Vertebrate Taphonomy and Paleoecology of a Cretaceous-Paleogene Marine Bonebed

In this dissertation, I characterize the vertebrate taphonomy and paleoecology of the Cretaceous-Paleogene Main Fossiliferous Layer (MFL) of the Hornerstown Formation, exposed at the Rowan Fossil Quarry in Mantua Township, New Jersey. The MFL has been proposed to represent a: 1) reworked deposit; 2) time-averaged deposit; or 3) a mass-death assemblage, possibly related to the K/Pg impact event. If the mass-death scenario is correct, the MFL would represent the only known vertebrate bonebed located stratigraphically at the K/Pg Boundary and would offer unique insight into the immediate aftermath of the bolide impact event. In spite of the potential importance of this site, no systematic taphonomic studies had been conducted prior to my research. Beginning in 2012, the MFL was systematically excavated and all contextual information was recorded. Several associated and articulated partial skeletons were recovered from an area of ~ 150 m2 in addition to hundreds of isolated bones. A “bloat and float” scenario can explain the abundance of isolated skeletal elements. Preservation of skeletal elements varies, although abrasion is typically minor or absent. Bioerosion is relatively common and may account for much of the damage to the bones. My taphonomic data, when viewed in light of other previous studies, favors the hypothesis that the MFL formed over a relatively short period of time due to a sudden influx of vertebrate carcasses. I also report the first recovery of soft-tissue-like structures from marine vertebrate fossils with known handling history and negative controls. Osteocyte-like structures were isolated from turtle shell elements of various taxa as well as from an indeterminate turtle humerus. Osteocyte- and vessel-like structures were also isolated from the femur of a marine crocodile, Thoracosaurus neocesariensis. However, not all of the sampled bone samples yielded soft-tissue-like structures. At least within the MFL, preservation of these microstructures is independent of taxon, skeletal element, or the macroscopic preservation of the bone. Instead, the best indicator of both the preservation of microstructures and bone microstructure is the fossil color. In the sampled bone fragments, tan colored samples yielded no or poorly preserved osteocyte-like structures whereas darker colored samples provided abundant and/or well-preserved cell-like structures. This study indicates that soft-tissue-like structures can be preserved in a marine setting and that they can be recovered from sediments completely waterlogged over geologic time. My third chapter focuses on the preservation and identification of vertebrate coprolites in the MFL. At least 178 coprolites were recovered from the MFL and at least seven morphotypes are recognized based on size, morphology, and the presence of inclusions. Heteropolar spiral coprolites are abundant and were likely produced by chondrichthyans with a spiral valve. Pellets, small cylindrical coprolites and large cylindrical coprolites may have been produced by bony fish, sea turtles, crocodilians, and/or mosasaurs. None of these morphotypes, except for the single large heteropolar spiral coprolite and a few indeterminate coprolite fragments, possess identifiable inclusions. Instead, most visible inclusions are small brown or black structures that may represent highly digested bone fragments. The phosphatic nature of the coprolites and the presence of some bone material suggest that carnivores likely produced many of them. However, the specific producer(s) cannot be identified. Complete coprolites are uncommon with most exhibiting some degree of pre-fossilization damage including breaks and bioerosion (e.g. coprophagy). For my final chapter, I described the shell bone histology of six of the eight turtle taxa known from the MFL. Based on the histology, overall architecture, and compactness of the bones, I was able to infer the habitat preference of the turtles. Agomphus pectoralis and Adocus beatus likely inhabited freshwater habitats near the shore, whereas Bothremys barberi and Taphrosphys sulcatus were shallow marine sea turtles. The bone histology of Peritresius ornatus suggests a shallow marine environment whereas the compactness values and overall shell morphology suggest a more pelagic lifestyle. Catapleura repanda is suggested to be a pelagic turtle based on bone histology, bone compactness values, and overall shell morphology.Ph.D., Biological Sciences -- Drexel University, 201

Microstratigraphic Analysis of Fossil Distribution in the Lower Hornerstown and Upper Navesink Formations at the Edelman Fossil Park, NJ

