Thirteen species, one subspecies and five varieties of the brachiopod genus Schizophoria have been studied from parts of the Devonian and Carboniferous of Western Europe. One Carboniferous species and the Devonian subspecies of S. pygmaea are new, and will be formally named in due course. All taxa are shown to be both externally and internally distinct. In the Devonian, Schizophoria is most abundant in the Middle Devonian of the Eifel region (Germany), and in the Lower to Upper Devonian of the Dinant basin (Belgium). In the Carboniferous, Schizophoria is most abundant in the Dinantian of the Dinant basin, and in the C-D zone reef facies of the British Isles. Species of Schizophoria from the Carboniferous are shown to be statistically distinct, when appropriate characters are selected. A detailed knowledge of morphology is necessary before accurate statistical work is undertaken. Insufficient material prevented similar work on Devonian species. Certain Carboniferous species are apparently restricted to particular areas of reef limestone, and more than one species can in some cases be collected from the same stratigraphical and geographical position. Most of the species are long ranging forms, except Schizophoria provulvaria (Maurer) and S. strigosa (Sowerby) of the Siegenian to Lower Emsian, S. vulvaria (Quenstedt), of the Lower Emsian to Lower Eifelian, and S. pygmaea Struve, of the Eifelian. Schizophoria pygmaea is a dwarf form occurring in two horizons within the Eifelian of the Eifel region. Schizophoria woodi Bond is restricted to the Visean. Phylogenetically the species were probably derived from two root stocks in the Lower Devonian, S. provulvaria and S.strigosa. An earlier ancestor is unknown. Four main lines are recognised in the Carboniferous. Lines of evolution are based externally on outline and ornament, and internally on muscle fields and the form of the brachiophore plates.

The secondary wood formed by cambial activity in the growth of trees records with varying degrees of precision the amount of seasonality and other aspects of the climate under which it grew. A survey is presented of the extent to which this climatic 'data-store' can be directly 'read back', based on the extensive literature on the environmental control of wood formation in modern plants. This led to the investigation of growth ring characters in selected fossil and recent wood in the course of which a cyclic phenomenon, apparently under endogenous control, was demonstrated. The potential of this information to deduce aspects of the palaeoclimate from fossil wood (of age extending back some 370 million years) is then considered. Attention was directed particularly to three intervals of geological time, namely the Upper Devonian, the Permo-Carboniferous and the later Mesozoic in which growth ring characteristics present features of particular interest. A classification of growth ring features is developed and five categories are defined. Some of these data are derived from direct observation of fossil wood material by the author and some from the literature. Growth ring characteristics are plotted on palaeo-reconstruction maps and the climatic significance is considered in relation to other indicators of palaeo-climate. Consideration is given to the phenomenon of tree growth (and very substantial increments) in high latitudes during two phases of geological time---the Permian and the later Mesozoic. At these times major forest growth evidently extended far beyond the present latitudinal range. Consideration of the radiation energy input at high latitudes, and the effect of a generally more isothermal global climate suggests that these growth ring phenomena can be explained in uniformitarian terms without the need to invoke shift in axial inclination or similar processes as some, have advocated.

Finely laminated carbonate columns---endostromatolites, grow in carbonate rock fissures in permafrost regions. Their formation is thought to be microbially mediated but the processes of accretion are thought to be very slow and possibly intertwined with abiotic mineralization processes. The samples analyzed in this study are from the Haughton impact structure, located on Devon Island, Nunavut in the Canadian high Arctic. The carbon and nitrogen isotopic composition of the endostromatolites, along will the microbial community diversity were determined. The delta13C and delta 15N of the organic matter contained within the endostromatolites averaged around -30‰ and 0‰, respectively. Scanning electron microscopy observations revealed the presence of spheroidal calcite and filamentous structures reminiscent of biological activity. Molecular phylogenetic analysis of the endostromatolites and soil samples found in Haughton crater showed that the endostromatolite microbial community is mostly aerobic and chemoheterotrophic, belonging in large part to the Phylum Actinobacteria and the subphylum Alphaproteobacteria. Rubrobacter radiotolerans was the dominant species in the endostromatolites. Soil bacterial communities were more diverse, harboring all the phyla found in the endostromatolites as well as many others which were not encountered in endostromatolites. Understanding the variability of microbial life between specific environments might shed some light on the mechanisms responsible for endostromatolite formation and provide useful data for contrasting abiotic and biotic systems on earth and other planetary bodies, such as Mars.

