An Assessment Of Convergence In The Feeding Morphology Of Xiphactinus Audax And Megalops Atlanticus Using Landmark-Based Geometric Morphometrics,
2020
Fort Hays State University
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 …
Exploring The Origins Of Secondary Growth – Two Lower Devonian (Emsian) Euphyllophytes From Gaspé, Canada, And Their Implications For The Evolution Of Secondary Growth,
2020
Humboldt State University
Exploring The Origins Of Secondary Growth – Two Lower Devonian (Emsian) Euphyllophytes From Gaspé, Canada, And Their Implications For The Evolution Of Secondary Growth, Kelly C. Pfeiler
Cal Poly Humboldt theses and projects
Secondary growth from a vascular cambium has a deep fossil record among euphyllophytes, with the earliest occurrence dated to 407 Ma. To date, Armoricaphyton and Franhueberia represent the only instances of secondary growth formally documented in the Early Devonian. Secondary growth diversified rapidly and was present in all major euphyllophyte lineages by the Middle Devonian. Here, I describe two new Early Devonian euphyllophytes exhibiting secondary growth, from the Emsian (c. 400-395 Ma) Battery Point Formation (Québec, Canada): Gmujij tetraxylopteroides gen. et sp. nov. and Perplexa praestigians gen et sp. nov. Both these plants possess mesarch actinosteles with Psilophyton-type …
Manus Descriptions Of An Undescribed Mastodon From The Latest Miocene-Earliest Pliocene Gray Fossil Site, With Comparisons To Other North American Proboscidean Taxa,
2019
East Tennessee State University
Manus Descriptions Of An Undescribed Mastodon From The Latest Miocene-Earliest Pliocene Gray Fossil Site, With Comparisons To Other North American Proboscidean Taxa, Brenna Hart-Farrar
Electronic Theses and Dissertations
A detailed morphological description of a proboscidean manus from the Gray Fossil Site (GFS), Gray, Tennessee is provided. Manus elements from an American mastodon (Mammut americanum), a Britt’s shovel-tusker (Amebelodon britti), an undescribed small gomphothere species, and a Columbian mammoth (Mammuthus columbi) are used for comparisons. Linear measurements indicate proportional differences between the GFS mastodon and other proboscidean taxa ranging from the Hemphillian to Rancholabrean land mammal ages. Possible pathologies are also described. The purpose of this study is to determine how the GFS mastodon differs in manus morphology and locomotion from different proboscidean …
Isotopic Palaeoecology Of Northern Great Plains Bison During The Holocene,
2019
University of North Dakota
Isotopic Palaeoecology Of Northern Great Plains Bison During The Holocene, Gaimi Davies, Blake Mccann, Jay Sturdevant, Fern Swenson, Igor V. Ovtchinnikov
Biology Faculty Publications
Bison (Bison bison) are one of the few terrestrial megafauna to survive the transition into the Holocene and provide a unique opportunity to study a species on a broad spatiotemporal scale. Today, bison are primarily managed in small and isolated herds with little known about their ancestral ecology. We studied the carbon and nitrogen isotopes of Northern Great Plains bison from the terminal Pleistocene and throughout the Holocene to gain insight into their paleoecology. This time span is contemporary with the first population bottleneck experienced by bison at the end of the Pleistocene and includes the second bottleneck …
Comparison Of Extraction Methods For Recovering Ancient Microbial Dna From Paleofeces,
2019
Max Planck Institute for the Science of Human History
Comparison Of Extraction Methods For Recovering Ancient Microbial Dna From Paleofeces, Richard W. Hagan, Courtney A. Hofman, Alexander Hübner, Karl Reinhard, Stephanie Schnorr, Cecil M. Lewis Jr., Krithivasan Sankaranarayanan, Christina G. Warinner
Anthropology Faculty Research
Objectives Paleofeces are valuable to archeologists and evolutionary biologists for their potential to yield health, dietary, and host information. As a rich source of preserved biomolecules from host‐associated microorganisms, they can also provide insights into the recent evolution and changing ecology of the gut microbiome. However, there is currently no standard method for DNA extraction from paleofeces, which combine the dual challenges of complex biological composition and degraded DNA. Due to the scarcity and relatively poor preservation of paleofeces when compared with other archeological remains, it is important to use efficient methods that maximize ancient DNA (aDNA) recovery while also …
Environmental Influences On The Stable Carbon Isotopic Composition Of Devonian And Early Carboniferous Land Plants,
2019
University of Cincinnati
