HUMAN EVOLUTION Vol. 9 - N. 2 (165-172)- 1994

C. Lalueza Fox A. P&ez-Pfrez Secc. Antropologia, Dept. Biologia Animal Facultad de Biologia, Universitat de Barcelona Avda. Diagonal 645 08028 Barcelona Spain

Key words: Fossil teeth, Cutmarks, ar- tificial striations, Scanning Electron Microscopy, Buccal surface

Cutmarks and post-mortem striations in fossil human teeth

A sample of 24 teeth from 10 human fossils have been examined by Scanning Electron Microscope. Large striations attributable to feed- ing behavior (dental cutmarks) and/or to post-mortem damage have been found in five of the specimens (Broken Hill, Tabun I, Skhul 4, La Quina 5 and Malarnaud). At high magnification, it is possible to observe differences between the internal morphology of these struc- tures and post-mortem striations that were probably inadvertently made during the process of study and cleaning the fossil remains. Cutmarks can be related to the behavior of placing meat or other matter between the anterior teeth while cutting pieces of it with a stone tool. The presence of this type of scratching on the enamel surface of teeth might be indirectly used as indicative of meat con- sumption.

Introduction

The presence of large striations, usually called cutmarks, in the buccal surface of the anterior teeth, has been reported in some middle and early Upper Pleistocene remains, such as Saint-Brais (Switzerland) (Koby, 1956), Angles-sur-l 'Anglin (France) (Patte, 1960), Atapuerca, La Quina 5, Cova Negra (Valencia, Spain) (Bermt~dez de Castro et al., 1988), Hortus (Lumley, 1973), Shanidar (Trinkaus, 1983), Broken Hill (Puech et al., 1980), and Mauer (Puech, 1978), among others. These cutmarks were produced ante-mortem, and have been ascribed by some authors to the behavior of holding some material, such as meat, between the maxillary and mandibulary anterior teeth while cutting pieces of it with a stone knife, scratching the enamel in the process (Martin, 1923; Lumley, 1973; Trinkaus, 1983; BermOdez de Castro et al., 1988).

Dental cutmarks are clearly directional with a parallel alignment. They may be found on the buccal surface of all front teeth, approximately from the left to the right canine, but they are not present in premolars and molars. Cutmarks are preferentially located in the center of the buccal surface, far from the cemento-enamel junction or the interproximal contact areas. They are usu- ally placed near the occlusal surface, but whenever teeth are severely worn down, they can be found close to the cervical area (Lumley, 1973). Typically, these striations run from disto-cervical to mesio-occlusal on the left side teeth and from mesio-cervical to disto-occlusal on the right side teeth, with regard to the occlusal plane. This orientation corresponds to fight-handed individuals. However, cutmarks in the opposite direction have been found in some specimens, such as Hortus VIII (Lumley, 1973), thus suggesting a left-handed individual. Cutmarks can also reflect the growing perfection of cutting tools; progressively sharper edges can produce narrower marks (Lalueza, 1992). Cutmarks are long (1 to 4 mm) and wide (more than 20 ~tm, and sometimes up to 100 ktm) structures (Bermt~dez de Castro et al., 1988) that are obliquely oriented (approxi- mately 45 ~ in relation to the long axis of the tooth). Striations attributed to the effect of diet, produced by opal phytoliths from plants or inorganic particles from the soil, are usually less than 20 ~tm wide (Lalueza, 1992).

166 LALUEZA and P~,REZ-Pf~REZ

Cutmarks can provide information about the handedness of the individual, and, indirectly, about the lateralization of the hominid brain during the Pleistocene (Bermfidez de Castro et al., 1988). Furthermore, these marks provide evidence for differences in feeding behavior of past human populations, which can be related to environmental conditions, diet, and culture. However, it is difficult to interpret the nature of these striations in some fossils, because they have been subjected to numerous manipulations since they were discovered, sometimes many years ago. Careless mechanical cleaning of these fossils might have produced post-mortem striations appar- ently similar to cutmarks.