I investigated cranial and dental morphology in 37 species of fossil and living peccaries, Family Tayassuidae, from North and South America. PAUP analysis of 94 apomorphous character states among 33 species represented by adequate samples produced a set of trees (C.I. = 0.74) which unequivocally support the monophyly of several clades within the Tayassuidae. The subfamily Tayassuinae comprises the three living species of peccary and 23 Miocene and younger species. The Miocene taxa Hesperhys, "Thinohyus" siouxensis, Floridachoerus, "Cynorca" sociale, and two unnamed species form a clade which is the sister group of the Tayassuinae. The Oligocene species Perchoerus probus is the sister group of the clade comprising Hesperhys and the Tayassuinae; another Oligocene species, Thinohyus lentus, is the sister group of all tayassuids surveyed. Analysis of a set of predominantly tayassuine taxa yielded a set of trees (C.I. = 0.84) which resolve relationships among several tayassuine clades. Tayassu is the sister group of a clade comprising Prosthennops (restricted to P. serus), Mylohyus, and Platygonus. Catagonus and Dicotyles are sister groups, and together form a clade which is the sister group of the clade which unites Tayassu and Platygonus. Progressively distant sister groups of that clade include three unnamed Miocene species, Macrogenis, "Prosthennops" xiphidonticus, "Prosthennops" niobrarensis, "Cynorca" occidentale, and Dyseohyus. Miocene and younger tayassuids possess within their nasal cavities an elaborate complex of bony structures that is unique among mammals. The floor of the nasal cavity is developed into a pneumatic, labyrinthine structure. The vomer is also pneumatic, and is developed into a pair of large, bilaterally symmetrical chambers. Many members of the clade of late Miocene and younger tayassuines that includes Macrogenis and its sister taxa have wing-like zygomatic processes; possession of these processes is primitive for that clade. Primitively both sexes (diagnosed by discretely bimodal canine diameters) possessed them, but they are sexually dimorphic in some species of Platygonus. Zygomatic processes were reduced in size in as many as five clades; their reduction was accompanied by reduction in the degree of canine dimorphism. A minimum of four dispersal events is required to account for the diversity of South American Tayassuidae.

The objective of this study is to study spatial and temporal paleontological distributions as they relate to the histories of Ninetyeast Ridge and Broken Ridge from ODP Leg 121. This study is important for establishing connections between different fossil assemblages, especially between those of the high latitudes and those of low latitudes. The assemblages were used to perform biostratigraphic analyses of sequences on Ninetyeast Ridge and Broken Ridge in the Indian Ocean and to compare assemblage changes to position changes of the tectonic plates through time. The zonation scheme used for the analysis is from Okada and Bukry (1980). Although there were some small changes within the assemblages of the holes described, the changes were not significant. The assemblages throughout the interval studied contained only low-latitude species. / A Thesis submitted to the Department of Earth, Ocean, and Atmospheric Science in partial fulfillment of the requirements for the degree of Master of Science. / Fall Semester, 2014. / November 7, 2014. / Calcareous Nannofossils, Micropaleontology / Includes bibliographical references. / Sherwood W. Wise, Jr., Professor Directing Thesis; William C. Parker, Committee Member; Yang Wang, Committee Member.

