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Dental Morphology In A Juvenile Mammal From The Late Cretaceous Of South America: Tooth Eruption And Development., Kayla E Newton

Electronic Theses and Dissertations

Meridiolestids are a diverse and distinct clade of Cretaceous–Miocene South American dryolestoid mammals ranging in size from small shrew-sized insectivores to large dog- sized omnivores. Cronopio dentiacutus from the Cenomanian La Buitrera locality, Rio Negro Province, Argentina (Candeleros Fm.) is the oldest and best known of them, represented by skull material and associated jaws. A juvenile skull as attributed to Cronopio dentiacutus, based on tooth size and morphology, was collected from the type locality. The specimen includes the skull and both articulated lower jaws. The fossil is poorly ossified and partially flattened; CT scanning reveals most of the dentition …

Rodent Dental Microwear Texture Analysis As A Proxy For Fine-Scale Paleoenvironment Reconstruction, Jenny H. E. Burgman

Graduate Theses and Dissertations

Dental microwear texture analysis (DMTA) of fossil fauna has become a valuable tool for dietary inference and paleoenvironment reconstruction. Most of this work has utilized larger taxa with larger home ranges. These studies may result in broader-scale habitat inferences that could mask the details of complex mosaic habitats. Rodent DMTA offers an opportunity to work at finer spatial scales because most species have smaller home ranges. Rodents are also keystone species within their ecosystems, abundant, ubiquitous, and found in many fossil deposits. These attributes make them excellent proxies for environmental reconstructions. However, the application of DMTA to rodents remains relatively …

The Effect Of An Historical Geology Course On Students’ Attitudes Towards Science And Their Knowledge Of Deep Time As A Threshold To Their Knowledge Of Evolution, Allan Nolan

Dissertations

In America there exists a conflict between a small group of its citizens and the concept of evolution. Researchers have studied this conflict and the ways in which teachers might approach educational methodologies that not only address evolution in a sensitive manner, but also remain legally acceptable.

This research was designed to address teaching evolution in the context of deep time – the concept that time is vast and that geology and biology operate in a timescale of hundreds of millions to billions of years. In previous peer-reviewed works, it has been stated that deep time acts as a threshold …

Redescription And Phylogenetic Analysis Of The Materials Assigned To The Taxon "Captorhinikos" Chozaensis, Jason Paul Jung

Electronic Theses, Projects, and Dissertations

“Captorhinikos” chozaensis is a multiple-tooth-rowed captorhinid reptile from the Lower Permian Clear Fork Group, undivided formation. Upon re-examination of the materials associated with the species from both the Chicago Field Museum of Natural History, and the Smithsonian United States National Museum, I reaffirm their affinity and collective identity as a valid taxon. “Captorhinikos” chozaensis does not, however, belong with either of the two members of its genus, C. valensis or “C.” parvus, instead occupying its own branch on the phylogenetic tree of the Captorhinidae. This conclusion is based in strong results from a combined phylogenetic parsimony analysis combined with …

The Homology And Phylogeny Of The Diploporita (Blastozoa: Echinodermata), Sarah Lynne Sheffield

Doctoral Dissertations

Evolutionary relationships of extinct echinoderms are poorly understood, especially within stem-bearing blastozoans, a large group of echinoderms with unique respiratory structures and feeding brachioles. They were highly experimental in their body plans and very unlike echinoderms today (e.g., sea urchins). Many of the blastozoan subgroups recognized in recent classifications do not represent clades (natural associations of organisms derived from a single ancestor); they are either grades of organization or groups united by superficially similar features. Consequently, these ‘traditional’ groupings cannot be used to analyze evolutionary questions, such as biogeography or rates of evolution. This problem is highlighted within the diploporitan …

G:, Taylor Lafe Cantrall

Senior Projects Spring 2017

Senior Project submitted to The Division of Languages and Literature of Bard College.

Evolution, Paleoecology, And Paleobiogeography Of The Late Ordovician Brachiopod Fauna Of Laurentia, Colin D. Sproat

Electronic Thesis and Dissertation Repository

During the early Katian (Late Ordovician), the North American craton was being inundated due to a major eustatic sea level rise and regional subsidence associated with the ongoing Taconic orogeny. The Trentonian brachiopod fauna, as a dominant group of the marine shelly benthos at that time, evolved and invaded the expanding epicontinental seas.

Three Trentonian brachiopod lineages were studied to trace their evolution. The Rostricellula-Rhynchotrema-Hiscobeccus lineage was characterized by an increase in shell size, globosity, and frilled lamellae, with Hiscobeccus becoming a prominent component of the Late Ordovician epicontinental brachiopod fauna.

