 .15 .74Lesotho m/c 57.40 70.60 34.60 26.30 10.50 101.50 .57 .70 .34 .26 .10 .08 .16 .66

1135FLORES HOMINID

et al. (2006) that LB1 is quite similar to some modernhuman microcephalics.

CASE FOR MICROCEPHALY

All of the factors discussed above led us to give moredetailed consideration to the possibility of pathologicalmicrocephaly raised by Henneberg and Thorne (2004),particularly as the authors of the original report on theLB1 skeleton did not discuss the relevant medical disor-ders known among modern humans. In the original pa-per, Brown et al. (2004) state without explanation nei-ther pituitary dwarsm, nor primordial microcephalicdwarsm in modern humans replicates the skeletal fea-tures present in LB1. The references cited in support ofthis statement do not present a modern understandingof pathological conditions in modern humans character-ized by severe short stature with microcephaly. We agreethat pituitary dwarsm and at least one type of primor-dial dwarsm, known as Majewski osteodysplastic pri-mordial dwarsm type 2 [MOPD type 2; taken as thefocal condition by Argue et al. (2006)], differ in severalrespects from the LB1 skeleton, yet that skeleton clearly

shares many features with syndromes of severe shortstature and microcephaly as a group, a point to whichwe will return.Similarly, Falk et al. (2005a) state that primary micro-

cephaly or microcephalia vera is characterized by smallcranial vaults relative to facial skeletons, sloping fore-heads and pointed vertices and imply that the lack ofthese shape features in the LB1 skull excludes primarymicrocephaly. That conclusion is unjustied as low slop-ing foreheads and pointed vertices are not seen in allaffected individuals with primary microcephaly (Woodset al., 2005). Falk et al. (2005a) go on to state thatmicrocephaly with simplied gyral pattern (MSG) isanother form of congenital microcephaly . . . manifestingreduced numbers and shallowness of cortical sulci. Thecortical topography of LB1s endocast precludes it fromthis form of microcephaly. In fact, MSG is not anotherform of congenital microcephaly at all, only a descriptiveterm that one of us (W.B.D.) has used to describe theappearance of the brain in individuals with primarymicrocephaly (Dobyns and Barkovich, 1999; Barkovichet al., 2001). In any case, the endocasts shown in the pa-per by Falk et al. (2005a) lack the ne details of the

TABLE 3. Results of principal component analyses carried out on the samplesillustrated in Figure 11, showing the rst two principal components (PC1, PC2)

(a) External endocast indices

i.

Principal component Eigenvalue Percentage of variance Cumulative percentage of variance

1 2.255 45.107 45.1072 2.002 40.039 85.146

ii.

Indices

Loadings

Principal component 1 Principal component 2

2/1 .964 .2643/1 .216 .8644/1 .401 .811(4-2)/1 .716 .5203/2 .779 .507

(b) Basal endocast indices

i.

Principal component Eigenvalue Percentage of variance Cumulative percentage of variance

1 4.203 52.54 52.542 2.747 34.34 86.88

ii.

Indices

Loadings

Principal component 1 Principal component 2

1/6 .861 .2432/6 .794 .2543/6 .031 .9854/6 .916 .3835/6 .620 .627(3-4)/6 .897 .373(4-5)/6 .895 .061(6-3)/6 .031 .985

1136 MARTIN ET AL.

Fig. 11. Plots of the rst two principal components (PC1, PC2)from analysis of indices derived from (a) external endocast measure-ments and (b) basal endocast measurements. The combined samplescomprise endocasts from modern humans of average stature [Homosapiens (1)], a modern human pygmy [Homo sapiens (2)], two australo-

pithecines (Sts 5; WT 17000), ve Homo erectus (Trinil 2; ZKD III, X,XI, XII), LB1, chimpanzees, gorillas, and the AMNH microcephalic skullcast, all from Falk et al. (2005a), with the addition of three microce-phalic endocasts: the Hunterian, Lesotho, and Stuttgart (original forthe AMNH cast) specimens (Tables 2 and 3).

