The microherpetofaunas recovered from the Kaiparowits Plateau, Utah, are described. Small reptiles and amphibians from 16 families and at least 22 genera were obtained from the Cenomanian Dakota, Turonian to Santonian Straight Cliffs, the early Campanian Wahweap, and the Campanian (Judithian) Kaiparowits Formations. A new genus and species of polyglyphanodontine, Manangyasaurus saueri, is described. The function of the unusual teeth of polyglyphanodontines is uncertain, but may have been related to frugivory. The polyglyphanodontines, in the restricted sense, appear to be confined to the western localities of the "southern communities" in the Judithian and Lancian. The early occurrence (Turonian) of Paraglyphanodon in the Straight Cliffs Formation suggests that the polyglyphanodontines may have been widespread during earlier Ages, permitting their dispersal to or from Asia. The genus Albanerpeton is best considered a member of the Order Caudata and its provisional assignment to the Family Prosirenidae is reasonable. The Polyglyphanodontidae, as presently defined, consists of a holophyletic group consisting of Polyglyphanodon, Paraglyphanodon, Manangyasaurus, and Cherminsaurus, and a poorly defined group consisting of the Asian "Macrocephalosauridae" Peneteius may also be a polyglyphanodontine, as the subfamily is presently defined.

Marine upwelling occurs when surface currents diverge or are deflected. Deeper water, often nutrient-rich, rises and generates a cascade of biological effects including elevated productivity and a unique assemblage of organisms. Macrofaunal characteristics of upwelling provide key evidence for oxygen-minimum zones, upwelling of cool water, and high productivity and are potentially useful indicators of ancient upwelling. The Upper Triassic Luning Formation in Nevada contains abundant, large ichthyosaurs and was deposited in a back-arc basin that could have experienced upwelling conditions. Luning Formation rocks at West Union Canyon were analyzed for sedimentological, geochemical, and paleontological upwelling indicators. Abundant suspension feeders, lack of corals and calcareous algae, modest total organic carbon and minor element concentrations in deeper marine facies, abundant cosmopolitan molluscs but no taxa restricted to low latitudes, and abundant fecal pellets and clotted fabrics in most facies suggest that upwelling could have influenced Luning deposition. Moderate-scale upwelling likely contributed to eutrophic conditions and ichthyosaur abundance at West Union Canyon. Marine reptiles might have had ties to upwelling areas to provide food, as do modern whales. A relational database containing 817 locality records and 1365 taxon-localities was assembled for ichthyosaurs, plesiosaurs, and mosasaurs. Marine reptile localities were compared with model-predicted upwelling and with upwelling-related lithologies (organic-rich rock, biogenic silica, phosphorite, and glauconite). Marine reptile occurrences intersected predicted upwelling more often than expected by chance for the Upper Cretaceous, Callovian, and Norian stages, and for all of the data together (P = 0.05). For age-restricted data, occurrences of Mosasauridae, Pliosauridae, and Plesiosauria intersected upwelling more often than expected by chance (P = 0.05). Average shortest distances between reptile fossil and upwelling lithology occurrences were smallest (one grid cell adjacent or smaller) for the Pliensbachian and four of five Cretaceous stages. Analytical biases and other aspects of reptile ecology may have affected the results, but overall, upwelling could have influenced marine reptile distribution, particularly for the Upper Cretaceous. Multiple radiations into the high-productivity, top-predator niche over the Mesozoic are suggested by the dominance of different taxa in grid cells containing upwelling lithologies: ichthyosaurs (early Mesozoic), plesiosaurs (middle Mesozoic), and finally mosasaurs (late Mesozoic).

