ANNOTATIONS This section of the Journal is devoted to one-page research notes.
Dental Sexual Dimorphism in the European Upper Paleolithic and Mesolithic* DAVID W. FRAYER Department of Anthropology, The University of Kansas, Lawrence, Kansas 66045, USA This study documents for two chronologically lineal samples a consistent reduction of sexual differences in tooth size, supporting Brace's contention (Yrbk Phy Anthropol, 16:31-49, 1973) for a progressive reduction in hominid dental sexual dimorphism over time. This sample consists of European Upper Paleolithic and Mesolithic specimens. The Upper Paleolithic sample is dated from 33,00010,2500 B.P.; mesolithic specimens from 10,500 to about 6,000 B.P. Specimens were sexed on the basis of cranial robusticity, postcranial morphology and burial items. No specimens were assigned sex on the basis of tooth size. For comparison, means, standard deviations and sample sizes are presented along with a percentage difference between males and females from each period which was calculated by the formula X -X9 (x100)/X8. In addition, percent differences in an extant Australian aborigine sample (Walbiri) are given. These data derive from BRACE (pers. comm.). Only the areas (m-d length X b-l breadth) of the canine through third molar are presented, although the individual mesio-distal and buccallingual dimen;ions show the same trends. All measurements ire in mm2. For the mandibular tooth areas, the Upper Paleolithic group is consistently more dimorphic Received for publication June 15, 1976. Accepted for publication September 17, 1976. * Research supported by NSF Grant GS-38067 and Rackham Graduate School Grant, University of Michigan.
J Dent Res July 1977 Vol. 56 No. 7
than either the Mesolithic or Walbiri samples. For all three samples, the canine is the most dimorphic tooth, followed by the second molar area. Mandibular molar areas, as a rule, are more dimorphic than the premolars. Overall, the Upper Paleolithic averages about 25% larger canine and posterior tooth areas than the Mesolithic, and about 20% larger when compared to the Walbiri. In maxillary tooth areas, differences between the three groups show a similar pattern, but the magnitude of the differences is greater than in the mandible. The Upper Paleolithic sample is again the most dimorphic group, and the canine and second molar areas represent the most dimorphic teeth in all three samples. Overall, Upper Paleolithic specimens are about 30% more dimorphic than maxillary teeth of their Mesolithic descendants, and about 15% more than the Walbiri. In both jaws, the Upper Paleolithic group exhibits considerably more dimorphism than either the Mesolithic or Walbiri group. The relative difference in tooth size sexual dimorphism shown here is not related to overall differences among the groups in absolute size, but is a separate phenomenon. These findings are consistent with Brace's hypothesis of an evolutionary trend for the decrease in male/female differences over the hominid lineage. Reduction in dental sexual dimorphism correlates with a decrease in male body size and robusticity. Females over the same two periods show less pronounced change. The gracilization of males accounts for the reduction of sexual dimorphism between the Upper Paleolithic and Mesolithic.
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Dental Sexual Dimorphism in the European Upper Paleolithic and Mesolithic* DAVID W. FRAYER Department of Anthropology, The University of Kansas, Lawrence, Kansas 66045, USA This study documents for two chronologically lineal samples a consistent reduction of sexual differences in tooth size, supporting Brace's contention (Yrbk Phy Anthropol, 16:31-49, 1973) for a progressive reduction in hominid dental sexual dimorphism over time. This sample consists of European Upper Paleolithic and Mesolithic specimens. The Upper Paleolithic sample is dated from 33,00010,2500 B.P.; mesolithic specimens from 10,500 to about 6,000 B.P. Specimens were sexed on the basis of cranial robusticity, postcranial morphology and burial items. No specimens were assigned sex on the basis of tooth size. For comparison, means, standard deviations and sample sizes are presented along with a percentage difference between males and females from each period which was calculated by the formula X -X9 (x100)/X8. In addition, percent differences in an extant Australian aborigine sample (Walbiri) are given. These data derive from BRACE (pers. comm.). Only the areas (m-d length X b-l breadth) of the canine through third molar are presented, although the individual mesio-distal and buccallingual dimen;ions show the same trends. All measurements ire in mm2. For the mandibular tooth areas, the Upper Paleolithic group is consistently more dimorphic Received for publication June 15, 1976. Accepted for publication September 17, 1976. * Research supported by NSF Grant GS-38067 and Rackham Graduate School Grant, University of Michigan.
J Dent Res July 1977 Vol. 56 No. 7
than either the Mesolithic or Walbiri samples. For all three samples, the canine is the most dimorphic tooth, followed by the second molar area. Mandibular molar areas, as a rule, are more dimorphic than the premolars. Overall, the Upper Paleolithic averages about 25% larger canine and posterior tooth areas than the Mesolithic, and about 20% larger when compared to the Walbiri. In maxillary tooth areas, differences between the three groups show a similar pattern, but the magnitude of the differences is greater than in the mandible. The Upper Paleolithic sample is again the most dimorphic group, and the canine and second molar areas represent the most dimorphic teeth in all three samples. Overall, Upper Paleolithic specimens are about 30% more dimorphic than maxillary teeth of their Mesolithic descendants, and about 15% more than the Walbiri. In both jaws, the Upper Paleolithic group exhibits considerably more dimorphism than either the Mesolithic or Walbiri group. The relative difference in tooth size sexual dimorphism shown here is not related to overall differences among the groups in absolute size, but is a separate phenomenon. These findings are consistent with Brace's hypothesis of an evolutionary trend for the decrease in male/female differences over the hominid lineage. Reduction in dental sexual dimorphism correlates with a decrease in male body size and robusticity. Females over the same two periods show less pronounced change. The gracilization of males accounts for the reduction of sexual dimorphism between the Upper Paleolithic and Mesolithic.
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