1137FLORES HOMINID

gyral pattern and depths of sulci that would be neededto recognize an MSG pattern.Thus, the analyses in both the initial paper describing

the LB1 skeleton (Brown et al., 2004) and the subse-quent report on the virtual endocast (Falk et al., 2005a)do not adequately reect current understanding ofhuman microcephaly and syndromes involving severeshort stature with microcephaly. Both of these publica-tions assume that only a few types exist, whereas asearch of the OMIM database using the single searchterm microcephaly nds more than 400 genetic syn-dromes associated with microcephaly (see also Gilbertet al., 2005). This gure is cited by Argue et al. (2006),although Richards (2006) gives a lower gure of 300.Any discussion of specic syndromes must rely on cor-

rect interpretation of the taxonomic status of the LB1fossil, which remains controversial. The primary pub-lished papers (Brown et al., 2004; Morwood et al.,2005a) devote little attention to the potential existenceof pathological features. Yet examination of a living mod-ern human with similar features in a medical geneticsclinic would yield the following conclusions for a youngadult female with height 106 cm, body mass 1629 kg,and head circumference (our estimate) 3941 cm; rela-tive to modern human standards, these values would begraphed at 9 to 10 standard deviations (SD) forheight, 4 to 6 SD for body mass, and 10 to 12 SDfor head circumference. Physical examination wouldreveal a recessed jaw with no chin, accompanied by con-genital dental anomalies consisting of absent mandibu-lar right P4 and maxillary right M3 (questioned by Jacobet al., 2006), small maxillary left M3, and pathologicalrotation of both maxillary P4s. [Lukacs et al. (2006) pro-vide additional comments on the dental anomalies ofLB1.] The long bones of the LB1 fossil appear dispropor-tionately broad and less modeled (less narrowing of thediaphysis) than long bones in modern humans, as wouldbe seen on radiographs (see also Jacob et al., 2006). Allof these abnormalities taken together would lead to di-agnosis of a severe short stature with microcephaly syn-drome, although the available data are not sufcient tomatch this to a specic known syndrome (Judith G.Hall, personal communication).If LB1 originated from a population in which very

short stature was characteristic, the head size, or atleast brain size, would still be too small (5 to 6 SD asdiscussed below), and other syndromes including pri-mary microcephaly would be considered in the differen-tial diagnosis. Some of these syndromes are compatiblewith survival into adult life, given help from normalindividuals. This relates back to our concerns regardingthe capabilities of the extant population rst raised inthe section on the stone tools found in Liang Bua.Importantly, essentially all of the syndromes in the dif-ferential diagnosis have autosomal recessive inheritanceand have the potential to recur within a small, inbredpopulation. Hence, as occurred in the mid-1800s in thesmall village of Plattenhardt with the Moegele family, itis entirely possible that more than one individual withthe same syndrome could occur in the same place, de-spite the overall relative rarity of the condition. Jacobet al. (2006) estimate that any human hunter/gathererpopulation inhabiting Flores would have been quitesmall, thus increasing the likelihood of inbreeding. How-ever, for the same reason, these authors question the

likelihood of survival of an isolated population on Floresfor over 800,000 years without immigration.As a next step, we can formally assess the reported

dimensions of LB1 in the light of alternative interpreta-tions regarding the fossils population of origin. LB1could represent a microcephalic individual from a mod-ern human population either with normal stature (hy-pothesis 1a) or with dwarfed stature (hypothesis 1b).LB1 could also represent a microcephalic individual froma contemporaneous Homo erectus population (dwarfed orundwarfed, hypotheses 2a and 2b) or an early offshoot ofa more primitive hominid line (hypothesis 3). Of course,in all cases the types of microcephaly to be consideredmust be restricted to those in which survival to adult-hood is possible. This would include microcephaly withnear normal cognitive abilities or mild-moderate mentalretardation. Human microcephalic syndromes can be di-vided into two categories, a high-functioning group anda low-functioning group (Dobyns, 2002; Gilbert et al.,2005). The former category is most relevant for compari-son with LB1, an individual that survived to adulthood,although in some cases survival into adulthood mayoccur even with moderate to severe microcephaly, as inhuman Seckel syndrome.Under the hypothesis that LB1 comes from a dwarfed

