Thesis (M. Sc.)--University of Stellenbosch, 2000. / Includes bibliographical references. Also available via the Internet.

Thesis (M.S.)--University of Oregon, 2000. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 192-199). Also available for download via the World Wide Web; free to UO users.

Thesis (Ph. D.)--University of Chicago, Committee on Evolutionary Biology, August 2001. / Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--University of Chicago, Department of Geophysical Sciences, August 2003. / Includes bibliographical references. Also available on the Internet.

<p> Recent studies have used ecomorphological methods to look at morphological variation in artiodactyl postcranial elements as indicators of paleoenvironment conditions. From these studies, a continuum of variations in the lower limb bones of members of Bovidae and Cervidae in association with habitat conditions have been developed. The focus of this study is to look at variation in a single species, white-tailed deer (<i>Odocoileus virginianus</i>), that occupies a wide range of habitats and determine if regional adaptations exist in populations of different habitat conditions. </p><p> This studies uses linear measurements to assess size and shape variations in the metacarpal, metatarsal, astragalus, and calcaneus between white-tailed deer populations associated with open- and closed-habitat conditions thought-out the Holocene and in modern populations. The Holocene was subdividing into three time units (10,000-5,000, 5,000-3,000, and 3,000-1,000 yr BP) based on environmental shifts and availability of samples. Variations in size and shape were assessed for 1) in open- and closed-habitat conditions in both Holocene and modern deer overall, 2) in habitat conditions in open-classified Holocene deer through time, 3) in modern deer populations along a latitudinal transect,4) between Holocene and modern deer overall, and5) in Holocene and modern for open-classified and closed-classified deer. </p><p> Results indicated that size differences existed between open- and closed-classified deer in both Holocene and modern populations and that deer associated with open-habitat were larger. Shape differences between open- and closed-classified deer in the Holocene appear to be adapted to the environment, however, modern deer offered only limited insight and lacked consistence in variations. Results for variation thought time in Holocene deer indicated that size increased from Early to late Holocene in both the astragalus and calcaneus. Results for shape offered limited and mixed results. Results for variation in population along a latitudinal transect indicated that deer size increase from lower to higher latitudes. Results for shape differences between populations offered limited insight into variation. However, results for the calcaneal tuber functional region did indicated that deer become more open-adapted in relation to the southern population from lower to higher latitudes,. For the comparison of Holocene and modern deer size overall, only the astragalus indicated a clear variation between the two. The astragalus indicated that Holocene deer were larger than modern deer. Results for variation in shape between the two indicated little difference between the two except for the calcaneus, which indicated that modern deer were more open-adapted. Results for size differences in Holocene and modern for open-classified and closed-classified deer offered limited and mixed results. Results for shape differences were also limited; however, the calcaneus strongly indicated that modern closed-classified deer are more open-adapted than Holocene closed-classified deer.</p>

With a radiometric age of 396 ± 12 ma, the Rhynie Cherts, Grampian Region, Scotland, are the oldest unequivocal surface expression of an epithermal system in the world. Data is presented from 8 cored boreholes drilled within 100m of the Rhynie Cherts subcrop. The cherts are present in the upper part of the Lower Devonian basin infill which forms the Rhynie outlier. The basin is a half-graben structure, with a northeast/southwest trending western boundary, following the regional stress trend. In the area of the Rhynie Cherts, the western boundary is complicated by a series of cross faults. The eastern boundary is unconformable. The basin infill, in the area of Rhynie village, is a fining upwards sequence, produced locally from the newly formed Caledonide mountains. The basal Pre-Lava Sandstones Unit is an alluvial fan deposit. This is overlain by a series of basaltic andesite lavas with associated agglomerates and lapillistones. The Tuffaceous Sandstones Unit, containing both airfall and fluvially reworked tuffaceous material was deposited at the close of volcanic activity. The next unit in the series is the Shales with Thin Sandstones Unit, which contains the Rhynie and Windyfield Cherts. These two units of the post-lava sequence represent alluvial plain deposition, with evidence for sub-aerial exposure. The uppermost unit in the outlier is the Quarry Hill Sandstones unit, comprising fluvial channel sandstones. Hot spring activity occurred during the deposition of the Shales with Thin Sandstones Unit, resulting in the deposition of the Rhynie and Windyfield Cherts. A 35m cored borehole permits study of a vertical section through the chert bearing strata.

