Master of Science (MS), Ohio University, 2022, Geological Sciences

Type Cincinnatian strata are among the best preserved Upper Ordovician deposits in the world and record a range of depositional environments as well as various biotic and abiotic changes, making them an ideal natural laboratory in which to study biotic and abiotic processes. The most substantial biotic change in the Type Cincinnatian Series is a biotic invasion known as the Richmondian Invasion. The first pulse of the Richmondian Invasion is referred to as the Clarksville Phase (Aucoin and Brett, 2016) and is the focal point of this study which quantifies the impact the Clarksville Phase had on the ecology and diversity of the fauna of the Cincinnati basin. A suite of methods were employed to quantify the invader impact including detrended correspondence analysis, cluster analysis, rarefaction, Simpson's index of dominance, guild analysis, and comparison of environmental preferences and tolerances through time. Results indicate the Clarksville Phase had numerous impacts on the fauna of the Cincinnati Sea including modification of occupied habitat, ecospace utilization, gradient structure, community structure, community composition, and biodiversity. Habitat occupation changed considerably following the introduction of the invaders with taxa shifting both their environmental tolerances and preferences. Ecospace utilization shifted as previously low diversity guilds were filled out with novel taxa. Faunal differentiation across the depth gradient increased with the introduction of the invaders. Generic richness increased within the basin, generic evenness decreased, and community composition became more complex. The results of this study contribute to our understanding of the Richmondian Invasion and our general understanding of earth history as well as provide new insights about the potential long term ecological and biodiversity impacts of biotic invasions today.

Committee: Alycia Stigall (Advisor); Gregory Springer (Committee Member); Katherine Fornash (Committee Member) Subjects: Ecology; Geobiology; Paleoecology; Paleontology

PhD, University of Cincinnati, 2021, Arts and Sciences: Geology

The Upper Ordovician (Katian, Richmondian) Waynesville-Liberty Formations are an important interval in geologic history. The Upper Ordovician, Katian, superbly exposed in the Cincinnati Arch records the transition stage between the rapid biological diversification initiated in the Early Ordovician and the terminal–Ordovician extinction in the Hirnantian. During this interval, we see the biotic turnover of the Richmondian Invasion, perturbations in the carbon cycle represented by the Arnheim isotopic carbon excursion (ICE) low, the Waynesville ICE, the Liberty Low and the Whitewater ICE and unique time specific facies. The Richmondian Biotic Invasion was characterized by the incursion of exotic taxa into the Cincinnati Arch region from other paleobasins. The Waynesville Formation is also host to unique time specific facies including trilobite butter shale Lagerstatten, nearshore verdine facies and unusual relict preservation of molluscan shell structure. In this dissertation, I employ carbon isotope chemostratigraphy, cathodoluminescence, scanning electron microscopy and other techniques to understand how these biotic, chemical and taphonomic events relate not only locally in the Cincinnati Arch, but across other paleobasins.

Committee: Carlton Brett Ph.D. (Committee Chair); Ben Dattilo Ph.D. (Committee Member); Daniel Sturmer (Committee Member); Arnold Miller Ph.D. (Committee Member); Warren Huff Ph.D. (Committee Member) Subjects: Geology

Master of Science, Miami University, 2018, Geology and Environmental Earth Science

The fossil record contains ecosystem changes, and can provide insights into ecological conditions over evolutionary timescales, particularly factors affecting community structure before and after disturbance. Our current understanding of these effects is based on changes in biodiversity, which cannot capture interactions between organisms. Food webs provide an alternative approach, representing interactions within a community. Food webs present unique challenges as they require assembling paleocommunity data for species across trophic levels. Numerous sources may be used to determine the species present in a paleocommunity. However, the potential effects of differences between data derived from museum collections and data compilations have not yet been tested. Here we examined differences between food web models of Late Ordovician marine communities assembled using two types of data: museum collections and field work; and the PBDB. To determine whether both data types produced consistent outcomes, paleocommunities were compared before and after the Richmondian Invasion. Relative differences in model outcomes across the invasion did not vary between data types. Differences in structure were consistent between the datatypes, with similar changes across the invasion. These findings suggest that both data types may be suitable for studies examining differences in resistance.

Committee: Carrie Tyler PhD (Advisor); Hailiang Dong PhD (Committee Member); Michael Brudzinski PhD (Committee Member); Peter Roopnarine PhD (Committee Member) Subjects: Geology; Paleoecology; Paleontology