population derived from either Homo sapiens or Homoerectus, we assume that the well-established relation-ships between body size and cranial volume among hom-inids would be maintained. If LB1 were a dwarfed Homosapiens with an estimated body mass of 1627.8 kg, theexpected cranial capacity, taking brain-body mass dataand the scaling exponent value for a modern Europeanpopulation (Holloway, 1980), would be 1,1091,223 cc(range, 8171,604 cc; Table 4). Using the same intraspe-cic scaling exponent, the expected cranial capacity ifLB1 were a dwarfed Homo erectus, taking cranialcapacity data from Stanyon et al. (1993), would be 794876 cc (overall range, 5831,107 cc; Table 5). Based onthe Dmanisi specimens, the expected cranial capacity ofa similarly dwarfed individual from this populationwould be 560662 cc (overall range, 495706 cc; Table5). The cranial capacity of 400 cc of LB1 would be5.46.2 standard deviations below the expected value forHomo sapiens. Using the same coefcient of variationfor brain size, the cranial capacity of LB1 would be 4.25.1 standard deviations below the expected value forHomo erectus, and 2.33.2 standard deviations below theexpected value for the Dmanisi sample (Tables 4 and 5).Among modern humans, severe congenital microcephalyor primary microcephaly is dened as head circumfer-ence (a surrogate for brain volume) three or more stand-ard deviations below the mean at birth (Dobyns, 2002)or more than four standard deviations below age andsex means (Woods et al., 2005). The brain volume ( 400cc) and estimated head circumference for the LB1 skullwould be more than four standard deviations below themean for either a dwarfed Homo sapiens or a dwarfedHomo erectus population (Tables 4 and 5).Microcephalic disorders are not particularly rare, as

one of us (W.B.D.) has ascertained more than 200 suchindividuals for study (see also Argue et al., 2006). Todate, four human genes have been cloned that result inprimary microcephaly with mild to moderate mentalhandicap and survival well into adult life (Woods et al.,2005). At least two of these (ASPM and MCPH1) have

1138 MARTIN ET AL.

evolved rapidly in hominids and other primates and arehypothesized to have contributed to the rapid increasein brain size shown in Figure 1 (Zhang, 2003; Evanset al., 2004; Kouprina et al., 2004; Wang and Su, 2004;Gilbert et al., 2005). It has been proposed that genesinvolved in regulating brain size, particularly a subsetof microcephaly genes in which mutations produce high-functioning forms of microcephaly, may have undergoneadvantageous mutations in evolution leading to brainenlargement with few deleterious side effects (Gilbertet al., 2005). Thus, it is certainly conceivable that LB1could represent a microcephalic individual from a smallhominid population.Alternatively, LB1 could be derived from an extant pop-

ulation of normal hominid stature, more likely Homosapiens than Homo erectus. Under this hypothesis, LB1would have a short stature with microcephaly syndromein which both body size and brain volume are far belowthe norms for the extant population. Various syndromeswith severe intrauterine growth retardation and propor-tionate (at least at birth) microcephaly have been de-

scribed in modern humans, including Bangstad, Bloom,Buebel, de Lange, Dubowitz, Kennerknecht, Meier-Gorlin,Okajima, and Seckel syndromes, as well as Majewski(microcephalic) osteodysplastic primordial dwarsm (MOPD)type 1, MOPD type 2, MOPD-Cervenka type, andMOPD-Tor-iello type (Toriello et al., 1986; Bangstad et al., 1989; Opitzand Holt, 1990; Meinecke et al., 1991; Lin et al., 1995; Buebelet al., 1996; Bongers et al., 2001; Silengo et al., 2001; Faivreet al., 2002; Okajima et al., 2002; Hall et al., 2004). Several ofthese syndromes are associated with survival to adulthood.In their original report on LB1, Brown et al. (2004)

state without discussion that primordial microcephalicdwarsm in modern humans does not replicate the skel-etal features present in LB1. To the contrary, we ndsuch a comparison interesting. The best studied of thesesyndromes is MOPD type 2. While the reported skeletalfeatures of LB1 differ from this syndrome in severalregards, the similarities in overall size are remarkableand instructive. Affected children have severe intrauter-ine and postnatal growth retardation and microcephalywith normal or mildly impaired intelligence and may

TABLE 4. Calculation of brain size of a dwarfed Homo sapiens with the same body weight as LB1

Variable Value Notes on additional calculations

Modern human data (Holloway, 1980):Average body weight (g) 67100Average brain weight (g) 1388Maximum body weight (g) 106000Minimum body weight (g) 40000Maximum brain weight (g) 1850Minimum brain weight (g) 1040s.d. brain weight 132 Calculated from male and female valuesBrain scaling exponent 0.168Brain scaling intercept 218Brain scaling intercept usingmax brain weight

