William I Ausich - Academia.edu (original) (raw)

Papers by William I Ausich

Journal of Paleontology, Jan 14, 2024

Non-technical Summary.-Monstrocrinus is a most unusual crinoid from the Devonian of Germany. It h... more Non-technical Summary.-Monstrocrinus is a most unusual crinoid from the Devonian of Germany. It has long, simple to complex spines attached to most calyx plates. A stem was not associated with the initial specimens on which this genus was named. Thus, it was assumed that Monstrocrinus was a stemless crinoid that sat directly on the sea floor and, when alive, rolled around on its spines. For a variety of reasons, this seems unlikely, but the rolling crinoid lifestyle interpretation has persisted in the literature. More thorough cleaning of historical specimens and, more importantly, a new specimen with an attached column clearly refute the classical lifestyle interpretation and demonstrate that Monstrocrinus was a typical crinoid attached to a long column that was presumably anchored to the sea floor. In addition to revising the lifestyle of this crinoid, the varieties of spine types are redefined with names that more accurately reflect their morphology. Monstrocrinus occurs in Europe and South America, and one previously described species is placed in synonymy so that the genus is now comprised of three species.

Journal of Paleontology, Dec 12, 2023

Treatise online, Jul 9, 2023

Journal of Paleontology, Mar 1, 2012

Preparing for this presentation, I got hold of a list of Bruce's invited lectures, given during t... more Preparing for this presentation, I got hold of a list of Bruce's invited lectures, given during the past ten years. There are 86 titles on almost as many subjects. I will mention what these presentations were about, so you can get an impression of this Renaissance mind: Carbon isotopes and ocean evolution; Precambrian-Cambrian stratigraphy; Molecular evolution and the fossil record; Ediacaran organisms; Life on Mars; Oxygen and metazoan evolution; Orbital dynamics of the Earth-Moon system; Snowball Earth; Multiplated mollusks; Mass-independent fractionation of sulfur; Biomineralization; The Cambrian Explosion; Geobiology in the Archean; Cross-calibration of geological and astronomical time scales; Origins of biological complexity; Astrobiology of the Earth; Astrobiology of everything else; The Acraman impact of the Ediacaran; Biosignatures in ancient rocks; Microbial metabolism in the Early Archean.

2014 GSA Annual Meeting in Vancouver, British Columbia (19–22 October 2014), Oct 19, 2014

GSA Annual Meeting in Indianapolis, Indiana, USA - 2018, 2018

2012 GSA Annual Meeting in Charlotte, Nov 4, 2012

GSA Annual Meeting in Denver, Colorado, USA - 2016, 2016

Paleontological Institute, University of Kansas eBooks, 2011

JOURNAL OF PALEONTOLOGY V. 52, NO. 4, P. 916-920, 3 TEXT-FIGS., JULY 1978 ... A NEW LOWER ORDOVIC... more JOURNAL OF PALEONTOLOGY V. 52, NO. 4, P. 916-920, 3 TEXT-FIGS., JULY 1978 ... A NEW LOWER ORDOVICIAN (MIDDLE CANADIAN) DISPARID CRINOID FROM UTAH ... STUART M. KELLY AND WILLIAM I. AUSICH Indiana University, Bloomington 47401

Canadian Journal of Earth Sciences, 2018

Hirnantian (latest Ordovician) localities containing echinoderm fossils are rare; the few that ha... more Hirnantian (latest Ordovician) localities containing echinoderm fossils are rare; the few that have been discovered primarily contain disarticulated crinoid ossicles. Therefore, relatively little is known about echinoderm evolutionary dynamics across the Late Ordovician− early Silurian boundary, especially non-crinoid echinoderms. New diploporitan echinoderms, Holocystites salmoensis and an unidentified holocystitid, from reefal facies of the Upper Ordovician Ellis Bay Formation of Anticosti Island provide a critical data point concerning diploporitan biogeography and evolutionary pathways undertaken during the Ordovician and Silurian. These fossils also provide a crucial link in understanding the ancestry of the Silurian Holocystites Fauna, an unusual diploporitan fauna from the middle Silurian of North America, whose origination dates back at least 15 million years earlier than previously thought with the discovery of taxa described here. New fossil data such as these stress the importance of uncovering new localities from underrepresented times and places in Earth's history, so that these evolutionary transitions can be better understood.