Environmental Influences On The Stable Carbon Isotopic Composition Of Devonian And Early Carboniferous Land Plants, Zhenzhu Wan, Thomas J. Algeo, Patricia G. Gensel, Stephen E. Scheckler, William E. Stein, Walter L. Cressler Iii, Christopher M. Berry, Honghe Xu, Harold D. Rowe, Peter E. Sauer
Earth & Space Sciences Faculty Publications
Systematic analysis of the stable carbon isotopic composition of fossil land plants (δ13Cp) has the potential to offer new insights regarding paleoclimate variation and plant-environment interactions in early terrestrial ecosystems. δ13Cp was measured for 190 fossil plant specimens belonging to 10 genera of Early to Late Devonian age (Archaeopteris, Drepanophycus, Haskinsia, Leclercqia, Pertica, Psilophyton, Rhacophyton, Sawdonia, Tetraxylopteris, and Wattieza) and 2 genera of Early Carboniferous age (Genselia and Rhodeopteridium) collected from sites located mainly in the Appalachian Basin (22–30°S paleolatitude). For the full carbon-isotopic dataset (n=309), δ13Cp ranges from −20.3‰ to −30.5‰ with a mean of −25.5‰, similar to values …
Improving Thorium-230 Determination In Marine Sediment,
2019
SIT Study Abroad
Improving Thorium-230 Determination In Marine Sediment, Katherine Mateos
Independent Study Project (ISP) Collection
Our oceans are intimately related to the climate of our planet. Paleoceanographic approaches aim to study oceans through geologic time to improve models of future climate. Radioisotopes provide us with chemical tracers that help us understand change through time. The uraniumseries decay chain contains thorium-230, a decay product of uranium-234. This isotope is useful to paleoceanographers in its disequilibrium to its parent isotope and in determining the flux of sediment falling to the ocean floor. In order to use 230Th to study oceans, we must be able to accurately measure the amount of thorium in sediment samples. Thorium is found …
Reorganization Of Surviving Mammal Communities After The End-Pleistocene Megafaunal Extinction,
2019
Macquarie University, Australia
Reorganization Of Surviving Mammal Communities After The End-Pleistocene Megafaunal Extinction, Anikó B. Tóth, S. Kathleen Lyons, W. Andrew Barr, Anna K. Behrensmeyer, Jessica L. Blois, René Bobe, Matt Davis, Andrew Du, Jussi T. Eronen, J. Tyler Faith, Danielle Fraser, Nicholas J. Gotelli, Gary R. Graves, Advait M. Jukar, Joshua H. Miller, Silvia Pineda-Munoz, Laura C. Soul, Amelia Villaseñor, John Alroy
School of Biological Sciences: Faculty Publications
Large mammals are at high risk of extinction globally. To understand the consequences of their demise for community assembly, we tracked community structure through the end- Pleistocene megafaunal extinction in North America.We decomposed the effects of biotic and abiotic factors by analyzing co-occurrence within the mutual ranges of species pairs. Although shifting climate drove an increase in niche overlap, co-occurrence decreased, signaling shifts in biotic interactions. Furthermore, the effect of abiotic factors on cooccurrence remained constant over time while the effect of biotic factors decreased. Biotic factors apparently played a key role in continental-scale community assembly before the extinctions. Specifically, …
Assessing Diagenetic Conditions In The Late Triassic Chinle Formation Through Petrographic And Geochemical Analysis Of Phytosaur Teeth,
2019
Southern Methodist University
Assessing Diagenetic Conditions In The Late Triassic Chinle Formation Through Petrographic And Geochemical Analysis Of Phytosaur Teeth, John Fortner
Earth Sciences Theses and Dissertations
The Upper Triassic (Norian; ~227-208 Ma) Chinle Formation of Petrified Forest (PeFo) National Park was deposited during a time of major tectonic breakup and profound changes in atmospheric circulation and faunal compositions. Little has been done however to assess whether surficial paleoenvironmental trends related to deterioration of the Late Triassic Megamonsoon resulted in similar trends in the early diagenetic environment. Here, we use phytosaur tooth dentin as a proxy for diagenetic conditions in the Chinle of PEFO, as its greater susceptibility to chemical alteration relative to enamel makes it an excellent substrate from which changing diagenetic conditions may be studied …
Eutherian Biogeography During The Puercan North American Land Mammal Age (Paleocene, Earliest Danian): Problems And Potential Solutions,
2019
University of New Mexico - Main Campus
Eutherian Biogeography During The Puercan North American Land Mammal Age (Paleocene, Earliest Danian): Problems And Potential Solutions, Jason Sterling Silviria
Earth and Planetary Sciences ETDs
