Permian gastropods

p. 177-275, [16] p. of plates : ill., map ; 28 cm.Thesis (Ph. D.)--Columbia University.Includes bibliographical references (p. 271-275)."The present paper contributes to the systematic summation of the Permian gastropods of the United States by describing members of six superfamilies from this largely unknown assemblage. The finest Permian section in the United States is in western Texas. Many of the limestones there yield quantities of silicified fossils upon solution in hydrochloric acid. Collecting and acidizing programs of the United States National Museum and the American Museum of Natural History have resulted in the accumulation of large gastropod collections, which form the basis for this work. In addition, smaller collections of both silicified and non-silicified specimens from other areas have been treated. Following a brief review of the technical terms and methods employed in description, some comments on the paleoecology are given. Gastropods occur chiefly in four kinds of assemblages. A characteristic example of each of these assemblages is described, and from the evidence presented it is concluded that two of these four are transported and mixed and two are approximately in situ. It is concluded that most gastropods were from shallow water, where algae were most abundant. Attention is called to possible differences between 'limestone' and 'shale' gastropod faunas, but collections available do not permit one to draw any conclusions at this time. The main part of the paper is given to systematic descriptions of species, genera, and higher categories. All diagnoses and descriptions are original. Superfamilies diagnosed are the following: Euomphalacea, Trochonematacea, Pseudophoracea, Anomphalacea, Craspedostomatacea, and Platyceratacea. Families diagnosed are the following: Euomphalidae, Omphalotrochidae, Trochonematidae, Pseudphoridae, Anomphalidae, Craspedostomatidae, and Platyceratidae. The Craspedostomatidae are divided into three subfamilies: Craspedostomatinae, Brochidinae, and Dichostasinae. The last two are new categories. Genera or subgenera heretofore known and rediagnosed are Straparollus (Euomphalus), Amphiscapha (Amphiscapha), Omphalotrochus, Cyclites, Anomphalus, Brochidium, and Platyceras (Orthonychia). Brochidium has not previously been reported in the Permian of North America. New genera or subgenera recognized are Amphiscapha (Cylicioscapha), Straparollus (Leptomphalus), Planotectus, Babylonites, Discotropis, Diploconula, Sallya, and Dichostasia. The remainder of the paper consists of descriptions of species of the genera listed above. These include two Pennsylvanian species, deemed pertinent to the Permian studies and not described or illustrated since the original diagnosis, and 45 Permian species given in approximate stratigraphic order. Thirty-nine of the Permian species are considered to be new, and 30 species are well enough known to warrant being formally named. Variation in one species of Platyceras (Orthonychia) is considered to be caused by the specimens' being modified to conform to the calyx of several different crinoids. Occurrence data given in connection with all the Permian species are summarized on a single table"--P. 179

A Systematic Review of the Literature on the Use of Rational Emotive Behaviour Therapy in Criminal Justice Work to Reduce Re-offending

A systematic review of the published literature from 1995 to 2007 considers the published evidence on the use of interventions employing Rational Emotive Behaviour Therapy in criminal justice efforts to reduce re-offending. Thirty-six studies are briefly described, summarised and appraised for research quality using a six point scale. Twenty-four studies were excluded from further analysis due to insufficiently rigorous or weak research design and method. Twelve studies were appraised as sufficiently robust to reliably inform the research interest. Further analysis of the studies indicated an association between negative emotional states and offending behaviour, some evidence of REBT effectiveness in treating emotional disturbance in offender populations, and mixed evidence of REBT effectiveness in reducing re-offending. It is concluded that interventions using REBT might be a promising approach for aiding criminal justice aims to reduce re-offending

Modeling durophagous predation and mortality rates from the fossil record of gastropods

Gastropods often show signs of unsuccessful attacks by durophagous predators in the form of healed scars in their shells. As such, fossil gastropods can be taken as providing a record of predation through geological time. However, interpreting the number of such scars has proved to be problematic—Would a low number of scars mean a low rate of attack or a high rate of success, for example? Here we develop a model of population dynamics among individuals exposed to predation, including both lethal and nonlethal attacks. Using this model, we calculate the equilibrium distributions of ages and healed scars in the population and among fossilized specimens, based on the assumption that predation is independent of age or scar number. Based on these results, we formally show that the rates of attack and success cannot be disambiguated without further information about population structure. Nevertheless, by making the assumptions that the non-durophagous predatory death rate is both constant and low, we show that it is possible to use relatively small assemblages of gastropods to produce accurate estimates of both attack and success rates, if the overall death rate can be estimated. We consider likely violations of the assumptions in our model and what sort of information would be required to solve this problem in these more general cases. However, it is not easy to extract the relevant information from the fossil record: a variety of important biases are likely to intervene to obscure the data that gastropod assemblages may yield. Nonetheless, the model provides a theoretical framework for interpreting summary data, including for comparison between different assemblages

The fate of the homoctenids (Tentaculitoidea) during the Frasnian-Famennian mass extinction (Late Devonian)

The homoctenids (Tentaculitoidea) are small, conical-shelled marine animals which are amongst the most abundant and widespread of all Late Devonian fossils. They were a principal casualty of the Frasnian-Famennian (F-F, Late Devonian) mass extinction, and thus provide an insight into the extinction dynamics. Despite their abundance during the Late Devonian, they have been largely neglected by extinction studies. A number of Frasnian-Famennian boundary sections have been studied, in Poland, Germany, France, and the United States. These sections have yielded homoctenids, which allow precise recognition of the timing of the mass extinction. It is clear that the homoctenids almost disappear from the fossil record during the latest Frasnian “Upper Kellwasser Event”. The coincident extinction of this pelagic group, and the widespread development of intense marine anoxia within the water column, provides a causal link between anoxia and the F-F extinction. Most notable is the sudden demise of a group, which had been present in rock-forming densities, during this anoxic event. One new species, belonging to Homoctenus is described, but is not formally named here

Palaeogeographic distribution and diversity of cephalopods during the Cambrian-Ordovician transition

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