Why didn’t abundance, diversity, and geographic distribution protect oreodonts from extinction in Miocene North America?
Claire Cleveland; Pennsylvania State University. Dissertation research.
Artistic reconstruction of Merycoidodon sp. by Mark Marcus (markmarcuson.com) for the Ashfall Fossil Beds State Historical Park & National Natural Landmark, Nebraska
What drives evolution and diversity is a fundamental question. Do environmental factors matter, are only biological interactions important, or is it all just a game of luck in the DNA lottery? Oreodonts represent one of the most extensive extinct mammal collections in North America during one of the most significant environmental and ecological shifts in the Cenozoic. The rich fossil record of oreodonts provides a rare opportunity to empirically test questions like these.
Oreodonts are one of the most abundant, widespread, and diverse mammal groups in middle Cenozoic North America. Yet, creodonts went extinct in the late Miocene while other less abundant groups such as camels and peccaries survived. During the Miocene, the climate cooled and became dryer as open grasslands slowly replaced closed forests. We expect environment to play a significant role in evolution and diversity during these global-scale changes and hypothesize environmental change likely increased selection pressure for grass eaters and animals that could walk efficiently between feeding patches (cursoriality). We expect grazer and cursorial morphologies (quantifiable skeletal forms) to become more widespread among surviving clades. Did oreodonts just not adapt to the changing environment?
Does oreodont morphology and their extinction correlate with grassland expansion in North America’s Central-Western Great Plains?
Claire Cleveland, Mark Patzkowsky, and Russell Graham; Pennsylvania State University. Presented at the 2018 Geological Society of America Annual Meeting in Indianapolis, IN.
ABSTRACT: Oreodonts are one of the most abundant, widespread, and diverse mammal groups in early Neogene North America. Yet, they went extinct in the late Miocene while other less abundant groups such as camels and peccaries survived. As grasslands expanded during the Miocene, open savannas replaced closed forests. This change increased selection for grazing morphologies reflecting a change of diet. As distances between feeding patches increased, efficiency of locomotive morphology (cursoriality) should become more widespread among species of surviving clades. To assess the response of oreodonts to environmental change and their likelihood for extinction, a series of 30 skull attributes and 34 postcranial attributes were measured. Of the 201 individuals, 98 include associated jaw and cranial elements, and 61 include associated skull and limb elements. All skeletal elements have been evaluated for deformation to ensure proportional accuracy in each measurement.
Preliminary results using principal component analysis indicate a trend through time toward grazing morphologies in the anterior skull and limbs. Although no correlation between body size and geologic age is observed, a temporal trend from specialist to generalist traits is correlated with decreasing diversity. Primary trends occur early, in the Oligocene, followed by diffusion into a wider, generalist morphospace in the Miocene. Despite this early shift toward grazing morphologies, oreodonts went extinct at the end of the Miocene.
Future research will investigate the amount and timing of change for the same morphological attributes in camels and peccaries. Then quantitative comparisons with oreodonts can be made to determine whether differences in morphological changes among oreodonts, camels, and peccaries can explain why oreodonts went extinct. Testing for correlation between extinction and changes in environment and morphology in deep time on empirical datasets like oreodonts is fundamental to our understanding of diversity and evolution and essential to developing models to interpret extinction risk in modern ecosystems.
Does the middle Eocene Río Pichileufú flora from Patagonia, Argentina record initial floristic response to global cooling and South American isolation?
Claire Cleveland; Pennsylvania State University. Presented at the 2016 Botanical Society of America Annual Meeting in Savannah, GA and the 2016 Geological Society of America Annual Meeting in Denver, CO.
ABSTRACT: Southern Hemisphere fossil plants indicate a Late Cretaceous and Early Paleogene rainforest biome across much of Gondwana, but global cooling and separation of South America and Australia from Antarctica are linked to significant ecological change during the middle and late Eocene. The Río Pichileufú fossil flora (RP) from Río Negro Province, Argentina offers an exceptional opportunity to observe the earliest stages of floral response to cooling in Patagonia and biogeographic signals of South American isolation. The principal record of Patagonian fossil plants during the Early Eocene Climatic Optimum (EECO) is from Laguna del Hunco (LH) in Chubut Province, Argentina, with an 40Ar/39Ar age of 52.22 (±0.22) Ma. RP has an 40Ar/39Ar age of 47.74 ±0.05 Ma, ca. 3 Ma after the EECO, during cooling and separation of South America from Antarctica. Previous work indicates that although many plant taxa are found at both sites, including the conifers Dacrycarpus and Agathis, RP lacks taxa observed at LH, including the angiosperms Eucalyptus and Gymnostoma. Additionally, taxa previously observed at RP are not represented at LH, including Asteraceae flowers. The 1938 E.W. Berry RP Type and Cohort collection, still represents the most diverse described Cenozoic fossil flora from South America. However, Berry’s collection provides only a qualitative record of RP, and just a fraction of its specimens have received modern paleobotanical treatment.
