Sahelanthropustchadensis: the facts

Sir, — In a recent article in this journal,1

Beauvilain and Le Guellec suggest thatour initial description of Sahelanthropustchadensis2 was flawed by the inaccurateidentification and association of specimens.Their claims are without foundation.

Beauvilain and Le Guellec1 offeredsupplementary information on thehypodigm and geological context of theoldest known hominid, Sahelanthropustchadensis, discovered at TM266, in theDjurab Erg, northern Chad, by theMission Paléoanthropologique Franco-Tchadienne2,3 (MPFT). Their stated inten-tion was to describe ‘the events surround-ing the discoveries themselves’1 (p. 142),although Beauvilain has already done soat length.4 Their contribution in the SouthAfrican Journal of Science alleges that: 1)Vignaud et al.3 failed to present correctlythe stratigraphic nature of the hominidsite TM266; 2) Brunet et al.2 neglectedcollected hominid specimens; 3) themandibular specimen TM266-02-154-1described by Brunet et al.2 is in fact a fossilhominid chimera manufactured by a leftM3 incorrectly glued to a right hemi-mandible; 4) together, these supposederrors affect the Minimum Number ofIndividuals (MNI) count for the site.

Beauvilain and Le Guellec1 do not ques-tion the attribution of the fossil to thehominid clade2 rather than to an Africanape, but attempt to show that the MPFTmembers reached inaccurate conclusions.The team firmly stands by its originalstatements.

Geological issuesGiven the thorough geological survey

performed by the MPFT in the Djurabsince 1994, including georadar investiga-tions,3,5–10 it is clear that the wholeToros-Menalla (TM) fossiliferous areashows no evidence whatsoever of a fault-ing during at least the last 7 Myr. Exceptfor the modern dunes, the entire land-scape is very flat. In the TM area, all of thesmall scarps pointed out by Beauvilainand Le Guellec1 are the consequences ofaeolian ‘over-digging’ at the foot of thedunes, as are very common across theSahara and in many other sandy deserts.These geomorphological features do notin our view represent any ‘reactivatedancient faulting’ as they allege (p. 142).The section given in Vignaud et al.3 issynthetic, showing the different encoun-tered facies related to the alternation ofhumid and dry periods. The section atTM266 is accurate as published, and all

fossil specimens reported in references 2and 3 were derived from this local sectionas published therein. There is no doubtabout their provenance.

Inventory issuesThe MPFT practices of inventorying

and publishing fossils does not differ fromthose normally practised in palaeontology.All collected specimens, including homi-nids, are registered under an inventorynumber comprising the name of the site,the year, a specimen number, and, in thecase of several pieces of the same individ-ual, a part number (e.g. the craniumnicknamed ‘Toumaï’ was numberedTM266-01-060-1). This attribution of aninventory number occurs at differentstages when processing the discoveries:1) for most of them, directly in the fieldafter a precise identification; 2) in thelaboratory (at N’djaména or Poitiers) forall the specimens recovered after sieving,or after cleaning for some specimens com-pletely embedded in matrix. Beauvilain, ageographer in charge of MPFT logistics,was unfamiliar with this process and theway in which specimens were assembledinto the published hypodigm of S.tchadensis.2

The first paper describing the new taxonS. tchadensis2 included only the specimenswhich were definitively identified ashominid by their anatomical characters.These specimens belong to several indi-viduals, as we reported in Nature:2 theholotype cranium is one of these speci-mens. Beauvilain and Le Guellec1 wonderwhy a very worn incisor (TM266-01-460)and a damaged partial mandibular sym-physis (TM266-02-203) were not includedin the paratype series. They were notincluded because their exact affinities areyet to be fully developed and determined.Further studies of more fragmentaryremains have identified additional indi-viduals, and the MNI count will expandas both excavations and preparation workcontinue.

