128 research outputs found
New Late Miocene North American dromomerycine artiodactyl from the Amazon Basin: implications for interchange dynamics
Late Pleistocene Pronghorn, \u3ci\u3eAntilocapra Americana\u3c/i\u3e, from Natural Trap Cave, Wyoming
Natural Trap Cave, Wyoming, has yielded one of the more reliable records of Antilocapra from the Late Pleistocene of North America. Generic assignment is based on horn cores from two individuals, with a minimum of 13 individuals represented by other elements. Morphometric analysis of postcranial material indicates that this form is indistinguishable from the living A. americana. Fossils were recovered from a stratum dated at 17,000-20,000 yr BP. Presence of Antilocapra at other sites is probably over-reported. Secure records based on horn cores are known from only two other sites. Antilocapra americana may have been the preferred prey of the American cheetah, Miracinonyx trumani. Teeth, horn cores, and much of the postcranial skeleton of the Natural Trap pronghorn are figured
Craniodental Morphology and Systematics of a New Family of Hystricognathous Rodents (Gaudeamuridae) from the Late Eocene and Early Oligocene of Egypt
BACKGROUND: Gaudeamus is an enigmatic hystricognathous rodent that was, until recently, known solely from fragmentary material from early Oligocene sites in Egypt, Oman, and Libya. Gaudeamus' molars are similar to those of the extant cane rat Thryonomys, and multiple authorities have aligned Gaudeamus with Thryonomys to the exclusion of other living and extinct African hystricognaths; recent phylogenetic analyses have, however, also suggested affinities with South American caviomorphs or Old World porcupines (Hystricidae). METHODOLOGY/PRINCIPAL FINDINGS: Here we describe the oldest known remains of Gaudeamus, including largely complete but crushed crania and complete upper and lower dentitions. Unlike younger Gaudeamus species, the primitive species described here have relatively complex occlusal patterns, and retain a number of plesiomorphic features. Unconstrained parsimony analysis nests Gaudeamus and Hystrix within the South American caviomorph radiation, implying what we consider to be an implausible back-dispersal across the Atlantic Ocean to account for Gaudeamus' presence in the late Eocene of Africa. An analysis that was constrained to recover the biogeographically more plausible hypothesis of caviomorph monophyly does not place Gaudeamus as a stem caviomorph, but rather as a sister taxon of hystricids. CONCLUSIONS/SIGNIFICANCE: We place Gaudeamus species in a new family, Gaudeamuridae, and consider it likely that the group originated, diversified, and then went extinct over a geologically brief period of time during the latest Eocene and early Oligocene in Afro-Arabia. Gaudeamurids are the only known crown hystricognaths from Afro-Arabia that are likely to be aligned with non-phiomorph members of that clade, and as such provide additional support for an Afro-Arabian origin of advanced stem and basal crown members of Hystricognathi
Geothermal Heat Recovery Complex: Large-Scale, Deep Direct-Use System in a Low-Temperature Sedimentary Basin
This feasibility study is the first assessment of geothermal resources in the Illinois Basin (ILB). The breadth of previous, geologic-based research in the ILB supported this thorough determination of geothermal resources in the Mt. Simon Sandstone (MSS) and the techno-economics of establishing a geothermal energy system (GES) at the University of Illinois at Urbana-Champaign (U of IL). An integrated, multi-disciplinary scientific and engineering approach allowed simulations for both the belowground and aboveground components of the GES that would meet the required baseload of 2 MMBtu/hr at the end-user agricultural research facilities (ARFs). This assessment contributes to the broader discussion surrounding the U of IL’s goal to achieve net-zero carbon emissions by 2050. Furthermore, a rigorous evaluation of the ILB’s geological, hydrological, and thermal frameworks facilitated a broader assessment of the feasibility of applying deep direct-use (DDU) technologies at facilities (e.g., military installations, hospitals, and school campuses) in other geographical areas in the ILB, and in other sedimentary basins in midcontinent of the US.U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Geothermal Technologies Office Award Number DE-EE0008106Ope
Scorpion incidents, misidentification cases and possible implications for the final interpretation of results
Late Miocene and Holocene mammals, exclusive of the Notoungulata of the Rio Acre region, western Amazonia
Volume: 374Start Page: 1End Page: 4
Late Miocene and Holocene mammals, exclusive of the Notoungulata of the Rio Acre region, western Amazonia
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