Open Access. Powered by Scholars. Published by Universities.®

Paleobiology Commons

Open Access. Powered by Scholars. Published by Universities.®

University of Nebraska - Lincoln

Series

Discipline
Keyword
Publication Year
Publication

Articles 1 - 30 of 162

Full-Text Articles in Paleobiology

Exploring The Relationships Between Mammalian Functional Trait Distributions And Regional Biomes, With Application To Miocene Paleoecology, Devra Hock-Reid Jul 2023

Exploring The Relationships Between Mammalian Functional Trait Distributions And Regional Biomes, With Application To Miocene Paleoecology, Devra Hock-Reid

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Paleoecology relies on understanding relationships between modern animals and their environment. Animals are adapted to niches in their environments, and those physical adaptations, or functional traits, are utilized as proxies to interpret aspects of paleo-ecosystems. Much is known about individual functional traits in extant mammals and their relationship to the environment. Less is known about how multiple functional traits across a community can be utilized for paleoecological interpretations. I develop models utilizing traits in mammalian communities at the biome level. For Chapter 1, I build a model for North American regional biomes using mammalian trait frequencies. I quantify changes in …


Observations On Late Cretaceous Micrampulla (Corethrales, Bacillariophyceae) From The Campbell Plateau (Zealandia), Southwest Pacific Ocean, Kenta Abe, David M. Harwood, Richard W. Jordan Oct 2022

Observations On Late Cretaceous Micrampulla (Corethrales, Bacillariophyceae) From The Campbell Plateau (Zealandia), Southwest Pacific Ocean, Kenta Abe, David M. Harwood, Richard W. Jordan

Department of Earth and Atmospheric Sciences: Faculty Publications

Late Cretaceous (late Campanian) diatom assemblages from the Campbell Plateau (Zealandia), southwest Pacific Ocean, obtained from Deep Sea Drilling Project (DSDP) Leg 29 Site 275, contain well-preserved specimens of two enigmatic diatom species currently assigned to the genus Ktenodiscus; Micrampulla parvula originally described from the Maastrichtian-age Moreno Shale, California, and Pterotheca cretacea from DSDP Site 275. In general, the two species share a number of common features with modern Corethron (domed valves, probable heterovalvate frustules, T-shaped serrated articulated spines, marginal sockets), but differ in the location of the sockets (i.e. vertically at the base of the valve dome and …


Male Mastodon Landscape Use Changed With Maturation (Late Pleistocene, North America), Joshua H. Miller, Daniel C. Fisher, Brooke E. Crowley, Ross Secord, Bledar A. Konomi Jan 2022

Male Mastodon Landscape Use Changed With Maturation (Late Pleistocene, North America), Joshua H. Miller, Daniel C. Fisher, Brooke E. Crowley, Ross Secord, Bledar A. Konomi

Department of Earth and Atmospheric Sciences: Faculty Publications

Under harsh Pleistocene climates, migration and other forms of seasonally patterned landscape use were likely critical for reproductive success of mastodons (Mammut americanum) and other megafauna. However, little is known about how their geographic ranges and mobility fluctuated seasonally or changed with sexual maturity. We used a spatially explicit movement model that coupled strontium and oxygen isotopes from two serially sampled intervals (5+ adolescent years and 3+ adult years) in a male mastodon tusk to test for changes in landscape use associated with maturation and reproductive phenology. The mastodon’s early adolescent home range was geographically restricted, with no evidence of …


The Sensitivity Of Neotoma To Climate Change And Biodiversity Loss Over The Late Quaternary, Catalina P. Tomé, S. Kathleen Lyons, Seth D. Newsome, Felisa A. Smith Jun 2021

The Sensitivity Of Neotoma To Climate Change And Biodiversity Loss Over The Late Quaternary, Catalina P. Tomé, S. Kathleen Lyons, Seth D. Newsome, Felisa A. Smith

