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2020

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Articles 31 - 42 of 42

Full-Text Articles in Paleontology

Revision Of The Eocene 'Platyrhina' Species From The Bolca Lagerstätte (Italy) Reveals The First Panray (Batomorphii: Zanobatidae) In The Fossil Record, Giuseppe Marramà, Giorgio Carnevale, Kerin M. Claeson, Gavin J P Naylor, Jürgen Kriwet Jan 2020

Revision Of The Eocene 'Platyrhina' Species From The Bolca Lagerstätte (Italy) Reveals The First Panray (Batomorphii: Zanobatidae) In The Fossil Record, Giuseppe Marramà, Giorgio Carnevale, Kerin M. Claeson, Gavin J P Naylor, Jürgen Kriwet

PCOM Scholarly Works

The fossil-Lagerstätte of Bolca (Italy) is well known for the diversity and exquisite preservation of its bony and cartilaginous fishes documenting tropical shallow-water marine environments associated with coral reefs in the western Tethys during the early Eocene. In this study, the taxonomic, systematic and phylogenetic position of two batoid species traditionally assigned to the living thornback ray genus Platyrhina is re-evaluated. †Platyrhina bolcensis Heckel, 1851 is recognized as a separate species of the Platyrhinidae because of its plate-like antorbital cartilage with an irregular outline and a small horn on the nasal capsules. Also, the rostral cartilage does not reach …


Lake Or Estuary? Sedimentary And Benthic Foraminiferal Characterization Of A Gulf Of Mexico Coastal Dune Lake, Kaylyn C. Bellais, Samuel T. Barber, Donald A. Beebe, Murlene W. Clark Jan 2020

Lake Or Estuary? Sedimentary And Benthic Foraminiferal Characterization Of A Gulf Of Mexico Coastal Dune Lake, Kaylyn C. Bellais, Samuel T. Barber, Donald A. Beebe, Murlene W. Clark

Gulf and Caribbean Research

Coastal dune lakes are shallow estuaries located within dune environments that share a permanent or intermittent connection with the sea. Because coastal dune lakes are found in few locations worldwide (e.g. Australia, New Zealand, Florida, etc.) they represent unique environments worthy of protection. However; there is a distinct lack of scientific data related to the function and ecology of coastal dune lakes, especially in the Gulf of Mexico. Therefore, the purpose of this study was to characterize the sedimentology and foraminifera of a representative coastal dune lake in Walton County, FL (i.e. Eastern Lake) and determine whether it shares geologic …


Correlating The Plant Height Of Wheat With Above-Ground Biomass And Crop Yield Using Drone Imagery And Crop Surface Model, A Case Study From Nepal, U. S. Panday, Nawaraj Shrestha, S. Maharjan, A. K. Pratihast, Shahnawaz, K. L. Shrestha, J. Aryal Jan 2020

Correlating The Plant Height Of Wheat With Above-Ground Biomass And Crop Yield Using Drone Imagery And Crop Surface Model, A Case Study From Nepal, U. S. Panday, Nawaraj Shrestha, S. Maharjan, A. K. Pratihast, Shahnawaz, K. L. Shrestha, J. Aryal

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


2019 Nebraska Water Leaders Academy Final Report, M.E. Burbach, R.M. Joeckel, G.S. Matkin Jan 2020

2019 Nebraska Water Leaders Academy Final Report, M.E. Burbach, R.M. Joeckel, G.S. Matkin

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


A Basilosaurid Archaeocete (Cetacea, Pelagiceti) From The Late Eocene Of Oregon, Usa, Mark D. Uhen, David Taylor Jan 2020

A Basilosaurid Archaeocete (Cetacea, Pelagiceti) From The Late Eocene Of Oregon, Usa, Mark D. Uhen, David Taylor

Geology Faculty Publications and Presentations

Background: Basilosaurid archaeocetes are known from the Late Eocene of virtually all coastlines bearing coeval marine rocks except the North Pacific Basin, until now. Here we report on three consecutive posterior thoracic vertebrae of a large, basilosaurid archaeocete from a Late Eocene horizon in the Keasey Formation in Oregon.

Methods: These vertebrae were morphologically and morphometrically compared to other vertebrae of similar age from around the world.

Results: The specimens were determined to be different from all currently named species of fossil cetacean, but most similar to those found in the Gulf Coast region of North America. …


An Assessment Of Convergence In The Feeding Morphology Of Xiphactinus Audax And Megalops Atlanticus Using Landmark-Based Geometric Morphometrics, Edward Chase Shelburne Jan 2020

An Assessment Of Convergence In The Feeding Morphology Of Xiphactinus Audax And Megalops Atlanticus Using Landmark-Based Geometric Morphometrics, Edward Chase Shelburne

Master's Theses or Doctor of Nursing Practice

Convergence is an evolutionary phenomenon wherein distantly related organisms independently develop features or functional adaptations to overcome similar environmental constraints. Historically, convergence among organisms has been speculated or asserted with little rigorous or quantitative investigation. More recent advancements in systematics has allowed for the detection and study of convergence in a phylogenetic context, but this does little to elucidate convergent anatomical features in extinct taxa with poorly understood evolutionary histories. The purpose of this study is to investigate one potentially convergent system—the feeding structure of Xiphactinus audax (Teleostei: Ichthyodectiformes) and Megalops atlanticus (Teleostei: Elopiformes)—using a comparative anatomical approach to assess …


