Numerical determination of entanglement entropy for a sphere

We apply Srednicki's regularization to extract the logarithmic term in the entanglement entropy produced by tracing out a real, massless, scalar field inside a three dimensional sphere in 3+1 flat spacetime. We find numerically that the coefficient of the logarithm is -1/90 to 0.2 percent accuracy, in agreement with an existing analytical result

The giant Cretaceous coelacanth (Actinistia, Sarcopterygii) Megalocoelacanthus dobiei Schwimmer, Stewart & Williams, 1994, and its bearing on Latimerioidei interrelationships

We present a redescription of Megalocoelacanthus dobiei, a giant fossil coelacanth from Upper Cretaceous strata of North America. Megalocoelacanthus has been previously described on the basis of composite material that consisted of isolated elements. Consequently, many aspects of its anatomy have remained unknown as well as its phylogenetic relationships with other coelacanths. Previous studies have suggested that Megalocoelacanthus is closer to Latimeria and Macropoma than to Mawsonia. However, this assumption was based only on the overall similarity of few anatomical features, rather than on a phylogenetic character analysis. A new, and outstandingly preserved specimen from the Niobrara Formation in Kansas allows the detailed description of the skull of Megalocoelacanthus and elucidation of its phylogenetic relationships with other coelacanths. Although strongly flattened, the skull and jaws are well preserved and show many derived features that are shared with Latimeriidae such as Latimeria, Macropoma and Libys. Notably, the parietonasal shield is narrow and flanked by very large, continuous vacuities forming the supraorbital sensory line canal. Such an unusual morphology is also known in Libys. Some other features of Megalocoelacanthus, such as its large size and the absence of teeth are shared with the mawsoniid genera Mawsonia and Axelrodichthys. Our cladistic analysis supports the sister-group relationship of Megalocoelacanthus and Libys within Latimeriidae. This topology suggests that toothless, large-sized coelacanths evolved independently in both Latimeriidae and Mawsoniidae during the Mesozoic. Based on previous topologies and on ours, we then review the high-level taxonomy of Latimerioidei and propose new systematic phylogenetic definitions

Bite marks of the giant crocodylian Deinosuchus on Late Cretaceous (Campanian) bones

The giant (~10 m) Late Cretaceous eusuchian crocodylians of the genus Deinosuchus are shown to have left large, blunt, sometimes penetrating bite marks on a significant number of sea turtle shells, and on several dinosaur specimens. The morphology of crocodylian bite marks is generally well documented, and the identification of bite traces specifically attributable to Deinosuchus may be made by reference to their size, age, habitat and prey selection. Deinosuchus species, and bite traces referable to the genus, are present on both sides of the Late Cretaceous Interior Seaway, and known only from Campanian deposits in the USA and northern Mexico. The heavily enameled, multi-layered, low-crowned posterior teeth of Deinosuchus were adapted specifically for bonecrushing feeding behavior, and the evidence of such is present in both the morphology of preserved bite traces and in characteristic wear patterns on their posterior teeth

A Velociraptorine tooth from Alabama and its Paleogeographic Implications

A single tooth recovered from the marine Mooreville Chalk Formation (Early Campanian) of western Alabama indicates the presence of dromaeosaurid theropods on the Appalachian subcontinent during the Late Cretaceous. The tooth compares closely with teeth referred to the small velociraptorine Saurornitholestes

An Aphelaspis zone (upper Cambrian, Paibian) trilobite faunule in the central Conasauga River Valley, North Georgia, USA

Middle and Upper Cambrian strata (Cambrian Series 3 and Furongian) in the southernmost Appalachians (Tennessee to Alabama) comprise the Conasauga Formation or Group. Heretofore, the youngest reported Conasauga beds in the Valley and Ridge Province of Georgia were of the late Middle Cambrian (Series 3: Drumian) Bolaspidella Zone, located on the western state boundary in the valley of the Coosa River. Two new localities sited eastward in the Conasauga River Valley, yield a diagnostic suite of trilobites from the Upper Cambrian Aphelaspis Zone. Very abundant, polymeroid trilobites at the primary locality are referable to Aphelaspis brachyphasis, which is a species known previously in western North America. A second locality has produced a few identifiable specimens of the aphelaspine Eugonocare (Olenaspella) separatum. Specimens at these two localities are generally complete individuals compressed in tan mudstones. The primary locality features abundant body cluster accumulations, implying mass mortality by bioimmuration. The trilobite assemblage also includes the agnostoids Glyptagnostus reticulatus, Agnostus inexpectans, and Aspidagnostus rugosus, all correlated to the global Paibian agnostoid Glyptagnostus reticulatus Zone. These localities contain the southeastern-most Late Cambrian faunule in the Appalachians. The trilobite species and carbonate-free, mudstone lithology, lacking evidence of infaunal bioturbation and burrowing, suggest accumulation eastward of a paleotopographic shelf-to-basin break, which is interpreted to be east of the Alabama Promontory and in the Tennessee Embayment. The preservation of abundant aphelaspine specimens by bioimmuration events may have been the result of mudflows down the shelf-to-basin slope