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A New Partial Skeleton Of A Cryptocleidoid Plesiosaur From The Upper Jurassic Sundance Formation Of Wyoming, Benjamin C. Wilhelm, F. Robin O’Keefe
A New Partial Skeleton Of A Cryptocleidoid Plesiosaur From The Upper Jurassic Sundance Formation Of Wyoming, Benjamin C. Wilhelm, F. Robin O’Keefe
Biological Sciences Faculty Research
Cryptocleidoid plesiosaurs from the Upper Jurassic are well known from the Oxford Clay (Callovian) of the United Kingdom. The plesiosaurs of the nearly coeval Sundance Formation (Oxfordian) of North America are poorly known, but are thought to include two cryptocleidoid taxa:Pantosaurus striatus and Tatenectes laramiensis. Here we present two specimens recently recovered from the Bighorn Basin of Wyoming. The first specimen comprises three articulated adult cervical vertebrae and fragments of a fourth. This specimen preserves a posteriorly directed cervical neural spine, a character diagnostic of Pantosaurus striatus. It also resembles Pantosaurus in the morphology of its cervical …
Spatial Heterogeneity Of Soil Nutrients And Plant Species In Herb-Dominated Communities Of Contrasting Land Use, Frank S. Gilliam, David A. Dick
Spatial Heterogeneity Of Soil Nutrients And Plant Species In Herb-Dominated Communities Of Contrasting Land Use, Frank S. Gilliam, David A. Dick
Biological Sciences Faculty Research
Recent interest in spatial pattern in terrestrial ecosystems has come from an awareness of theintimate relationship between spatial heterogeneity of soil resources and maintenance of plant species diversity. Soil and vegetation can vary spatially inresponse to several state factors of the system. In this study, we examined fine-scale spatial variability of soil nutrients and vascular plant species in contrasting herb-dominated communities (a pasture and an oldfield) to determine degree of spatial dependenceamong soil variables and plant community characteristics within these communities by sampling at 1-m intervals. Each site was divided into 25 1-m 2 plots. Mineral soil was sampled (2-cm …
Evidence Of Pachyostosis In The Cryptocleidoid Plesiosaur Tatenectes Laramiensis From The Sundance Formation Of Wyoming, Hallie P. Street, F. Robin O’Keefe
Evidence Of Pachyostosis In The Cryptocleidoid Plesiosaur Tatenectes Laramiensis From The Sundance Formation Of Wyoming, Hallie P. Street, F. Robin O’Keefe
Biological Sciences Faculty Research
In this paper we present evidence for pachyostosis in the cryptocleidoid plesiosaur Tatenectes laramiensis Knight, 1900 (O'Keefe and Wahl, 2003a). Pachyostosis is not common in plesiosaurs and is particularly rare in non-pliosaurian plesiosaurs, although enlarged gastralia were first recognized in Tatenectes by Wahl (1999). This study aims to investigate the nature of the disproportionately large gastralia of Tatenectes m greater depth, based on new material. A recently discovered partial skeleton consisting of a dorsal vertebral series, ribs, gastralia, and a complete pelvic girdle was collected from the Jurassic-aged Sundance Formation of the Bighorn Basin in Wyoming during the summer of …
Global Assessment Of Nitrogen Deposition Effects On Terrestrial Plant Diversity : A Synthesis, R. Bobbink, K. Hicks, J. Galloway, T. Spranger, R. Alkemade, M. Ashmore, M. Bustamante, S. Cinderby, E. Davidson, F. Dentener, B. Emmett, J. W. Erisman, M. Fenn, Frank S. Gilliam, A. Nordin, L. Pardo, W. Devries
Global Assessment Of Nitrogen Deposition Effects On Terrestrial Plant Diversity : A Synthesis, R. Bobbink, K. Hicks, J. Galloway, T. Spranger, R. Alkemade, M. Ashmore, M. Bustamante, S. Cinderby, E. Davidson, F. Dentener, B. Emmett, J. W. Erisman, M. Fenn, Frank S. Gilliam, A. Nordin, L. Pardo, W. Devries
Biological Sciences Faculty Research
Atmospheric nitrogen (N) deposition is a recognized threat to plant diversity in temperate and northern parts of Europe and North America. This paper assesses evidence from field experiments for N deposition effects and thresholds for terrestrial plant diversity protection across a latitudinal range of main categories of ecosystems, from arctic and boreal systems to tropical forests. Current thinking on the mechanisms of N deposition effects on plant diversity, the global distribution of G200 ecoregions, and current and future (2030) estimates of atmospheric N-deposition rates are then used to identify the risks to plant diversity in all major ecosystem types now …