286 Calculated using brain scaling exponent,maximum brain weight and average body weight

Brain scaling intercept usingmin brain weight

161 Calculated using brain scaling exponent,minimum brain weight and average body weight

Estimated brain weight (g) or cranial capacity (cc) (approximately equivalent (Martin, 1990))for dwarf Homo sapiens with the same body weight as LB1

At body weight estimate 28.7 kg:Average brain weight (g) orcranial capacity (cc)

1223

Maximum brain weight (g) orcranial capacity (cc)

1604 Calculated using brain scalingintercept for maximum brain weight

Minimum brain weight (g) or cranial capacity (cc) 902 Calculated using brain scaling interceptfor minimum brain weight

At body weight estimate 16 kg:Average brain weight (g) or cranial capacity (cc) 1109Maximum brain weight (g) or cranial capacity (cc) 1454 Calculated using brain scaling intercept

for maximum brain weightMinimum brain weight (g) or cranial capacity (cc) 817 Calculated using brain scaling intercept

for minimum brain weight

Difference between the average cranial capacity estimate for dwarf Homo sapiens and the actualcranial capacity of LB1 (400 cc) in standard deviations calculated for brain weight variation for theHomo sapiens sample

At body weight estimate 28.7 kg:LB1 cranial capacity in standard deviations belowexpected size for dwarf Homo sapiens

6.2

At body weight estimate 16 kg:LB1 cranial capacity in standard deviations belowexpected size for dwarf Homo sapiens

5.4

Data and statistics from Holloway (1980) for a large sample of Danish humans (n 667) carefully selected by removal ofcases of pathologies likely to affect brain weight, and extremes of body mass. Some further statistics were estimated or cal-culated, as indicated.

1139FLORES HOMINID

survive to adulthood (Hall et al., 2004). They are re-markably small, with weight, length, and head circum-ference at birth proportionately reduced to the size of a28-week gestation fetus. Postnatal growth is poor, withhead growth much slower even than stature, resultingin an adult height of 100110 cm and head circumfer-ence of 3841 cm. These values are well in line with theLB1 skeleton. A small jaw with deviant development ofthe chin and dental anomalies is common, including dys-plastic and missing teeth in both primary and secondarydentition. The LB1 fossil also has a small jaw with dys-

plastic and missing teeth, although, as we have noted,other skeletal changes differ. Development of the chin ishighly variable in microcephalics. The chin is particu-larly prominent in some cases, as in the Stuttgart micro-cephalic (Figs. 3 and 6), whereas in others the mentaleminence is weak or lacking. Dokladal (1958), for exam-ple, reported on a 57-year-old microcephalic with a cra-nial capacity of 405 cc having a small mandible withweak development of the chin.Seckel syndrome consists of similar intrauterine and

postnatal growth retardation and microcephaly, typically

TABLE 5. Calculation of brain size of a dwarfed Homo erectus or dwarfed individualfrom the Dmanisi population with the same body mass as LB1

Variable

Homo erectus

Dmanisi

NotesStanyonet al.

Gabunia et al.;Rightmire et al.;Vekua et al.

n 28 3Average body weight (kg) 60 50 Kappelman (1996);

Gabunia et al. (2001)Average cranial capacity (cc) 991 664Maximum cranial capacity (cc) 1251 775Minimum cranial capacity (cc) 727 600 Calculated using coefcient

of variation for brain weight ofHomo sapiens sample (see Table 4)and average cranial capacityfor Homo erectus sample

Estimated population s.d. cranial capacity 94 63 Using value for Homo sapiens sampleCranial capacity scaling exponent 0.168 0.168Cranial capacity scaling intercept 156.2 107.8Cranial capacity scaling intercept -using maximum cranial capacity

197.3 125.9

Cranial capacity scaling intercept -using minimum cranial capacity

114.6 97.4

Estimated cranial capacity (cc) for dwarf Homo erectus and Dmanisi population with the same body weightas LB1

At body weight estimate 28.7 kg:Average cranial capacity (cc) 876 605Maximum cranial capacity (cc) 1107 706 Calculated using cranial

capacity scalingintercept for maximumcranial capacity

Minimum cranial capacity (cc) 643 547 Calculated using cranialcapacity scaling interceptfor minimum cranial capacity

