Ontogenetic insights into the significance of mandibular corpus shape variation in hominoids: Developmental covariation between M2 crypt formation and corpus shape

M. K. Pitirri, David Begun

Research output: Contribution to journalArticle

Abstract

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.

Original languageEnglish (US)
Pages (from-to)76-88
Number of pages13
JournalAmerican Journal of Physical Anthropology
Volume171
Issue number1
DOIs
StatePublished - Jan 1 2020

Fingerprint

Growth
Pongo pygmaeus
Pan paniscus
Pan troglodytes
Principal Component Analysis
Least-Squares Analysis
evidence

All Science Journal Classification (ASJC) codes

  • Anatomy
  • Anthropology

Cite this

@article{0f2e639ccfc8470d87a39b53b856a707,
title = "Ontogenetic insights into the significance of mandibular corpus shape variation in hominoids: Developmental covariation between M2 crypt formation and corpus shape",
abstract = "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.",
author = "Pitirri, {M. K.} and David Begun",
year = "2020",
month = "1",
day = "1",
doi = "10.1002/ajpa.23969",
language = "English (US)",
volume = "171",
pages = "76--88",
journal = "American Journal of Physical Anthropology",
issn = "0002-9483",
publisher = "Wiley-Liss Inc.",
number = "1",

}

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

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.

UR - http://www.scopus.com/inward/record.url?scp=85074979025&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85074979025&partnerID=8YFLogxK

U2 - 10.1002/ajpa.23969

DO - 10.1002/ajpa.23969

M3 - Article

C2 - 31710703

AN - SCOPUS:85074979025

VL - 171

SP - 76

EP - 88

JO - American Journal of Physical Anthropology

JF - American Journal of Physical Anthropology

SN - 0002-9483

IS - 1

ER -