MS, University of Cincinnati, 2017, Arts and Sciences: Geology

The Late Ordovician has been recognized as one of the most substantial periods of intracratonic flooding in the history of the North American continent and one of the most dynamic periods of climatic and sea level fluctuations in Earth history. Paleoceanographic changes in water temperature, turbidity, and nutrient supply during this time were accompanied by an episode of major ecological change known as the Richmondian Invasion. During this event, over 50 warmer water taxa were introduced to the Cincinnati Arch region in several waves over the course of 500,000 years, resulting in substantial reorganization of the ecologic community structure. Although the overall structure of this invasion is well known, the details and timing of individual invasion events are largely unknown, and the proper study of these attributes requires well a constructed high-resolution stratigraphic framework. I have identified a series of discrete horizons and faunal epiboles within the previously undifferentiated Bull Fork Formation and the Rowland Member of the Drakes Formation in central Kentucky that are characteristic of the Waynesville Formation in southwestern Ohio. In doing so, I have recognized multiple erosive surfaces representing sequence boundaries (one being the “Mid-Richmondian unconformity”), as well as distinct lithologic and biologic gradients which have allowed us to trace the Waynesville and its component units for approximately 200 km from its type area in southwestern Ohio to central Kentucky. These correlations, supported by historical studies and limited carbon isotopic data, provide a high-resolution stratigraphic framework within which to study changes in paleoecologic structure. This framework was utilized to determine the absolute depth ranges of benthic assemblages along the Waynesville depositional ramp. I first constructed a depth-calibrated ramp model of the study interval. The proximal end-member (shoreline) is indicated by desiccation cracks (open full item for complete abstract)

Committee: Carlton Brett Ph.D. (Committee Chair); Ben Dattilo Ph.D. (Committee Member); David Meyer Ph.D. (Committee Member); Arnold Miller Ph.D. (Committee Member) Subjects: Geology

Master of Science (MS), Ohio University, 2015, Geological Sciences (Arts and Sciences)

Late Ordovician strata of the Cincinnati Basin record an invasion during the Richmondian Age. Competing hypotheses exist in the literature about the origin and dispersal routes used by the invasive taxa. In this thesis, a suite of traditional and novel paleobiogeographic methods are used to (1) identify geographic source regions for the invasive taxa, (2) reconstruct dispersal paths used, and (3) analyze speciation patterns that influenced biogeographic evolution of taxa. Parsimony Analysis of Endemicity (PAE) applied to over 60 genera that participated in the invasion interval for the C1-C5 depositional sequences supported multiple dispersal routes within Laurentia and between Laurentia and Baltica. Larval type for invasive taxa was dominantly planktotrophic or planula larvae; both have high dispersal potential. Phylogenetic biogeographic analyses using parsimony and model-based approaches were applied to ten clades of Middle-Late Ordovician taxa to compare ancestral range reconstructions characterized speciation type and identify dispersal paths. Methods recovered similar patterns, but differed when interpreting speciation mode. Based on these analyses and a review of the literature, Richmondian invaders are determined to include taxa from multiple geographic areas. Local and global oceanic currents and changing tectonic factors, promoted the immigration of taxa with high larval dispersal potential into the Cincinnati basin.

Committee: Alycia Stigall (Advisor); Damian Nance (Committee Member); Dave Kidder (Committee Member); Greg Springer (Committee Member) Subjects: Earth; Geology; Paleoclimate Science; Paleoecology; Paleontology

MS, University of Cincinnati, 2014, Arts and Sciences: Geology

The Upper Ordovician Waynesville Formation of the Ohio, Kentucky and Indiana tri-state region is situated during and between two major paleoecological events:, the Richmondian Invasion, and the End Ordovician Extinction. Because of this juxtaposition, understanding the regional stratigraphy of this interval is vital to interpreting these events. Stratigraphic and paleontological work on this interval dates back to the late 1800s, and, as a result, numerous nomenclature schemes (biostratigraphical, lithostratigraphical, and state-line geology) have been developed to characterize the Waynesville Formation. The variety of schemes has inhibited the ability to make detailed bed-by-bed correlations. This study has attempted to rectify this issue by selecting the best nomenclature scheme, and create bed-by-bed correlations that cross state lines. The results of the study herein demonstrate that correlations are indeed possible from the deepest water facies to the shallowest water facies fairly readily. The study has also resulted in the discovery of a Mid-Richmondian Unconformity which has previously gone undocumented. This unconformity, which separates the Waynesville Formation from the overlying Blanchester Formation, at places cuts through the entirety of the Clarksville Member of the Waynesville. If extended further south, this unconformity likely removes the Fort Ancient Member and the underlying Arnheim Formation. The discovery of Mid-Richmondian Unconformity will have important implications for paleoecological studies of this interval.

Committee: Carlton Brett Ph.D. (Committee Chair); Ben Dattilo Ph.D. (Committee Member); Brenda Hunda Ph.D. (Committee Member); David Meyer Ph.D. (Committee Member); Arnold Miller Ph.D. (Committee Member) Subjects: Geology

Master of Science (MS), Ohio University, 2014, Geological Sciences (Arts and Sciences)

Systematic revision of the Late Ordovician brachiopod genus Eochonetes was conducted utilizing multivariate analyses and a species-level phylogenetic analysis. Thaerodonta has been previously synonymized with Eochonetes; multivariate and phylogenetic analyses support the synonymy of the two genera. The multivariate analyses allowed delineation of species in morphospace and phylogenetic analysis was used to establish evolutionary relationships among species. Three species which were previously in open nomenclature were described and recognized as valid, these include: Eochonetes maearum, E. minerva, and E. voldemortus. The resulting phylogenetic hypothesis was then utilized to reconstruct biogeographic patterns and speciation mode at cladogenetic events within the genus. Phylogenetic biogeographic analysis of Eochonetes and additional Ordovician brachiopod genera was conducted to uncover large-scale geologic drivers of faunal diversification. Area cladograms indicate oceanographic patterns were the main geologic driver of biogeographic patterns within the focal taxa. Furthermore, the Taconic tectophase contributed to the separation of the Appalachian and Central Basins as well as the two Midcontinent Basins. Four migration pathways into the Cincinnati Basin were recognized, further supporting the multidirectional pathway hypothesis for the Richmondian Invasion.