Parastrophina is a widely reported but non-dominant taxon of …

First Major Appearance Of Brachiopod-Dominated Benthic Shelly Communities In The Reef Ecosystem During The Early Silurian, Cale A.C. Gushulak

Electronic Thesis and Dissertation Repository

The early Silurian reefs of the Attawapiskat Formation in the Hudson Bay Basin preserved the oldest record of major invasion of the coral-stromatoporoid skeletal reefs by brachiopods and other marine shelly benthos, providing an excellent opportunity for studying the early evolution, functional morphology, and community organization of the rich and diverse reef-dwelling brachiopods. Biometric and multivariate analysis demonstrate that the reef-dwelling Pentameroides septentrionalis evolved from the level-bottom-dwelling Pentameroides subrectus to develop a larger and more globular shell. The reef-dwelling brachiopods in the paleoequatorial Hudson Bay Basin were more diverse than contemporaneous higher latitude reef-dwelling brachiopod faunas, with ten distinct …

Documenting Mantle And Crustal Contributions To Flood Basalt Magmatism Via Computational Modeling Of The Steens Basalt, Southeast Oregon, Sylvana J. Bendaña

All Master's Theses

Flood basalts are enormous volcanic events with volumes of volcanic cover and intrusive equivalents that are affected by and significantly affect the crust. Steens Basalt represents 31,800 km³ of flood basalt lavas that erupted in eastern Oregon ~16.8 Ma in less than 300,000 years. Analytical data of flows from a 1 km vertical exposure at Steens Mtn. documents time-transgressive changes in composition of two geochemically distinct units: (1) lower Steens, MgO-rich lavas with lower incompatible trace element concentrations and ⁸⁷Sr/⁸⁶Sr, and (2) upper Steens, MgO-poor, with higher incompatible trace element concentrations and ⁸⁷Sr/⁸⁶Sr. …

Molecular Systematics, Historical Biogeography, And Evolution Of Spider Wasps (Hymenoptera: Pompilidae), Juanita Rodriguez

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The study of the diversity and classification of any group of organisms provides a foundation for further scientific studies in ecology, evolution, and conservation. Insects are among the most diverse organisms that inhabit the planet, but knowledge of their diversity and classification is still limited. One understudied group of insects is spider wasps. These are solitary parasitoids that use one spider to lay a single egg. There are approximately 5,000 described species, and many more to be described. Unfortunately, fewer than 10 scientists worldwide study these insects. One reason the group has not been very well studied is the difficulty …

Shape Evolution And Sexual Dimorphism In The Mandible Of The Dire Wolf, Canis Dirus, At Rancho La Brea, Alexandria L. Brannick

Theses, Dissertations and Capstones

The Rancho La Brea tar pits are a classic fossil lagerstätten, famous for the deposition of episodic accumulations of large numbers of fossils over short intervals in the late Pleistocene. I analyzed 157 Canis dirus (dire wolf) hemi-mandibles from Rancho La Brea through a 2D landmark-based morphometric analysis to test for size and shape changes through time. I scored 16 landmarks on each mandible gathered from four pits of different ages: 61/67 (~13-14 thousand years ago [ka]), 13 (~17-18 ka), 2051 (~26 ka), and 91 (~28 ka). Analyses indicate size does change through time, and shares a broad correlation with …

The Trentonian (Late Ordovician) Brachiopod Fauna Of Ontario: Evolution Through A Global Warming Event, Akbar Sohrabi Hashjin

Electronic Thesis and Dissertation Repository

This thesis, which examines the evolution of the Late Ordovician (early Katian) brachiopod fauna of Ontario, consists of two main parts: 1) a case study of the Late Ordovician Rhynchotrema–Hiscobeccus lineage of North America to investigate the morphological variations and evolutionary trends of brachiopod fauna in time and space, 2) the paleobiogeography of early Katian brachiopod fauna to explore their distribution patterns at a global scale and controlling factors.

During the Katian, the North American craton experienced a first-order marine transgression. The early stage of this event in the early Katian (Trentonian, Chatfieldian) was marked by the development …

Paleobiological Assessment Of Controls Underlying Long-Term Diversity Dynamics, Andrés L. Cárdenas

USF Tampa Graduate Theses and Dissertations

Deciphering the factors underlying both long-term patterns of diversity and taxonomic turnover rates (i.e., extinction, and origination) has been one of Paleobiology's major foci for the past three decades. The importance of documenting these components is that they will expand our ability to interpret and model the evolutionary processes underlying those trends, highlight the evolutionary impact of historical events, and contribute to the formulation of robust predictions about the future of global diversity in response to the current anthropologically driven environmental changes. Accordingly, the first part of this study examines the possible occurrence of global marine evolutionary environmental controls into …

Dactyls Reveal Evolutionary Patterns In Decapod Crustaceans, Jeffrey Guy Agnew

LSU Doctoral Dissertations

Because of their high preservation potential and uses in foraging and defense, decapod crustacean dactyls (movable fingers of claws) are potentially excellent test subjects for an ongoing debate concerning the relative importance of top-down (predators) and bottom-up (prey) controls on morphologic diversification and evolution. The utility of dactyls for inferring evolutionary patterns were evaluated using living and subfossil xanthoid crabs sampled from the southeast U.S. Atlantic and Gulf of Mexico coasts, and were used to: (1) distinguish the roles of selection and constraint on dactyl morphology through allometric and shape comparisons in the context of the crab’s phylogenetic relationships and …

