Dentition of a Mesolithic Population from

The dentition of a Mesolithic population (8,000-11,000 years old) from Wadi Halfa, Sudan, can be characterized as morphologically complex, massive and relatively free from pathology except that associated with extreme wear. Maxillary incisors show shoveling. All of the maxillary molars show some development of the hypocone. Supernumerary cusps appear frequently. Almost one-half of the second lower molars observed show distally located third cusps. Over one-half of the maxillary third molars show an extra cusp. A high percentage of mandibular molars show six cusps. Overall the teeth from this population compare favorably in size with those of an Australian aborigine tribe and are slightly larger than the teeth of the Neanderthaloids from Skuhl. The teeth show wear of a degree greater than that found in present day Eskimo or Australian aborigine groups. This data may be intcrpreted as indicating that this Mesolithic group was subjected to rigorous selective pressures favoring large and/or morphologically complex teeth. This pressure was apparently intensive wear, presumably caused by the inclusion of large amounts of grit in the diet through the eating of vegetable food macerated on coarse grinding stones. During the 1963-1964 field season of the University of Colorado's Nubian Expedition, a series of 39 permineralized fossil skeletons were discovered by expedition archaeologists and excavated by the expedition's three physical anthropologists (George Armelagos, George Ewing and David Greene) . Preliminary analysis by the archaeologist directly responsible for this site, Arthur Saxe ('66), indicates that it has Mesolithic affinities and is at least 8,000-1 1,000 years old. The site from which the skeletons were uncovered, given the designation 6-B-36, lies between 31 and 35 m above the mean Nile level at Wadi Halfa. This is about 151 to 155 m above the mean sea level at Alexandria and back 2.5 km from the Nile into what is now desert. Lithic material recovered from living areas on the site has been included in the Wadi complex of Wheat and Irwin ('65) and appears to be similar to the Quadan complex described by Shiner ('65) and Wendorf, Shiner and Marks ('65). Most of the 39 skeletons were deliberately buried as single and double interments and were oriented with their heads to the southeast. There was also a large burial complex in which orientation of the skulls varied from east to south. The burials were usually flexed, lying on their left side, except for one individual resting on his back. Preliminary descriptions of these skeletons have been made elsewhere (Hewes et al., '64; Armelagos et al., '65). Important aspects of the skeletal morphology with regard to the dentition as part of a functioning morphological complex are the existence of structures that indicate heavy masticatory musculature. Temporal lines on the frontal bone are heavily marked and most of the skulls show a pronounced glabellar protrusion which arches and diminishes laterally to a point approximately above the supraorbital foramina. These cannot properly be called tori but they probably bear a functional relationship to masticatory stress by providing struts against lateral stresses in the frontal bone (Ewing, '66). The mandibles also show features related to heavy masIField work for this study was in part financed through National Scienoe Foundation Grants GS-7, GS-286, and GS-557. (Principle Investigator: Dr. C . W. Hewes.) 41 AM. J. Pays. ANTHROP., 27: 41-56. 42 DAVID L. GREENE, GEORGE H. E W I N G AND GEORGE J. ARMELAGOS Fig. 1 Typical individual from 643-36 showing marked temporaI lines, gIabelIar protrusion, gonial eversion and a massive mandible all indicative of heavy masticatory musculature. ticatory musculature. Many show proMorphology nounced gOnid eversion and in general are massive with heavy bodies and broad ascending rami. The dentition from site 6-B-36 can be characterized as morphologically complex and massive. Almost all individuals, where DENTITION O F A MESOLITHIC POPULATION 43 the observation is possible, show some degree of lingual elaboration, or shoveling, of the maxillary incisors. Because of postmortem loss and the high degree of dental attrition present in this population, only 11 individuals have incisors on which this trait can be observed. Four of these have deciduous incisors; all have distinct labial ridges and slight fossae which correspond to what Hanihara ('61) calls semishoveled deciduous teeth. Two of the individuals with permanent teeth show no indication of shoveling; five have what HrdliEka ('20) called trace shoveling (distinct traces of the enamel rim); one has a distinct enamel rim plus a shallow fossa (semishoveled), and one has a marked enamel rim and a well developed fossa (shoveled). Most of the maxillary incisors also have finger-like projections running on the lingual surface from the basal tubercle to the incisal edge similar to those on teeth from Jarmo, described by Dahlberg ('60). As would be expected (HrdliEka, ' 20 ) , shoveling is not as prominent in the mandibular incisors. Two out of eight individuals with permanent teeth show very slight development of marginal ridges that might be classed as trace shoveling. Lingual elaboration or shoveling continues into the maxillary and mandibular canines. This observation has been made in other populations (Hanihara, '61 ). Generally, both upper and lower canines are monocuspid teeth with noticeable mesial and distal lingual marginal ridges which produce the shoveled contour. Of the eight individuals with maxillary teeth and a similar number with mandibular teeth, none show noticeable development of cinguli. Ten individuals have observable