Issues of restoration andinterpretation

In the Djurab desert, the discovery offossils is facilitated by an intense erosionof the sediments in which they are em-bedded through the action of the sandblown by winds across the sedimentaryunits. When the fossils are unearthed, thesame aeolian erosion also affects them.The damage mostly consists of polishing,cracking, breaking, dispersion of the dif-ferent parts, and, finally, total destructionof the specimens if they are not collectedalmost immediately after their first expo-sure. For example, the cranium TM266-01-060-1 of Sahelanthropus tchadensis waspartially unearthed when found and had

suffered from such a weathering by sand-blasting. During its exposure, it lostmost of its front teeth. As reported inBeauvilain and Le Guellec, the brokenright canine belonging to this skull wasfound separately. There is no doubt thatthis canine belonged to this cranium,because, as correctly noted by Beauvilainand Le Guellec1 (p. 143): ‘The toothconsisted of two fragments which fittedperfectly onto the right canine root’.However, they erroneously reported it asa ‘complete’ canine whereas in fact it is thedistal half of the canine. This canine waspublished in its natural position on thecranium.2

A parallel case occurred for the mandiblein question. The right third molar hadbeen displaced from the tooth row byerosion and transported by wind towhere it was recovered, some decimetresdistant from the mandible with the re-maining teeth. After recovery, we estab-lished that it belonged to the mandibleitself, and we attached it where it belonged,as a right M3 of the hemi-mandibleTM266-02-154-1. Beauvilain and LeGuellec now assert that this tooth hasbeen attributed to and mounted on theincorrect side.

This moderately worn tooth bearssubstantial occlusal anatomy whichunambiguously identifies it as a thirdmolar. The identification of the side wasbased on two decisive independentcriteria, one set physical and the other setbiological. First, there is an unambiguousmatch between the lower surface of thetooth and its roots, which remained in themandible. There is no doubt about theintegrity of this join (Fig. 1A, B, C, F, G).This is further confirmed by the matchinginterproximal facet preserved on themesial surface of the tooth in questionand the second molar retained by themandible. Second, the anatomy of thethird molar allows unambiguous siding.As in all hominoid teeth, the buccal cuspsare the more worn, with a larger, mostheavily worn cusp (the protoconid),marked here by heaviest occlusion andplaced mesiobuccally (Fig. 1D, E). Theocclusal rims of the lingual cusps standout slightly but distinctly, from less weardue to well-known masticatory mecha-nisms common to modern humans, fossilhominids, and fossil and modern apes.

ConclusionThe logistical contributions of Beauvilain

to the fieldwork in Chad are gratefullyacknowledged, but the claims and asser-tions by him and Le Guellec1 have nobearing on either the interpretation of thegeology of TM266 or of the associations,taxonomy, or phylogeny of Sahelanthropustchadensis.

Correspondence South African Journal of Science 100, September/October 2004 443

We thank the Chadian authorities (Ministère del’Education Nationale de l’Enseignement Supérieuret de la Recherche, Université de N’djaména, CNAR).We extend gratitude for their support to the Frenchministries, Ministère français de l’EducationNationale (Faculté des Sciences, Université dePoitiers), Ministère de la Recherche (CNRS : SDV &

ECLIPSE), Ministère des Affaires Etrangères (DCSUR,Paris and SCAC N’djamena), to the RégionPoitou-Charentes, to the RHOI (F.C. Howell and T.D.White) funded by the NSF and also to the ArméeFrançaise, MAM and Epervier, for logistic support. Wespecially thank G. Suwa (University Museum, Uni-versity of Tokyo) for the CT scans, and C.O. Lovejoy

and T.D. White for stimulating discussions. We espe-cially thank also all the other MPFT members whojoined us for the field missions, and G. Florent, C.Noël and S. Riffaut for administrative and technicalsupport.

1. Beauvilain A. and Le Guellec Y. (2004). Furtherdetails concerning fossils attributed to Sahel-anthropus tchadensis (Toumaï). S. Afr. J. Sci. 100,142–144.

2. Brunet M., Guy F., Pilbeam D., Mackaye H.T.,Likius A., Ahounta D., Beauvilain A., Blondel C.,Bocherens H., Boisserie J-R., Bonis L. de, CoppensY., Dejax J., Denys C., Duringer P., Eisenmann V.,Fanoné G., Fronty P., Geraads D., Lehmann T.,Lihoreau F., Louchart A., Mahamat A., MerceronG., Mouchelin G., Otero O., Pelaez CampomanesP., Ponce De Leon M., Rage J-C., Sapanet M.,Schuster M., Sudre J., Tassy P., Valentin X.,Vignaud P., Viriot L., Zazzo A. and Zollikofer C.(2002). A new hominid from the Upper Mioceneof Chad, Central Africa. Nature 418, 145–151.