At body weight estimate 16 kg:Average cranial capacity (cc) 794 548Maximum cranial capacity (cc) 1103 640 Calculated using cranial

capacity scaling intercept formaximum cranial capacity

Minimum cranial capacity (cc) 583 495 Calculated using cranial capacityscaling intercept for minimumcranial capacity

Difference between the average cranial capacity estimates for dwarf Homo erectus and dwarf Dmanisiindividual and the actual cranial capacity of LB1 (400cc) in standard deviations

At body weight estimate 28.7 kg:LB1 cranial capacity in standard deviationsbelow expected size or dwarf Homo erectus

5.1 3.2

At body weight estimate 16 kg:LB1 cranial capacity in standard deviationsbelow expected size or dwarf Homo erectus

4.2 2.3

Data from Gabunia et al. (2000, 2001), Kappelman (1996), Rightmire et al. (2006), Stanyon et al. (1993), and Vekua et al.(2002).

1140 MARTIN ET AL.

more than seven standard deviations below the mean,with moderate to severe mental retardation but frequentsurvival to adulthood (McKusick et al., 1967; Majewskiand Goecke, 1982; Faivre et al., 2002). Skeletal changesare present, but less severe than in MOPD type 2 (Tsu-chiya et al., 1981).While it is not possible to match any of these syn-

dromes exactly with the LB1 fossil based on the limiteddata available, the features of several are informative.We nd that this group of syndromes shares several fea-tures with the LB1 fossil, including very similar smallstature and head size, a small and receding jaw, anddental anomalies. Lacking the soft tissues and someskeletal components of LB1, we cannot conclude thatLB1 had any particular one of these syndromes, but wedo think that the substantial overlap in features sup-ports this possibility. One major limitation for compara-tive studies is the absence of information on the postcra-nial skeleton in museum specimens of human microce-phalics. In closing, it should be noted that the thirdhypothesis, that LB1 may derive from a more primitive(pre-erectus) population, cannot be addressed by consid-eration of modern human developmental abnormalities.

CONCLUSIONS

We conclude that the features of LB1 best support theinterpretation that it is a pathological, microcephalicdwarf specimen of Homo sapiens (see also Jacob et al.,2006). Richards (2006), in a study emphasizing growthprocesses, reached a similar conclusion that LB1 prob-ably belonged to a modern human population withreduced stature (attributable to a modication in thegrowth hormone/insulin-like growth factor I axis), butalso suffered from a mutation in the MCPH gene family.However, he differs in regarding this combined conditionas nonpathological. If further specimens directly resem-bling the Flores skull with respect to the tiny cranialcapacity were to be discovered, the probability that suchan explanation is correct might diminish. However, thelikely autosomal recessive inheritance of such a syn-drome means that such evidence would not necessarilybe critical. On the basis of present evidence, it seemsmost likely that the LB1 specimen is a pathologicalanomaly, not a new species.While this account has focused on the LB1 skeleton,

because brain size is known only for that individual,some comment is required on the other specimens thathave been reported from Flores. These have been inter-preted as providing evidence that a small-bodied homi-nid inhabited Flores at least between 95,000 and 15,000years ago. As has been explained, the presence of othersmall-bodied individuals in itself poses no problem. It isthe tiny brain size of LB1 that poses a problem. How-ever, the discovery of a second mandible lacking a chin(LB6/1) does raise questions, particularly because it isclaimed that it is only 15,000 years old and hence 3,000years younger than the LB1 skeleton (Morwood et al.,2005a). If the lack of a chin is interpreted as a sideeffect of microcephaly in LB1, it would be difcult to as-cribe this condition in the second mandible to persist-ence of a rare autosomal recessive condition for 3,000years on Flores. However, the dating of the second man-dible depends on the interpretation that the cave sedi-ments have remained undisturbed and that no intrusive

burials occurred. The apparent mingling of at least twodifferent assemblages of stone tools in the deposits sug-gests that the sediments have not remained completelyundisturbed. An alternative possibility is that the LB6/1mandible is from a small-bodied individual that did notsuffer from microcephaly and that the absence of a chinin both known mandibles is in fact a local variant attrib-utable to some other cause. It should be noted that a sig-nicantly reduced chin is found in some modern Africanand Indonesian pygmy populations and Australo-Mela-nesians (Jacob et al., 2006; Richards, 2006). Further-more, it should be emphasized that, although the twoFlores mandibles are broadly similar in overall size,there are several differences of detail. Unlike that ofLB1, the LB6/1 mandible shows no obvious dentalanomalies, its dental arcade differs in shape, and theascending ramus is markedly smaller in height.Brown et al. (2004) stated that LB1 is megadont rela-

