Publication Date

2018

Document Type

Dissertation/Thesis

First Advisor

Scherer, Reed P.

Degree Name

M.S. (Master of Science)

Department

Department of Geology and Environmental Geosciences

LCSH

Paleontology||Geobiology||Biometry

Abstract

Since its discovery in 1939, the Late Jurassic, Cleveland-Lloyd Dinosaur Quarry (CLDQ) has been assumed to be a Jurassic predator trap by most visitors to the site. This idea's longevity is due in part to the disproportionately high ratio of carnivores to herbivores (3:1) uncovered from the quarry. However, despite decades of active research on the taphonomy and geochemistry of the deposit, the predator trap hypothesis remains unproven. In order to test whether the quarry has or does not have the characteristics of a predator trap, this study specifically analyzed the population of the quarry's most abundant animal, Allosaurus fragilis. The widely accepted predator trap that is the La Brea Tar Pits (LBTP) of Los Angeles, California was used for comparison. For the most accurate analysis, femora belonging to Allosaurus fragilis from the CLDQ were compared to femora of Canis dirus from the LBTP by their femoral lengths and ratios. Every available bone from each animal was measured to produce as precise an analysis as possible. After all of these values were compiled, they were statistically compared using the Kolmogorov-Smirnov test. Results suggest that the two quarries do not exhibit the same population distribution. However, the same population at LBTP when divided into individual pits, exhibited the same population distribution as the CLDQ. Hence, a Simpson's paradox has been achieved, which is when one trend is observed in separate groups of data but the trend reverses when the data is combined, which means that there is some additional variable that has not yet been considered that is swaying the data. This leads to the conclusion that the quarry is not a predator trap, though in order to resolve the paradox future studies and additional measurements are needed to complete a more thorough analysis.

Comments

Advisors: Reed Scherer.||Committee members: Joseph Peterson; Karen Samonds.||Includes illustrations.||Includes bibliographical references.

Extent

159 pages

Language

eng

Publisher

Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

Media Type

Text

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