@article{straight_barrick_eberth_2004, title={Reflections of surface water, seasonality and climate in stable oxygen isotopes from tyrannosaurid tooth enamel}, volume={206}, ISSN={["0031-0182"]}, DOI={10.1016/j.palaeo.2004.01.006}, abstractNote={Patterns of isotopic variation in enamel of eight Albertosaurus teeth from the Campanian/Maastrichtian Horseshoe Canyon Formation, Alberta, were measured by serial sampling along the growth axis. Cycles in the isotopic values appear to correlate to published tooth growth rates for tyrannosaurids. Tyrannosaurid dinosaur teeth of ~50 mm in length provide ideal repositories of terrestrial climatic information as each records a full annual cycle of body water isotopic variation. The relatively thin enamel precludes problems associated with time-averaging associated with complex growth patterns found in thick mammalian enamel. The most consistent and striking pattern associated with all of the teeth are two relatively closely spaced subequal maxima. These appear to be associated with onset of a seasonal episode of high humidity after the activation of the “amount effect,” where the influence of ambient temperature on surface water (and body water) δ18O ends while temperatures remain above 20 °C. Teeth within a single fossiliferous horizon show the same general isotopic pattern and range. A notable difference in pattern shape and magnitude of isotopic variation between tyrannosaurid teeth from several stratigraphic intervals of the lower Horseshoe Canyon Formation section indicates a climatic changes from strong seasonality (high annual temperature range with distinct precipitation and humidity maxima during each year) at the base of the section to milder seasonality at the top.}, number={3-4}, journal={PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY}, author={Straight, WH and Barrick, RE and Eberth, DA}, year={2004}, month={Apr}, pages={239–256} }
 @article{dietl_kelley_barrick_showers_2002, title={Escalation and extinction selectivity: Morphology versus isotopic reconstruction of bivalve metabolism}, volume={56}, DOI={10.1111/j.0014-3820.2002.tb01338.x}, abstractNote={Abstract Studies that have tested and failed to support the hypothesis that escalated species (e.g., those with predation-resistant adaptations) are more susceptible to elimination during mass extinctions have concentrated on the distribution and degree of morphological defenses in molluscan species. This morphological approach to determining level of escalation in bivalves may be oversimplified because it does not account for metabolic rate, which is an important measure of escalation that is less readily accessible for fossils. Shell growth rates in living bivalves are positively correlated with metabolic rate and thus are potential indicators of level of escalation. To evaluate this approach, we used oxygen isotopes to reconstruct shell growth rates for two bivalve species (Macrocallista marylandica and Glossus markoei) from Miocene-aged sediments of Maryland. Although both species are classified as non-escalated based on morphology, the isotopic data indicate that M. marylandica was a faster-growing species with a higher metabolic rate and G. markoei was a slower-growing species with a lower metabolic rate. Based on these results, we predict that some morphologically non-escalated species in previous tests of extinction selectivity should be reclassified as escalated because of their fast shell growth rates (i.e., high metabolic rates). Studies that evaluate the level of escalation of a fauna should take into account the energetic physiology of taxa to avoid misleading results. Corresponding Editor: D. Geary}, number={2}, journal={Evolution}, author={Dietl, G. P. and Kelley, P. H. and Barrick, R. and Showers, W.}, year={2002}, pages={284–291} }
 @article{showers_barrick_genna_2002, title={Isotopic analysis of dinosaur bones}, volume={74}, ISSN={["0003-2700"]}, DOI={10.1021/ac021968b}, abstractNote={ADVERTISEMENT RETURN TO ISSUEPREVFeaturesNEXTPeer Reviewed: Isotopic Analysis of Dinosaur BonesA new pyrolysis technique provides direct evidence that some dinosaurs were warm-blooded.William J. Showers, Reese Barrick, and Bernard GennaCite this: Anal. Chem. 2002, 74, 5, 142 A–150 APublication Date (Web):March 1, 2002Publication History Published online1 March 2002Published inissue 1 March 2002https://doi.org/10.1021/ac021968bRIGHTS & PERMISSIONSArticle Views1803Altmetric-Citations7LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (10 MB) Get e-AlertscloseSUBJECTS:Anatomy Get e-Alerts}, number={5}, journal={ANALYTICAL CHEMISTRY}, author={Showers, WJ and Barrick, R and Genna, B}, year={2002}, month={Mar}, pages={142A–150A} }