School of Biological Sciences: Faculty Publications

The late Quaternary in North America was marked by highly variable climate and considerable biodiversity loss including a megafaunal extinction event at the terminal Pleistocene. Here, we focus on changes in body size and diet in Neotoma (woodrats) in response to these ecological perturbations using the fossil record from the Edwards Plateau (Texas) across the past 20,000 years. Body mass was estimated using measurements of fossil teeth and diet was quantified using stable isotope analysis of carbon and nitrogen from fossil bone collagen. Prior to ca. 7,000 cal yr BP, maximum mass was positively correlated to precipitation and negatively correlated …


Our Past Creates Our Present: A Brief Overview Of Racism And Colonialism In Western Paleontology, Pedro M. Monarrez, Joshua B. Zimmt, Annaka M. Clement, William Gearty, John J. Jacisin Iii, Kelsey M. Jenkins, Kristopher Mm. Kusnerik, Carmi Milagros Thompson, Ashley W. Poust, Selina V. Robson, Judith A. Sclafani, Kelsey T. Stilson, Shamindri D. Tennakoon Jan 2021

Our Past Creates Our Present: A Brief Overview Of Racism And Colonialism In Western Paleontology, Pedro M. Monarrez, Joshua B. Zimmt, Annaka M. Clement, William Gearty, John J. Jacisin Iii, Kelsey M. Jenkins, Kristopher Mm. Kusnerik, Carmi Milagros Thompson, Ashley W. Poust, Selina V. Robson, Judith A. Sclafani, Kelsey T. Stilson, Shamindri D. Tennakoon

School of Biological Sciences: Faculty Publications

As practitioners of a historical science, paleontologists and geoscientists are well versed in the idea that the ability to understand and to anticipate the future relies upon our collective knowledge of the past. Despite this understanding, the fundamental role that the history of paleontology and the geosciences plays in shaping the structure and culture of our disciplines is seldom recognized and therefore not acted upon sufficiently. Here, we present a brief review of the history of paleontology and geology in Western countries, with a particular focus on North America since the 1800s. Western paleontology and geology are intertwined with systematic …


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 Sep 2019

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, …


Changes In Mammalian Abundance Through The Eocene-Oligocene Climate Transition In The White River Group Of Nebraska, Usa, Robert Gillham Jul 2019

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. …


Index Apr 2019

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 Mar 2019

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, 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 Jan 2019

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 …


Diatom-Inferred Records Of Paleolimnological Variability And Continental Hydrothermal Activity In Yellowstone National Park, Usa, Sabrina Brown Jan 2019

Diatom-Inferred Records Of Paleolimnological Variability And Continental Hydrothermal Activity In Yellowstone National Park, Usa, Sabrina Brown

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Fossil diatoms were used to reconstruct paleoclimatic and hydrothermal conditions in Yellowstone National Park. First, an extensive literature review summarizes the current state of knowledge about eukaryotic organisms characteristic of continental hydrothermal environments. Eukaryotes in hydrothermal systems can live at extremes of acidity (pH 9.0), and at moderately high temperatures (<62 >C). Silicate and carbonate precipitation in continental hydrothermal environments is mediated by eukaryotic organisms, which are important members of biofilm communities.

A case study of alkaline-chloride sinter deposits in Yellowstone Lake and the Upper Geyser Basin inferred in-situ diatom growth rather than post-depositional accumulation of valves settling from …


Body Size Downgrading Of Mammals Over The Late Quaternary, Felisa A. Smith, Rosemary E. Elliott Smith, S. Kathleen Lyons, Jonathan L. Payne Apr 2018

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 …


Review Of The Ends Of The World: Volcanic Apocalypses, Lethal Oceans, And Our Quest To Understand Earth's Past Mass Extinctions, By Peter Brannen, Robert F. Diffendal Jr. Jan 2018

Review Of The Ends Of The World: Volcanic Apocalypses, Lethal Oceans, And Our Quest To Understand Earth's Past Mass Extinctions, By Peter Brannen, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

In his new best-selling book, Peter Brannen, award-winning science writer, takes you on a fascinating trip through the run-up to the end of the Cretaceous extinction event and the K-Pg (Cretaceous/Paleogene) boundary, formerly called the K-T (Cretaceous/Tertiary) boundary.