Maastrichtian–Danian sediments of the Navesink and Hornerstown formations at the Jean and Ric Edelman Fossil Park of Rowan University in Mantua Township, New Jersey, have long intrigued paleontologists. Within the basal Hornerstown Formation occurs the Main Fossiliferous Layer (MFL), a regionally well-known and diverse bonebed. The lithostratigraphic and chronostratigraphic position of this fossil layer have been debated for more than 50 years, fueling debate over its origin. Herein, we present the results of a microstratigraphic analysis of the fossil composition and distribution of the MFL undertaken to rectify these discrepancies. Through methodical top-down excavation, we recorded the three-dimensional position of every fossil encountered. Three-dimensional visualization and analyses of these data in ArcGIS Pro yielded an unprecedented view of this bonebed. Most reported discrepancies about the stratigraphic placement and thickness of the MFL can be explained by the presence of two distinct fossil assemblages within this interval that are occasionally combined into a single bonebed. The stratigraphically-lower assemblage, herein termed an “oyster layer”, is geometrically-tabular and exhibits low taxonomic diversity, high abundance of the oyster Pycnodonte, and moderate taxonomic richness. The stratigraphically-higher assemblage, the MFL, occurs approximately 9 cm higher in section and exhibits high values of taxonomic diversity, fossil abundance, and taxonomic richness. Sedimentological homogeneity throughout this interval suggests that these faunal contrasts arise from the two assemblages having formed via independent taphonomic pathways. Specifically, prevalence of Pycnodonte in the oyster layer implies formation by a selective mortality event, whereas the diversity of the MFL appears to reflect a more universal agent of mortality. Spatial variations in the stratigraphic distribution of fossils within the MFL in our excavation area indicate this assemblage does not form a simple, tabular layer as previously thought and may, in part, record original bathymetry. Importantly, our definition of the MFL and detailed characterization of its stratigraphic placement are essential for future studies on the taphonomic origin and chronostratigraphy of this bonebed. Universal use of this definition would allow researchers to confidently elucidate the exact lithostratigraphic positions of precise chronostratigraphic indicators within the MFL and accurately estimate the degree of time averaging of its fossils

Convalescent plasma in patients admitted to hospital with COVID-19 (RECOVERY): a randomised controlled, open-label, platform trial

SummaryBackground Azithromycin has been proposed as a treatment for COVID-19 on the basis of its immunomodulatoryactions. We aimed to evaluate the safety and efficacy of azithromycin in patients admitted to hospital with COVID-19.Methods In this randomised, controlled, open-label, adaptive platform trial (Randomised Evaluation of COVID-19Therapy [RECOVERY]), several possible treatments were compared with usual care in patients admitted to hospitalwith COVID-19 in the UK. The trial is underway at 176 hospitals in the UK. Eligible and consenting patients wererandomly allocated to either usual standard of care alone or usual standard of care plus azithromycin 500 mg once perday by mouth or intravenously for 10 days or until discharge (or allocation to one of the other RECOVERY treatmentgroups). Patients were assigned via web-based simple (unstratified) randomisation with allocation concealment andwere twice as likely to be randomly assigned to usual care than to any of the active treatment groups. Participants andlocal study staff were not masked to the allocated treatment, but all others involved in the trial were masked to theoutcome data during the trial. The primary outcome was 28-day all-cause mortality, assessed in the intention-to-treatpopulation. The trial is registered with ISRCTN, 50189673, and ClinicalTrials.gov, NCT04381936.Findings Between April 7 and Nov 27, 2020, of 16 442 patients enrolled in the RECOVERY trial, 9433 (57%) wereeligible and 7763 were included in the assessment of azithromycin. The mean age of these study participants was65·3 years (SD 15·7) and approximately a third were women (2944 [38%] of 7763). 2582 patients were randomlyallocated to receive azithromycin and 5181 patients were randomly allocated to usual care alone. Overall,561 (22%) patients allocated to azithromycin and 1162 (22%) patients allocated to usual care died within 28 days(rate ratio 0·97, 95% CI 0·87–1·07; p=0·50). No significant difference was seen in duration of hospital stay (median10 days [IQR 5 to >28] vs 11 days [5 to >28]) or the proportion of patients discharged from hospital alive within 28 days(rate ratio 1·04, 95% CI 0·98–1·10; p=0·19). Among those not on invasive mechanical ventilation at baseline, nosignificant difference was seen in the proportion meeting the composite endpoint of invasive mechanical ventilationor death (risk ratio 0·95, 95% CI 0·87–1·03; p=0·24).Interpretation In patients admitted to hospital with COVID-19, azithromycin did not improve survival or otherprespecified clinical outcomes. Azithromycin use in patients admitted to hospital with COVID-19 should be restrictedto patients in whom there is a clear antimicrobial indication

Insights into cranial morphology and intraspecific variation from a new subadult specimen of the pan-cheloniid turtle Euclastes wielandi Hay, 1908