The Puercan North American Land Mammal Age (NALMA) is the earliest major North American terrestrial biochron of the Cenozoic era, spanning roughly the first one million years of the Paleogene period (Paleocene epoch, Danian stage; ~66.04-65.12 Ma). It is typified by the explosive ecomorphological diversification of the mammalian clade Eutheria (particularly our subclade, Placentalia), following the annihilation of non-avian dinosaurs and “archaic” mammal groups during the Cretaceous/Paleogene (K-Pg) mass extinction event. The spatiotemporal mode and tempo of Puercan eutherian diversification has long been the subject of debate, with disagreements over biogeographic zonation. The traditional model – based largely on well-sampled, …
Changes In Mammalian Abundance Through The Eocene–Oligocene Climate Transition In The White River Group Of Nebraska, Usa,
2019
University of Nebraska-Lincoln
Changes In Mammalian Abundance Through The Eocene–Oligocene Climate Transition In The White River Group Of Nebraska, Usa, Robert Gillham
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
Marine records show major cooling during the Eocene-Oligocene Climate Transition (EOCT). Most proxy studies in the White River Group suggest drying across the EOCT, and some suggest cooling. The lower resolution continental record has hindered a direct correlation of the marine climate record to Nebraska. I explore various correlation schemes and what they imply for faunal changes. This study compiles and analyzes data from 4,875 specimens in the University of Nebraska State Museum (UNSM) collection to test the hypothesis that climate change across the Eocene-Oligocene (E-O) boundary caused significant abundance changes in mammals. A series of binning schemes was created. …
An Early Modern Human Outside Africa,
2019
CUNY Lehman College
An Early Modern Human Outside Africa, Eric Delson
Publications and Research
Analysis of two fossils from a Greek cave has shed light on early hominins in Eurasia. One fossil is the earliest known specimen of Homo sapiens found outside Africa; the other is a Neanderthal who lived 40,000 years later.
Constraining The Oxygen Values Of The Late Cretaceous Western Interior Seaway Using Marine Bivalves,
2019
University of New Mexico - Main Campus
Constraining The Oxygen Values Of The Late Cretaceous Western Interior Seaway Using Marine Bivalves, Camille H. Dwyer
Earth and Planetary Sciences ETDs
The Western Interior Seaway (WIS) remains an oceanographic enigma, including its circulation, similarity to the open ocean, and the fidelity of geochemical proxies to reconstruct paleoenvironments. Across the late Campanian and early Maastrichtian I test whether: 1) the WIS had unique δ18OVPDB compared to other marine settings, 2) increasing oceanographic restriction changed the stable isotope composition, and 3) biases, e.g., taxonomy or diagenesis, influenced stable isotope compositions. Results indicate distinct δ18OVPDB in the WIS compared to other marine settings. δ18OVPDB values were stable through time, suggesting insignificant oceanographic restriction and a …
Identifying Dietary And Migratory Patterns Of Illinois Woolly Mammoth Populations Using Isotope Analysis Of Carbon, Oxygen, And Strontium,
2019
Augustana College, Rock Island Illinois
Identifying Dietary And Migratory Patterns Of Illinois Woolly Mammoth Populations Using Isotope Analysis Of Carbon, Oxygen, And Strontium, Matthew Harrington, Chris Widga, Al Wanamaker, Doug Walker
Celebration of Learning
The extinct woolly mammoth (Mammuthus primigenius) ranged from Alaska to the Northeastern Seaboard throughout the Late Pleistocene (100-10 Ka). Although it is recognized that woolly mammoths coincided with and lived in a region heavily influenced by glacial ice sheets, little is known about their dietary or migratory behavior. This study classifies and provides insight into the diet and mobility of Midwestern mammoths by analyzing stable isotopes of carbon, oxygen, and strontium preserved in the tooth enamel of these extinct elephantids. A woolly mammoth tooth from Moline, IL, was bulk-sampled and micromilled to extract the aforementioned isotopes from the …
Behavioral Causes Of Paleopathologies In Cretaceous Edmontosaurus Annectens, Lance Formation, Wyoming,
2019
Loma Linda University
Behavioral Causes Of Paleopathologies In Cretaceous Edmontosaurus Annectens, Lance Formation, Wyoming, Bethania C. T. Siviero
Loma Linda University Electronic Theses, Dissertations & Projects
