Halszka Glowacka1, Shannon C McFarlin2,3, Kierstin K Catlett1, Antoine Mudakikwa4, Timothy G Bromage5,6, Michael R Cranfield7, Tara S Stoinski8, Gary T Schwartz1. 1. Institute of Human Origins, School of Human Evolution and Social Change, Arizona State University, Tempe, AZ. 2. Department of Anthropology and Center for the Advanced Study of Human Paleobiology, the George Washington University, DC. 3. Division of Mammals, National Museum of Natural History, Smithsonian Institution, DC. 4. Rwanda Development Board, Tourism and Conservation, Rwanda. 5. Department of Biomaterials and Biomimetics, New York University College of Dentistry, NY. 6. Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, NY. 7. Mountain Gorilla Veterinary Project, University of California Davis, CA. 8. Dian Fossey Gorilla Fund International, Atlanta, GA.
Abstract
OBJECTIVES: Great ape teeth must remain functional over long lifespans. The molars of the most folivorous apes, the mountain gorillas, must maintain shearing function for 40+ years while the animals consume large quantities of mechanically challenging foods. While other folivorous primates experience dental senescence, which compromises their occlusal surfaces and affects their reproductive success as they age, it is unknown whether dental senescence also occurs in mountain gorillas. In this article, we quantified and evaluated how mountain gorilla molars change throughout their long lifespans. MATERIALS AND METHODS: We collected high-resolution replicas of M(1)s (n = 15), M(2)s (n = 13), and M(3)s (n = 11) from a cross-sectional sample of wild mountain gorilla skeletons from the Virunga Volcanoes, ranging in age from 4 to 43 years. We employed dental topographic analyses to track how aspects of occlusal slope, angularity, relief index, and orientation patch count rotated change with age. In addition, we measured the relative length of shearing crests in two- and three-dimensions. RESULTS: Occlusal topography was found to decrease, while 2D relative shearing crest length increased, and 3D relative crest lengths were maintained with age. DISCUSSION: Our findings indicate that shearing function is maintained throughout the long lifetimes of mountain gorillas. Unlike the dental senescence experienced by other folivorous primates, mountain gorillas do not appear to possess senesced molars despite their long lifetimes, mechanically challenging diets, and decreases in occlusal topography with age.
OBJECTIVES: Great ape teeth must remain functional over long lifespans. The molars of the most folivorous apes, the mountain gorillas, must maintain shearing function for 40+ years while the animals consume large quantities of mechanically challenging foods. While other folivorous primates experience dental senescence, which compromises their occlusal surfaces and affects their reproductive success as they age, it is unknown whether dental senescence also occurs in mountain gorillas. In this article, we quantified and evaluated how mountain gorilla molars change throughout their long lifespans. MATERIALS AND METHODS: We collected high-resolution replicas of M(1)s (n = 15), M(2)s (n = 13), and M(3)s (n = 11) from a cross-sectional sample of wild mountain gorilla skeletons from the Virunga Volcanoes, ranging in age from 4 to 43 years. We employed dental topographic analyses to track how aspects of occlusal slope, angularity, relief index, and orientation patch count rotated change with age. In addition, we measured the relative length of shearing crests in two- and three-dimensions. RESULTS: Occlusal topography was found to decrease, while 2D relative shearing crest length increased, and 3D relative crest lengths were maintained with age. DISCUSSION: Our findings indicate that shearing function is maintained throughout the long lifetimes of mountain gorillas. Unlike the dental senescence experienced by other folivorous primates, mountain gorillas do not appear to possess senesced molars despite their long lifetimes, mechanically challenging diets, and decreases in occlusal topography with age.
Authors: Kate McGrath; Amandine B Eriksen; Daniel García-Martínez; Jordi Galbany; Aida Gómez-Robles; Jason S Massey; Lawrence M Fatica; Halszka Glowacka; Keely Arbenz-Smith; Richard Muvunyi; Tara S Stoinski; Michael R Cranfield; Kirsten Gilardi; Chantal Shalukoma; Emmanuel de Merode; Emmanuel Gilissen; Matthew W Tocheri; Shannon C McFarlin; Yann Heuzé Journal: Proc Biol Sci Date: 2022-02-23 Impact factor: 5.530
Authors: Jordi Galbany; Alejandro Romero; Mercedes Mayo-Alesón; Fiacre Itsoma; Beatriz Gamarra; Alejandro Pérez-Pérez; Eric Willaume; Peter M Kappeler; Marie J E Charpentier Journal: PLoS One Date: 2014-04-14 Impact factor: 3.240