© 2018 by Zachary Klukkert

Primate Biomechanics

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 the pattern of stress distribution in CT-scans of monkey skulls were used test alternative hypotheses for the evolution of canine tooth shape in primates (Klukkert 2014;2017).

My doctoral research examined the anatomical diversity of the teeth and jaws in platyrrhine primates. In the course of this work I have modeled the mechanics of these structures to better understand how the differences affect the utility of the jaws in life, and also how the morphology reflects evolutionary processes that lead to the diversity of the radiation today.

A central theme of that work was the effect of food size on the mechanical challenge of feeding. 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.

Selected Publications  [Full CV]

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.