Paleobiology Commons^™

Recognition Of Two Potential Warming Events In The Paleocene Terrestrial Record Of North America And Associated Mammalian Responses, Ross Secord, Daniel J. Peppe, Thomas E. Williamson, Caitlin E. Leslie, Stephen L. Brusatte, Andrew G. Flynn

Department of Earth and Atmospheric Sciences: Faculty Publications

Numerous early Cenozoic transient warming events (“hyperthermals”) have been recognized in the marine record, but few have been located in fossiliferous terrestrial strata. Locating warming events is critical for understanding how terrestrial animals and plants responded to past climate change. We recognize two carbon isotope excursions (CIEs) in lower Paleocene (Danian) strata of the San Juan Basin, New Mexico, United States, based on sustained decreases in carbon isotope values in bulk organic carbon. The upper excursion correlates closely with the Latest Danian Event (LDE) hyperthermal, previously known with confidence only from the marine record. We correlate the lower excursion to …

Minerals Rock!: Improving Audience Engagement And Interest In Stem Through Enhancement Of The In-Person And Online Mineral Collection At Ursinus College, Juliette Lyons

Environment and Sustainability Summer Fellows

Museums are a vital source of educational resources for the general public. They provide information on a variety of topics and disciplines and encourage visitors to be excited about and engaged in learning something new. As we work to comprehend key topics such as climate change, it is especially important for the broader public to better understand science, including geology. While the geological collection at Ursinus, Pieces of Earth’s History, is not in a museum, implementing methods that museums use can improve the reception of the collection. Through the application of research gathered through articles, journals, books, and talking with …

Updates To The Caniform Fauna (Carnivora, Caniformia) Of The John Day Formation, Oregon, Usa, John D. Orcutt, Kevin C. Talbott, Michael J. Monroe, Nicholas A. Famoso

Biology Faculty Scholarship

The John Day Formation of central Oregon preserves a diversity of Oligo-Miocene caniform carnivorans, many of which were first described from the formation. However, many historically important specimens lack detailed locality or stratigraphic information, complicating any analysis of faunal change through time. Here, we describe 16 new specimens of caniforms from the John Day Formation, most with precise stratigraphic information. We report multiple specimens of the amphicyonids Daphoenus Leidy, 1853, Paradaphoenus cuspigerus (Cope, 1878), and Temnocyon altigenis (Cope, 1878), all previously known from the formation. We also report the first definitive occurrence of the hesperocyonine canid Osbornodon Wang, 1994 from …

Shallow-Marine Crinoid Genera May Have Been More Resilient Across Permian Extinction Events In Terms Of Richness Than Deep-Marine Crinoid Genera, Amelia C. Kolstad

University Honors Theses

Throughout the Phanerozoic, one of the most successful phyla of marine invertebrates has been Echinodermata. Echinodermata was particularly successful throughout the Paleozoic, with class Crinoidea making up a majority of occurrences. The proportion of echinoderm occurrences that are crinoids declined massively at the end of the Permian and continued to decrease into modern day, never fully recovering. One of the factors thought to have been so important for crinoid success in the Paleozoic and their decreasing success throughout geologic time has been their propensity for success in shallow-marine environments, though crinoids also exist within deep-marine environments. This study seeks to …

Segmented Inner Skull Cavities Of Eothoracosaurus Mississippiensis (Msu 3293), Amy Moe-Hoffman, Renee Clary

Research Data

Dunn-Seiler Museum specimen data:

• Catalog Number: DSM/MSU#3293 HOLOTYPE 
  
• Geographic Locality: Oktibbeha County, MS Rock Hill vicinity 
  
• Geologic Locality: Ripley Formation 
  
• Age: Cretaceous (Maastrichtian)   

Specimen includes Cranium, Mandible, loose teeth, and post-cranial elements.  