At present, the lack of information about post-mortem striations limits the possibilities of the analysis of cutmarks. The purpose of this study is the microscopic observation of cutmarks and post-mortem marks in the teeth of some human fossils, in order to establish possible differences in the morphology of these structures.

Materials and Methods

Casts of the buccal surface of some teeth from different human fossils have been obtained, by the application of a plastic solution of Triafol (Balzers Union BU 008 002 T), dissolved in chloroform. The plastic is removed after 10 minutes, without any enamel damage. Casts were directly sputter-coated with a 400]k gold layer, and observed with a Scanning Electron Micro- scope (SEM) Hitachi s-2300, at the "Servei de Microsc6pia de la Universitat de Barcelona". Photographs were taken at different magnifications, at 20 kV accelerating voltage and 0 ~ of tilt angle. The replication method is the same previously used in Lalueza and P6rez-P6rez (1993), and Latueza et al., (1993). Eleven human fossil specimens from different periods and geographical areas were examined.

Museum Specimens

British Museum (Natural History) (London)

Broken Hill (Zambia) Tabun I (CI) (Israel)

Rockefeller Museum (Jerusalem) Skhul 4 (Israel) Amud 1 (Israel) Qafzeh 9 (Israel)

Mus6e de l 'Homme (Paris) La Quina 5 (France) Malarnaud (France) Abri Pataud (France) Montmaurin (France) Cro-Magnon 4 (France)

Some of the casts that were obtained from the fossil remains were discarded for SEM observation, due to enamel erosion. The sample finally studied consist of 24 teeth. For this reason, it was not possible to undertake an exhaustive examination of all teeth present in each fossil specimen.

CUTMARKS IN FOSSIL HUMAN TEETH 167

Results

Results of the SEM observation are shown in Table 1. The whole sample comprises 24 teeth, although only 8 can be considered as belonging to the anterior dentition (from canine to canine). Three fossils (Broken Hill, Tabun I(CI) and La Quina 5) from the studied sample have cutmarks, and all of them suggest right-handedness of the individuals considered, as has been previously described. The specimens of Montmaurin, Cro-Magnon 4 and Malarnaud do not have anterior teeth. Good quality casts of the anterior dentition of the specimens of Qafzeh 9, Abri Pataud and Amud 1 could not be obtained due to the fact that these old remains had been painted with some type of hardening product. This procedure makes it difficult at present to obtain good dental casts.

Some human fossils (Skhul 4, La Quina 5 and Malarnaud) display marks that are macro- scopically similar to cutmarks, although they show some differences when observed microscopi- cally. The origin of these marks can be related to post-mortem manipulations of the specimen, and these marks can thus be called post-mortem striations. La Quina 5 presents both cutmarks and

TABLE I- Results of the SEM observation for the different human fossils considered.

Teeth Cutmarks Post-mortem marks

Broken Hill left 12 left C' right M t

Tabun I (CI) left 11 right C, left M~

Skhul 4 right 11 left Pm 4

Amud 1 left M l

Qafzeh 9 left Pm 3 left Pm 4 left M L

La Quina 5 right 11 left 12 left C, left M~ right M~

Malarnaud right M~

Abri Pataud left M L

Montmaurin left M~ right M 1

Cro-Magnon 4 left Pm 4 left Pm 4 left M ~

-I-

+

168 LALUEZA and PI~REZ-Pt~REZ

post-mortem striations in the dentition, which can cause some confusion in studies on cutmarks. All these marks, either ante-mortem or post-mortem, were observed using different degrees