3. Vignaud P., Duringer P., Mackaye H.T., Likius A.,Blondel C., Boisserie J-R., Bonis L. de, EisenmannV., Etienne M-E., Geraads D., Guy F., Lehmann T.,Lihoreau F., Lopez-Martinez N., Mourer-Chauviré C., Otero O., Rage J-C., Schuster M.,Viriot L., Zazzo A. and Brunet M. (2002). Geologyand palaeontology of the Upper MioceneToros-Menalla hominid locality, Chad. Nature 418,152–155.

4. Beauvilain A. (2003). Toumaï, l’aventure humaine. LaTable Ronde, Paris.

5. Brunet M., Beauvilain A., Coppens Y., Heintz E.,Moutaye A.H.E. and Pilbeam D. (1995). The firstaustralopithecine 2500 kilometres west of the RiftValley (Chad). Nature 378, 273–274.

6. Brunet M., Beauvilain A., Geraads D., Guy F.,Kasser M., Mackaye H.T., Maclatchy L.M.,Mouchelin G., Sudre J. and Vignaud P. (1998).Tchad: découverte d’une faune de Mammifèresdu pliocène inférieur. C. R. Acad. Sci. Paris 326,153–158.

7. Brunet M. and M.P.F.T. (2000). Chad: discovery ofa vertebrate fauna close to the Mio-Plioceneboundary. J. Vert. Paleont. 20(1), 205–209.

8. Schuster M. (2002). Sédimentologie et paléoécologiedes séries à vertébrés du paléolac Tchad depuis leMiocène supérieur. Ph.D. thesis, Université LouisPasteur, Strasbourg.

9. Ghienne J.M., Schuster M., Bernard A., DuringerPh. and Brunet M. (2001). The Holocene giantLake Chad revealed by digital elevation models.Quat. Int. 87, 81–85

10. Schuster M., Duringer Ph., Ghienne J.F.,Beauvilain A., Mackaye H.T., Vignaud P. andBrunet M. (2003). Discovery of coastal conglomer-ates around the Hadjer El Khamis Inselbergs(Western Chad, Central Africa): a new evidencefor lake Mega-Chad episodes. The coastal con-glomerates of Lake Mega-Chad. Earth Surf. Proc.Landf. 28(10), 1059–1069.

Michel Bruneta* and MPFT†

†Jean-Renaud Boisseriea , b, DjimdoumalbayeAhountac, Cécile Blondela, Louis de Bonisa, YvesCoppensd, Christiane Denyse, Philippe Duringerf,Véra Eisenmanne, Pierre Frontya, Denis Geraadsg,Gongdibé Fanonéc, Franck Guya , k , ThomasLehmanna, Fabrice Lihoreaua,h, Andossa Likiush,Antoine Loucharti, Hassane Taisso Mackayeh, OlgaOteroa, Pablo Pelaez Campomanesj, David Pilbeamk,Marcia Ponce De Leonl, Jean-Claude Ragee, MathieuSchusterf, Pascal Tassye, Xavier Valentina, PatrickVignauda, Laurent Viriota and Christoph Zollikoferl.aCNRS UMR 6046, Université de Poitiers, 40 Avenue duRecteur Pineau, 86022 Poitiers Cedex, France; bLaboratoryfor Human Evolutionary Studies, University of California,3060 Valley Life Sciences Building, Berkeley, CA 94720,U.S.A.; cCentre National d’Appui la Recherche, BP 1228,N’Djaména, Tchad; dCollège de France, place Marcellin

444 South African Journal of Science 100, September/October 2004 Correspondence

Fig. 1. Right hemi-mandible TM266-02-154-1 of Sahelanthropus tchadensis. A, B, and C: CT scans (courtesy:University Museum, University of Tokyo) at the level of the M3. The mandibular corpus and the retained roots ofthe M3 are in light red. The crown of the third lower molar found separately and claimed to be a left one is in blue. Aprecise matching between the M3 crown and the corresponding roots in the hemi-mandible can be observed.The interstitial space between the M3 and its roots corresponds to thickness of the glue used to affix the tooth toits roots. A, Sagittal sections with mesial side at right – from right to left, CT scans are respectively shot at3.33 mm, 4.41 mm, 7.83 mm, and 8.70 mm from the buccal edge of the tooth; B, transversal sections with lingualside at right – from right to left, CT scans are respectively shot at 2.67 mm, 3.69 mm, 4.11 mm, and 9.36 mm fromthe mesial edge of the tooth; C, sections parallel to the occlusal surface, at the cervix level and below, with mesialside at top – from right to left, CT scans are respectively shot at 6.93 mm, 7.14 mm, 7.44 mm, and 7.80 mm fromthe occlusal edge of the tooth. Mesially, the mesio-buccal and mesio-lingual roots remaining in the corpus (seeF) appear in light red and show exact matching with the M3 crown (in blue); D, occlusal view of the completespecimen with its M3; E, occlusal view of the M3; F, occlusal view of the M3 roots; G, disto-lingual view of the join(white arrow) between the M3 and its distal root. All scale bars are 0.5 mm.