<p> Investigation of decapod fossils from the Pawpaw Shale, Albian, Texas, has yielded 17 new species, and seven new genera. In total, 14 brachyuran; 3 astacidean; 4 anomuran; 8 axiidean; 5 palinuridean, and one stomatopod species were described and classified according to the latest classification scheme. Shale samples from a single locality in Fort Worth were analyzed for their grain size, mineral and trace element content. The Pawpaw Shale consists of sediments derived from the Llanos uplift to the southwest of Fort Worth, and represents a fining upward sequence deposited in a restricted lagoonal environment. The decapod fauna of the Pawpaw Shale is one of the richest decapod faunas of Albian age known to date, composed of a population of adult and juvenile crabs and lobsters. The peculiar small size of the individual lobsters of this fauna is attributed to their representing an early ontogenetic stage. No trace elements known to affect the biology an physiology of extant decapods could be found in the shale samples analyzed to indicate an environmental cause for the reduced size of the Pawpaw lobsters.</p>

<p>The discovery of hundreds of fossil hominin remains from the Dinaledi Chamber of Rising Star cave in South Africa included dozens of immature elements attributed to multiple individuals. Some of these elements are amongst the most complete in the Dinaledi assemblage, but have not yet been fully studied. Thorough examination of these immature remains is important because they can provide a more complete understanding of the morphology of the Dinaledi hominins, facilitate an assessment of morphological development in the assemblage, and allow for direct comparisons with other immature fossil hominins. This dissertation focuses on the most diagnostic specimens of the immature lower limb (with reference to the immature upper limb and the mature sample) from the site and utilizes a comparative approach examining developmental variation in the proximal femur and limb proportions of extinct and extant ape species to discern the ontogenetic basis of the adult Dinaledi hominin form.</p><p>The first portion of this dissertation addresses the development of proximal femoral shape in an ontogenetic series of femora from the Dinaledi hominins, modern humans, chimpanzees, and gorillas. Results indicate that the development of proximal diaphyseal shape and neck-shaft angle are conserved within Homininae, but that neck shape may develop differently in bipeds than non-bipeds. The absolute shape of the femoral neck, however, markedly differs between the Dinaledi sample and modern humans, with greater anteroposterior constriction of the neck in the former, potentially due to increased superioinferior loading of the region associated with differing locomotor kinematics between species. </p><p>The second portion of this dissertation investigates the relative proportions of the immature Dinaledi lower limb. To date, the only lower limb long bone preserving the entire diaphysis and an articular surface to be recovered from the chamber, is the immature tibia, U.W. 101-1070. The length of this specimen was evaluated relative to the size of the preserved joint surface in an ontogenetic context and was found to be relatively long compared to other fossil hominins and even modern humans. The humero-tibial proportions of the immature Dinaledi hominins were found to be outside of the range of chimpanzees and gorillas, but comparable to modern humans and the immature Homo erectus specimen KNM-ER 15000. Together, these findings demonstrate that, with respect to relative lower limb length, the Dinaledi hominins are highly derived. </p><p>The mixture of primitive (australopith-like) and derived (Homo-like) features of the Dinaledi hominins identified in this dissertation are consistent with other early work on the assemblage and imply that the Dinaledi chamber contains Plio-Pleistocene hominins. Given small brain and predicted body sizes for the Dinaledi hominins, the results presented here suggest that relative limb elongation may have occurred prior to increases in brain and body size during hominin evolution and that bipedal energetic efficiency may have been the primary locus of selection. </p> / Dissertation

