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Premolar root and canal variation in extant non‐human hominoidea
Author(s) -
Moore N. Collin,
Hublin JeanJacques,
Skinner Matthew M.
Publication year - 2015
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.22776
Subject(s) - premolar , biology , extant taxon , taxon , context (archaeology) , hylobates , root canal , gorilla , australopithecus , molar , anatomy , evolutionary biology , orthodontics , zoology , ecology , paleontology , medicine
Objectives The premolar sub‐cervical region in four non‐human extant ape genera are examined to: 1) define a classification scheme for the premolar root system in order to rigorously characterize, quantify and document variation in root and canal, form, number and configuration; 2) compare this variation within and between genera; and 3) test the hypotheses that sex and size (i.e., the “size/number continuum,” Shields, [Shields ED, 2005]) of the premolar are determinants of root/canal form and/or number. Materials and Methods Microtomography and 3D visualization software are utilized to examine a large sample of Hylobates , Pan , Gorilla , and Pongo ( n = 951 teeth). Each premolar root system is examined to ascertain the expected level of variability for each taxon. Cervical surface area (mm 2 ) serves as a metric proxy for tooth size. A Chi‐square test of independence is used to assess for variability differences between and within each taxon, and Mann–Whitney U tests are employed to assess the predicted relationship between tooth size and variation within each taxon. Results Our findings indicate that root and canal configurations, non‐metric root traits and tooth size can distinguish between extant ape genera. Within the four ape taxa, premolar size variation is generally, but not always, correlated with canal/root number. Our results indicate that males and females within genera differ in tooth size but not in canal/root form and number. Discussion We report previously undocumented variation in the study taxa. Our results are discussed within the context of Miocene Apes as well as the developmental and systematic implications. Am J Phys Anthropol 158:209–226, 2015. © 2015 Wiley Periodicals, Inc.