*Author for correspondence.E-mail: michel.brunet@univ-poitiers.fr

Berthelot, 75005 Paris, France; eMuséum Nationald’Histoire Naturelle et CNRS UMR 8569, rue Cuvier, 75005Paris, France; fCNRS UMR 7517, Université Louis Pasteur, 1rue Blessig, 67084 Strasbourg, France; gCNRS UPR 2147,44 rue de l’Amiral Mouchez, 75014 Paris, France;hUniversité de N’Djaména, BP 1117, N’Djaména, Tchad;iCNRS UMR 5125, Université Claude Bernard, 27–43 Bd du11 novembre 1918, 69622 Villeurbanne, France; jMuseo deCiencias Naturales, C/Guttierez Abascal 2, 28006 Madrid,Spain; kPeabody Museum, Harvard University, 11 DivinityAvenue, Cambridge, MA 02138, U.S.A.; lAnthropolo-gisches Institut/Multimedia Laboratorium, UniversitätZürich-Irchel, Winterthurer Str. 190, 8057 Zürich, Switzer-land.

Beauvilain and Le Guellec reply

Brunet et al.1 criticize three main pointsin our article2: a) the tectonic origin of theToros-Menalla scarp, b) the determina-tion of side of an isolated molar that wasstuck onto a right mandible attributed toSahelanthropus tchadensis from site TM 266,and c) the inventory of fossils. We respondto each of these criticisms in turn andconclude that our original hypothesis andinterpretation are likely to be correct.

Geological issues in the DjourabBrunet et al.1 report that georadar did

not yield any evidence of faulting in theToros-Menalla region, and they ascribethe formation of the scarp to ‘overdigging’by wind. Whilst wind deflation doesindeed cause depressions in deserts, suchbasins are seldom linear, usually beingundulating in outline or spoon-shaped.The fact that the scarp in question is recti-linear over a distance of more than 40 kmsuggests an underlying tectonic origin.Elsewhere in the Chad Basin3 there isevidence of neotectonic activity includingthe western shore of Lake Chad, whichruns straight NNW–SSE for nearly250 km, a trend that continues along theDilia Valley (Niger) over an even greaterdistance. The Bahr el Ghazal Valley isalmost straight NNE–SSW for more than450 km, with a cliff on the left bank in itslower reaches. This neotectonic activityfrequently reactivates ancient fractures.4

Georadar was indeed used in January1999 but only at sites east of the Bahr elGhazal (the Toros-Menalla region is onthe west side). On fossil and recent dunesit revealed reflectors only 1 to 2 metresthick,5 and in sandstone it ‘did not yieldan image at depths greater than 1 metre.’5

This georadar equipment is not designedto locate evidence of faulting, and it wasnot used to search for faults in the Djourab.Thus failure of the equipment to revealfaults in the region does not provide asound argument against our view that thelinear stuctures that occur there are likelyto be of tectonic origin.

We thus maintain our original view thatthe Toros-Menalla scarp, which yieldedall the fossils of Sahelanthropus tchadensis,

owes its origins to tectonic activity. It hassubsequently been deflated by the wind,but this has only modified its form ratherthan being the original cause of it.

Restoration and interpretation ofSahelanthropus fossils

The fossils from the Djourab are wellmineralized but are often abraded bywind-blown sand. There are strong dailychanges in temperature, which can rangefrom 50°C air temperature at ground levelin the day to light frost at night. At midday,pebbles and fossils lying on the surface ofthe ground can be too hot to touch. Thesechanges lead to fissuring of fossils, whichusually have planar fracture surfacesrather than strongly curved ones. Crustscovering the fossils are either in the formof a very adhesive, hard grey, chemi-cally-resistant matrix, or as an iron-richconcretion, coloured by manganese,often separated from the fossil itself by asmall space occupied by sand (see Fig. 1).

