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Articles 1 - 5 of 5
Full-Text Articles in Paleobiology
Geometric Morphometric Analysis Of Modern Viperid Vertebrae Facilitates Identification Of Fossil Specimens, Lance D. Jessee
Geometric Morphometric Analysis Of Modern Viperid Vertebrae Facilitates Identification Of Fossil Specimens, Lance D. Jessee
Electronic Theses and Dissertations
Snake vertebrae are common in the fossil record, whereas cranial remains are generally fragile and rare. Consequently, vertebrae are the most commonly studied fossil element of snakes. However, identification of snake vertebrae can be problematic due to extensive variation. This study utilizes 2-D geometric morphometrics and canonical variates analysis to 1) reveal variation between genera and species and 2) classify vertebrae of modern and fossil eastern North American Agkistrodon and Crotalus. The results show that vertebrae of Agkistrodon and Crotalus can reliably be classified to genus and species using these methods. Based on the statistical analyses, four of the …
Distinguishing Mustela From Neogale (Mustelidae) Through Both A Qualitative And Quantitative Analysis Of Skull And Tooth Morphology, Ronald W. Peery
Distinguishing Mustela From Neogale (Mustelidae) Through Both A Qualitative And Quantitative Analysis Of Skull And Tooth Morphology, Ronald W. Peery
Electronic Theses and Dissertations
Weasels and mink (Mustela and Neogale) can be difficult to distinguish osteologically due to similarities in morphology, thus suggesting the need for an accurate tool in distinguishing among taxa. This study utilized a combination of character state and stepwise discriminant function (DFA) analyses to examine potential distinguishing features of skull and tooth morphology. Measurements and ratios were collected from all 18 extant musteline species, as well as the extinct Neovison macrodon, Mustela rexroadensis, Mustela meltoni, Mustela gazini, and Mustela jacksoni. Unidentified musteline specimens from the Gray Fossil Site were also included. Results of …
Paleoenvironmental Reconstruction Of Quaternary Saltville, Virginia, Using Ostracode Autecology, Austin Gause
Paleoenvironmental Reconstruction Of Quaternary Saltville, Virginia, Using Ostracode Autecology, Austin Gause
Electronic Theses and Dissertations
The Saltville valley in southwestern Virginia is home to Quaternary localities containing paleontological and archaeological remains. Historically the valley has been mined for salt and the small lakes, ponds and springs along the valley floor have a brackish signature. A preliminary report on the site’s ostracode fauna suggested that the site’s water was not always saline. This study analyzed modern and Quaternary ostracodes to understand the valley’s hydrologic and chemical evolution. Sediments contained primarily freshwater species, including the environmentally sensitive Candona crogmaniana. The presence of Pelocypris tuberculatum and a new Fabaeformiscandona species throughout a vertical section spanning the latest Pleistocene …
Encephalization In Commensal Raccoons: A Unique Test Of The Cognitive Buffer Hypothesis, Peter M. Anderson
Encephalization In Commensal Raccoons: A Unique Test Of The Cognitive Buffer Hypothesis, Peter M. Anderson
Electronic Theses and Dissertations
This study investigated selective pressures associated with encephalization in mammals and discussed broader implications. Relative brain size as measured by EQ (Encephalization Quotient) was compared between ecological categories. Omnivores had higher average EQ than ecological specialists. Since specialists are disproportionately affected by extinction events, selection for ecological generalism is proposed as encephalization mechanism. This mechanism may reinforce the more widely known Cognitive Buffer Hypothesis (CBH)—the idea that possessing relatively large brains has buffered lineages against environmental change. CBH is tested here by comparing EQs in Procyon lotor (raccoon) in urban and rural environments. CBH predicts that raccoons in the most …
A Tale Of Two Species: Black-Tailed And White-Tailed Prairie Dog Biogeography From The Last Interglacial To 2070, April Dawn Bledsoe
A Tale Of Two Species: Black-Tailed And White-Tailed Prairie Dog Biogeography From The Last Interglacial To 2070, April Dawn Bledsoe
Electronic Theses and Dissertations
Ecological niche models (ENMs) were created for White-tailed and Black-tailed prairie dogs and projected into the Last Interglacial (LI), the Last Glacial Maximum (LGM), and mid-Holocene (mid-H) to discern possible past suitable habitat for both species. Additionally, ENMs were projected into the future year 2070 representative concentration pathways (RCPs) 2.6 and 8.5 to discern how climate change may affect future habitat suitability. Kernel density estimations, minimum convex polygons, and median distribution centers of White-tailed and Black-tailed occurrence records were examined between time-periods to discern the effects of anthropogenic westward expansion on both species’ distributions. Current ENMs were constructed from commonly …