tive to both Homo ergaster and Homo sapiens. In fact,examination of the scaling of lower molar teeth area invarious hominids compared to a large sample of mon-keys and apes reveals that LB1 is similar to typicalanthropoids and early Homo, with relatively smallerteeth than the truly megadont australopithecines (Fig.12). While normal modern humans have relatively smallteeth in relation to body size, the mandibular molar areain the Lesotho microcephalic is very close to the valuefor LB1, at a very similar body mass. Hence, if LB1 ismegadont to any degree, so is the Lesotho microcephalic.However, because scaling of teeth follows a similar pat-tern to the scaling of brain size during dwarng, individ-uals with reduced body size would be expected to showsomewhat overscaled dental dimensions (Shea andGomez, 1993). Interestingly, the molars in the LB6/1mandible are appreciably smaller in area than those ofthe LB1 mandible, providing a further difference betweenthe two specimens.Argue et al. (2006) recently applied canonical variate

analysis (CVA) to compare the skull of LB1 with a com-prehensive sample of modern Homo sapiens, two micro-cephalic H. sapiens, representatives of fossil Homo(specimens attributed to H. erectus and H. ergaster),australopithecines (Australopithecus and Paranthropus),and chimpanzees (Pan paniscus and P. troglodytes). Inseparate plots of CV1 against CV2 using different datasets, the two microcephalics were found to occupy a pe-ripheral position relative to the general cluster of pointsfor Homo sapiens, while the point for LB1 was distantfrom that cluster and close to Homo ergaster (notablyKNM-ER 3733). In fact, the microcephalics are in bothcases located in the general vicinity of LB1, but LB1 isundoubtedly further removed from the general clusterfor H. sapiens. As Argue et al. (2006) themselves acknowl-edge, microcephaly is an extremely heterogeneous con-dition and, while our results are suggestive, it may bethat they would differ should a larger sample of microce-phalics be studied. In fact, the two microcephalicsincluded in their study are problematic in variousrespects. Both are archaeological specimens dating back2,000 y or more, one from Crete (Poulianos, 1975) andone from Japan (Suzuki, 1975), and therefore lack anydocumentation of their condition. In the Minoan micro-cephalic skull from Crete, the third molars were notfully erupted, so the individual concerned presumablydied before reaching adulthood. For reasons explained

1141FLORES HOMINID

above, that skull is therefore not really suitable for com-parison with LB1. This objection does not apply to theJapanese skull (Sano 3), which is dentally adult. How-ever, both the Minoan and the Sano skulls have largercranial capacities than LB1. Unfortunately, Argue et al.(2006) give two different values for the cranial capacityof the Minoan microcephalic: 350 and 530 cc. It is thehigher value that is correct. In the case of the Sanoskull, the recorded cranial capacity of 730 cc is almosttwice the average of about 400 cc for modern humanmicrocephalics and the value of about 400 cc for LB1.Argue et al. (2006) also considered certain postcranial

elements (radius and femur) in comparing LB1 withapes and hominids (though not with microcephalics, asno postcranial elements were discovered with the Min-oan or Japanese microcephalic skulls). As had beennoted previously, in the LB1 skeleton the arms are un-usually long relative to the legs (Morwood et al., 2005a).Taking an unconventional ratio of radius length to fe-mur length, Argue et al. (2006) conclude that LB1 is in-termediate between African apes and extant Homo sapi-ens, being more similar to Australopithecus garhi thanto other hominids. It should, however, be noted that theradius is unknown for LB1 and that the length of theradius taken by Argue et al. (2006) was actually inferredfrom the length of the (incomplete) ulna of LB1 byMorwood et al. (2005a). While it is surely true thatthe forelimb:hindlimb ratio of LB1 shows some resem-blance to a more primitive condition in hominid evolu-tion, the signicance of this cannot be properly assessed