maxillary premolars. In both the first and second premolar, the lingual and buccal cusps are almost equally developed with the buccal being only slightly larger. Most have well marked mesial and distal marginal ridges which are occasionally bisected by a central groove. Mandibular first premolars are bicuspid with a noticeable lingual cusp. Two individuals out of nine have lingual cusps approximating the size of their buccal cusps. All have well marked mesial and distal pits and those with larger lingual cusps have well developed triangular ridges connecting with the buccal cusp. All nine individuals observed with mandibular second premolars have well developed lingual cusps. Five of these exhibit bilaterally a third distal lingual supernumerary cusp. In general, these teeth have mesial and distal pits, but the triangular ridge is not as well developed as in the first premolars. Permanent molars are also morphologically complex. All ten of the individuals observed have well developed hypocones on their maxillary first molars. Second maxillary molars show more variation. Only one individual has a well developed hypocone, five show a slight reduction in the size of the hypocone and three show reduction of the hypocone to a cuspule. Although third molars show a wide range of morphological variation, (Dahlberg, '45) this sample of 12 individuals is relatively homogeneous. Two individuals have molars with only a slight reduction in the hypocone, two show only a cuspule for a hypocone, while one has no hypocone. Seven have fifth cusps which were probably produced by a splitting of the hypocone. In the three cases where both right and left teeth were present, this morphological variant was bilaterally expressed. In a very large sample from historic Nubian populations, this occurred bilaterally with a highly significant association (0.01 2 P 2 0.001) between left and right sides of the jaw (Greene, '65). Such mirror imagery in a bilateral structure suggests that this split hypocone variant has a genetic basis. Some of the maxillary molars present show elaboration of the lingual side of the protocone in the form of cusps, pits and grooves. Some dental anthropologists feel that the pits and grooves that occur a t this location are not part of the same morphological complex as the cusps. They restrict the term Carabelli Trait or Carabelli Cusp to the various gradations of cusps that may occur (Weidenreich, '37; Hanihara, '63). Other dental anthropologists (Korenhof, '60; Kraus, '51) include cusps, pits and grooves in the same complex. Carabelli phenomena when iound are not restricted to any particular maxillary molar. They can occur on any of the maxillary molars including the second deciduous molar ,44 DAVID L. GREENE, GEORGE H. EWING AND GEORGE J. ARMELAGOS Fig. 2 Mandible showing second premolar with a supernumerary third cusp located distally on its lingual surface. The right third molar, and possibly the second and first as well, has six cusps. (Dietz, '44; Tsuji, '58). In this sample, 4 out of 12 individuals with first maxillary molars display some elaboration of the lingual side of the protocone (one pit; one slight cusp with groove; two medium cusps). Two individuals out of ten show pits or grooves on their second molars. And 2 out of 12 have slight cusps on their third molars. Cusp number and fissure pattern in mandibular molars are probably independent morphological and genetic variables (J@rgenson, '55; Greene, '65); so their occurrence is listed separately. With regard to the first mandibular molar, all 11 individuals with relatively unworn cusps show five distinct cusps. Six of these individuals have supernumerary sixth cusps located between the metaconid and hypoconulid. Supernumerary cusps in this location have been termed C6 (Nelson, '38). In the three cases where individuals retain both left and right teeth, this variant is bilateral, Out of 11 individuals with second mandibular molars, five have at least five cusps with two of these also having supernumerary C6 cusps. Out of ten individuals with third mandibular molars, five have five cusps with three of these also having C6 supernumerary cusps. The remaining five individuals have only four cusps on their third mandibular molars. DENTITION O F A MESOLITHIC POPULATION 45 Fig. 3 Maxilla showing incisor shoveling, slight canine shoveling, and left first molar with a small Carabelli Cusp. Fissure patterns on the mandibular molars can vary from a Y pattern (Dryopithecine) to a + (crucilorm) pattern (Hellman, '28). The Y pattern occurs in seven out of nine individuals with first molars, 5 out of 11 with second molars, and none out of six with third molars. All of the remainder show cruciform patterns. Two individuals with maxillary third molars and two each with mandibular first, second, and third molars have wrinkled enamel comparable to that found in the dentition of a Neanderthal child described by Carbonell ('65 j . Two individuals show some evidence of the protostylid. One has pits on the mesial buccal surface of the protoconid of its second mandibular molars which are not in contact with the buccal groove. The other shows a medium-si7ed cusp on the left third mandibular molar and a pit on the right third mandibular molar. Comparing the dental morphology of incisors and molars of the 6-B-36 population with that of a later Meroitic population from the same geographical area which dates from 350 B.C. to 450 A.D. indicates that the Mesolithic population displays a higher frequency of supernumerary cusps in both maxillary and mandibular molars, a higher frequency of maxillary molars with well developed or just slightly reduced hypocones, and a higher frequency of shoveling in the maxillary incisors.