Paleobiology Commons^™

Ontogenetic And Adult Shape Variation In The Endocast Of Tapirus: Implications For T. Polkensis From The Gray Fossil Site, Thomas M. Gaetano

Electronic Theses and Dissertations

Endocranial morphology provides evidence of sensory ecology and sociality of extinct vertebrates. The Earliest Pliocene Gray Fossil Site (GFS) of NE Tennessee features a conspicuous dominance of skeletal elements belonging to the dwarf tapir, Tapirus polkensis. Numerous individuals in one fossil locality often suggests gregarious behavior, but sociality in T. polkensis contradicts behavior documented for extant Tapirus species. I test T. polkensis for variation in sensory and social ecology using computed tomography and 3D digital endocasts from an ontogenetic sequence. I compare the T. polkensis endocasts with extant Tapirus species using Encephalization Quotients (EQs) and 3D geometric morphometrics. Results …

A Tale Of Two Species: Black-Tailed And White-Tailed Prairie Dog Biogeography From The Last Interglacial To 2070, April Dawn Bledsoe

Electronic Theses and Dissertations

Ecological niche models (ENMs) were created for White-tailed and Black-tailed prairie dogs and projected into the Last Interglacial (LI), the Last Glacial Maximum (LGM), and mid-Holocene (mid-H) to discern possible past suitable habitat for both species. Additionally, ENMs were projected into the future year 2070 representative concentration pathways (RCPs) 2.6 and 8.5 to discern how climate change may affect future habitat suitability. Kernel density estimations, minimum convex polygons, and median distribution centers of White-tailed and Black-tailed occurrence records were examined between time-periods to discern the effects of anthropogenic westward expansion on both species’ distributions. Current ENMs were constructed from commonly …

Encephalization In Commensal Raccoons: A Unique Test Of The Cognitive Buffer Hypothesis, Peter M. Anderson

Electronic Theses and Dissertations

This study investigated selective pressures associated with encephalization in mammals and discussed broader implications. Relative brain size as measured by EQ (Encephalization Quotient) was compared between ecological categories. Omnivores had higher average EQ than ecological specialists. Since specialists are disproportionately affected by extinction events, selection for ecological generalism is proposed as encephalization mechanism. This mechanism may reinforce the more widely known Cognitive Buffer Hypothesis (CBH)—the idea that possessing relatively large brains has buffered lineages against environmental change. CBH is tested here by comparing EQs in Procyon lotor (raccoon) in urban and rural environments. CBH predicts that raccoons in the most …

Paleoecology Of Columbian And Pygmy Mammoths In Southern Nevada And California: How Terminal Pleistocene Ecosystems Shaped Mammoths At The Individual, Population, And Community Level, Lauren Elizabeth Parry

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this dissertation research is to examine the paleoecology of the Columbian mammoth (Mammuthus columbi) and the pygmy mammoth (M. exilis) on the individual, population, and community level, emphasizing factors internal to their ecosystem that may have contributed to their extinction. I focus specifically on mammoths from Southern Nevada and Southern California to add regional data to the complex and evolving study of North American mammoth paleoecology.

Chapter 2 documents the permitted excavation of a partial mammoth (Mammuthus sp.) between 2016-2018 from late Pleistocene groundwater-discharge deposits near Fairbanks Spring in the Amargosa Valley, Nevada. A preliminary radiocarbon date …

Revision Of The Genus Styxosaurus And Relationships Of The Late Cretaceous Elasmosaurids (Sauropterygia: Plesiosauria) Of The Western Interior Seaway, Elliott Armour Smith

Theses, Dissertations and Capstones

Growing evidence indicates that elasmosaurid plesiosaurs from the Late Cretaceous Western Interior Seaway are members of a single clade, the Styxosaurinae. The styxosaurines are reported to be mostly Campanian in age, and taxa within the clade obtain the longest necks, by number of cervical vertebrae, of any known vertebrate. The styxosaurines are morphologically diverse and include taxa that exhibit a secondary reduction in neck length. Given the evolutionary plasticity of postcranial characters in plesiosaurs in general, and neck length in elasmosaurs, scrutiny of cranial osteology is pertinent to advancing understanding of Western Interior Seaway elasmosaurids. This study finds that an …

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

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, 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 …

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, …

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, …

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.

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 …

Index

Bulletin of the University of Nebraska State Museum

No abstract provided.

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 …

H.B. Bozeman Collection, University Archives And Special Collections, Prescott Memorial Library, Louisiana Tech University

Manuscript Finding Aids

Specimen of petrified palm wood found by Estes B. Bozeman in 1962-63 on the southeast flank of the Sikes Salt Dome, Winn Parish, Louisiana. Palm trees grew in the Winn Parish area 30-40 million years ago during the Tertiary Period of the Cenozoic Era.

