94% of researchers rate our articles as excellent or good
Learn more about the work of our research integrity team to safeguard the quality of each article we publish.
Find out more
ORIGINAL RESEARCH article
Front. Ecol. Evol.
Sec. Behavioral and Evolutionary Ecology
Volume 13 - 2025 | doi: 10.3389/fevo.2025.1492411
This article is part of the Research Topic Ecology, Evolution, and Diversity of Papionini Primates View all articles
The evolution of facial length and molar proportions in cercopithecid monkeys
Provisionally accepted- 1 Western Washington University, Bellingham, United States
- 2 Human Evolution Research Center, Berkeley, United States
ABSTRACTPapionins are a well-studied and morphologically diverse clade of cercopithecid monkeys. Understanding how craniodental morphology varies in this clade has implications for interpreting taxonomic variation in the fossil record and for our understanding of primate evolution. We quantified the phenotypic relationship between facial length and dental proportions in N=314 cercopithecid individuals across 10 species (six papionins, two cercopithecins, and two colobines) using dental ratios MMC (molar module component, ratio of the lengths of the third and first molars) and PMM (premolar-molar module, ratio of the lengths of the second molar and the fourth premolar) and two metrics of facial length: palatal length and prosthion – glabella. Facial length and molar dental proportions are significantly correlated interspecifically across cercopithecids (PGLS, p<0.01), where species with longer faces have relatively longer maxillary and mandibular third molars. With exception of Mandrillus and Macaca, these traits are not intraspecifically correlated in the cercopithecids sampled. Our data demonstrate that prognathic faces evolved convergently at least twice in papionins, with parsimony supporting that Papio/Theropithecus shared a prognathic ancestor after the divergence of Lophocebus. Additionally, this study lends support to the hypothesis that facial reduction and third molar reduction in human evolution were coordinated and may be the result of pleiotropy alongside changes in diet.
Keywords: dental proportions, Prognathism, Papionini, African fossil record, Allometry
Received: 06 Sep 2024; Accepted: 14 Mar 2025.
Copyright: © 2025 Monson and Brasil. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Tesla A Monson, Western Washington University, Bellingham, United States
Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.