without information on the condition of the postcranialskeleton in modern human microcephalics. In fact, asnoted by Richards (2006), the ratio of forelimb length tohindlimb length (intermembral index) increases withdecreasing body size as a consequence of allometric scaling(Shea and Bailey, 1996), although this does not account forthe extreme condition found in LB1 (Argue et al., 2006).It is marginally possible that the hominid remains

from Flores provide evidence of a new species from a lin-eage that diverged at a very early australopithecinestage, about 3 Ma ago, when cranial capacity was stillvery small. However, this would require convergent evo-lution of many similarities to Homo species, and thecomplete lack of documentation of such a lineage in thefossil record represents a major problem. Furthermore,in this case it certainly cannot be argued with anydegree of plausibility that Homo oresiensis producedthe stone tools found in association with the skeletalremains. On the basis of all the evidence presented here,it seems to us most probable that LB1 was a microce-phalic modern human.

ACKNOWLEDGMENTS

Thanks are due to Martyn Cooke for preparation ofthe endocast of the microcephalic hemiskull at the Hunt-erian Museum, Royal College of Surgeons, London; KenMowbray at the American Museum of Natural History,New York, for providing initial information on the micro-

Fig. 12. Plot of unilateral summed mandibular molar area for 76monkeys and apes (nonhominid anthropoids) compared with a sampleof hominids. A least-squares regression line has been tted to thenonhominid anthropoids as a visual guide. As expected, the megadontaustralopithecines (Australopithecus and Paranthropus) all lie abovethe line, whereas representatives of Homo lie on the line or below it.Key to points for Homo: 1 Homo habilis; 2 Homo erectus; 3 Tasmanian aboriginal Homo sapiens; 4 17th-century EuropeanHomo sapiens (London); 5 Lesotho microcephalic Homo sapiens; 6 Flores LB1 mandible; 7 Flores LB6/1 mandible. Molar dimensions

for nonhuman anthropoids from Kanazawa and Rosenberger (1989),Lucas et al. (1986), and Swindler (1976); for fossil hominids from Blu-menberg and Lloyd (1983); for modern Homo sapiens from Brace(1979); for LB1 from Morwood et al. (2005a). Gary Sawyer kindly pro-vided measurements of the lower molars from the AMNH cast of theLesotho microcephalic mandible. Body mass values for nonhumananthropoids from Smith and Jungers (1997) and for fossil hominidsfrom McHenry (1994). Note that the same body mass of 23 kg hasbeen taken for both LB1 and LB6/1.

1142 MARTIN ET AL.

cephalic skull cast and for measurement of its cranialcapacity; Matt Grove at the Field Museum, Chicago, forpreparation of an endocast from the original Stuttgartmicrocephalic skull; Will Pestle for locating the microce-phalic skull cast and endocast from Lesotho in the col-lections of the Field Museum and for measurement ofthe endocast volume; Jill Seagard for providing draw-ings for Figures 8 and 9; John Weinstein for producingthe photographs for Figure 9; and Michel Hofman forproviding access to the data used in his 1984 paper.Dean Falk readily provided information on the AMNHmicrocephalic skull from which a virtual endocast wasgenerated for her published study (Falk et al., 2005a).We are grateful to Ian Tattersall and Gary Sawyer inthe Department of Anthropology, AMNH, for their helpin providing access to the microcephalic skull cast andaccompanying documentation from the collections intheir care. Ian Tattersall kindly provided permission forthe removal of minute samples by Gary Sawyer from thecast for chemical analysis. Gary Sawyer also generouslyprepared an endocast from the AMNH microcephalicskull cast and drew our attention to the key paper byVogt (1867) that proved to contain a description of theoriginal skull in Stuttgart. Thanks are also due to Jef-frey Schwartz for generating electronic images of theAMNH microcephalic skull cast. Chemical analysis ofsamples from the calotte and lower part of the craniumof the AMNH microcephalic skull cast was conducted byLaure Dussubieux using an ICP-MS acquired with agrant from the National Science Foundation (PI: P. RyanWilliams). Thanks are due to Laure Dussubieux and P.Ryan Williams of the Field Museum for valuable discus-sion both in planning of the chemical analysis and ininterpretation of the results. Elmar Heizmann kindlyprovided valuable information, including electronicimages, concerning the original microcephalic skull inthe collection of the Staatliches Museum fur Natur-kunde, Stuttgart. Doris Morike in the Zoology Depart-ment of the Staatliches Museum fur Naturkunde help-fully provided an estimate of the age of that individualand also graciously provided permission for a 6-monthloan of the specimen. Edna Davion and ElizabethShaeffer provided valuable logistic support at the FieldMuseum, notably with literature searches, data collec-tion and analysis, and preparation of several gures.Able assistance with nal preparation of gures wasalso provided by Julie Delamare-Deboutteville. JonathanBrown deserves special thanks for conducting computedtomography of the Stuttgart microcephalic skull andproducing virtual reconstructions. Computed tomogra-phy of the Stuttgart skull was carried out at Northwest-ern Memorial Hospital using a Siemens Somaton Sensa-tion 64 CT Scanner, and the support of NorthwesternUniversity Feinberg School of Medicine Department ofRadiology is gratefully acknowledged. Three-dimensionalimage reconstruction from CT data was performed withan iView workstation, kindly loaned to the Field Mu-seum by TeraRecon, Inc. (San Mateo, CA). Thanks arealso due to Judith Hall for helpful discussions regardinghuman syndromes characterized by short stature andmicrocephaly, and to Louise Roth for providing informa-tion on dwarf elephants. We are grateful to Robert Eck-hardt for providing valuable information and numerouscomments, and to Ralph Holloway for sharing his expertknowledge of hominid endocasts.

