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Functional Morphology of Mastication in Musteloid Carnivorans

Davis, Jillian S.
http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1405694251

Abstract Details

2014, Doctor of Philosophy (PhD), Ohio University, Biological Sciences (Arts and Sciences).
Masticatory morphology, jaw muscle activity pattern, and kinematics were studied in two species of musteloid carnivorans: the ferret (Mustela putorius furo), a carnivorous mustelid, and the kinkajou (Potos flavus), a frugivorous procyonid. Morphology of the jaw adductors was studied using gross dissection and Lugol's iodine-enhanced microCT scanning, jaw muscle activity patterns were studied using electromyography, and kinematics were studied using XROMM (X-ray Reconstruction of Moving Morphology; Brainerd et al., 2010). These closely-related but dietarily divergent species were used to identify shared characteristics in masticatory form and function among carnivorans and test hypotheses about adaptation and constraint in the masticatory apparatus. For example, although kinkajous are derived from carnivorous ancestors, their frugivorous diet places different mechanical demands on their masticatory apparatus, which may be expected to correlate with differences in form and function. Ferrets and kinkajous were found to have many general similarities in masticatory form and function. For example, both species have general similarities in craniofacial morphology, near-simultaneous activity of all jaw adductor muscles during mastication, and predominantly vertical jaw movements during mastication. However, we also identified some functionally important differences in masticatory form and function in the kinkajou. Kinkajous differ from ferrets morphologically in that have increased the size and mechanical advantage of the masseter muscle at the expense of extremely large gapes, and their cheek teeth are flattened with horizontally-oriented occlusal surfaces, unlike the vertically-oriented occlusion that occurs along the tall shearing cusps of ferret cheek teeth. Additionally, the balancing-side deep masseter of kinkajous was found to reach peak activity slightly later than all other adductors, and this appears to contribute a transverse component to the power stroke of mastication, which may be important for grinding fruits. We also documented the precise hemimandibular movements that take place relative to the temporomandibular and mandibular symphyseal joints in the ferret and propose that although these movements are important for facilitating occlusion in the ferret, they may limit balancing-side muscle recruitment during forceful mastication. Kinkajous have a fused mandibular symphysis that prohibits independent movements of the hemimandibles and exhibit relatively higher balancing-side muscle recruitment. This study provides greater phylogenetic and dietary breadth to the sample of mammals for which mastication has been studied in vivo, and provides a basis for developing more informed hypotheses regarding patterns of adaptation and constraint in the mammalian masticatory apparatus.
Susan Williams, PhD (Advisor)
Lawrence Witmer, PhD (Committee Member)
Audrone Biknevicius, PhD (Committee Member)
Robert Druzinsky, PhD (Committee Member)
Betty Sindelar, PhD (Committee Chair)
234 p.
Anatomy and Physiology; Animals; Biology; Biomechanics; Comparative; Evolution and Development; Morphology; Organismal Biology; Physical Anthropology; Zoology
mastication; morphology; kinkajou; ferret; Carnivora; Potos flavus; Mustela putorius furo; electromyography; motor pattern; XROMM; kinematics; frugivore; carnivore; evolutionary functional morphology

Recommended Citations

Citations

  • Davis, J. S. (2014). Functional Morphology of Mastication in Musteloid Carnivorans [Doctoral dissertation, Ohio University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1405694251

    APA Style (7th edition)

  • Davis, Jillian. Functional Morphology of Mastication in Musteloid Carnivorans. 2014. Ohio University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1405694251.

    MLA Style (8th edition)

  • Davis, Jillian. "Functional Morphology of Mastication in Musteloid Carnivorans." Doctoral dissertation, Ohio University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1405694251

    Chicago Manual of Style (17th edition)

ohiou1405694251
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© 2014, all rights reserved.
This open access ETD is published by Ohio University and OhioLINK.