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Estimating Taxonomic Diversity Using Centrum Growth Profiles And Stinger Morphology Of 36 Million Year Old Stingrays From North Dakota, Persia S. Tillman
Estimating Taxonomic Diversity Using Centrum Growth Profiles And Stinger Morphology Of 36 Million Year Old Stingrays From North Dakota, Persia S. Tillman
Theses and Dissertations
Stingrays are a diverse and popular group of vertebrates; however, nothing is known about the relationships between growth biology and climate change. Freshwater stingrays once inhabit the United States and Canada during very warm times in the geologic record. No stingray material has been recorded from the northern part of the United States for the last 33 million years. The Earth’s climate cooled from 50 to 33 million year ago when many warm adapted organisms were relegated to warmer, southern latitudes in North America. Today, freshwater stingrays only inhabit subtropical and tropical environments. We are interested in the freshwater stingrays …
Earliest Known Material Of Amia, Bowfin, From The Sentinel Butte Formation (Paleocene), Medora, North Dakota, Abby Grace Moore
Earliest Known Material Of Amia, Bowfin, From The Sentinel Butte Formation (Paleocene), Medora, North Dakota, Abby Grace Moore
Theses and Dissertations
Amia calva is an icon in the field of comparative osteology, yet we have a poor understanding of the evolution of the genus because many fossil amiid bones have gone unidentified. Here we identify new material of the genus, Amia, with evidence of two unidentified species. Previously, the oldest known material identifiable as Amia cf. A. pattersoni, was a specimen from the Paleocene epoch of Alberta, Canada approximately 58 million years in age. Fossils of the two unidentified species of Amia were found in the Sentinel Butte Formation, a geologic formation of Paleocene age (~ 60 million years ago) near …