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Full-Text Articles in Paleobiology

Holocene Rice Rats (Genus Oryzomys) From The Upper Mississippi River Drainage Basin, Hugh H. Genoways Jul 2023

Holocene Rice Rats (Genus Oryzomys) From The Upper Mississippi River Drainage Basin, Hugh H. Genoways

Zea E-Books Collection

The expansion and collapse of the geographic range of the Texas rice rat (Oryzomys texensis) in the upper Mississippi River drainage basin at the end of the Holocene was a unique event in North American mammals. In a period of about 4000 years with a point of origin near the American Bottom in Illinois, these small rodents extended their geographic range in a straight-line distance of over 950 km to the west into Nebraska and the same distance to the east into Pennsylvania. Then in less than 400 years this range expansion collapsed back to a point where …


Reconstructing The Ecological Relationships Of Late Cretaceous Antarctic Dinosaurs And How Functional Tooth Morphology Influenced These Relationships, Ian D. Broxson May 2022

Reconstructing The Ecological Relationships Of Late Cretaceous Antarctic Dinosaurs And How Functional Tooth Morphology Influenced These Relationships, Ian D. Broxson

2022 Symposium

The Sandwich Bluff Formation of the James Ross Basin of Antarctica has recently yielded a group of five late Cretaceous dinosaurs that lived contemporaneously with each other, a first for Antarctica. These five dinosaurs include fragmentary remains of two differently sized elasmarian ornithopods, a possible megaraptor, a hadrosaur, and a nodosaur. In this study we will construct a model of the ecological relationships of late Cretaceous Antarctica. Additionally, we will look at what specific factors allowed this group of four herbivores and a carnivore to coexist in a restricted locality and what niches were filled by each species. Methods to …


Terrestrial Soldier Crab (Coenobita Clypeatus, Fabricius 1787) And Cerion Spp. (Röding 1798) Shell Relationship On San Salvador Island, Bahamas, Harley Hunt May 2021

Terrestrial Soldier Crab (Coenobita Clypeatus, Fabricius 1787) And Cerion Spp. (Röding 1798) Shell Relationship On San Salvador Island, Bahamas, Harley Hunt

Biology Theses

The Caribbean terrestrial soldier crab, Coenobita clypeatus(Fabricius 1787), coexist and utilize the shells of numerous species of land and marine gastropods. Soldier crabs rely on gastropod shells for protection as the crabs have a soft abdomen, leaving them vulnerable for predation and desiccation, threatening their survival. This creates a strong pressure to obtain well-fitting shells that provide adequate protection against water loss. Cerion of Röding (1798) shells are one of the most commonly used shells among living colonies of C. clypeatuson San Salvador Island. This study is interested in the frequency of shell use by C. clypeatus crabs …


Holocene Records Of Nebraska Mammals, Hugh H. Genoways Mar 2021

Holocene Records Of Nebraska Mammals, Hugh H. Genoways

Zea E-Books Collection

A survey of the archeological and paleontological literature allowed a compilation of Holocene records of mammals in Nebraska. This survey identified Holocene records from 338 sites in 62 of the 93 Nebraska counties. These counties were located throughout state, but there was a concentration of sites in southwestern Nebraska where there were 27 fossil sites in Frontier County and 22 in Harlan County. Fossils sites were underrepresented in the Sand Hills region. Records of fossil mammals covered the entire Holocene period from 13,000 years ago until AD 1850. A minimum of 57 species (with eight additional species potentially present) representing …


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

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

Master's Theses

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 …