The American alligator, Alligator mississippiensis, is a large extant archosaur and member of the Order Crocodilia. Crocodilian ontogeny has been studied in great detail, the skull being of particular interest. One aspect of the skull left unstudied is how individual cranial elements change through ontogeny independent of one another. This study observed morphological change in a growth series of 34 specimens of A. mississippiensis from ETSU Vertebrate Paleontology Lab collections. The premaxilla, maxilla, nasal, jugal, frontal, and parietal were analyzed using landmark morphometrics. The frontal, jugal, and parietal showed more allometric growth with the orbits reducing in size posteriorly. The premaxilla, maxilla, and nasal showed more isometric growth. This suggests the common observation that the snout elongates with age is mistaken. The cranium showed allometric growth in very early in life but more isometric growth after that. Unique to this study, the premaxilla showed almost no shape change throughout ontogeny.
| Identifer | oai:union.ndltd.org:ETSU/oai:dc.etsu.edu:etd-3867 |
| Date | 01 May 2015 |
| Creators | Harris, William Henry |
| 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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