The skull of Toumaï, which was foundupside down on the sand, was protectedfrom erosion by the second type of crust,whereas the right hemi-mandible TM266-02-154-1 had traces of grey matrix(Fig. 2), which also covered the base of theisolated M3. For this reason we considerthat the cranium on the one hand, and themandible and the M3 on the other werenot fossilized in the same deposits and arethus probably not contemporary.

The simplest reconstruction of the historyof the M3 and the right hemi-mandible isthat they were broken before burial andfossilization some 6 to 7 million years ago,as shown by the matrix covering thebroken surface of the distal root of the M3(Fig. 2). Later on, they became encrustedunder near-surface conditions. Recentlyexhumed by the wind, abrasion hasremoved much of their cover of matrixand has polished their surface, whilethermal variations have resulted indamage to some of the teeth. The M3 waspresumably the last specimen to erodeout of the sediments as its surface is well

preserved. Conversely, the other rightmandible (TM 266-02-203), discovered inMarch 2002 without teeth a dozen metresfrom the mandible and M3, was the first toerode out.

Biological considerations of the M3

One of the arguments put forward byBrunet et al.1 concerning the determina-tion of side of the isolated M3 is the wearpattern. However, examination of the lastupper molar in the skull of Toumaï (Fig. 1)indicates that we need to be cautiousabout the interpretation of wear on cuspsin general. Curiously, in this particularinstance wear on the buccal cusps isclosely similar to that on the lingual ones.

Because of this, from the beginning ofour study,2 we attached more importanceto the grooves, which were less affectedby wear during life (and more recentlyby wind abrasion), and are thus betterpreserved than the tops of the cusps.Firstly, the similarity between the fossil M3and a ‘modern’ human molar is striking.The alignment on a regular curve of thethree buccal cusps (protoconid, hypo-conid, hypoconulid) and their decreasein size mesio-distally constitute a deter-mining criterion. Secondly, the inter-cuspid column that we named themetaconulid in our article evokes more amorphological variant of the lingualsurface of the tooth than one of the buccalsurface. Thirdly, the orientation of themain disto-buccal groove accords pre-cisely in its occlusal articular dynamicrelationship with the oblique crest (cristaobliqua) [‘pont d’émail’] of the non-workingmaxillary molar when the opposite side ofthe jaw is engaged in chewing as in otheranthropomorphs.6

A second line of argument employed byBrunet et al.1 to demonstrate that the M3fits onto the right mandible was a series ofscans in which the broken surface of thebase of the tooth and the roots in themandible were shown to be compatiblewith each other, being separated only by athin but continuous layer of glue. It is

Correspondence South African Journal of Science 100, September/October 2004 445

Figs 1–3. Photographs of specimens attributed to Sahelanthropus tchadensis (taken of the cranium at 08:00 on19 July 2001): 1, the M3 in the cranium; 2, oblique lingual view of the roots of the M3 in the mandible (note in partic-ular the relatively planar fracture surface of the distal root, which curves distally and buccally at a constant level(black arrow), and compare it with the antero-posteriorly curved surface marked by an arrow in the imageprovided by Brunet et al.1) ; 3, root of the right C1 in the cranium of Toumaï. (Scale bars: 10 mm.)

necessary to recognize the detailed workwhich allowed the fitting of the M3 crownso precisely onto the roots of the hemi-mandible. The hard sandy matrix whichcovered the base of the isolated molarwhen it was found first had to be removedand then the space now occupied by gluehad to be prepared millimetre by milli-metre. A similar operation was requiredfor the parts of the root in the mandible,which were similarly covered in matrix(Fig. 2). In general, a section immediatelybeneath the cervix of left and right man-dibular molars reveals radicular surfacesthat may be superposed to within aboutone millimetre. So, it is not surprising inthis particular case that a left toothseemed to correspond to the roots in aright mandible.

The right upper canine of ToumaïWe apologize for the possibility that our

text regarding Toumaï’s right C1 could bemisinterpreted, the canine root being insitu in the skull as shown in Fig. 3. In con-trast we could only write that the caninecrown found in November 2001 fits ontothe root, we being in the Djourab, and theskull at the University of Poitiers.

