The Making of a Monster: Postnatal Ontogenetic Changes in Craniomandibular Shape in the Great Sabercat Smilodon

Derived sabercats had craniomandibular morphologies that in many respects were highly different from those of extant felids, and this has often been interpreted functionally as adaptations for predation at extreme gape angles with hypertrophied upper canines. It is unknown how much of this was a result of intraspecific postnatal ontogeny, since juveniles of sabercats are rare and no quantitative study has been made of craniomandibular ontogeny. Postnatal ontogenetic craniomandibular shape changes in two morphologically derived sabercats, Smilodon fatalis and S. populator, were analysed using geometric morphometrics and compared to three species of extant pantherines, the jaguar, tiger, and Sunda clouded leopard. Ontogenetic shape changes in Smilodon usually involved the same areas of the cranium and mandible as in extant pantherines, and large-scale modularization was similar, suggesting that such may have been the case for all felids, since it followed the same trends previously observed in other mammals. However, in other respects Smilodon differed from extant pantherines. Their crania underwent much greater and more localised ontogenetic shape changes than did the mandibles, whereas crania and mandibles of extant pantherines underwent smaller, fewer and less localised shape changes. Ontogenetic shape changes in the two species of Smilodon are largely similar, but differences are also present, notably those which may be tied to the presence of larger upper canines in S. populator. Several of the specialized cranial characters differentiating adult Smilodon from extant felids in a functional context, which are usually regarded as evolutionary adaptations for achieving high gape angles, are ontogenetic, and in several instances ontogeny appears to recapitulate phylogeny to some extent. No such ontogenetic evolutionary adaptive changes were found in the extant pantherines. Evolution in morphologically derived sabercats involved greater cranial ontogenetic changes than among extant felids, resulting in greatly modified adult craniomandibular morphologies

Integrated geological-engineering model of Patrick Draw field and examples of similarities and differences among various shoreline barrier systems

The Reservoir Assessment and Characterization Research Program at NIPER employs an interdisciplinary approach that focuses on the high priority reservoir class of shoreline barrier deposits to: (1) determine the problems specific to this class of reservoirs by identifying the reservoir heterogeneities that influence the movement and trapping of fluids; and (2) develop methods to characterize effectively this class of reservoirs to predict residual oil saturation (ROS) on interwell scales and improve prediction of the flow patterns of injected and produced fluids. Accurate descriptions of the spatial distribution of critical reservoir parameters (e.g., permeability, porosity, pore geometry, mineralogy, and oil saturation) are essential for designing and implementing processes to improve sweep efficiency and thereby increase oil recovery. The methodologies and models developed in this program will, in the near- to mid-term, assist producers in the implementation of effective reservoir management strategies such as location of infill wells and selection of optimum enhanced oil recovery methods to maximize oil production from their reservoirs

Integrated geological-engineering model of Patrick Draw field and examples of similarities and differences among various shoreline barrier systems

The Reservoir Assessment and Characterization Research Program at NIPER employs an interdisciplinary approach that focuses on the high priority reservoir class of shoreline barrier deposits to: (1) determine the problems specific to this class of reservoirs by identifying the reservoir heterogeneities that influence the movement and trapping of fluids; and (2) develop methods to characterize effectively this class of reservoirs to predict residual oil saturation (ROS) on interwell scales and improve prediction of the flow patterns of injected and produced fluids. Accurate descriptions of the spatial distribution of critical reservoir parameters (e.g., permeability, porosity, pore geometry, mineralogy, and oil saturation) are essential for designing and implementing processes to improve sweep efficiency and thereby increase oil recovery. The methodologies and models developed in this program will, in the near- to mid-term, assist producers in the implementation of effective reservoir management strategies such as location of infill wells and selection of optimum enhanced oil recovery methods to maximize oil production from their reservoirs

Reservoir Characterization, Production Characteristics, and Research Needs for Fluvial/Alluvial Reservoirs in the United States

The Department of Energy's (DOE's) Oil Recovery Field Demonstration Program was initiated in 1992 to maximize the economically and environmentally sound recovery of oil from known domestic reservoirs and to preserve access to this resource. Cost-shared field demonstration projects are being initiated in geology defined reservoir classes which have been prioritized by their potential for incremental recovery and their risk of abandonment. This document defines the characteristics of the fifth geological reservoir class in the series, fluvial/alluvial reservoirs. The reservoirs of Class 5 include deposits of alluvial fans, braided streams, and meandering streams. Deposit morphologies vary as a complex function of climate and tectonics and are characterized by a high degree of heterogeneity to fluid flow as a result of extreme variations in water energy as the deposits formed

Paleoecological reconstruction of a lower Pleistocene large mammal community using biogeochemical (δ 13

Ecomorphological and biogeochemical (trace element, and carbon, nitrogen, and oxygen isotope ratios) analyses have been used for determining the dietary niches and habitat preferences of large mammals from lower Pleistocene deposits at Venta Micena (Guadix-Baza Basin, Spain). The combination of these two approaches takes advantage of the strengths and overcome the weakness of both approaches. The range of δ13Ccollagen values for ungulate species indicates that C3 plants were dominant in the diet of these mammals. δ13Ccollagen values vary among ungulates: perissodactyls have the lowest values and bovids the highest ones, with cervids showing intermediate values. The hypsodonty index measured in lower molar teeth and the relative length of the lower premolar tooth row indicate that the horse, Equus altidens, was a grazing species, whereas the rhino, Stephanorhinus etruscus, was a mixed feeder in open habitats. The similar δ13Ccollagen values shown in both perissodactyls does not reflect differences in feeding behavior with other ungulates, but rather a lower isotope enrichment factor in these monogastric herbivores than in ruminants, owing to their lower metabolic efficiency. The cervids Eucladoceros giulii and Dama sp. show low hypsodonty values, indicating that they were mixed feeders or browsers from forested habitats, an ecomorphologically based conclusion corroborated in the former by its low δ15Ncollagen content (canopy effect). Bovid species (Bovini aff. Leptobos, Soergelia minor, and Hemitragus albus) presumably inhabited open environments, according to their comparatively high hypsodonty and δ15Ncollagen values. Carnivore species (Homotherium latidens, Megantereon whitei, Pachycrocuta brevirostris, Canis falconeri, and Canis etruscus) exhibit higher δ15Ncollagen values than ungulates. These results record the isotopic enrichment expected with an increase in trophic level and are also supported by low bone Sr.Zn ratios. The elevated δ15Ncollagen value for a sample of Mammuthus meridionalis, which came from an individual with unfused epiphyses, confirms that it was a suckling animal. The δ15Ncollagen value of the scimitar-cat H. latidens is well above that obtained for the young individual of Mammuthus, which indicates that juvenile elephants were an important part of its diet. The hippo, Hippopotamus antiquus, yielded unexpectedly high δ15Ncollagen values, which suggest feeding on aquatic, non-N2-fixing plants. The high δ18Ohydroxyl values of bovids Hemitragus and Soergelia and of cervid Dama indicate that these ungulates obtained most of their water requirements from the vegetation. The megaherbivores and Eucladoceros exhibit the lowest δ18Ohydroxyl values, which suggest increased water dependence for them. Paleosynecological analysis was based on the relative abundance of species of large mammals from different ecological categories, determined by feeding behavior and locomotion types. The comparison of the frequencies of such categories in Venta Micena with those found in modern African communities indicates that the composition of the paleocommunity closely resembles those of savannas with tall grass and shrubs. The net above-ground primary productivity estimated for the on-crop biomass of the mammalian species preserved in the fossil assemblage also yields a figure congruent with that expected for an open environment