Betting & Hierarchy In Paleontology, Leonard Finkelman

Faculty Publications

In his Rock, Bone, and Ruin: An Optimist’s Guide to the Historical Sciences, Adrian Currie argues that historical scientists should be optimistic about success in reconstructing the past on the basis of future research. This optimism follows in part from examples of success in paleontology. I argue that paleontologists’ success in these cases is underwritten by the hierarchical nature of biological information: extinct organisms have extant analogues at various levels of taxonomic, ecological, and physiological hierarchies, and paleontologists are adept at exploiting analogies within one informational hierarchy to infer information in another. On this account, fossils serve the role …

Crossed Tracks: Mesolimulus, Archaeopteryx, And The Nature Of Fossils, Leonard Finkelman

Faculty Publications

Organisms leave a variety of traces in the fossil record. Among these traces, vertebrate and invertebrate paleontologists conventionally recognize a distinction between the remains of an organism’s phenotype (body fossils) and the remains of an organism’s life activities (trace fossils). The same convention recognizes body fossils as biological structures and trace fossils as geological objects. This convention explains some curious practices in the classification, as with the distinction between taxa for trace fossils and for tracemakers. I consider the distinction between “parallel taxonomies,” or parataxonomies, which privileges some kinds of fossil taxa as “natural” and others as “artificial.” The motivations …

Microbiome And Metagenome Of An Anthropogenic Hyperalkaline Slag-Fill Waterway In South Chicago, Illinois, Usa, Jan Ingemar Ohlsson

Graduate Research Theses & Dissertations

The aquifers and waterways around the Lake Calumet area of south Chicago, IL, USA have been affected by a century of intensive industrial waste dumping. Steel slag in particular was used as infilling to claim most of the Calumet Wetlands for industrial and residential development. Since the prohibition and cessation of these disposal activities, a growing body of research has recorded the environmental and health effects of the infill, particularly where interactions between slag minerals and rainwater produces extremely alkaline groundwater (pH ≥13). Atmospheric carbon dioxide interacting with these calcium hydroxide-rich slag fluids produces massive precipitation of a loose, white …

Climatic Range Filling Of North American Trees, Benjamin Seliger

Electronic Theses and Dissertations

Understanding the degree to which species distributions are controlled by climate is crucial for forecasting biodiversity responses to climate change. Climatic equilibrium, when species are found in all places which are climatically suitable, is a fundamental assumption of species distribution models, but there is evidence in support of climate disequilibria in species ranges. Long-lived, sessile organisms such as trees may be especially vulnerable to being outpaced by climate change, and thus prone to disequilibrium. In this dissertation, I tested the degree to which North American trees are in equilibrium with their potential climatic ranges using the ‘range filling’ metric, which …

Belowground Rhizomes In Paleosols: The Hidden Half Of An Early Devonian Vascular Plant, Jinzhuang Xue, Zhenzhen Deng, Pu Huang, Kangjun Huang, Michael J. Benton, Ying Cui

Ying Cui

The colonization of terrestrial environments by rooted vascular plants had far-reaching impacts on the Earth system. However, the belowground structures of early vascular plants are rarely documented, and thus the plant−soil interactions in early terrestrial ecosystems are poorly understood. Here we report the earliest rooted paleosols (fossil soils) in Asia from Early Devonian deposits of Yunnan, China. Plant traces are extensive within the soil and occur as complex network-like structures, which are interpreted as representing long-lived, belowground rhizomes of the basal lycopsid Drepanophycus. The rhizomes produced large clones and helped the plant survive frequent sediment burial in well-drained soils …

Body Size Downgrading Of Mammals Over The Late Quaternary, Felisa A. Smith, Rosemary E. Elliott Smith, S. Kathleen Lyons, Jonathan L. Payne

School of Biological Sciences: Faculty Publications

Since the late Pleistocene, large-bodied mammals have been extirpated from much of Earth. Although all habitable continents once harbored giant mammals, the few remaining species are largely confined to Africa. This decline is coincident with the global expansion of hominins over the late Quaternary. Here, we quantify mammalian extinction selectivity, continental body size distributions, and taxonomic diversity over five time periods spanning the past 125,000 years and stretching approximately 200 years into the future. We demonstrate that size-selective extinction was already under way in the oldest interval and occurred on all continents, within all trophic modes, and across all time …

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 …

Two Post-Glacial Sagebrush Steppe Fire Records At The Wildland-Urban Interface, Eastern Cascades, Washington, Dusty Pilkington

