Premium
T he B iomechanics of B ony F acial “ B uttresses” in S outh A frican A ustralopiths: A n E xperimental S tudy U sing F inite E lement A nalysis
Author(s) -
Ledogar Justin A.,
Benazzi Stefano,
Smith Amanda L.,
Weber Gerhard W.,
Carlson Keely B.,
Dechow Paul C.,
Grosse Ian R.,
Ross Callum F.,
Richmond Brian G.,
Wright Barth W.,
Wang Qian,
Byron Craig,
Carlson Kristian J.,
De Ruiter Darryl J.,
Pryor Mcintosh Leslie C.,
Strait David S.
Publication year - 2017
Publication title -
the anatomical record
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.678
H-Index - 62
eISSN - 1932-8494
pISSN - 1932-8486
DOI - 10.1002/ar.23492
Subject(s) - premolar , pillar , anatomy , orthodontics , biology , structural engineering , medicine , molar , engineering
Australopiths exhibit a number of derived facial features that are thought to strengthen the face against high and/or repetitive loads associated with a diet that included mechanically challenging foods. Here, we use finite element analysis (FEA) to test hypotheses related to the purported strengthening role of the zygomatic root and “anterior pillar” in australopiths. We modified our previously constructed models of Sts 5 ( Australopithecus africanus ) and MH1 ( A. sediba ) to differ in the morphology of the zygomatic root, including changes to both the shape and positioning of the zygomatic root complex, in addition to creating variants of Sts 5 lacking anterior pillars. We found that both an expanded zygomatic root and the presence of “anterior pillars” reinforce the face against feeding loads. We also found that strain orientations are most compatible with the hypothesis that the pillar evolved to resist loads associated with premolar loading, and that this morphology has an ancillary effect of strengthening the face during all loading regimes. These results provide support for the functional hypotheses. However, we found that an anteriorly positioned zygomatic root increases strain magnitudes even in models with an inflated/reinforced root complex. These results suggest that an anteriorly placed zygomatic root complex evolved to enhance the efficiency of bite force production while facial reinforcement features, such as the anterior pillar and the expanded zygomatic root, may have been selected for in part to compensate for the weakening effect of this facial configuration. Anat Rec, 300:171–195, 2017. © 2016 Wiley Periodicals, Inc.