Brannen interviewed many scientists who studied these events and went on field trips with them to major Cretaceous sites and to those where earlier and later extinction events happened. He presents clear explanations of what is known and not known about all of these events in a largely error-free book. Brannen details the other four big extinction events in geologic history: the …


Middle Miocene Paleoenvironmental Reconstruction Of The Central Great Plains From Stable Carbon Isotopes In Large Mammals, Willow H. Nguy Jul 2017

Middle Miocene Paleoenvironmental Reconstruction Of The Central Great Plains From Stable Carbon Isotopes In Large Mammals, Willow H. Nguy

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Middle Miocene (18-12 Mya) mammalian faunas of the North American Great Plains contained a much higher diversity of apparent browsers than any modern biome. This has been attributed to greater primary productivity, which may have supported greater browser diversity that commonly corresponds with densely vegetated habitats. However, several lines of proxy evidence suggest that open woodlands or savannas dominated middle Miocene biomes; neither of which support many browsers today. Stable carbon isotopes in mammalian herbivore tooth enamel were used to reconstruct vegetation structure of middle Miocene biomes.

Stable carbon isotopes in C3 dominated environments reflect vegetation density and herbivores …


Santonian—Campanian Calcareous Nannofossil Paleobiogeography, Brandi R. Moore Jul 2016

Santonian—Campanian Calcareous Nannofossil Paleobiogeography, Brandi R. Moore

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Calcareous nannofossil abundance data from 11 DSDP/ODP sites were analyzed by multivariate methods to assess the paleoceanographic change that is associated with the Santonian-Campanian boundary transition. Data were divided into Santonian or Campanian age groups based on the presence or absence of the lower Campanian nannofossil species, Aspidolithus parcus parcus. All assemblages are dominated by Watznaueria barnesiae, Micula decussata, and Prediscosphaera intercisa. Analyses determined that the relative abundance of M. decussata generally reflects a change in temperature, with a preference for cool water. Prediscosphaera intercisa appears to have had an inverse abundance relationship with M. decussata, suggesting that …


Reconstructing The Paleoecology And Biogeography Of Rhinoceroses (Mammalia: Rhinocerotidae) In The Great Plains Of North America, Leading Up To Their Extinction In The Early Pliocene, Bian Wang Jul 2016

Reconstructing The Paleoecology And Biogeography Of Rhinoceroses (Mammalia: Rhinocerotidae) In The Great Plains Of North America, Leading Up To Their Extinction In The Early Pliocene, Bian Wang

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Members of the family Rhinocerotidae first appeared in the middle Eocene and were one of most successful mammal groups of the Oligocene and Miocene in North America. Their extinction in the early Pliocene has been attributed to several causes, including cooling climate, an expansion of C4 grasslands, and faunal turnover favoring high-crowned, open habitat-adapted mammalian taxa. This study tests whether the extinction of North American rhinoceroses in the Great Plains was abrupt or gradual by examining changes in their paleogeographic distribution in a series of time-slices through the Barstovian, Clarendonian, and Hemphillian North American land-mammal ages. It further examines …


Constraining Neogene Temperature And Precipitation Histories In The Central Great Plains Using The Fossil Record Of Alligator, Evan Whiting Apr 2016

Constraining Neogene Temperature And Precipitation Histories In The Central Great Plains Using The Fossil Record Of Alligator, Evan Whiting

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Most amphibians and reptiles (excluding birds) are poikilothermic; their internal body temperature varies with that of their external environment. This makes them useful as climate proxies, especially when linked to geographic distributions of ambient climate. I evaluate the utility of the extant crocodylian genus Alligator as a paleoclimate proxy for the Central Great Plains (CGP) using species distribution modeling. Alligator is a readily identifiable taxon with a good CGP fossil record during the Neogene (~23–2.6 Ma). Alligator first appeared in the CGP in the late Eocene (~37 Ma), was absent during most of the Oligocene, reappeared in the early Miocene …