The "adaptationist research program" has been faulted on occasion for permitting excessively ad hoc explanation, for being untestable, and for being unscientific. Various modes of explanation in non-adaptive terms have been offered as alternative and preferable research programs. The present work argues that non-adaptive explanation is not an alternative to adaptive explanation, but rather is part of the adaptationist research program, following as a corollary of sorts from the black box to translucid box transition of evolutionary theory. "Research programs" in general are not testable, and all of science incorporates high-level generalizations which are not testable in any straightforward manner. Among the roles which such generalizations may play in science are the provision of acceptable terms and relations to be incorporated into valid explanations (paradigms), or they may take the form of theoretical entities which are not themselves observable, but which allow the generation of testable implications which would not be possible without them (Watkins' Organic Fertility Requirement). The non-adaptationist research program is as untestable as the adaptationist program in these senses. Adaptive and non-adaptive modes of explanation seek to answer different questions, and for logical and epistemological reasons the adaptationist approach has priority. So-called "non-adaptive" explanations in terms of allometry and heterochrony in fact deal with adaptively neutral, proximate causal mechanisms of change. An attempt is made herein to synthesize the adaptive and non-adaptive approaches to explanation, showing how they address different but complementary questions. Ideally, the synthesis of the two approaches to explanation should result in a broader and more comprehensive evolutionary theory.

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Master of Arts (MA)

Pachyrhinosaurus perotorum, a paleo-Arctic centrosaurine ceratopsid from the Kikak-Tegoseak Quarry (North Slope, Alaska) represents a unique opportunity to add to the understanding of ceratopsian bone histology, which is poorly understood due to the minimal preservation of growth markers (e.g. lines of arrested growth) and limited histological sampling across the ceratopsian lineage. Histological analyses of eight rib fragments from P. perotorum were conducted to add to the understanding of ceratopsian growth dynamics. Cyclical growth is preserved within ribs from P. perotorum allowing for the assignment of relative ontogenetic ages. One juvenile (DMNH 23891), 4 sub-adults (DMNH 21574, DMNH 24384, DMNH 24228, and DMNH 23888), and one adult (DMNH 24237) were identified. Radial and reticular fibrolamellar bone is prevalent in juvenile and sub-adult individuals indicating P. perotorum grew rapidly during ontogeny. Dense secondary bone is widespread in adult and three sub-adult individuals, which obscures most primary bone tissue and lines of arrested growth (LAGs). The degree of remodeling is higher than that previously reported in dinosaur rib histology, and may be attributable to differences in element-specific growth rate, environmental or biomechanical stresses. However, more histological studies of P. perotorum comparing growth between different postcranial long bones are needed to constrain the controls of secondary bone within this paleo-Arctic species. Although previous studies have interpreted taphonomy of the Kikak-Tegoseak Quarry (KTQ) using sedimentological and paleontological data, less is known about the geochemical taphonomy of this assemblage. P. perotorum bone has been altered from carbonate-hydroxyapatite to carbonate fluorapatite. XRD full width half maximum (FWHM) values display narrower peak widths (0.29-0.35°) than modern bone indicating a more crystalline apatite lattice structure. ATR-FTIR infrared splitting factor (IR-SF) values in P. perotorum specimens are greater (3.3-3.6) than in modern bone indicating that apatite crystallite sizes are larger than what is typically found in non-fossil bone. Higher crystallinity is a common result in fossil bone due the growth of authigenic apatite. ATR-FTIR spectra reveal elevated carbonate due to the addition of B-type carbonate into the apatite lattice. Relative amounts of carbonate correlates with ontogeny which could reflect a biological signal, although the effect of diagenetic alteration cannot be ruled out. Based on the elevated carbonate within bones of P. perotorum, there is potentially significant diagenetic alteration of the δ18Ocarbonate signal, therefore future stable isotope studies from the KTQ P. perotorum specimens should be cautious. Determining the potential chemical alteration of the δ18Ophosphate is more difficult since crystallinity data cannot differentiate between biogenic and secondary phosphate in bone. However, depleted carbonate: phosphate ratios can indicate the addition of more phosphate and thus, potential diagenetic alteration of the δ18Ophosphate. REE spider patterns yield different patterns between P. perotorum bones, which indicates taphonomic reworking (spatial and/or temporal) due to the preservation of different redox conditions and diffusion periods between bones. This observation is surprising due to the lack of significant/variable bone weathering or abrasion. / Geology