Journal of Paleontology, Nov 1, 1991

Systematic revisions and revised stratigraphic occurrences are made toAorocrinus, Dorycrinus, Mac... more Systematic revisions and revised stratigraphic occurrences are made toAorocrinus, Dorycrinus, Macrocrinus, Paradichocrinus, Strotocrinus, andUperocrinusfrom the Osagean and Meramecian stratotype region in Iowa and Missouri. Systematic revisions include the assignment ofBatocrinus procerusMiller and Gurley as a junior synonym ofMacrocrinus mundulus. Batocrinus heteroclitusMiller and Gurley,B. vicinusMiller and Gurley, andB. stelliformisMiller and Gurley are assigned toUperocrinus heteroclitusn. comb. The concept ofAorocrinus spinosulus(Hall) did not match characteristics of the holotype. Consequently, the appropriate name for this concept isAorocrinus kelloggi(Worthen) n. comb., andA. spinosulusis assigned toDorycrinus mississippiensisas a junior synonym.Batocrinus strenuusis assigned toAorocrinus strenuusn. comb.?; andStrotocrinus glyptusis regarded as the valid name for the only species recognized in this genus.These systematic revisions result in the restriction ofStrotocrinus glyptusto the middle Osagean Burlington Limestone, and extension ofAorocrinus, Dorycrinus, Macrocrinus, andUperocrinusinto the Meramecian upper Warsaw Formation.

Paleobiology, 1987

Distributional patterns of late Osagean (Mississippian) crinoids from the east-central United Sta... more Distributional patterns of late Osagean (Mississippian) crinoids from the east-central United States are examined using multivariate analysis of crinoid species diversity and species abundance data. We confirm previous hypotheses that three well-defined crinoid associations existed during the late Osagean. These associations were dominated, respectively, by 1) monobathrid camerates preserved in carbonate packstones; 2) poteriocrine inadunates in higher-energy siltstones and sandstones; and 3) disparid inadunates, cyathocrine inadunates, and flexibles in mudstones where neither monobathrids nor poteriocrines dominated. In conjunction with petrologic data on the enclosing sediments, the analyses suggest that these associations occurred along a spectrum of increasing current velocity at the seafloor. Camerates, poteriocrine inadunates, and flexibles are interpreted to display preferences for specific environmental conditions, whereas disparid and cyathocrine inadunates are inferred to be environmental generalists.The different environmental distributions of the major crinoid groups are interpreted to be a function of the mode or modes of aerosol filtration feeding used by each group. This inference is possible through functional morphologic and morphometric studies of crinoid arms, because the skeletal elements of the arms, which are commonly preserved, are directly involved in feeding.

Proceedings of the Geologists' Association, Mar 1, 2022

AGU Fall Meeting Abstracts, Dec 1, 2006

ABSTRACT Diffusion studies of He in calcite suggest a potential to use carbonates as an alpha the... more ABSTRACT Diffusion studies of He in calcite suggest a potential to use carbonates as an alpha thermochronometer (Tc ~ 65°C). These results are all from coarse-grained calcite and dolomite but carbonate mud is a common constituent in many limestones. However, coarse calcite can usually be found in even the most micritic limestones in the form of biotic allochems. We have investigated the suitability of using crinoid columnals and shells of the bivalve Inoceramus for alpha thermochronolgy in limestones. After the death of a crinoid, the high-Mg calcite converts to low-Mg calcite with no loss of optical continuity, and the porosity is filled with syntaxial cement thus becoming permineralized. Bivalves undergo typical diagenesis where the high- Mg calcite converts to low-Mg calcite. Two of four crinoid samples yield reasonable alpha ages: A crinoid from the Thrifty Fm. (Pennsylvanian) in Texas gives an age of 120 Ma (0.7-4.0 ppm U) and one from the Edwardsville Fm. of the Borden Group (Lower Mississippian) in Indiana gives an age of 64 Ma (0.9 ppm U). Each of these results are consistent with the tectonic history of the regions. Crinoid pieces from the New Providence Shale Mbr. of the Borden Fm. (Lower Mississippian) in Kentucky have very low [U] (less than 90 ppb) and give Archean ages. Crinoids from the Hughes Creek Shale (Permian) in Kansas have seemingly robust amounts of U (0.7-2.1 ppm) but this sample also seems to be dominated by common He, yielding Proterozoic ages. Inoceramus from the Burditt Fm. of the Austin Gr. (Upper Cretaceous) in Texas gives an age of 0.5 Ma, suggesting that the closure temperature may be much lower than 65°C. Our preliminary conclusion is that crinoid columnals with more than 500 ppb U may be generally suitable for alpha thermochronology but that the closure temperature of He in Inoceramus shells may be too low for geologic application.