Iron Concretions In The Cretaceous Dakota Formation, Anthony Kohtz, Richard Kettler, David Loope Apr 2016

Iron Concretions In The Cretaceous Dakota Formation, Anthony Kohtz, Richard Kettler, David Loope

UCARE Research Products

The Cretaceous Dakota Formation contains abundant iron oxide concretions. The precursors to the iron concretions are siderite (FeCO3) nodules that formed in a reducing floodplain environment. A variety of concretion morphologies formed when the precursor siderite nodules were dissolved by oxidizing groundwater in a paleoaquifer. Iron-oxidizing bacteria are able to oxidize aqueous Fe(II) to Fe(III) oxy-hydroxide at microaerophilic and neutrophilic conditions. This study investigated these concretions to determine if there was a microbial element in their formation and to characterize the concretion morphologies present in the Dakota. This is important for complete paleoenvironment interpretations and astrobiology pursuits.


Unraveling The Consequences Of The Terminal Pleistocene Megafauna Extinction On Mammal Community Assembly, Felisa A. Smith, Catalina P. Tomé, Emma A. Elliott Smith, S. Kathleen Lyons, Seth D. Newsome, Thomas W. Stafford Jan 2016

Unraveling The Consequences Of The Terminal Pleistocene Megafauna Extinction On Mammal Community Assembly, Felisa A. Smith, Catalina P. Tomé, Emma A. Elliott Smith, S. Kathleen Lyons, Seth D. Newsome, Thomas W. Stafford

School of Biological Sciences: Faculty Publications

Recent studies connecting the decline of large predators and consumers with the disintegration of ecosystems often overlook that this natural experiment already occurred. As recently as 14 ka, tens of millions of large-bodied mammals were widespread across the American continents. Within 1000 yr of the arrival of humans, ∼80% were extinct including all > 600 kg. While the cause of the late Pleistocene (LP) extinction remains contentious, largely overlooked are the ecological consequences of the loss of millions of large-bodied animals. Here, we examine the influence of the LP extinction on a local mammal community. Our study site is Hall’s Cave …


8000 Years Of Environmental Evolution Of Barrier–Lagoon Systems Emplaced In Coastal Embayments (Nw Iberia), Rita González-Villanueva, Marta Pérez-Arlucea, Susana Costas, Roberto Bao, Xose L. Otero, Ronald J. Goble Nov 2015

8000 Years Of Environmental Evolution Of Barrier–Lagoon Systems Emplaced In Coastal Embayments (Nw Iberia), Rita González-Villanueva, Marta Pérez-Arlucea, Susana Costas, Roberto Bao, Xose L. Otero, Ronald J. Goble

Department of Earth and Atmospheric Sciences: Faculty Publications

The rocky and indented coast of NW Iberia is characterized by the presence of highly valuable and vulnerable, small and shallow barrier– lagoon systems structurally controlled. The case study was selected to analyse barrier–lagoon evolution based on detailed sedimentary architecture, chronology, geochemical and biological proxies. The main objective is to test the hypothesis of structural control and the significance at regional scale of any highenergy event recorded. This work is also aimed at identifying general patterns and conceptualizing the formation and evolution of this type of coastal systems. The results allowed us to establish a conceptual model of Holocene evolution …


A New Taeniolabidoid Multituberculate (Mammalia) From The Middle Puercan Of The Nacimiento Formation, New Mexico, And A Revision Of Taeniolabidoid Systematics And Phylogeny, Thomas E. Williamson, Stephen L. Brusatte, Ross Secord, Sarah Shelley Oct 2015