1. CT Scan description: The specimen MSU 3293 was scanned at the Mississippi State University College of Veterinary Medicine using a GE LightSpeed VCT (GE Healthcare, Chicago, Illinois, USA; www.gehealthcare.com ) on May 4th 2022, with scan energies of 120kV and 200mA. This produced 1593 images with a slice thickness of 625µm. 
2. 3D models: 3D models of segmented inner skull cavities based on segrmetation of the CT scanned …

The Hitchhiker's Guide To The Host: Fleas And The History Of Pikas In North America, Josh Pletcher

All NMU Master's Theses

Parasite phylogenetics can offer windows into the cryptic evolutionary history of hosts, often highlighting events that are not recorded by the phylogenetics of the host. Pikas (small lagomorphs) host a diverse parasite community comprising endoparasites (e.g., coccidians, nematodes, and cestodes) and ectoparasites (e.g., fleas and mites). Phylogenetic analysis of pika endoparasites has revealed pikas evolved in Asia and colonized North America in two waves, and that contact between these two pika lineages allowed parasites to be transferred from one lineage to another and to survive the extinction of their original host. To uncover these cryptic histories, understanding the biogeography of …

On The Paleontology Of Belize, Alson Ovando

Electronic Theses and Dissertations

Paleontology can be considered an underrepresented and emerging area of science in Belize. A primary aim of this thesis is to provide a background of paleontology in Belize and present the first comprehensive study of Quaternary vertebrate fossils known from the country. Quaternary fossil sites across Belize include caves, rivers, and sinkholes. In addition to reviewing and assessing material from known sites, this thesis presents new information and discoveries that were made while investigating Belize’s Quaternary fossil record. This thesis also includes a geospatial model depicting ecoregions in Belize during the last glacial maximum. Overall, the results presented here demonstrate …

Ontogeny And The Effects Of Perinatal Stress In The First Immature Skeleton Of Teleoceras Aepysoma (Perissodactyla, Rhinocerotidae), Joe Gajewski

Electronic Theses and Dissertations

Recovery of an immature fossil rhinoceros (Teleoceras aepysoma) skeleton (ETMNH 32999) from the Gray Fossil Site in Tennessee offers the first insights into the ontogeny of the species. ETMNH 32999 is interpreted to be a subadult male in an age class equivalent to ~17-20% of potential lifespan. Comparative analyses support the hypothesis that subadults of related taxa are typically ~91% of average adult size in most dimensions. However, certain cranial dimensions are substantially lower than expected in ETMNH 32999, averaging only ~74% of the average conspecific adult. Such departure from typical growth rates is suggested to be attributable …

Mumm Vs. Minium: A Tale Of Two Quarries, Kale Link, Amanda Peng

SACAD: Scholarly Activities

In 2025, a discrepancy was discovered in the field numbers of a selection of mammal fossils, which had been mistakenly catalogued as originating from the Minium Quarry in Graham County, KS instead of the Mumm Quarry in Rawlins County, KS. While both quarries belong to the Ogallala Formation, they demonstrate differing biostratigraphic ages, faunal assemblages, and taphonomic settings. Mumm is Clarendonian aged, while Minium is Hemphillian. To correct this issue, all the Mumm specimens were assigned to an updated locality with more precise geographic and biostratigraphic data.

Mandibular Ecomorphology Of Tylosaurus (Reptilia: Mosasauridae), Andrew I. Price, Amanda Peng

SACAD: Scholarly Activities

The large mosasaur Tylosaurus is known to have been a predator of large marine animals. Performing beam theory analysis, a computational technique that uses linear dimensions of a structure to calculate its resistance to bending, on the mandibles of six Tylosaurus specimens from the Smoky Hill Chalk of Kansas indicates dorsoventral and mediolateral bending strength both increase posteriorly along the mandible. Comparisons with Varanus komodoensis indicate relatively greater mediolateral bending strength mid-dentary in Tylosaurus, suggesting that resisting torsional forces of struggling prey was more important at this landmark in Tylosaurus and that more of its jaw length was used …

