Despite being separated by millions of years of evolution, black bears (Ursus americanus) and brown bears (Ursus arctos) can be difficult to distinguish based on skeletal and dental material alone. Complicating matters, some Late Pleistocene U. americanus are significantly larger in size than their modern relatives, obscuring the identification of the two bears. In the past, fossil bears have been identified based on differences in dental morphology or size. This study used geometric morphometrics to look at overall differences in cranial shape and used step-wise discriminant analysis to identify specific characters that distinguish cranial morphology between black and brown bears. Such differences could prove important in identifying fossil bears when crania are present but teeth are missing. Furthermore, being able to properly identify U. arctos and U. americanus crania is important in understanding evolutionary and ecological distinctions among both fossil and modern bears. Principal components, discriminant, and thin plate spline analyses indicated a clear morphological separation between the crania of U. americanus and U. arctos and highlighted key identifying features including a more convex forehead and a narrower, more elongate rostrum in U. arctos than U. americanus.
| Identifer | oai:union.ndltd.org:ETSU/oai:dc.etsu.edu:etd-4669 |
| Date | 01 May 2017 |
| Creators | Hillesheim, Benjamin James |
| Publisher | Digital Commons @ East Tennessee State University |
| Source Sets | East Tennessee State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Electronic Theses and Dissertations |
| Rights | Copyright by the authors. |
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