A New Taeniolabidoid Multituberculate (Mammalia) From The Middle Puercan Of The Nacimiento Formation, New Mexico, And A Revision Of Taeniolabidoid Systematics And Phylogeny, Thomas E. Williamson, Stephen L. Brusatte, Ross Secord, Sarah Shelley

Department of Earth and Atmospheric Sciences: Faculty Publications

Multituberculates were amongst the most abundant and taxonomically diverse mammals of the late Mesozoic and the Paleocene, reaching their zenith in diversity and body size in the Paleocene. Taeniolabidoidea, the topic of this paper, includes the largest known multituberculates, which possess highly complex cheek teeth adapted for herbivory. A new specimen from the early Paleocene (middle Puercan; biochron Pu2) of the Nacimiento Formation, New Mexico represents a new large-bodied taeniolabidoid genus and species, Kimbetopsalis simmonsae. A phylogenetic analysis to examine the relationships within Taeniolabidoidea that includes new information from Kimbetopsalis gen. et sp. nov. and gen. nov. and …


Aulacoseira Stevensiae Sp. Nov. (Coscinodiscophyceae, Bacillariophyta), A New Diatom From Ho Ba Bê, Bac Kan Province, Northern Viêt Nam, D. Marie Weide Oct 2015

Aulacoseira Stevensiae Sp. Nov. (Coscinodiscophyceae, Bacillariophyta), A New Diatom From Ho Ba Bê, Bac Kan Province, Northern Viêt Nam, D. Marie Weide

Department of Earth and Atmospheric Sciences: Faculty Publications

A new species of Aulacoseira Thwaites is described from piston core samples from Ho Ba Bê in the karst region of northern Viêt Nam. Although it closely resembles Aulacoaseira subborealis (Nygaard) Denys, Muylaert & Krammer, A. stevensiae Weide sp. nov. is designated a new species based mainly on morphological differences in the spines, including invariably inclined spines that are rounded, differences in the Ringleiste, areola pattern and overall size. Aulacoseira stevensiae is present throughout a core that spans the last 500 years. It was a major component of the diatom community, but the populations have recently decreased, possibly being outcompeted …


Ecology And Morphology Of The Late Miocene Musk Deer, Longirostromeryx Wellsi (Artiodactyla: Moschidae: Blastomerycinae), Katheryn Y. C. Chen Aug 2015

Ecology And Morphology Of The Late Miocene Musk Deer, Longirostromeryx Wellsi (Artiodactyla: Moschidae: Blastomerycinae), Katheryn Y. C. Chen

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Longirostromeryx wellsi, one of the latest surviving members of the extinct clade Blastomerycinae (Artiodactyla: Moschidae), possesses highly derived craniodental morphology that deviates from typical musk deer form. Previous work suggests that the unique anatomy of L. wellsi represents adaptations for occupying open savannas. To test this hypothesis I conduct principal components analysis on five postcranial bones of L. wellsi, comparing them to that of several extant ruminant artiodactyls, which are divided among seven habitat categories. These elements are also compared with the postcrania of other blastomerycines. These analyses indicate that L. wellsi anatomy is most similar to that of other …


Another Possible Source Of Archeological Maize Found In Chaco Canyon, Nm: The Tohatchi Flats Area, Nm, Usa, Deanna Grimstead, Sharon M. Buck, Bradley J. Vierra, Larry V. Benson Jan 2015

Another Possible Source Of Archeological Maize Found In Chaco Canyon, Nm: The Tohatchi Flats Area, Nm, Usa, Deanna Grimstead, Sharon M. Buck, Bradley J. Vierra, Larry V. Benson

United States Geological Survey: Staff Publications

Understanding the linkage and relationship between Chaco Canyon and its residents to surrounding communities has been a primary research question for several decades. This research has focused on identifying the Chacoan road systems, similar architectural designs, and the sourcing of economic and non-economic goods to outlier communities of origin. Extensive fieldwork has been completed to identify potential source regions of Chacoan corncobs, but the San Juan Basin and surrounding regions are vast and many potential agricultural features remain uninvestigated. One such region is the Tohatchi Flats, located near modern day Gallup, New Mexico. This paper uses 87Sr/86Sr …