Committee: Alycia Stigall (Advisor); Daniel Hembree (Committee Member); Gregory Nadon (Committee Member) Subjects: Geology; Paleontology

Master of Science (MS), Ohio University, 2011, Geological Sciences (Arts and Sciences)

Geographic ranges of type-Cincinnatian brachiopod species were reconstructed using Geographic Information Systems in order to analyze geographic distributions through space and time. Area polygons were digitized around species occurrence points plotted on the Cincinnatian outcrop belt (Ohio, Kentucky, Indiana), resulting in almost 100 individual maps spanning four depositional sequences. Individual species displayed patterns of habitat tracking as well as range expansion and contraction in response to regional sea level fluctuations. Statistical results show that species that established large geographic ranges preferentially survived the influx of extra-basinal species during the Richmondian Invasion. A systematic revision of the North American articulated brachiopod genus Hebertella Hall and Clarke is proposed. Specimens representing 13 species were coded for morphologic character analysis. A single most parsimonious tree produced from analysis of character data shows the evolution of characters. Biogeographic patterns derived from the cladogram as well as those analyzed in the previous study suggest east to mid-continent dispersal of Hebertella species from the Middle to Late Ordovician.

Committee: Alycia Stigall PhD (Advisor); Elizabeth Gierlowski-Kordesch PhD (Committee Member); David Kidder PhD (Committee Member) Subjects: Biological Oceanography; Earth; Environmental Geology; Environmental Science; Geobiology; Geographic Information Science; Geological; Geology; Oceanography; Paleontology

Master of Science (MS), Ohio University, 2009, Geological Sciences (Arts and Sciences)

The C4 sequence of the Richmondian Stage records a large biotic invasion, providing a unique study interval for paleobiogeographic studies. Two separate but related analyses quantify the geographic ranges of taxa using ecological niche modeling (ENM) and spline methods. The ENM approach calculates species' niches using a suite of species occurrence and sedimentary data. Results indicate that generalist species are less affected by the introduction of invaders and lowering relative sea level while ecological specialists are displaced. The ENM method requires a large sedimentary data set and is not suitable for all study areas. The spline geographic range estimation method is less data-intensive for reconstructing ranges from faunal abundance data. This method is best for evenly distributed abundance data in regions with poor sedimentary data coverage. GIS is a powerful tool for paleontological analyses and provides a means to quantify species range fluctuations in a spatial and temporal framework.

Committee: Alycia L. Stigall PhD (Advisor); Douglas Green PhD (Committee Member); Dina Lopez PhD (Committee Member) Subjects: Geology

Master of Science (MS), Ohio University, 2013, Geological Sciences (Arts and Sciences)

Changes in niche stability levels in deep time are evaluated by assessing the niche dynamics of a diverse suite of invertebrate taxa from the Late Ordovician Cincinnatian series of North America. During this interval, periodic sea-level fluctuations, storm events, and extrabasinal species invasions disrupted stable shallow-marine communities as taxa responded to both rapid and gradual environmental changes. Variations in relative niche stability through time and across clades are determined using ecological niche modeling (ENM) to produce and compare models for 11 invertebrate genera (crinoids, trilobites, bivalves, gastropods, bryozoans and corals) at high spatial and temporal resolution. The maximum entropy (Maxent) algorithm was used to generate ecological niche models for each genus for 9 time-slices across three sequences. Previous studies provided sedimentologically derived environmental layers, and geo-referenced occurrence data were compiled from primary field research augmented by published data. To evaluate niche stability, models were compared geospatially (in two-dimensional G-space), and in environmental space (n-dimensional E-space) between time-slices. Environmental parameters, which define individual niche models, were also tested for statistical dissimilarity between time-slices. These analyses were designed such that high degrees of similarity and range-overlap indicate niche stability, whereas statistical dissimilarity and low percentage range overlap indicate niche evolution. Complementary ENM studies of brachiopod species across this interval have documented higher levels of niche evolution during intervals of rapid sea-level rise and during the Richmondian Invasion. To determine if niche responses were congruent across clades, this analysis focuses on the niche dynamics of non-brachiopod taxa at the genus level and comparison of niche stability patterns between different clades, feeding styles, and at different taxonomic scales. The res (open full item for complete abstract)

Committee: Alycia Stigall PhD (Advisor); Douglas Green PhD (Committee Member); David Kidder PhD (Committee Member) Subjects: Ecology; Geology; Paleontology