Dissertation/Thesis Abstract

The author has requested that access to this graduate work be delayed until 2020-08-30. After this date, this graduate work will be available on an open access basis.
Comparative Morphology of Cervidae Mandibles with Respect to Diet
by Giacomini, Sarah, M.S., Southern Illinois University at Edwardsville, 2016, 96; 10157505
Abstract (Summary)

The mandible is a complex morphological structure that is made up of a variety of different parts and processes that play a key role in an animal’s development and digestion. It functions to aid in the intake and mastication of food, thus beginning the process of digestion. By studying morphology of the mammalian mandible, further ontogenetic and phylogenetic variation can be observed. (Atchley and Hall, 1991). Previous research alludes to the functional relationship between feeding type and jaw morphology in a number of different omnivorous and carnivorous species. Current research thus far is broad and focuses on a wide number of species from multiple different families. In order to further and more easily understand the relationship for all feeding ecologies, more research needs to be done on herbivorous species. Consequently, the species chosen for the family are from the Cervid family because of their diverse habitats and diets, and also because of their suitability for the study of evolutionary patterns and processes (Cronin, 1991).

This is a comparative study of mandibular morphology between 4 species within the Cervid family which include Odocoileus virginianus (White tail deer), Odocoileus hemionus (Mule Deer), Rangifer tarandus (Caribou) , Cervus elaphus (Elk) and Bison bison (Bison). A total of 21 landmarks each were placed on the medial and lateral side of the mandible, and from there 31 linear distances total were recorded. These linear distances were grouped by region (Ramus and Body) and used to analyze relationships exhibited between species and determine whether they are reflective of diet. Within this study, a sexual dimorphism test was performed on Odocoileus virginianus in order to determine if Cervid species were size dimorphic. Following this test, an interspecies pairwise comparison was conducted in order to study similarities and differences between each species within the different regions of the mandible. A principle component analysis was then performed in order to determine which traits were most often contributing towards the size and shape of the mandible. In order to estimate the amount of bite force exhibited during mastication, mechanical advantage was calculated for each species. Lastly, a discriminate function analysis was used in order to determine if each specimen could be grouped into its given species based off of mandibular traits alone. This study is important for understanding how the mandible functions in the process of digestion.

Indexing (document details)
Advisor: Kohn, Luci
Commitee: Brunkow, Paul, Williams, Jake
School: Southern Illinois University at Edwardsville
Department: Biological Sciences
School Location: United States -- Illinois
Source: MAI 56/01M(E), Masters Abstracts International
Source Type: DISSERTATION
Subjects: Zoology
Keywords: Mandible, Morphology, Ontogenetics
Publication Number: 10157505
ISBN: 9781369125313