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The morphology and wear of the lingual notch in macaques and langurs
Author(s) -
Teaford Mark F.
Publication year - 1983
Publication title -
american journal of physical anthropology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.146
H-Index - 119
eISSN - 1096-8644
pISSN - 0002-9483
DOI - 10.1002/ajpa.1330600103
Subject(s) - cusp (singularity) , biology , interspecific competition , anatomy , molar , shearing (physics) , zoology , morphology (biology) , ecology , geometry , materials science , mathematics , paleontology , composite material
Although interspecific differences in the relative development of molar occlusal features have been documented for most primate species, wear‐related changes in these features are only beginning to be understood. In the present study, the notch between the metaconid and entoconid of M 2 was examined in a skeletal sample of Macaca fascicularis , Presbytis cristatus , and Presbytis rubicunda from the Museum of Comparative Zoology at Harvard University. Photogrammetric analyses yielded X, Y, and Z coordinates that were used to compute three angular measurements and two length measurements at the lingual notch. Statistical analyses of measurements from unworn dentitions indicated that the mesial slope of the entoconid is steeper than the distal slope of the metaconid in all three species. In addition, interspecific comparisons demonstrated that P. cristatus has the steepest lingual notch bordered by the largest molar shearing crests, while P. rubicunda and M. fascicularis have molar shearing crests of similar size, with P. rubicunda merely having higher cusps that are closer together than those of M. fascicularis. Fanally, P. cristatus shows a smaller decrease in lingual cusp relief with wear than M. fascicularis , while P. cristatus and P. rubicunda probably show similar decreases in lingual cusp relief with wear. The differences in wear‐related changes in lingual cusp relief between M. fascicularis and P. cristatus may well be related to the frugivorous/folivorous dietary differences between these species.