All Master's Theses

Recent increases in large fires in the rapidly developing wildland-urban interface (WUI) areas of central Washington, where development intermixes with wildland fuels, contribute to federal firefighting costs exceeding of $1 billion annually. In addition, cheatgrass (Bromus tectorum) invasion and anthropogenic-caused warming shorten fire return intervals while lengthening fire seasons. These climatic, ecological, economic, and social factors combine with fuel accumulation resulting from historic fire suppression to threaten lives and property in the WUI. To plan for safe growth in WUI areas, long-term fire histories are needed to expand understanding of past fire regimes in an understudied ecosystem, sagebrush …

Sustainability At Sit: A Look At The Past, A Plan For The Future, Taliesin Haugh

Capstone Collection

Climate change threatens our world and way of life. Intelligent development and investment could mitigate the worst threats of climate change, while simultaneously providing continuous growth for the global economy. The New Climate Economy proposes efforts to combat this ecological collapse that would result in $30 trillion in new annual economic growth by 2030. Stockholm Resilience Center agrees, giving a framework based on global ecological systems that calls for five critical tasks that can bring growth and stability: Renewable energy

Sustainable local food production

New development models, based on what has worked globally

Reduction of wealth inequity

Education, health, and …

A Redescription Of The Ichnospecies Koreanaornis Anhuiensis (Aves) From The Lower Cretaceous Qiuzhuang Formation At Mingguang City, Anhui Province, China, Li-Da Xing, Yuan-Chao Hu, Jian-Dong Huang, Qing He, Martin G. Lockley, Michael E. Burns, Jun Fang

Research, Publications & Creative Work

The Cretaceous bird trackway originally labeled Aquatilavipes anhuiensis, in 1994, had previously been examined, photographed and replicated, but never described or illustrated in detail. However, it has been part of a widening discussion about the distribution of Aquatilavipes and Koreanaornis in China (and Korea). Here we illustrate and formally describe the holotype in detail and assign it to Koreanaornis (Koreanaornis anhuiensis) as informally proposed by previous authors. We also demonstrate that most authenticated reports of Koreanaornis, including the Anhui occurrence, are from the Lower Cretaceous, not from the Upper Cretaceous as previously reported.

New Genera And Species Of Fossil Marine Amioid Fishes (Actinopterygii, Holostei) From The Late Cretaceous Agoult Locality In Southeastern Morocco, Mark V. H. Wilson, Alison M. Murray, Terry C. Grande

Terry Grande

No abstract provided.

Behavioral Paleoecology Of Lower Cambrian Deposit Foragers: Reinterpreting Looping And Meandering Traces Using Optimal Foraging Theory And Quantitative Analysis, Zachary Andrew Jensen

UNLV Theses, Dissertations, Professional Papers, and Capstones

The early Cambrian was a period of transition during which the seafloor environment was changing from a microbial-mat-dominated environment to a bioturbation-dominated environment. The result was a patchy landscape of variable food resources for foraging burrowers to exploit. Looping trace fossils, such Psammichnites gigas and Taphrhelminthopsis nelsoni, appear in strata worldwide during this transitional period, and the ecological niche they filled is a subject of debate among ichnologists. The objectives of this study are (1) to determine the foraging strategies preserved by looping traces through the application of optimal foraging theory and quantitative analysis, and (2) use those results to …

G:, Taylor Lafe Cantrall

Senior Projects Spring 2017

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

Belowground Rhizomes In Paleosols: The Hidden Half Of An Early Devonian Vascular Plant, Jinzhuang Xue, Zhenzhen Deng, Pu Huang, Kangjun Huang, Michael J. Benton, Ying Cui

Dartmouth Scholarship

The colonization of terrestrial environments by rooted vascular plants had far-reaching impacts on the Earth system. However, the belowground structures of early vascular plants are rarely documented, and thus the plant−soil interactions in early terrestrial ecosystems are poorly understood. Here we report the earliest rooted paleosols (fossil soils) in Asia from Early Devonian deposits of Yunnan, China. Plant traces are extensive within the soil and occur as complex network-like structures, which are interpreted as representing long-lived, belowground rhizomes of the basal lycopsid Drepanophycus. The rhizomes produced large clones and helped the plant survive frequent sediment burial in well-drained soils …

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 …

Testing The Temporal Stability Of The Climate Response Of Tree Species At Norris Dam State Park, Tennessee, U.S.A., Allison Elizabeth Ingram

Masters Theses

Temporal stability of the climate-tree growth relationship means that over time, tree species were responding to a specific climate variable and continue to respond to that variable into the present. The stability of this response is important to test prior to attempting to reconstruct past climate. In this study, I sampled oaks (white oak = Quercus alba L. and chestnut oak = Quercus montana Willd.) and pines (Virginia pine = Pinus virginiana Mill. and shortleaf pine = Pinus echinata Mill.) growing in Norris Dam State Park in eastern Tennessee and tested the temporal stability of these species and their potential …