The study of dinosaur paleopathology has enriched our understanding of their living conditions and their intra- and interspecific behavior. In this study, I examined lesions on bones from a monospecific bone bed (Edmontosaurus annectens) and their implications for E. annectens behavior and the ecological conditions that affected this population. The bone bed contains abundant, mostly well-preserved, scattered, and disarticulated bones, mostly representing an adult population of E. annectens. From the 3013 bones examined, 96 bones displayed genuine pathologies such as: hypertrophic ossification, healed fractures, tooth traces, idiopathic or traumatic shaft angulation, bone fusion, degenerative joint diseases, osteochondrosis, infection, neoplasm, and …
Genetic Sequencing For Measuring Biodiversity In Recent And Ancient Marine Sediments,
2019
Augustana College, Rock Island Illinois
Genetic Sequencing For Measuring Biodiversity In Recent And Ancient Marine Sediments, Lauren Judge
Celebration of Learning
Taxonomic biodiversity, measured by counting the number of species present in a given area, is the most common method of capturing ecosystem biodiversity in recent and ancient environments. While this method is widely accepted, it is limited by poor preservation and identification of many individuals, making it impossible to include every species within an ecosystem and resulting in the loss of some diversity information. To address this issue, we measured the genetic biodiversity (in which species are determined based on sequencing of their DNA) of shallow marine ecosystems by extracting and sequencing the 18S ribosomal gene from bulk carbonate sediment …
Giant Beaver Palaeoecology Inferred From Stable Isotopes,
2019
The University of Western Ontario
Giant Beaver Palaeoecology Inferred From Stable Isotopes, Tessa Plint, Fred J. Longstaffe, Grant Zazula
Earth Sciences Publications
This is a multi-individual (n = 11), stable carbon and nitrogen isotope study of bone collagen (δ13Ccol and δ15Ncol) from the giant beaver (genus Castoroides). The now-extinct giant beaver was once one of the most widespread Pleistocene megafauna in North America. We confirm that Castoroides consumed a diet of predominantly submerged aquatic macrophytes. These dietary preferences rendered the giant beaver highly dependent on wetland habitat for survival. Castoroides’ δ13Ccol and δ15Ncol do not support the hypothesis that the giant beaver consumed trees or woody …
Index,
2019
University of Nebraska - Lincoln
Index
Bulletin of the University of Nebraska State Museum (1924–2023)
No abstract provided.
The Accelerating Influence Of Humans On Mammalian Macroecological Patterns Over The Late Quaternary,
2019
University of New Mexico
The Accelerating Influence Of Humans On Mammalian Macroecological Patterns Over The Late Quaternary, Felisa A. Smith, Rosemary E. Elliott Smith, S. Kathleen Lyons, Jonathan L. Payne, Amelia Villaseñor
School of Biological Sciences: Faculty Publications
The transition of hominins to a largely meat-based diet ~1.8 million years ago led to the exploitation of other mammals for food and resources. As hominins, particularly archaic and modern humans, became increasingly abundant and dispersed across the globe, a temporally and spatially transgressive extinction of large-bodied mammals followed; the degree of selectivity was unprecedented in the Cenozoic fossil record. Today, most remaining large-bodied mammal species are confined to Africa, where they coevolved with hominins. Here, using a comprehensive global dataset of mammal distribution, life history and ecology, we examine the consequences of “body size downgrading” of mammals over the …
Defining The Morphological Quality Of Fossil Footprints. Problems And Principles Of Preservation In Tetrapod Ichnology With Examples From The Palaeozoic To The Present,
2019
Urweltmuseum GEOSKOP/Burg Lichtenberg (Pfalz)
Defining The Morphological Quality Of Fossil Footprints. Problems And Principles Of Preservation In Tetrapod Ichnology With Examples From The Palaeozoic To The Present, Lorenzo Marchetti, Matteo Belvedere, Sebastian Voigt, Hendrik Klein, Diego Castanera, Ignacio Díaz-Martínez, Daniel Marty, Lida Xing, Silverio Feola, Ricardo N. Melchor, James O. Farlow
Department of Earth and Atmospheric Sciences: Faculty Publications
The morphology of fossil footprints is the basis of vertebrate footprint ichnology. However, the processes acting during and after trace fossil registration which are responsible for the final morphology have never been precisely defined, resulting in a dearth of nomenclature. Therefore, we discuss the concepts of ichnotaphonomy, ichnostratinomy, taphonomy, biostratinomy, registration and diagenesis and describe the processes acting on footprint morphology. In order to evaluate the morphological quality of tetrapod footprints, we introduce the concept of morphological preservation, which is related to the morphological quality of footprints (M-preservation, acronym MP), and distinguish it from physical preservation (P-preservation, acronym PP), which …