Aptian To Santonian Foraminiferal Biostratigraphy And Paleoenvironmental Change In The Sverdrup Basin As Revealed At Glacier Fiord, Axel Heiberg Island, Canadian Arctic Archipelago, Claudia J. Schröder-Adams, Jens O. Herrle, Ashton F. Embry, James W. Haggart, Jennifer M. Galloway, Adam T. Pugh, David M. Harwood Nov 2014

Aptian To Santonian Foraminiferal Biostratigraphy And Paleoenvironmental Change In The Sverdrup Basin As Revealed At Glacier Fiord, Axel Heiberg Island, Canadian Arctic Archipelago, Claudia J. Schröder-Adams, Jens O. Herrle, Ashton F. Embry, James W. Haggart, Jennifer M. Galloway, Adam T. Pugh, David M. Harwood

ANDRILL Research and Publications

Exceptional exposures of a High Arctic Cretaceous sedimentary record were studied at Glacier Fiord, Axel Heiberg Island. The succession reveals a complex Aptian to Santonian paleoenvironmental history of the Sverdrup Basin that documents several global events. Foraminiferal faunas in combination with rare macrofossil occurrences permit the distinction of nine zones that facilitate biostratigraphic correlations to other High Arctic locales, the Beaufort Mackenzie Basin and the Western Interior Sea. The depositional environment as exposed in the Christopher, Hassel, Bastion Ridge and Kanguk formations changed frequently from a shelf to a shoreface setting. Most sequence boundaries appear to be conformable where shoaling …


Discovery Of A 240 Million Year Old Nematode Parasite Egg In A Cynodont Coprolite Sheds Light On The Early Origin Of Pinworms In Vertebrates, Jean-Pierre Hugot, Scott Gardner, Victor Borba, Priscilla Araujo, Daniela Leles, Átila Da-Rosa, Juliana Dutra, Luis Fernando Ferreira, Adauto Araújo Nov 2014

Discovery Of A 240 Million Year Old Nematode Parasite Egg In A Cynodont Coprolite Sheds Light On The Early Origin Of Pinworms In Vertebrates, Jean-Pierre Hugot, Scott Gardner, Victor Borba, Priscilla Araujo, Daniela Leles, Átila Da-Rosa, Juliana Dutra, Luis Fernando Ferreira, Adauto Araújo

Harold W. Manter Laboratory of Parasitology: Faculty and Staff Publications

Background: We report the discovery of a nematode parasite egg (Nemata: Oxyurida) from a coprolite closely associated with the remains of several species of Cynodontia, dated to 240 million years old. This finding is particularly significant because this is the oldest record of an oxyurid nematode yet discovered, and because the cynodonts are considered a stem-group of the mammals.

Methods: We extracted material from a fully mineralized coprolite by both scraping the surface, and removing fragments from its interior with clean dental instruments used a single time. A single drop of glycerol from a new vial was added as a …


Laurentian Great Lakes Phytoplankton And Their Water Quality Characteristics, Including A Diatom-Based Model For Paleoreconstruction Of Phosphorus, Euan D. Reavie, Adam J. Heathcote, Victoria L. Shaw Chraïbi Aug 2014

Laurentian Great Lakes Phytoplankton And Their Water Quality Characteristics, Including A Diatom-Based Model For Paleoreconstruction Of Phosphorus, Euan D. Reavie, Adam J. Heathcote, Victoria L. Shaw Chraïbi

Department of Earth and Atmospheric Sciences: Faculty Publications

Recent shifts in water quality and food web characteristics driven by anthropogenic impacts on the Laurentian Great Lakes warranted an examination of pelagic primary producers as tracers of environmental change. The distributions of the 263 common phytoplankton taxa were related to water quality variables to determine taxon-specific responses that may be useful in indicator models. A detailed checklist of taxa and their environmental optima are provided. Multivariate analyses indicated a strong relationship between total phosphorus (TP) and patterns in the diatom assemblages across the Great Lakes. Of the 118 common diatom taxa, 90 (76%) had a directional response along the …