Paleo-Environmental Change In Deer Lagoon, Whidbey Island Interpreted From Diatoms And Lithology, Lourdes Garcia

All Master's Theses

Puget Sound is a densely populated, tectonically active area that can be affected by earthquakes from local crustal faults and the Cascadia subduction zone capable of producing abrupt coseismic subsidence. Tidal wetlands are particularly sensitive to abrupt changes because they are depositional environments that reside at sea-level and their lithology and ecological communities are strongly controlled by elevation within the tidal frame. As a result, coseismic subsidence can disrupt established environmental gradients and leave distinguishable signatures preserved within the stratigraphy, like tidal mud directly over peat deposits. These preserved records provide an opportunity to reconstruct past earthquakes and associated relative …

A New Parsimony-Based Method For Reconstructing Sequences Of Developmental Events And Estimating Rates Of Intraspecific Variation, With Applications To Trilobites, Alexander Benjamin Bradley

Graduate Theses, Dissertations, and Problem Reports (ETD)

Ontogenetic Sequence Analysis (OSA) is a method for reconstructing multiple sequences of abrupt phenotypic transformations (developmental events) for sampled populations of any kind of organism. It makes use of cladistic parsimony software to produce a network, or graph, whose vertices represent unique phenotypes at different stages of maturity (“semaphoronts”) and whose edges describe the developmental events occurring between semaphoronts. It is a powerful tool for constraining the range of developmental variation possible for a given species and generating sample statistics capable of identifying both the most common and the outlier ontogenetic sequences. However, OSA has seen little use since its …

New Fossil Mygalomorph Spiders (?Idiopidae, Pycnothelidae) From The Lower Cretaceous Crato Formation Of Brazil, Elis Maria Gomes Santana

Graduate Theses, Dissertations, and Problem Reports (ETD)

The infraorder Mygalomorphae represents one of the earliest-diverging lineages of spiders, but its fossil record remains sparse relative to the modern diversity of the group. This is a reflection of both ecological and preservational biases, such as the predominantly fossorial habits of many mygalomorphs and the strong bias of the spider fossil record toward amber deposits. Compression fossils from rock deposits are therefore especially important for documenting the evolutionary history of the group. Here, two new mygalomorph fossils from the Lower Cretaceous Crato Formation, Araripe Basin (Brazil) are described. The first specimen is tentatively referred to ?Idiopidae based on male …

Overview And Methods Of Molecular Paleontology: A Review, Shelby Touchstone

Williams Honors College, Honors Research Projects

Molecular paleontology—the study of ancient biomolecules preserved in fossils and sediments, including ancient DNA, lipids, and proteins—has motivated researchers since the 1950s, inspiring both scientific inquiry and broader cultural imagination. Think Jurassic Park. This honors thesis presents a comprehensive review of the history, current state, and methods of the field of molecular paleontology. Drawing on peer-reviewed literature and scholarly resources accessed through databases such as EBSCO and Bierce library, this review examines key techniques such as Next Generation Sequencing and amino acid racemization and will go over limitations and controversies in the field. It will also explore potential new …

Late-Surviving New Mexican Dinosaurs Illuminate High End-Cretaceous Diversity And Provinciality, Andrew G. Flynn, Stephen L. Brusatte, Alfio Alessandro Chiarenza, Jorge García-Girón, Adam J. Davis, C. Will Fenley Iv, Caitlin E. Leslie, Ross Secord, Sarah Shelley, Anne Weil, Matthew T. Heizler, Thomas E. Williamson, Daniel J. Peppe

Department of Earth and Atmospheric Sciences: Faculty Publications

It has long been debated whether non-avian dinosaurs went extinct abruptly or gradually at the end-C retaceous (66 million years ago), because their fossil record at this time is mostly limited to northern North America. We constrain a dinosaur-rich unit to the south, the Naashoibito Member in New Mexico, to the very latest Cretaceous (~66.4 to 66.0 million years), preserving some of the last-known non-avian dinosaurs. Ecological modeling shows that North American terrestrial vertebrates maintained high diversity and endemism in the latest Cretaceous and early Paleogene, with bioprovinces shaped by temperature and geography. This counters the notion of a low-diversity …