About 2,500 specimens of small mammal fossils were collected from 10 localities in the Pliocene Panaca Formation in Meadow Valley, southeast Nevada. The most common taxa are cricetid and heteromyid rodents, and lagomorphs. Twenty-seven species, including five new species, were recognized from the fauna. A new genus of microtine rodent, Nevadomys, including three new species, N. fejfari, N. lindsayi, and N. downsi, is recognized. Nevadomys was probably derived from the Hemphillian Paramicrotoscoptes. Repomys minor n. sp. is another new species of high-crowned cricetid that was detected in the Panaca local fauna. With abundant upper and lower third molars of Repomys, it was possible to amend the diagnoses of genus Repomys. The fifth new species recognized from the fauna is a shrew, Paranotiosorex panacaensis n. gen. and sp. Enamel microstructure of molars of the microtine rodents Mimomys panacaensis and Nevadomys n. gen. from the fauna were examined under the scanning electronic microscope. Mimomys panacaensis shows the same schmelzmuster among different populations. Nevadomys has a more primitive schmelzmuster compared to Mimomys panacaensis. Both its leading and trailing edges are entirely composed of radial enamel. The assemblage of small mammal fossils suggests that the Panaca local fauna represents the early Blancan land mammal age. The first appearance datum of Mimomys panacaensis is suggested as the beginning of Blancan land mammal age, and the absolute age of the lowest stratigraphic datum of M. panacaensis in the Panaca Formation is interpolated from magnetostratigraphy and is considered as the age of the Hemphillian-Blancan boundary. The magnetostratigraphy of the Panaca Formation in Meadow Valley is established based on four sections in the basin. The ash in the Rodent Hill section was dated at 4.64 +/- 0.03 Ma, which constrains the correlation of the reversed polarity magnetozone in the Rodent Hill section to the C3n.2r in the Geomagnetic Polarity Time Scale (GPTS). The other three sections are correlated to the Rodent Hill section based on the ashes. The Panaca Formation in Meadow Valley was deposited from 4.50--5.30 Ma, and the Hemphillian-Blancan boundary is around 4.95 Ma, close to the termination of Thvera Subchron in the GPTS.

Plant-feeding insects are the most species-rich group on the planet today. Models have been proposed to explain this diversity, but few use the fossil record to evaluate hypotheses. I conduct studies in modern systems to examine (1) taphonomic biases in insect preservation and how this may affect our understanding of insect diversity trends through time and (2) patterns of herbivory in modern ecosystems to improve the comparability of fossil and modern datasets. I then use the Cenozoic fossil record to examine the history of ecological associations between insects and plants and how these interactions respond to environmental change. I conducted an actualistic study on the preservation of beetles in Willcox Playa, an ephemeral lake in SE Arizona. I compared the insect death assemblage in shoreline sediments to the living beetle assemblage. The sediments captured 56% of the live-collected beetle families, and 28% of the live-collected beetle genera. The relative abundances of living beetles were not reflected in the death assemblage. Beetle diet, feeding habitat, and size influenced the composition of the death assemblage. Necrophagous, ground-dwelling and smaller beetles were over-represented in the death assemblage. Such biases should be considered in insect paleoepology and in studies of diversity change. Annual variation in herbivory was compared within and between two lowland neotropical forests Costa Rica. Herbivory did not vary significantly within sites between years, but was significantly different: between sites. Modern herbivory data collected with discrete sampling techniques is compartable to herbivory data from fossil forests. Herbivory data from one-time collections of leaf litter are most suitable for comparison with fossil herbivory. I compared herbivory between two Eocene floras and between the Eocene floras and six modern floras. A decline in levels of herbivory corresponds with a decline in temperature from the middle to the late Eocene. Fossil herbivore damage was significantly lower than modern herbivore damage. This pattern may result from taphonomic bias, environmental differences between the fossil and modern sites or evolutionary change.

No description available.

No description available.

No description available.