of magnification. Although they look alike at low magnification (around x50), the increasing of resolution shows important differences. Tabun I(CI), has numerous cutmarks in the anterior dentition. Figure 1 (x60) shows the cutmarks of the buccal surface of the right lower canine of Tabun CI, running from mesio-cervical to disto-occlusal. Also La Quina 5 presents cutmarks in the anterior dentition (Figure 2, xl00, left lower canine), very similar to those observed in Tabun I(CI). At higher magnification (Figure 3, x400), it can be observed that the enamel is crushed and cracked in numerous microscopic facets, forming a wide, irregular depression, approximately semicircular in section. The same cutmarks can be observed in the right upper first incisor of La Quina 5 (Figure 4, x80). The enamel surface is eroded and, consequently, the scratch seems to be discontinuous and irregular at x600 magnification (Figure 5). The same fossil also displays marks in the right lower first molar (Figure 6, x150), but, unlike the marks of the anterior dentition, these are morphologically distinct. These marks are more regular in shape, with well-defined margins and sharp edges. The interior of the groove also looks more regular than the typical cutmarks. The difference became evident at xl000 magnification (Figure 7). The groove is formed by numerous regular and parallel lines. The same pattern can be found in the fight lower first molar of Malarnaud (Figure 8, x200). At x2000, the marks are very similar to those observed in La Quina 5 (Figure 9). This kind ofpost-mortem marks cannot be made by a broad lithic instrument, and can only be attributed to some kind of metallic insmament.

Skhul 4 has some horizontal marks in the buccal surface of the right I ~, which can also be considered artificial striations, although their morphology is not as clear as those of La Quina 5 and Malarnaud. In premolar and molar teeth, all the hominids present only fine striations (less than 5 gm wide), attributable to the effect of inorganic particles mixed with the food.

Discussion

In order to characterize the morphology of artificial marks, we have made some scratches in the surface of medieval teeth, with the aid of a needle. Observed by SEM, the artificial scratches

Figure l-cutmarks in the fight lower canine of Tabun Figure 2 - cutmarks in the left lower canine of La CI neanderthal (x60, line length: 500 gin). Quina 5 neanderthal (xl00, line length: 500 gm),

CUTMARKS IN FOSSIL HUMAN TEETH 169

are different from the typical cutmarks, and are similar to the artificial marks observed in Malamaud and La Quina 5. The edges are regular and sharp, and no microfractures are present in the grooves. However, the response of the enamel to mechanical stress can be different in dried, fossilized teeth than in ante-mortem dentition.

Shipman and Rose (1984) and Bermtidez de Castro et al., (1988), have pointed out that dental cutmarks, such as those of La Quina 5, although abraded in human fossils, show traces of fine striations parallel to the long axis of the grooves in their internal structure. But in Figures 1, 2, 3, 4 and 5 (from Tabun CI and La Quina 5), we see no signs of internal fine striations. Our interpretation is that a stone flake most probably produces a broad fracture on the enamel surface. Structures with fine striations must be attributed to post-mortem damage, possibly related to the action of metallic instruments, such as scalpels or needles. Post-mortem damage of the enamel was probably made inadvertently during the process of cleaning and studying of the fossil. This is not surprising, considering that Malamaud was discovered in 1889, and La Quina 5 in 1911.

According to Gordon (1984), Bromage and Boyde (1984) and Bermfidez de Castro et al., (1988), the direction of the cutmarks can be inferred looking at the formation of Hertzian fracture cones on the margins of the marks. All the marks in maxillary teeth show a cervical to occlusal direction, opposed to that observed in mandibulary teeth, as expected. However, only small fracture planes can be distinguished in artificial striations (Figures 6, 7, 8 and 9), in which sometimes the pattern of fracturing is not discernible. This could be due both to differences in the implements used (lithic or metallic instruments) and to differences in the enamel structure be- tween in vivo and fossilized teeth. The direction of these artificial marks corresponds to a front-to- back movement, with regard to the dental arch.