 @article{barrick_kohn_2001, title={Multiple taxon-multiple locality approach to providing oxygen isotope evidence for warm-blooded theropod dinosaurs: Comment}, volume={29}, number={6}, journal={Geology (Boulder, Colo.)}, author={Barrick, R. E. and Kohn, M. J.}, year={2001}, pages={565–566} }
 @article{stoskopf_barrick_showers_2001, title={Oxygen isotope variability in bones of wild caught and constant temperature reared sub-adult American alligators}, volume={26}, ISSN={["0306-4565"]}, DOI={10.1016/S0306-4565(00)00041-3}, abstractNote={(1) The mean delta18O(BP) ( per thousandSMOW) for any given bone sampled from captive alligators maintained at high constant temperature was lower (indicative of higher temperatures of bone deposition) than that of the same bone from wild alligators caught in Northern Florida, but these differences were only greater than two standard deviations from the mean for the thoracic vertebrae and metatarsal bones. (2) Inter-bone variability of delta18O(BP) ( per thousandSMOW) was similar for captive alligators maintained at constant temperatures and the wild alligators, but intra-bone variability was much greater in wild alligators. (3) The order of mean delta18O(BP) ( per thousandSMOW) of bones (from highest to lowest) differed between treatment groups. However, intra-bone variability obscured the significance of those differences. Nevertheless, the thoracic vertebra had the highest mean delta18O(BP) ( per thousandSMOW), indicative of lower temperatures, and the lowest variability of bones in both groups of alligators. Conversely, the tibia was one of the warmest and more variable bones in both groups of alligators. (4) The pattern of delta18O(BP) ( per thousandSMOW) values across sites within long bones were identical between alligator treatment groups for the femur and humerus but differed between groups for the tibia and metatarsus, and differed between different long bones. The predicted intra-bone pattern for long bones of increasing delta18O(BP) ( per thousandSMOW) indicative of lower temperatures in more distal sampling sites was only obtained from the femurs. (5) Paired cortical and cancellous bone samples from the same site from all individuals in both treatment groups were available for proximal humeri and distal femurs. delta18O(BP) ( per thousandSMOW) values from cortical bone were more variable than those from cancellous bone for both bones. (6) Cortical bone had lower delta18O(BP) ( per thousandSMOW) values indicative of warmer temperatures than cancellous bone at sites sampled on the proximal humeri and distal femurs of all three animals from both treatment groups.}, number={3}, journal={JOURNAL OF THERMAL BIOLOGY}, author={Stoskopf, MK and Barrick, RE and Showers, WJ}, year={2001}, month={Jun}, pages={183–191} }
 @misc{russell_stoskopf_fisher_barrick_2000, title={At the crocodilian heart of the matter - Response}, volume={289}, number={5485}, journal={Science}, author={Russell, D. A. and Stoskopf, M. K. and Fisher, P. E. and Barrick, R. E.}, year={2000}, month={Sep}, pages={1688} }
 @article{fisher_russell_stoskopf_barrick_hammer_kuzmitz_2000, title={Cardiovascular evidence for an intermediate or higher metabolic rate in an ornithischian dinosaur}, volume={288}, ISSN={["0036-8075"]}, DOI={10.1126/science.288.5465.503}, abstractNote={Computerized tomography scans of a ferruginous concretion within the chest region of an ornithischian dinosaur reveal structures that are suggestive of a four-chambered heart and a single systemic aorta. The apparently derived condition of the cardiovascular system in turn suggests the existence of intermediate-to-high metabolic rates among dinosaurs.}, number={5465}, journal={SCIENCE}, author={Fisher, PE and Russell, DA and Stoskopf, MK and Barrick, RE and Hammer, M and Kuzmitz, AA}, year={2000}, month={Apr}, pages={503–505} }
