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Primate Biomechanics

Monkey jaw muscles excursion

The temporalis and superficial masseter muscles lengthen at different rates as the mandible is depressed, resulting in changes in sum and proportional force. Length was determined by using landmarks on the muscle attachment sites of skulls configured at different gapes (Klukkert, 2018).

Canine tooth models were used to identify how the shape

and size of canine teeth affects the pattern of stress in the jaws. Fracture rates and stress distributions in alveolar tissues modeled from CT-scans were examined to test hypotheses for the evolution of canine tooth shape in primates (Klukkert 2014;2017).

Canine tooth FEA stress strain
Pithecia2_M_Brazil_absess remodeling.jpg

The primary focus of my research is the interplay between functional and phylogenetic influences that shape the teeth and jaws in primates. A central theme of this work is the effect of food size on the mechanical challenge of feeding, i.e., how the dentognathic complex produces and distributes stresses in open-gape configurations. My results show that primates have evolved an array of strategies and tools that correspond with the size and material properties of critical foods. This research extends what is known about the functional significance of the jaw and canine teeth to reveal innovations, constraints, and functional compromises aimed to maximize the capacity of the jaws for low- or high-gape strategies during ingestion.

2023    Cooke SB and Klukkert ZS. Diet, dentition, and jaw shape in Aotus. In Fernandez-Duque, E (Ed). Owl Monkeys.        

            Developments in Primatology: Progress and Prospects. Springer, Cham.

2016    Cooke SB, Gladman JT, Halenar LB, Klukkert ZS, and Rosenberger AL. The paleobiology of the recently extinct  

            platyrrhines of Brazil and the Caribbean. In Ruiz-Garcia M and Shostell JM (Eds.) Phylogeny, Molecular Population

            Genetics, Evolutionary Biology and Conservation of the Neotropical Primates. Nova Science Publishers, Inc.,  

            Hauppauge NY.

2013    Rosenberger AL, Klukkert ZS, Cooke SB, and Rímoli R. Rethinking Antillothrix: the mandible and its implications.      

            American Journal of Primatology, 75(8): 825-836.

2012    Klukkert ZS, Teaford MF, and Ungar PS. A dental topographic analysis of chimpanzees. American Journal of Physical 

            Anthropology 148: 276-284.

Representative Conference Presentations

2019    Klukkert ZS. Functional correlates of jaw shape diversity in platyrrhine sclerocarpic harvesters. American Association of

            Physical Anthropologists, Cleveland, OH, March 2019.

2018    Klukkert ZS. Jaw muscle positions facilitate gape-specific feeding strategies in platyrrhines. American Association of Physical               Anthropologists, Austin, TX, April 2018.

2017    Klukkert ZS. Canine tooth robusticity mitigates stress in the jaw. American Association of Physical Anthropologists,

            New Orleans, LA, April 2017.

2014    Klukkert ZS. Canine bending strength and fracture in durophagous platyrrhines. American Association of Physical

            Anthropologists, Calgary AB, April 2014.  

2012    Klukkert ZS and Harrison T. Jaw shape diversity in platyrrhine sclerocarpic foragers. American Association of Physical

            Anthropologists, Minneapolis MN, April 2012.

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