LITERATURE CITED

Accordi FS, Palombo MR. 1971. Morfologia endocranica degli ele-fanti nani pleistocenici di Spinagallo (Siracusa) e comparazionecon lendocranio di Elephas antiquus. Atti Accad Naz Lincei Ren-diconti 51:111124.

Allen H. 1991. Stegodonts and the dating of stone tool assemblagesin Island Southeast Asia. Asian Perspect 30:243265.

Ambrosetti P. 1968. The Pleistocene dwarf elephants of Spinagallo.Geol Romana 7:277398.

Argue D, Donlon D, Groves C, Wright R. 2006. Homo oresiensis:Microcephalic, pygmoid, Australopithecus, or Homo? J Hum Evol[epub ahead of print] doi: 10.1016/j.jhevol.2006.04.013.

Bangstad HJ, Beck-Nielsen H, Hother-Nielsen O, Nystad R, Tryg-stad O, Pedersen O, Aagenaes O. 1989. Primordial birdheadednanism associated with progressive ataxia, early onset insulin re-sistant diabetes, goiter and primary gonadal insufciency: a newsyndrome. Acta Paediatr Scand 78:488493.

Barkovich AJ, Kuzniecky RI, Jackson GD, Guerrini R, Dobyns WB.2001. Classication system for malformations of cortical develop-ment: update 2001. Neurology 57:21682178.

Bartstra GJ, Soegondho S, van der Wijk ,A. 1988. Ngandong man:age and artifacts. J Hum Evol 17:325337.

Bartstra GJ. 1992. Pacitan and Sangiran, and Java mans tools. In:Bellwood P, editor. Man and his culture. New Delhi: Books andBooks. p 93103.

Beals KL, Smith CL, Dodd SM. 1984. Brain size, cranial morphol-ogy, climate, and time machines. Curr Anthropol 25:301330.

Blumenberg B, Lloyd AT. 1983. Australopithecus and the origin ofthe genus Homo: aspects of biometry and systematics with accom-panying catalogue of tooth metric data. Biosystems 16:127167.

Bongers EM, Opitz JM, Fryer A, Sarda P, Hennekam RC, Hall BD,Superneau DW, Harbison M, Poss A, van Bokhoven H, HamelBC, Knoers NV. 2001. Meier-Gorlin syndrome: report of eightadditional cases and review. Am J Med Genet 102:115124.

Brace CL. 1979. Krapina, classic Neanderthals, and the evolutionof the European face. J Hum Evol 8:527550.

Bronson RT. 1979. Brain weight: body weight scaling in breeds ofdogs and cats. Brain Behav Evol 16:227236.

Brown P, Morwood MJ. 2004. Comments from Peter Brown andMike Morwood. Before Farming 1:57.

Brown P, Sutikna T, Morwood MJ, Soejono RP, Jatmiko, Wayhu Sap-tomo E, Rokus Awe Due. 2004. A new small-bodied hominin fromthe Late Pleistocene of Flores, Indonesia. Nature 431:10551061.

Brumm A, Aziz F, van den Berg GD, Morwood M, Moore MW, Kur