 @article{barrick_fischer_showers_1999, title={Oxygen isotopes from turtle bone: Applications for terrestrial paleoclimates?}, volume={14}, ISSN={["0883-1351"]}, DOI={10.2307/3515374}, abstractNote={The oxygen isotope values (8) of turtle-bone phosphate for two freshwater emydid genera from the United States vary linearly with isotopic values (8J of environmental water. Mud, box, and snapping turtles do not fall on this regression line, while a soft-shelled turtle and marine loggerhead and leatherback turtles do. Although ectothermic, emydid turtles depend upon basking to raise their body temperatures. The mean temperature of bone growth is similar (3133?C) in emydid individuals analyzed as indicated by their bone and body-water oxygen isotopes. Unlike regressions for mammals, the slope of 8p versus 8, for these emydid turtles is unity, suggesting that the divergence from equilibrium is due to simple fractionation between environmental water and body water. Thus, bone 8, values from these genera of turtles (and potentially others) may be used to reconstruct local meteoric water 8w values in the fossil record. Concurrent study of fossil freshwater fish or molluscs may then be used to reconstruct local paleotemperatures.}, number={2}, journal={PALAIOS}, author={Barrick, RE and Fischer, AG and Showers, WJ}, year={1999}, month={Apr}, pages={186–191} }
 @article{anderson_lucas_barrick_heckert_basabilvazo_1998, title={Dinosaur skin impressions and associated skeletal remains from the upper Campanian of southwestern New Mexico: New data on the integument morphology of hadrosaurs}, volume={18}, ISSN={["0272-4634"]}, DOI={10.1080/02724634.1998.10011102}, abstractNote={ABSTRACT Skin impressions from the tail region of an indeterminate hadrosaur recently excavated from the Upper Cretaceous Ringbone Formation, southwest New Mexico represent the first known dinosaur specimen from New Mexico with impressions of the integument preserved in association with skeletal remains. The mid- to distal-caudal region is represented by 20 articulated centra, other disarticulated centra, a single chevron, ossified tendons and fragmentary bone, including poorly preserved neural spines. The skin impressions are preserved in negative and positive relief between two very fine-grained sandstone beds, interpreted as part of a fluvio-lacustrine facies package. The impression surface is directly below the ossified tendons, and 2.5 m from the articulated vertebral column. The skin impressions are six discrete patches characterized by predominantly apical, circular to ovate tubercles. Measurements of the long and short axes of individual tubercles demonstrate that a distribution of relatively homo...}, number={4}, journal={JOURNAL OF VERTEBRATE PALEONTOLOGY}, author={Anderson, BG and Lucas, SG and Barrick, RE and Heckert, AB and Basabilvazo, GT}, year={1998}, month={Dec}, pages={739–745} }
 @inproceedings{barrick_1998, title={Isotope paleobiology of the vertebrates: ecology, physiology, and diagenesis}, booktitle={Paleotechniques (Special publication (Paleontological Society) ; no. 4)}, publisher={Knoxville, TN: Dept. of Geologial Sciences, University of Tennessee}, author={Barrick, R. E.}, editor={R. M. Feldmann, R. E. Chapman and Hannibal, J. T.Editors}, year={1998}, pages={101–137} }
 @article{barrick_stoskopf_marcot_russell_showers_1998, title={The thermoregulatory functions of the Triceratops frill and horns: Heat flow measured with oxygen isotopes}, volume={18}, ISSN={["0272-4634"]}, DOI={10.1080/02724634.1998.10011103}, abstractNote={ABSTRACT Variability of body temperature within fossil vertebrates can be measured by the oxygen isotopie composition of bone phosphate (δp). Intrabone and interbone δp variations indicate heat flow within an individual and can be used to establish thermoregulatory strategies such as homeothermy and regional heterothermy. This method is applied to an individual Triceratops skeleton where the results suggest very high and uniform heat flow through the parietal frill, maintaining mean frill temperatures between 0–4°C below the body core. Heat flow to the postorbital horn-core is much more variable. The frill and horn cores of Triceratops were used as thermoregulatory structures with the horn cores interpreted as being especially important in the stabilization of brain temperatures at extreme ambient temperatures and the frill serving a more consistent role in body temperature regulation.}, number={4}, journal={JOURNAL OF VERTEBRATE PALEONTOLOGY}, author={Barrick, RE and Stoskopf, MK and Marcot, JD and Russell, DA and Showers, WJ}, year={1998}, month={Dec}, pages={746–750} }