To prepare for quantitative tests of paleofloral response to cooling and biogeographic change, I begin with a comprehensive update of RP, including consideration of more than 1100 specimens from recent, unbiased RP collections. A project database, developed using FileMaker Pro Advanced v. 14.0.4, provides data management and automated leaf architecture descriptions to assist manuscript preparation for this work. Here, I present new evidence from the combined RP collections, supported by morphotype characterization based on the Manual of Leaf Architecture, 2009. Through future quantitative comparisons of the RP and LH assemblages, I predict that shifts in floral relative abundance will be observed as well as net loss of ancient Gondwanan rainforest associations and net gain of new occurrences.
Complexities of modern leaf morphology, climate proxies and applicability in the fossil record
Claire Cleveland, Jennifer Hargrave, Betsy Bancroft, and R. Matthew Ogburn; Southern Utah University. Presented at the 2014 Ecological Society of America Annual Meeting in Sacramento, CA and the 2014 Geological Society of America Annual Meeting in Vancouver, Canada.
Betula occidentalis stomata under magnification
ABSTRACT: Leaf morphological traits including roundness, toothiness, and stomatal densities have been used as indicators of paleoclimate with some success. However, interpretation of these indicators is complicated by a range of evolutionary and environmental interactions. This research investigates a modern species analogue relevant to taphonomic bias and its implications for further study with application to the fossil record. Betula occidentalis (western water birch) was studied at three sites over an 1100 m elevation gradient in southwestern Utah to observe morphological changes in response to variations in temperatures and CO2 concentrations. Random leaf samples were collected from shrubs growing adjacent to perennial stream channels, thus limiting water stress variability. Leaf samples were analyzed for roundness and toothiness using the ImageJ plugin ObjectJ 1.03p and stomatal densities were calculated across each lamina perpendicular to the midvein. Statistical analyses were completed using R 3.1.0. Results indicate negative correlations between toothiness and elevation (p=0.00004) and stomatal density and elevation (p=0.0002). Conversely, a positive relationship between roundness and elevation (p=0.001) was observed. Due to the responses observed within B. occidentalis and the taphonomic bias in the fossil record for water facultative and obligate species, the complexity and interactions of physiological responses should be considered. Although contrasting results were observed in this study, combinations of continuous morphological traits might provide stronger resolution for paleoenvironmental interpretations.
GSA Annual Meeting 2014: poster.pptx; Senior Thesis.pdf
An illustrated history of plant evolution
Jennifer Hargrave, Claire Cleveland, John S. MacLean, R. Matthew Ogburn; Southern Utah University (December 2014)
This project evolved from a Paleontology class assignment with Dr. Jennifer Hargrave, Southern Utah University. We were challenged to teach a topic to the class that was not covered in lecture. I chose to put together a visual lab that was then adopted by geology and biology professors. The illustrated history is currently being investigated for its effectiveness in classroom teaching. Future directions will include redeveloping the chart format into the style of a phylogenetic tree.
Strain Accommodation in the Footwall of the Ruby’s Inn Thrust Fault, Hillsdale Canyon, Southern Utah
Claire Cleveland, Rhiannon M. Garrard, Devin M. McLemore, Jeff C.E. Yon, Genevieve Kidman, and John S. MacLean; Southern Utah University. Published in The Compass: Earth Science Journal of Sigma Gamma Epsilon: Vol. 86: Iss. 4, Article 2.
Strained petrified wood from the Cretaceous, Wahweap Formation
ABSTRACT: The Rubys Inn thrust fault in southern Utah has produced several styles of deformation in its footwall. This project describes four exceptionally well exposed examples of strain accommodation, including a mountain-scale, ductile footwall drag fold, cataclastic flexural slip between bedding surfaces of differing competencies, plastically deformed petrified wood within the zone of flexural slip, and cataclastic shear expressed as deformation bands. Such examples show how various lithologies can be deformed into a wide array of structures during a single deformation event. Furthermore, some of these structures result in changes in permeability, which are important for those interested in subsurface fluid flow.