Interpretive Geologic Maps And Cross Sections For Phelps, Kearney, And Adams Counties In Nebraska, Dana Divine, Leslie M. Howard Jan 2020

Interpretive Geologic Maps And Cross Sections For Phelps, Kearney, And Adams Counties In Nebraska, Dana Divine, Leslie M. Howard

Conservation and Survey Division: Faculty and Staff Publications

Data from thousands of test-hole and well logs were interpreted to improve understanding and management of the High Plains aquifer in a three-county study area adjacent to the Big Bend reach of the Platte River. Five principal conclusions resulted from these interpretations: (1) the extent of Neogene Ogallala deposits beneath the study area is different than previously mapped; (2) a large paleovalley incised into Cretaceous bedrock probably cuts across Kearney and Adams counties and may be the course of the ancestral Platte River prior to formation of the Big Bend; (3) a groundwater mound created by irrigation canals artificially raises …


Paleoecological Successions From Shallow-Marine Depositional Environments In Upper Silurian Carbonate Rocks Of Blair County, Pennsylvania, Shadya El-Ashkar Jan 2020

Paleoecological Successions From Shallow-Marine Depositional Environments In Upper Silurian Carbonate Rocks Of Blair County, Pennsylvania, Shadya El-Ashkar

Graduate Theses, Dissertations, and Problem Reports (ETD)

Studies of paleoenvironment and paleoecology are important for investigating relationships between the different environmental and biological variables that influenced biodiversification patterns during the Silurian Period. The mixed carbonate and siliciclastic rocks of the Bloomsburg and Mifflintown Formations in central Pennsylvania represent transitions between carbonate ramp and deltaic settings. The goal of this study was to assess changes in depositional environment and paleoecology of an undescribed Bloomsburg/Mifflintown locality in Bellwood, Pennsylvania. In central Pennsylvania, the interfingered relationship of mixed carbonate and siliciclastic mudstones of the Mifflintown Formation with red fine-grained sandstones and shales of the Bloomsburg Formation presented challenges for deciphering …


Paleoecology Of Bivalves In The Carmel Formation (Middle Jurassic, Bajocian) Of Utah, Evan L. Shadbolt Jan 2020

Paleoecology Of Bivalves In The Carmel Formation (Middle Jurassic, Bajocian) Of Utah, Evan L. Shadbolt

Senior Independent Study Theses

The Carmel Formation of the Middle Jurassic has many mysteries. One of these enigmas is its bivalves. The formation contains the famous oyster balls called ostreoliths. Despite bivalves making up 80 percent of the fossils found in the Carmel Formation, it is not understood how the bivalves lived in this community. The formation is located in southwestern and central Utah. It was deposited when an epicontinental seaway covered most of Utah. The paleoclimate of Utah was hot and dry, which meant that the environment was evaporite heavy. This also meant that the seawater at the southernmost extent of the seaway …


Paleoenvironments Containing Coryphodon In The Fort Union And Willwood Formations Spanning The Paleocene-Eocene Thermal Maximum (Petm), Bighorn Basin, Wyoming, Emily N. Randall Jan 2020

Paleoenvironments Containing Coryphodon In The Fort Union And Willwood Formations Spanning The Paleocene-Eocene Thermal Maximum (Petm), Bighorn Basin, Wyoming, Emily N. Randall

Senior Independent Study Theses

Preliminary data point toward a new hypothesis in which Coryphodon lived in wetter habitats before the Paleocene-Eocene Thermal Maximum (PETM), but was able to adapt to drier habitats in order to survive post-PETM. Early Paleogene nonmarine strata are extensively exposed in the Bighorn Basin of northwestern Wyoming. The Fort Union and Willwood Formations represent alluvial deposition within a Laramide Basin formed from the Paleocene through early Eocene. Therefore, the basin is an ideal place to study the local effects of the PETM, a rapid global warming event that occurred about 55.5 million years ago at the Paleocene–Eocene boundary. During this …


Fossil Fortunes: Regulating Commercial Paleontology & Incentivizing Fossil Discovery, Ashlee A. Paxton-Turner Jan 2020

Fossil Fortunes: Regulating Commercial Paleontology & Incentivizing Fossil Discovery, Ashlee A. Paxton-Turner

Faculty Scholarship

No abstract provided.


Estimating Evolutionary Volatility In A Maximum-Likelihood Framework, Samuel Warren Tybout Jan 2020

Estimating Evolutionary Volatility In A Maximum-Likelihood Framework, Samuel Warren Tybout

Graduate Theses, Dissertations, and Problem Reports (ETD)

Evolutionary volatility is a trait that encompasses a clade’s combined capacity for origination and extinction. High volatility increases extinction risk, and declining global extinction rates are thought to be linked to declining volatility. Despite volatility’s scientific importance, there is no standardized way of measuring it. This study provides a new method, derived from a stochastic birth-death model, of estimating evolutionary volatility from fossil data. Simulations indicate that the method produces accurate and precise estimates for large fossil datasets. Analysis of fossil data for five bivalve families (Lucinidae, Mytilidae, Pectinidae, Pholadomyidae, and Veneridae) indicates that diversity projections made from the estimates …