TY - JOUR
T1 - Ontogenetic insights into the significance of mandibular corpus shape variation in hominoids
T2 - Developmental covariation between M2 crypt formation and corpus shape
AU - Pitirri, M. K.
AU - Begun, David
N1 - Funding Information:
We would like to thank the Smithsonian's Division of Mammals and Human Origins Program for the scans of USNM specimens used in this research. These scans were acquired through the generous support of the Smithsonian 2.0 Fund and the Smithsonian's Care and Preservation Fund. We would also like to thank Dr. Emmanuel Gilissen for the use of the scans of the RMCA specimens in this research. We are grateful to the University of Toronto for funding this research.
Funding Information:
We would like to thank the Smithsonian's Division of Mammals and Human Origins Program for the scans of USNM specimens used in this research. These scans were acquired through the generous support of the Smithsonian 2.0 Fund and the Smithsonian's Care and Preservation Fund. We would also like to thank Dr. Emmanuel Gilissen for the use of the scans of the RMCA specimens in this research. We are grateful to the University of Toronto for funding this research.
Publisher Copyright:
© 2019 Wiley Periodicals, Inc.
PY - 2020/1/1
Y1 - 2020/1/1
N2 - Objectives: Here, we quantify and compare the cross-sectional shape of the mandibular corpus between M1 and M2 during growth in Pan paniscus, Pan troglodytes, and Pongo pygmaeus. The goal is to assess the hypothesis that the shape of the corpus is influenced by the development of permanent molars in their crypts, by examining ontogenetic changes in corpus shape and investigating covariation between corpus shape and M2 and M3 molar crypt forms. Materials and Methods: Ontogenetic changes in mandibular corpus shape were assessed using landmarks and semilandmarks, and measurements of length, width, and height were used to quantify molar crypts (M2 and M3). Ontogenetic changes in corpus growth from the eruption of M1 to the eruption of M3 were evaluated for each species through generalized Procrustes analysis and principal components analysis in shape–space and form–space. The relationship between corpus shape and molar crypt form was investigated at three different developmental stages using two-block partial least squares (2B-PLS) analysis. Results: The results show clear differences in growth patterns among all three species and provide evidence that species-level differences in mandibular corpus growth occur prior to the emergence of M1. The results of the 2B-PLS analysis reveal that significant covariance between corpus shape and molar crypt form is limited to the developmental stage marked by the emergence of M1, with covariance between corpus shape and M2 crypt width. Corpora that are relatively narrower in the inferior portion of the cross section covary with relatively narrower M2 crypts. Conclusions: These results have important implications for understanding the taxonomic and phylogenetic significance of mandibular corpus shape variation in the hominoid fossil record.
AB - Objectives: Here, we quantify and compare the cross-sectional shape of the mandibular corpus between M1 and M2 during growth in Pan paniscus, Pan troglodytes, and Pongo pygmaeus. The goal is to assess the hypothesis that the shape of the corpus is influenced by the development of permanent molars in their crypts, by examining ontogenetic changes in corpus shape and investigating covariation between corpus shape and M2 and M3 molar crypt forms. Materials and Methods: Ontogenetic changes in mandibular corpus shape were assessed using landmarks and semilandmarks, and measurements of length, width, and height were used to quantify molar crypts (M2 and M3). Ontogenetic changes in corpus growth from the eruption of M1 to the eruption of M3 were evaluated for each species through generalized Procrustes analysis and principal components analysis in shape–space and form–space. The relationship between corpus shape and molar crypt form was investigated at three different developmental stages using two-block partial least squares (2B-PLS) analysis. Results: The results show clear differences in growth patterns among all three species and provide evidence that species-level differences in mandibular corpus growth occur prior to the emergence of M1. The results of the 2B-PLS analysis reveal that significant covariance between corpus shape and molar crypt form is limited to the developmental stage marked by the emergence of M1, with covariance between corpus shape and M2 crypt width. Corpora that are relatively narrower in the inferior portion of the cross section covary with relatively narrower M2 crypts. Conclusions: These results have important implications for understanding the taxonomic and phylogenetic significance of mandibular corpus shape variation in the hominoid fossil record.
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U2 - 10.1002/ajpa.23969
DO - 10.1002/ajpa.23969
M3 - Article
C2 - 31710703
AN - SCOPUS:85074979025
SN - 0002-9483
VL - 171
SP - 76
EP - 88
JO - American Journal of Physical Anthropology
JF - American Journal of Physical Anthropology
IS - 1
ER -