We describe a nearly complete skull and mandible of a subadult of Euclastes wielandi, a pan-cheloniid turtle recently recovered at the Jean and Ric Edelman Fossil Park at Rowan University in Mantua Township, New Jersey, which yields new information about the osteology, ontogeny, and intraspecific variation of this taxon. The specimen was collected from the earliest Danian Main Fossiliferous Layer (MFL) of the Hornerstown Formation. Although discovered immediately adjacent to remains of two pleurodires, Taphrosphys sulcatus and Bothremys sp., the skull and mandible can be definitively assigned to Pan-Cheloniidae based on its V-shaped basisphenoid and rod-like rostrum basisphenoidale. Among three pan-cheloniid taxa known from the MFL, the specimen is assigned to Eu. wielandi based on its low skull with dorsally-directed orbits, symphyseal swelling in the mandibular triturating surface, and high dorsum sellae. Comparisons with other specimens of Eu. wielandi and adults and juveniles of other pan-cheloniids revealed variations in the type and timing of cranial ontogenetic changes in the clade, as well as anatomical traits subject to intraspecific variation, such as the depth of the sella turcica, paths of the foramina nervi hypoglossi, and development of a precolumellar fossa. The relative contribution of the frontal to the orbital margin and precise path of the prefrontal-supraorbital scale sulcus are subject to individual variation in Eu. wielandi, as well as ontogenetic variation and bilateral asymmetry in other cryptodirans, signifying that the widespread use of frontal retraction in taxon diagnoses and as a phylogenetic character should be reconsidered. As in multiple other taxa, the mandibular triturating surface expands through growth in Eu. wielandi, demonstrating that increased durophagy with age was a common life strategy among Cryptodira

Insights into cranial morphology and intraspecific variation from a new subadult specimen of the pan-cheloniid turtle Euclastes wielandi Hay, 1908

We describe a nearly complete skull and mandible of a subadult of Euclastes wielandi, a pan-cheloniid turtle recently recovered at the Jean and Ric Edelman Fossil Park at Rowan University in Mantua Township, New Jersey, which yields new information about the osteology, ontogeny, and intraspecific variation of this taxon. The specimen was collected from the earliest Danian Main Fossiliferous Layer (MFL) of the Hornerstown Formation. Although discovered immediately adjacent to remains of two pleurodires, Taphrosphys sulcatus and Bothremys sp., the skull and mandible can be definitively assigned to Pan-Cheloniidae based on its V-shaped basisphenoid and rod-like rostrum basisphenoidale. Among three pan-cheloniid taxa known from the MFL, the specimen is assigned to Eu. wielandi based on its low skull with dorsally-directed orbits, symphyseal swelling in the mandibular triturating surface, and high dorsum sellae. Comparisons with other specimens of Eu. wielandi and adults and juveniles of other pan-cheloniids revealed variations in the type and timing of cranial ontogenetic changes in the clade, as well as anatomical traits subject to intraspecific variation, such as the depth of the sella turcica, paths of the foramina nervi hypoglossi, and development of a precolumellar fossa. The relative contribution of the frontal to the orbital margin and precise path of the prefrontal-supraorbital scale sulcus are subject to individual variation in Eu. wielandi, as well as ontogenetic variation and bilateral asymmetry in other cryptodirans, signifying that the widespread use of frontal retraction in taxon diagnoses and as a phylogenetic character should be reconsidered. As in multiple other taxa, the mandibular triturating surface expands through growth in Eu. wielandi, demonstrating that increased durophagy with age was a common life strategy among Cryptodira

Chemical Design Process for Production of 2,5-Furandicarboxylic Acid via a Hydroxymethylfurfural Pathway

The topic of this senior design project was provided by Micromidas Inc. (Sacramento, CA) and was completed under the advisement of the Department of Chemical and Materials Engineering at the University of Nevada, Reno. The problem statement – proposed by Micromidas’ CEO and Head of Engineering – requested that the team design a chemical process to produce a chemical precursor to 2,5-furandicarboxylic acid (FDCA), an important chemical used in the production of plastics. The intermediate precursor was to be derived from fructose – a sustainable feed obtainable from biomass – and was selected by the team to be hydroxymethylfurfural (HMF). The chemical process designed was based off methods from scientific literature, scaled up using chemical engineering techniques, and analyzed using CHEMCAD simulation software. Both a base case process and alternative case process were developed and an economic comparison was performed