The width, measured at the mid point of the cutmarks, ranges approximately from 40 to 60 gm in La Quina 5 and Tabun CI: x=44.6 ~tm, S.D. =7.59, n=9 (Tabun CI, right C,); x=62 gin, S.D. =7.72, n=4 (La Quina 5, left C,); x=55.5 gm, S.D.=15.69, n=6 (La Quina 5, right F). The width of the artificial marks is slightly smaller (around 15-20 gin) than that of cutmarks, and less variable: x=14.8 p.m, S.D.=3.08, n--8 (Malarnaud, right M~); x=17.1 p.m, S.D.=6.39, n=10 (La Quina 5, right Ml).

Other ante-mortem marks, similar to cutmarks, can be found on the enamel surface of human fossil teeth. The action of tightening and pulling outward abrasive materials across the

Figure 3 - internal structure of La Quina 5 cutmarks (left C, ), at high magnification (x400, line length: 100 gm). Note the presence of narrower striations, which can be attributed to the abrasiveness of the diet.

170 LALUEZA and PEREZ-PEREZ

Figure 4 pattern of cutmarks in La Quina 5 (right I t, x80, line length: 500 ~un).

Figure 5 - detail of cutmarks of La Quina 5 (right It), at high magnification (x600, line length: 50 ~tm).

anterior teeth may produce striations that can be related to a wide spectrum of paramasticatory activities (Ryan and Johanson, 1989). The ethnographic literature, particularly regarding Eskimo populations, describes some of these activities (De Poncins, 1941; Vanstone, 1962). However, these marks are distributed along the buccal surface, parallel to the main axis of the tooth, while cutmarks show an oblique direction. Other differences seem to be the preferential distribution of cutmarks in maxillary teeth, while striations related to manipulative tasks are mainly present in mandibulary teeth.

Cutmarks are not restricted to one geographical area, nor to a specific period of the human evolutionary process. The relative importance of some cultural behaviors related to the presence

Figure 6 - artificial striations in the right lower first molar of La Quina 5 (x150, line length: 200 Nn). The differences with the structure of cutmarks can be seen.

Figure 7 artificial marks of the right M~ of La Quina 5, displayed at high magnification (xl000, line length: 50 gm). Note the presence of small frac- ture planes in the margins.

CUTMARKS IN FOSSIL HUMAN TEETH 171

Figure 8 - pattern of artificial striations in the fight M t, of Malamaud (x200, line length: 200 ~tm). Mor- phological similarities with the marks of Figure 6 can be seen.

Figure 9 - artificial marks of the right M l of Malarnaud, at high magnification (x2000, line length: 20 gin).

of cutmarks can be ascertained by the existence of cutmarks in subadult individuals (Bermtldez de Castro et al., 1988). Nevertheless, sex or age related distribution of these marks can only be investigated with the analysis of larger samples.

If the hypothesis of the relationship between feeding behavior and cutmarks is correct, we can expect to find these marks in meat-caters more frequently than other hunter-gatherer groups. In this regard, it is interesting to confirm that cutmarks have been described in the dentition of aborigines from Tierra del Fuego (Lalueza, 1992), and that the habit of cutting off pieces of meat or fish held with the anterior dentition has been described in Eskimos (Vanstone, 1962). There- fore, it may seem that dental cutmarks can also indirectly provide evidence of diet, regarding meat consumption.

From our point of view, a complete replication of both buccal and occlusal surfaces from all the available anterior teeth in these fossil specimens, would represent a step forward in this kind of study. The exact number, length, width, orientation and distribution of cutmarks can increase our knowledge about cultural activities in past human populations.

ACKNOWLDGMBNTS--We are grateful to Jean Louis Heim (Muste de l'Homme, Paris), Chris Stringer (British Museum of Natural History, London), and Joe Zias (Rockefeller Museum, Jerusalem), for permission to examine the specimens preserved in their respective institutions.

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Bromage, T.G. and Boyde, A. 1984. Microscopic criteria for the determination of direcionality of cutmarks on bone. American Journal of Physical Anthropolgy . 65: 359-366.

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172 LALUEZA and P/~REZ-P/~REZ

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Received 18 May 1993 Accepted 24 September 1993