A Multi-Isotope Investigation Of Mammoth Diet, Habitat, And Movement Patterns In The Central Great Plains, U.S.A., Jacob Mccloskey

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

During the Last Glacial Maximum (LGM), the Great Plains in Nebraska consisted of wooded parklands and grasslands, whereas spruce (Picea) forests, parklands, and steppe grasslands dominated east of the Missouri River. I analyzed bulk carbon (δ¹³C), oxygen (δ¹⁸O), and strontium (⁸⁷Sr/⁸⁶Sr) isotopes from tooth enamel in isolated mammoth (Mammuthus) molars to compare diet and movement patterns in two late Pleistocene assemblages: one in Nebraska (n = 24), and one in western Iowa and Missouri (n = 17). Furthermore, I identified a morphometric subset of molars as …

Ediacaran Paleocommunity Structure, Body Size Evolution, And The Rise Of Complex Animals, Matthew Philip Craffey

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

The Ediacaran period (635-538ma) is a key interval in the evolution of life as it records the first macroscopic animal communities. Major extinction pulses appear to have altered the composition of the global marine biosphere between each sub-interval of the Ediacaran Period: the Avalon, White Sea, and Nama assemblage Zones. While considerable attention has been paid to the causes of these extinction pulses, less has been afforded to the consequences of Ediacaran biotic turnover for community organization and function. Moreover, it is unclear how body size - the defining trait of macrofauna - affected the transition between animal groups across …

The Petm: A Window Into Earth's Future Climate, Jacalyn M. Wittmer Malinowski

Climate Change and the Individual, 2025-26

The Paleocene-Eocene Thermal Maximum (PETM) is not just an event that occurred in Earth’s distant past (~55 million years ago) but is a crucial lesson for today’s meteoric climate change. The PETM offers a historical parallel of rapid flux of greenhouse gases into the atmosphere that caused global warming, ocean acidification, dramatic changes in weather, and extinctions. This global warming event was the result of 20,000 years of “rapid” warming (in geological terms) however, we are experiencing rates of warming that are 5-10x higher than PETM levels. We are not experiencing rapid warming today, in comparison to the past, we …

The Human Legacy: Agriculture, Civilizations, Strife, And Pandemics Changing Our Climate, Jacalyn M. Wittmer Malinowski

Climate Change and the Individual, 2025-26

For most of human history, climate has shaped our lives, while our influence on it remained minimal. However, the notion that early humans had no measurable impact on the climate before industrialization is inaccurate. Early in human history, activities – such as the rise of agriculture, the growth of civilizations, periods of conflict, and pandemics – altered greenhouse gas levels in the atmosphere. These changes contributed to significant periods of climate change long before the burning of fossil fuels set us on the path to today’s global climate crisis.

Enamel Carbon, Oxygen, And Strontium Isotopes Reveal Limited Mobility In An Extinct Rhinoceros At Ashfall Fossil Beds, Nebraska, Usa, Clark T. Ward, Brooke E. Crowley, Ross Secord

Department of Earth and Atmospheric Sciences: Faculty Publications

Ashfall Fossil Beds in Nebraska, USA, was a mid-Miocene (11.86 ± 0.13 Ma) watering-hole that preserved hundreds of herbivores in volcanic ash. The short-legged, barrel-bodied rhinoceros, Teleoceras major (Mammalia; Rhinocerotidae), is abundant at Ashfall (> 100 individuals), leading some researchers to suggest individuals formed large groups, while others have argued they congregated at Ashfall seeking refuge from the ash that ultimately caused their death. Here, we evaluated three types of mobility—natal dispersal of subadults, seasonal migration, and response to natural disaster—using carbon, oxygen, and strontium isotope ratios in tooth enamel from thirteen T. major adult individuals. We bulk and …