Quaternary Evolution Of The Colorado River At Lees Ferry, Arizona, William Scott Cragun

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A well-exposed suite of Colorado River fill terraces preserved at Lees Ferry records the oscillating history of this major river superimposed on its overall downcutting of the Colorado Plateau. Detailed mapping, sedimentology, cross-sectional surveys, and the use of two geochronometers have been used in order to establish a detailed chronostratigraphy for the area. Eight distinct deposits have been identified along the Colorado River (Ml -M7, and S3), and four deposits have been identified along the Paria River (Pl -P4).

Geochronology of six of these deposits using optically stimulated luminescence and cosmogenic ¹⁰Be exposure techniques indicates a long-term average bedrock …

The Evolution From Late Miocene West Salton Detachment Faulting To Cross-Cutting Pleistocene Oblique Strike-Slip Faults In The Sw Salton Trough, Southern California, Alexander N. Steely

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Field studies in the southwest Salton Trough between Yaqui Ridge and Borrego Mountain show that the West Salton detachment fault was active during the Pliocene and may have initiated during the latest Miocene. At Yaqui Ridge dominantly east-directed extension is recorded by slickenlines on the NW-striking detachment fault, and shows that the fault is actually a low-angle dextral oblique strike-slip fault. Crustal inheritance is responsible for the position of the fault at Yaqui Ridge, which reactivates a late Cretaceous reverse-sense mylonite zone at map scale.

Late Miocene to Pliocene basin fill deposits at Borrego Mountain display progressive unconformities, contain detritus …

Quaternary Geology And Landscape Evolution Of Eastern Grand Canyon, Arizona, Matt D. Anders

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Tectonics and drainage evolution are controlling overall landscape incision in eastern Grand Canyon. Superimposed on downcutting are dynamic responses of hillslopes, tributary streams, and the Colorado River to glacial-interglacial climate cycles. Five tributary stream fill terraces have been identified, and luminescence dating indicates aggradation was occurring 50- 34 ka {S3), 12-7 ka (S2), and 5-3.5 ka (S1). Seven Colorado River fill terraces have been identified, and luminescence and U-series dating indicate deposition was occurring 343-322 ka (M5), 151-118 ka (M4), and 71-64 ka (M3).

Aggradation by the Colorado River in eastern Grand Canyon begins during glacial advances and continues into …

Evolution Of A Miocene-Pliocene Low-Angle Normal-Fault System In The Southern Bannock Range, Southeast Idaho, Stephanie M. Carney

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Geologic mapping, basin analysis, and tephrochronologic analysis in the Clifton quadrangle of southeast Idaho indicates that the modern Basin-and-Range topography is only a few million years old and that the bulk of Cenozoic extension was accommodated by slip on an older low-angle normal-fault system, the Bannock detachment system. The detachment system was active between ~12 and < 4 Ma and accommodated ~50 % extension.

Cross-cutting relationships show that the master detachment fault, the Clifton fault, is the youngest low-angle normal fault of the system, was active at a low angle, and has not been rotated to a low-dip angle through time. Map patterns and relationships indicate that the …

A Hydrogeochemical Study Of The Evolution Of The Headwaters Of The Bear River In The Uinta Mountains, Utah, Michael F. Leschin

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The headwaters of the Bear River in the Uinta Mountains of Utah provide a good setting in which to examine the influence of geological materials on stream chemistry. Ionic contributions to the stream-water from soils, vegetation, and the atmosphere generally are sparse enough that they do not mask the geologic contributions. Samples from 37 sites on the four major headwater streams and several minor tributaries were examined geochemically. Data derived from the samples allowed the construction of a hydrogeochemical weathering model specific to the study area. A significant feature of this model is that carbonic acid is the dominant chemical …

Internal Deformation, Evolution, And Fluid Flow In Basement-Involved Thrust Faults, Northwestern Wyoming, James V. Goddard

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

An integrated field, microstructure, fracture statistic , geochemistry, and laboratory permeability study of the East Fork and White Rock fault zones, of similar age and tectonic regime but different structural level and hydrogeologic history, provides detailed information about the internal deformation and fluid flow processes in fault zones. The primary conclusions of this research are: 1) Fault zones can be separated into subzones of protolith, damaged zone , and gouge /cataclasite, based on physical morphology and permeability structure. At deep structural levels, gouge/cataclasite zones are more evolved (thicker with increased grain size reduction) due to strain localization, higher pressure and …

Scholasticism An Intellectual Basis And Unifying Principle Of Modern Science, Alice V. Johnson

Electronic Thesis and Dissertation

No abstract provided.