<p> Ceratopsian dinosaurs are one of the most diverse dinosaur groups in the Cretaceous, and an outstanding question is how growth strategies of this group evolved in relation to their shift from small bipedal basal ceratopsians to larger quadrupedal ceratopsids. Previous bone histology studies have investigated several basal ceratopsians and centrosaurine ceratopsids (e.g., <i>Centrosaurus, Pachyrhinosaurus, Einiosaurus</i>), but no chasmosaurine ceratopsids have been investigated. I conducted histological analysis of humeri, ulnae, femora, tibiae, ribs, and ossified tendons from multiple specimens of two species of chasmosaurine ceratopsid dinosaurs from the late Campanian (Upper Cretaceous) Kaiparowits Formation of southern Utah, <i>Kosmoceratops richardsoni</i> and <i>Utahceratops gettyi</i>, to examine bone microstructure indicators of growth rate and maturity. I also reexamined the long-bone histology of the ceratopsian dinosaurs <i>Psittacosaurus mongoliensis, Protoceratops andrewsi</i>, and <i>Centrosaurus apertus </i>. All elements of <i>Utahceratops</i> and <i>Kosmoceratops </i> examined are dominated by densely vascularized tissue, indicative of sustained fast growth. Radially-oriented vascular canals as well as dense osteocytes from throughout ontogeny are further indicators of rapid growth. I identified juvenile (UMNH VP 20444, UMNH VP 20454), subadult (UMNH VP 16681) and adult (UMNH VP 16860, UMNH VP 16861, UMNH VP 12198) specimens of <i> Utahceratops</i>, and two subadult to adult specimens (UMNH VP 17000, UMNH VP 21339) of <i>Kosmoceratops</i>. </p><p> I conclude that basal ceratopsians grew more slowly than the large quadrupedal ceratopsids, as evidenced by a generally higher number of definitive growth lines prevalent throughout development. In contrast, the presence of dense osteocytes, and reticular and radially-oriented vascular canals are rapid growth indicators shared by all sampled large ceratopsids, and imply an elevated metabolism for all ceratopsians. Sampled specimens of <i>Utahceratops </i> and <i>Kosmoceratops</i> do not preserve any evidence of annual lines of arrested growth (LAGs). Placed in context with the number of LAGs observed in Alaskan <i>Pachyrhinosaurus, Centrosaurus</i> from Alberta, and <i>Einosaurus</i> from Montana, these data suggest a latitudinal gradient in the number of LAGs, which suggests that bone growth is reacting to the climate.</p>

In this paper we explored variation in Cr/Co and V/Co ratios with time in 21 pelagic clay samples from various locations in Pacific Ocean. We also included data from previous researchers to illustrate the trend we observed. Reasons for the observed change are explained and pros and cons for each one are examined. What motivated us to start this research is that redox evolution of oceans through time is one of the most desired but elusive parameters in paleo-oceanography. Most attempts have focused on tracking variations in redox-sensitive elements in anoxic margin sediments. However, redox conditions in marginal basins vary widely due to local effects and do not necessarily represent the conditions of the open ocean. As an alternative approach, bulk-rock Cr/Co and V/Co ratios in oxic pelagic clays are explored here as tracers of redox-evolution of the global oceans on the million year timescale. Bulk-rock Cr/Co and V/Co ratios are always much lower than that of riverine inputs. One of the explanations for this phenomenon is that Cr and V are probably sequestered in anoxic environments on oceanic margins whereas the open ocean appears to be the major sink for Co. Based on this mass balance approach, it seems that, in theory, it should be possible to use these elemental ratios as potential tracers of redox state in the ocean. However, here we were not able to confirm this possibility. Bulk-rock Cr/Co and to a lesser extent V/Co ratios in several pelagic clay sites in the Pacific show a rise from ~25 Ma ago to the present. While this secular change in bulk ratios might suggest an increase in oxygenation of the Pacific Ocean, the changes can be simply explained by an increase in detrital component, such as wind-blown dust or volcanic ash, or equivalently, by a proportional decrease in hydrothermal inputs. In order to minimize influence on the change caused by detrital component, we tried to calculate hydrogenous component in our samples by subtracting out a detrital component that has a constant composition, which in reality is likely to vary significantly and the value is not known well. Besides variation in the composition of the detrital component, there are other explanations including diagenetic effects and changes in the composition of the dissolved inputs into rivers with time. We conclude that although Cr/Co and V/Co hold promise as potential redox-sensitive tracers, interpreting their signals is presently frustrated by many complicating factors.

Piston cores and single-channel seismic profiles were collected from the western South Orkney Plateau to investigate glacial history, survey the seismic stratigraphy, and test the feasibility of paleoceanographic interpretation as a site survey for O.D.P Leg 113 drilling operations. Data reveal evidence for past grounded ice to 240 meters depth, and expanded floating ice cover over the entire plateau. Paleoceanographic interpretation is difficult because nearly 75% of slope cores are affected by sediment gravity flow. All dip-oriented seismic lines show large-scale slumping. Surface sample textural data indicate that wind-driven currents are redistributing sediments in a predictable pattern to about 450 meters depth. Total grain size analyses are necessary to differentiate ice-rafted-debris from other sands. Seismic data support previous interpretations of a passive margin setting, and show up to three seismic sequences within sediment fill on the margin and plateau.