Scholarship & Research
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Item Nest site taphonomy of modern archosaurs(Montana State University - Bozeman, College of Letters & Science, 2016) Ferguson, Ashley Lynn; Chairperson, Graduate Committee: David Varricchio; David J. Varricchio, Carlos I. Piña and Frankie D. Jackson were co-authors of the article, 'From eggs to hatchlings: nest site taphonomy of American crocodile (Crocodylus acutus) and broad snouted caiman (Caiman latirostris)' submitted to the journal 'Palaios' which is contained within this thesis.; David J. Varricchio and Alex J. Ferguson were co-authors of the article, 'Nest site taphonomy of colonial ground nesting birds at Bowdoin National Wildlife Refuge' submitted to the journal 'Palaios' which is contained within this thesis.The goal of this thesis is to investigate the taphonomic processes that affect crocodylian and modern bird nesting localities in the hope that they would shed light into the identification of fossil nesting grounds and the interpretation of juvenile developmental stage. This project in particular observed nests of American crocodiles (Crocodylus acutus) at the Turkey Point Power Plant in Homestead, Florida, broad snouted caiman (Caiman latirostris) nests in the Northern Santa Fe and Chaco Provinces of Argentina, and colonial ground nesting birds (American white pelicans, double-crested cormorants, ring-billed and California gulls) at Bowdoin National Wildlife Refuge (BNWR) east of Malta, Montana. A major component of this project is the documentation of potentially preservable components, i.e., specimens (bones, eggshell, etc.) and structures (e.g. nesting traces) that might be represented in the fossil record. This thesis documents the agents and processes influencing bone and egg accumulations and nesting trace preservation across diverse biologies and environments.Item Multivariate analysis of avian and non-avian theropod pedal phalanges(Montana State University - Bozeman, College of Letters & Science, 2008) Kambic, Robert Emmett; Chairperson, Graduate Committee: David VarricchioThe relationship between morphology and behavior in theropods was examined using multivariate analyses performed on a set of linear measurements of pedal non-ungual phalanges in a sample of 132 extant and 13 extinct taxa. Principal component analysis reveals that modern birds with terrestrial lifestyles tend to cluster away from those with raptorial and non-predatory grasping lifestyles although the division is not clean. Most non-avian dinosaurs tend to cluster with terrestrial species although Deinonychus and some Tyrannosaurids cluster with raptorial taxa. Terrestrial taxa tend to have phalanges that are comparatively shorter distally, are relatively wide, and have shallow grooving of the distal trochleae, while grasping taxa show opposing trends. Predatory graspers have proportionately wider phalanges than non-predatory graspers. Discriminant function analysis performs well in distinguishing among species with specialized behavior while taxa with less stereotyped behaviors are harder to classify. Predatory graspers are easily separated from non-predatory graspers. Troodon and Elmisaurus are grouped with terrestrial/cursorial taxa. Tyrannosaurus, Allosaurus, Daspletosaurus, and Albertosaurus are identified as terrestrial/cursorial with some possible predatory grasping ability. Deinonychus and Bambiraptor appear to have more grasping ability than Troodon.