Curatorial issuesWriting catalogue numbers on fossil

specimens is a daily activity in the field. Atsuch an important site as TM 266, all thefossils were collected. That is why, fromJuly to December 2001, 52 postcranialbones, whose zoological group could notbe determined in the field, were cata-logued, in the expectation that some ofthem might belong to Sahelanthropus.Among these fragments, 36 are longbones (tibia, femur, humerus and ulna)including intact specimens and brokendiaphyses. Considering the excellentpreservation of the Toumaï cranium, acareful examination of these bonesshould yield interesting information, aswe consider it likely that postcranialfossils of a large primate may be presentat the site, although nothing has beenreported until now. Note that in the cata-

logue returned to N’Djaména by theUniversity of Poitiers in December 2001, asingle fossil had been added to the fieldcatalogue. It consists of specimen TM266-01-447 (a right M3 according to Brunetet al.7), whereas the catalogue entry statesthat it is ‘Classification – primate; Descrip-tion – fragments morceaux racines M1/M3; Dépôt – Poitiers (reliquat tamis)’.These specimens were returned to theCNAR, N’Djaména, on 30 January 2002.

ConclusionsWe see no compelling reason to modify

radically our hypothesis about the geo-morphology of the Toros-Menalla region,nor our interpretation of the isolated leftM3 and damaged right mandible fromlocality TM 266 attributed to Sahelanthro-pus tchadensis. Finally, given the excellentpreservation of fossils at the site, weconsider it likely that the collection ofpostcranial elements collected there maywell contain some specimens that belongto Sahelanthropus.

Alain BeauvilainUniversité de Paris X Nanterre, 200 avenue de laRépublique, 92000 Nanterre Cedex, France.

Yves Le GuellecRue du Manoir, 76190 Yvetot, France.

1. Brunet M. et al. (2004). Sahelanthropus tchadensis:the facts. S. Afr. J. Sci. 100, 443–445.

2. Beauvilain A. and Le Guellec Y. (2004). Furtherdetails concerning fossils attributed to Sahel-anthropus tchadensis (Toumaï). S. Afr. J. Sci. 100,142–144.

3. Morin S. (2000). Géomorphologie. In Atlas de laprovince Extrême-Nord Cameroun, pp. 7–17. IRD-LCA/France–MINREST-INC/Cameroun.

4. Neev D., Hall J.K. and Saul J.M. (1982). ThePelusium Megashear System across Africa andassociated lineament swarms. J. Geophys. Res. 87,B2, 1015–1030.

5. Schuster M. (2002). Sédimentologie et paléoécologiedes séries à vertébrés du paléolac Tchad depuis le Mio-cène supérieur. Thesis, University of Strasbourg.

6. Lautrou A., University of Paris V – René Descartes,pers. comm. (author of Anatomie Dentaire, Masson,Paris).

7. Brunet M. et al. (2002). A new hominid from theUpper Miocene of Chad, Central Africa. Nature418, 145–151.

446 South African Journal of Science 100, September/October 2004 Correspondence

Sir, — We, the undersigned, have carefully examined the photographs and digitalcrown images of a fossilized third molar from the upper Miocene of Chad. This toothwas originally identified by the discoverers (Brunet et al. 2002, Nature 418, 145–151) as aright third mandibular molar. A recent paper by Beauvilain and Le Guellec (2004, S. Afr.J. Sci. 100, 142–144) claimed that this tooth had been misidentified and was in fact a leftlower third molar. Based on crown anatomy evident in the images examined by us, weconfirm the identity of this tooth as a right molar, as originally published by Brunet et al.(2002).

F. Clark HowellLaboratory for Human Evolutionary Studies, Museum ofVertebrate Zoology, The University of California at Berkeley,Berkeley, CA 94720, U.S.A.E-mail: fchlhes@socrates.berkeley.edu

Tim D. WhiteLaboratory for Human Evolutionary Studies, Museum ofVertebrate Zoology and Department of Integrative Biology, TheUniversity of California at Berkeley, Berkeley, CA 94720,

U.S.A. E-mail: timwhite@socrates.berkeley.edu

David R. BegunDepartment of Anthropology, University of Toronto, Toronto,ON M5S 3G3, Canada.E-mail: begun@chass.utoronto.ca

Yaowalak ChaimaneePaleontology Section, Bureau of Geological Survey, Depart-ment of Mineral Resources, Rama VI Road, Bangkok 10400,Thailand. E-mail: yaowalak@dmr.go.th

Marie-Antoinette de LumleyInstitut de Paléontologie Humaine, 75013 Paris, France.E-mail: prehist@mnhn.fr

Philip D. GingerichMuseum of Paleontology, University of Michigan, Ann Arbor,MI 48109-1079, U.S.A. E-mail: gingeric@umich.edu

