iii Acknowledgments v List of Tables ix List of Figures x 1 Introduction 1 2 Bison Phylogeny and Paleoecology 3 3 Carbon and Oxygen Isotope Paleoecology 11 3.1 Carbon Reservoirs in Plants 11 3.2 Oxygen Signatures in Precipitation 12 3.3 Properties of Enamel and Use in Isotopic Studies 13 3.4 Isotopic Signals of Seasonality 16 4 Geologic Setting of Localities 19 4.1 American Falls Reservoir Mid-elevation Fossil Site, American Falls, Idaho ........ 19 4.2 Ziegler Reservoir High-elevation Fossil Site, Snowmass, Colorado 20 4.3 Diamond Valley Lake Reservoir Low-elevation Fossil Site, Hemet, California .... 21 5 Methodology 23 6 Results and Interpretation 26 6.1 American Falls Formation Results 27 6.2 American Falls Formation Interpretation 32 6.3 Snowmastodon Results 34 6.4 Snowmastodon Interpretation 40 6.5 Diamond Valley Lake Results 41 6.6 Diamond Valley Lake Interpretation 46

/pdf/stable-isotope-analysis-of-bison-latifrons-and-4732fy38fp.pdf

Pleistocene Mammals of North America

Stable Isotope Analysis of Bison latifrons and Paleoecological Inferences

Author(s): Cahill, James Andrew | Advisor(s): Shapiro, Beth | Abstract: The concept of the species has traditionally been the principal unit for the classification of the diversity of life. Although the conceptual and legal relevance of the idea of species is profound and wide ranging it is also increasingly evident that the concept of species is a significant oversimplification of the complex processes at work in nature. The growing body of evidence from genomic data, and other sources, indicates that interspecific hybridization plays a much more substantial role in evolution than had previously been appreciated and that speciation, the formation of new species, is likely a more gradual process than had been appreciated. In my dissertation work, I have applied whole genome sequencing and ancient DNA based techniques to examine the evolutionary relationship of two closely related species, polar bears (Ursus maritimus) and brown bears (Ursus arctos), which occupy substantially different ecological niches. This work is presented in a series of three papers that have contributed to reshaping scientific understanding of the relatedness of polar bears and brown bears and suggest that climate changes can profoundly impact the frequency of hybridization between these two species. I have also contributed to method development – in a fourth paper my coauthors and I developed a novel application of existing analysis tools to estimate the end point of the speciation process, the time at which all gene flow has ceased, from genomic data. Finally, in collaboration with my co-first author Axel Barlow and colleagues, I have examined the evolutionary relationship between polar and brown bears and their closest extinct relatives, the cave bears, which has revealed previously undocumented admixture between cave bears and brown bears and provides insights into the extent of diversity within the paleo-species groups of cave bear.

Investigating the Causes and Consequences of Admixture between Polar Bears and Brown Bears using Ancient and Modern Genomes

F eeling much older than my 42 years, I sank to my knees in snow as we crossed a gully and climbed towards the top of the plateau. Gasping for breath, I forced myself to speed up just so I could move one step ahead of the man beside me, Russia’s premier living tiger expert, Dimitri Pikinov. Dimitri grunted, lengthened his stride, and moved ahead of me again, never taking his eyes off the ground while he scanned intently for the telltale tracks or sign of the animal we were there to find. I smiled to myself, pleased I had at least elicited a grunt, then planned my next attack when we hit a downhill slope. It was a game that both of us played, while pretending we were not. Though I had no expectation of outpacing Dimitri on his home turf and in sub-zero weather, the physical challenge and the competition with a man I respected was exhilarating. I was giving him a run for his money, of that I was sure. The voices drifting downwind from behind us were our fellow cat experts, Drs. Howard Quigley and Dale Miquelle, who were quietly amused at this test of wills between Dimitri and myself that started with our first meeting in Vladivostok and had continued into the wintry cold of the Russian Far East. It was primal. Two middle-aged, type-A personalities, pounding their chests.

The Pleistocene Jaguar Corridor

background

A Quantitative analysis of European Horses from Pleistocene to Holocene

Remains of at least six individuals of Harlan's muskox {Bootherium bombifrons = Symbos cavifrons) are reported from five Indiana localities. One partial male cranium was dis- covered in 1938 during water main construction in Muncie, Delaware County, but only recently has been acquired for the State Museum collection. Another partial male cranium was recovered in 1987 from a Madison County peat deposit. Sand and gravel pits in Clark and Gibson counties produced the only two portions of female skulls known from Indiana. Associated remains of two individuals, consisting of isolated teeth, podial elements, and fragments of various other elements were found deep within King Leo Pit Cave, Harrison County, approximately 77 m from an old entrance that is now closed. The microfauna associated with the King Leo muskoxen contains at least twenty-six taxa, including such northern species as the heather vole (Phenacomys intermedins) , southern red-backed vole {Clethrionomys gapperi), and fisher (Martes pennanti), and suggests the presence of boreal conifer forest interspersed with more open areas during deposition of the faunal remains in the cave.

/pdf/new-records-of-harlan-s-muskox-bootherium-bombifrons-and-an-2ksl0lzp1b.pdf

Pleistocene Mammals of North America

Citations

Stable Isotope Analysis of Bison latifrons and Paleoecological Inferences

Investigating the Causes and Consequences of Admixture between Polar Bears and Brown Bears using Ancient and Modern Genomes

The Pleistocene Jaguar Corridor

A Quantitative analysis of European Horses from Pleistocene to Holocene

NEW RECORDS OF HARLAN'S MUSKOX (Bootherium bombifrons) AND AN ASSOCIATED FAUNA FROM THE LATE PLEISTOCENE OF INDIANA

Related Papers (5)

The Mammals of North America

Walker's mammals of the world

Mammal Species of the World: A Taxonomic and Geographic Reference

MODELTEST: testing the model of DNA substitution.

Some genetic consequences of ice ages, and their role in divergence and speciation