The Mio-Pliocene age Gray Fossil Site of northeastern Tennessee has the largest collection of tapir postcranial skeletons in the world. Though representing a single species, a few localized structures show high variability. This paper deals with variation of the first metatarsal, which in tapirs was reduced as an early adaptation for running and then retrofitted to serve as a special origin for flexors and adductors of the proximal phalanges. The first metatarsal connects the medial ankle with a posterior process of the third metatarsal in tapiroids. In Tapirus indicus, T. webbi, and 6 out of 31 T. polkensis feet at Gray, it extends more laterally to articulate with the fourth metatarsal. This condition is too variable for species distinction but is correlated with a decrease in the metatarsophalangeal joint facet, suggesting a mobility reduction likely related to the increased range and feeding strategy seen in extant T. indicus.
| Identifer | oai:union.ndltd.org:ETSU/oai:dc.etsu.edu:etd-2432 |
| Date | 01 May 2011 |
| Creators | Hawkins, Patrick Lawrence |
| Publisher | Digital Commons @ East Tennessee State University |
| Source Sets | East Tennessee State University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Electronic Theses and Dissertations |
| Rights | Copyright by the authors. |
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