<p> The universality and importance of cooking both culturally and biologically is well established. Knowing when, where, and how in the archaeological record human groups began employing this practice can help answer questions concerning the timing and mechanism of both behavioral and anatomical changes in hominins. Identifying cooking in the archaeological record, however, is a complex taphonomic issue. When, where, and how hominins started controlling fire in the past is a greatly debated topic. Analyses of microscopic traces in soil and on bone may offer new lines of taphonomic evidence needed to demonstrate a specific use for fire. Specific cooking practices may also leave behind specific traces of macro-, micro-, faunal, and artifactual evidence. Previous research showed no change in the mineral component of human bone when boiled. To test the hypothesis that crystallinity changes also do not occur under low intensity thermal alteration, domestic pig limb bones were boiled for varying lengths of time. This study determined that even at longer periods of boiling, no observable change is observed in the crystallinity of the hydroxyapatite of bone. What was noted, however, was the existence of patina fractures on fleshed bone when boiled to certain lengths of time. Continued study of this novel observation may offer new insights into what degree of thermal intensity is needed for certain macroscopic observations and what micro- or primary structural properties of bone account for them. Other methods that examine the microstructure of bone may be able to detect changes that occur with low intensity thermal alteration that are unrelated to the state of the hydroxyapatite minerals. Further investigation is needed to understand which methods are best able, if possible, to identify differences that occur in bone that undergoes different diagenetic processes (i.e. weathering vs. low intensity thermal alteration vs. high intensity thermal alteration). Such investigations can illuminate how fire was utilized in the past.</p>

Organisms that grow by skeletal accretion contain a geochemical record of environmental conditions--they are, in effect, biological chart recorders. Thus, shell-bearing organisms are an important source of data on modern and ancient environments. Geochemical analysis of shell material sampled along an ontogenetic profile can provide time-series of the environmental variation experienced when the organism was growing. However, variations in growth rates and complete cessations of growth can bias biogeochemical archives. Thus, careful calibration of environmental conditions with shell growth is critical if reliable records are desired. Here, I present several studies designed to understand the relationship between bivalve shell growth and environmental variation. This is accomplished through careful calibration of temperature, geochemical variability, and growth increment variation (sclerochronology). I then apply the findings of these calibration studies to address paleobiological and paleoclimatic questions. I conducted a cross-calibration study relating annual temperature variation with stable oxygen isotope (δ¹⁸O) variation. I used daily increments to assign dates to each δ¹⁸O sample. I then compared the geochemically based temperature estimates with the actual temperatures from the same dates. Results indicate that combined geochemical and sclerochronological analyses can provide reliable estimates of environmental variation, as well as shed light on aspects of the clam's biology, such as the rate and timing of shell growth. The results of this study were then incorporated into a more generalized investigation of the relationship between annual temperature variation and growth rate. This study indicates that the resolution and fidelity of geochemically based environmental reconstructions depends strongly on growth rate and duration. Together, the results of these studies were applied to address paleobiological and paleoclimatic issues. First, I used sclerochronologically calibrated annual isotope profiles to detect time-averaging and spatial mixing. This study indicates that short duration time-averaging (<50 years), previously undetectable using traditional dating techniques, can be identified using oxygen isotope variation. Results also suggest that within-habitat spatial mixing can be detected. Results of the calibration studies were also applied to paleoclimate questions. Seasonality is an important aspect of paleoclimate reconstruction and is often inferred from annual oxygen isotopic variation in fossil shells. However, because many organisms do not grow throughout the year, their shells do not record the full range of seasonal temperatures. This limitation can be overcome by using stable oxygen isotope variation from two species, each of which continues to grow while the other has shut down. The method was demonstrated using two common venerid bivalves from the eastern Pacific. The reconstructed estimate of seasonality matches published sea-surface temperature data from the same site. I also used differences in δ¹⁸O values and daily increment numbers from modern and Pleistocene (last interglacial, ∼125,000 ybp) bivalves to estimate temperature change in the shallow marine environment off the coast of southern California. Data indicate that temperatures were∼3°C cooler than present, however, more data are needed to confirm these initial results.