Full Text Article.pdf (please note that Claire Cleveland’s contribution to this article is found in the section titled “Strained Petrified Wood.”)
Connecting college students to success: a holistic approach to return on investment
Claire Cleveland, John MacLean, Paul Spruell, and Todd Petersen; Southern Utah University. Presented at the 2013 Southern Utah University College of Science and Engineering Undergraduate Research Symposium.
INTRODUCTION: As the costs and benefits of a college education are increasingly critically evaluated, students are seeking engagement in their field of study that will generate tangible benefits and sustainable value. Recently, Gallup scientists presented five elements of well-being that most directly correlate with perceived success: career, social, financial, physical, and community. By connecting these elements of well-being with the application of Donald Super’s theory of self-concept, metacognition, and self-understanding, students are able to conceptualize the five elements of well-being and define successful outcomes for themselves through the development of authentic self-concepts. With this self-ascribed vision of success and Southern Utah University’s support system of opportunity, students will be able to connect with the value of their education and fully realize their return on investment.
Hosted dialogues, informal meetings, and surveys including more than 25 professors and more than 75 students have provided experiential evidence for and insight into the challenges of this effort. The resulting recommendations are intended to connect students with actionable self-concepts that will generate intrinsic motivation and drive self-directed investigations and developmental success in the student’s chosen field of study.
These incentives apply not only to young adults, but also to midlife career changers. As life spans increase, multiple careers will become increasingly attractive if not demanded by rapidly evolving marketplaces. By attracting these adults into the Southern Utah University community, younger students will benefit from the insights of those who have experienced career and life choices and their associated outcomes. Additionally, Southern Utah University will expand its applicant pool.
The following recommendations are a collection of existing best practices and proposed strategies that support the development of authentic student self-concept and visions of success that drive intrinsic motivation and self-directed investigations uniquely satisfying individual outcomes and allowing students to realize tangible benefits and sustainable value through their Southern Utah University experience.
Insights into the Late Quaternary paleo-environment of northwestern Arizona
Claire E. Cleveland, Terri J. Hildebrand, John S. MacLean, and Jennifer E. Hargrave; Southern Utah University. Published in the Southwestern Naturalist 60:15-20 and presented at the 2013 Botanical Society of America Annual Meeting in New Orleans, LA.
Vertical life zones compiled from current data for the Great Basin and Colorado Plateau regions; known indicators lie along the y-axis for reference.
ABSTRACT: Because of the nature and process of precipitation, tufa deposits offer the potential to serve as sedimentary signatures of hydrology, climate, ecology, and biodiversity in areas otherwise lacking such historic archives. This study investigated a previously undocumented tufa site located in northwestern Arizona. Field mapping, X-ray diffraction, and thin-section analyses revealed a wedge-shaped deposit of nearly pure calcitic tufa. Leaf and bark molds were identified as closely resembling water birch (Betula occidentalis ) and conifer species as well. A dense understory of tubular fossils suggestive of horsetails (Equisetum ) and other wetland species were also found. Biotic content, lack of ikaite, and proximity to pluvial lake systems strongly correlate the deposit’s age with numerous lacustrine deposits in the region and possibly extend the lake system to the south.
Effects of Dissolved Oxygen Concentration and Flow Rate on Watercress Germination and Growth
C. Cleveland and L. Mauger: Southern Utah University (December 2012)
Experimental set up of watercress germination.
ABSTRACT: By identifying optimal conditions for survival, growth, and reproduction, ecologists are able to develop models that predict the geographic abundance and distribution of particular species. When those models are compared to existing data, locations of inconsistencies may indicate insufficiencies within the model, inaccurate assertions regarding localized conditions or possible contamination sites. The specificity of watercress growth at spring headwaters is intriguing due to its possible implications for creating an ecological marker. In an effort to identify limiting elements for optimal growth conditions, it was hypothesized that watercress (Nasturtium officinale) would show significantly higher germination and growth in flowing and augmented dissolved oxygen concentration environments. To test this hypothesis, watercress beds were prepared in four environments varying only dissolved oxygen concentration and water circulation for both dormant and germinated specimens. Overall, a modestly positive relationship was found between flowing environments and watercress growth (p-value=0.0057). Conversely, a negative relationship was found between watercress growth and augmented dissolved oxygen concentrations for both flowing and stagnant specimens (p-value=0.015). Future research identifying the limiting aspects of watercress growth and the environmental conditions it represents, will further define its potential use as an ecological marker.
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