New Insights Into Skeletal Morphology Of The Oldest Known Silicoflagellates : Variramus, Cornua And Gleserocha Gen. Nov. = Nouvelles Connaissances Sur La Morphologie Du Squelette Des Plus Anciennes Silicoflagellés Connus : Variramus, Cornua Et Gleserocha Gen. Nov., Kevin Mccartney, Jakub Witkowski, David M. Harwood Jun 2014

New Insights Into Skeletal Morphology Of The Oldest Known Silicoflagellates : Variramus, Cornua And Gleserocha Gen. Nov. = Nouvelles Connaissances Sur La Morphologie Du Squelette Des Plus Anciennes Silicoflagellés Connus : Variramus, Cornua Et Gleserocha Gen. Nov., Kevin Mccartney, Jakub Witkowski, David M. Harwood

ANDRILL Research and Publications

Two of the oldest known silicoflagellate-bearing sediments, lower Albian at Ocean Drilling Program Site 693 in the Weddell Sea of Antarctica and Santonian in the Devon Island sequence of the Canadian Archipelago, are re-examined with a focus on silicoflagellate genera Variramus, Cornua, and Gleserocha that lack basal rings, a feature appearing during late Santonian/early Campanian time within the genus Corbisema. The extraordinary variability of Variramus aculeifera is studied, and a new genus Gleserocha is proposed for taxa with apical structures made of three struts, but without pikes. This new genus includes previously described Variramus wisei and Cornua …


The Evolution Of Respiratory O2/No Reductases: An Out-Of-The-Phylogenetic-Box Perspective, Anne-Lise Ducluzeau, Barbara Schoepp-Cothenet, Robert Van Lis, Frauke Baymann, Michael J. Russell, Wilfgang Nitschke Jun 2014

The Evolution Of Respiratory O2/No Reductases: An Out-Of-The-Phylogenetic-Box Perspective, Anne-Lise Ducluzeau, Barbara Schoepp-Cothenet, Robert Van Lis, Frauke Baymann, Michael J. Russell, Wilfgang Nitschke

Department of Biochemistry: Faculty Publications

Complex life on our planet crucially depends on strong redox disequilibria afforded by the almost ubiquitous presence of highly oxidizing molecular oxygen. However, the history of O2-levels in the atmosphere is complex and prior to the Great Oxidation Event some 2.3 billion years ago, the amount of O2 in the biosphere is considered to have been extremely low as compared with present-day values. Therefore the evolutionary histories of life and of O2-levels are likely intricately intertwined. The obvious biological proxy for inferring the impact of changing O2-levels on life is the evolutionary history …


Rapid Fluctuations In Mid-Latitude Siliceous Plankton Production During The Middle Eocene Climatic Optimum (Odp Site 1051, Western North Atlantic), Jakub Witkowski, Steven M. Bohaty, Kirsty M. Edgar, David M. Harwood Jan 2014

Rapid Fluctuations In Mid-Latitude Siliceous Plankton Production During The Middle Eocene Climatic Optimum (Odp Site 1051, Western North Atlantic), Jakub Witkowski, Steven M. Bohaty, Kirsty M. Edgar, David M. Harwood

ANDRILL Research and Publications

The Middle Eocene Climatic Optimum (MECO; ~ 40 million years ago [Ma]) is one of the most prominent transient global warming events in the Paleogene. Although the event is well documented in geochemical and isotopic proxy records at many locations, the marine biotic response to the MECO remains poorly constrained. We present new high-resolution, quantitative records of siliceous microplankton assemblages from the MECO interval of Ocean Drilling Program (ODP) Site 1051 in the subtropical western North Atlantic Ocean, which are interpreted in the context of published foraminiferal and bulk carbonate stable isotope (δ18O and δ13C) records. …