Colin GrovesSchool of Archaeology and Anthropology, Australian NationalUniversity, Canberra, A.C.T. 0200, Australia.E-mail: colin.groves@anu.edu.au

Erksin GüleçDepartment of Physical Anthropology and Paleoanthropology,University of Ankara, 06100, Sihhiye, Ankara, Turkey.E-mail: erksin.gulec@humanity.ankara.edu.tr

Yohannes Haile-SelassieCleveland Museum of Natural History, 1 Wade Oval Drive,Cleveland, OH 44106, U.S.A. E-mail: yhailese@cmnh.org

Leslea HluskoDepartment of Integrative Biology, The University of Californiaat Berkeley, Berkeley, CA 94720, U.S.A.E-mail: hlusko@socrates.berkeley.edu

Jean-Jacques JaegerEquipe Phylogénie, Paléobiologie & Paléontologie, I.S.E.M.,CNRS-Université Montpellier II, UMR 5554, Cc 064 PlaceEugéne Bataillon, 34095 MONTPELLIER CEDEX 5, France.E-mail: jaeger@isem.univ-montp2.fr

Jay KelleyDepartment of Oral Biology, College of Dentistry, University ofIllinois at Chicago, Chicago, IL 60612, U.S.A.E-mail: jkelley@uic.edu

Meike KöhlerInstitute de Paleontologia M. Crusafont, c/ Escola Industrial 23,08201 Sabadell, Barcelona, Spain.E-mail: kohlerlm@diba.es

Wu LiuInstitute of Vertebrate Paleontology and Paleoanthropology,Chinese Academy of Sciences, Beijing 100044, China.E-mail: liuwu@ivpp.ac.cn

David LordkipanidzeGeorgian State Museum, 0105 Tbilisi, Georgia.E-mail: geonathist@ip.osgf.ge

C. Owen LovejoyMatthew Ferrini Institute for Human Evolutionary Research,Department of Anthropology, Kent State University, Kent, OH44242, U.S.A. E-mail: olovejoy@aol.com

Lawrence B. MartinDepartment of Anthropology and of Anatomical Sciences, TheGraduate School, Stony Brook University, NY 11794-4433,U.S.A. E-mail: lawrence.martin@stonybrook.edu

Monte L. McCrossinDepartment of Sociology and Anthropology, MSC 3BV, NewMexico State University, P.O. Box 30001, Las Cruces, NM88003-8001, U.S.A. E-mail: mmccross@nmsu.edu

Jacopo Moggi-CecchiLaboratori di Antropologia, Dipartimento di Biologia Animale eGenetica, Universitá di Firenze, via del Proconsolo 12, 50122Firenze, Italy. E-mail: jacopo@unifi.it

Salvador Moyà-SolàInstitute de Paleontologia M. Crusafont, c/ Escola Industrial 23,08201 Sabadell, Barcelona, Spain. E-mail:moyass@diba.es

Lorenzo RookDipartimento di Scienze della Terra, Università di Firenze,via G. La Pira, 4, 50121 Firenze, Italy.E-mail: Lrook@geo.unifi.it

Pat SmithDepartment of Anatomy, The Hebrew University HadassahMedical School, Jerusalem, Israel. E-mail: pat@cc.huji.ac.il

Gen SuwaThe University Museum, The University of Tokyo, Hongo,Bunkyo-ku, Tokyo, 113-0033, Japan.E-mail: suwa@um.u-tokyo.ac.jp

Mark TeafordCenter for Functional Anatomy and Evolution, Johns HopkinsUniversity School of Medicine, Baltimore, MD 21205, U.S.A.E-mail: mteaford@jhmi.edu

Phillip V. TobiasSchool of Anatomical Sciences, University of the Witwaters-rand, Johannesburg, South Africa.E-mail: tobiaspv@anatomy.wits.ac.za

Alan WalkerDepartments of Anthropology and Biology, The PennsylvaniaState University, University Park, PA 16802, U.S.A.E-mail: axw8@psu.edu

Phil WalkerDepartment of Anthropology, The University of California atSanta Barbara, Santa Barbara, CA 93106, U.S.A.E-mail: pwalker@anth.ucsb.edu

Steven WardDepartment of Anatomy, NEOUCOM, Rootstown, OH 44272-0095, U.S.A. E-mail: scw@neoucom.edu