Fossils assigned to the predominantly deep-sea asteroid family Benthopectinidae Verrill, 1894 are described and their affinities reappraised. Detailed comparative morphology of ambulacrals, adambulacrals marginal ossicles has revealed that only some extinct taxa fall within morphological range modern representatives family. These include Jurapecten hessi Gale, 2011, J. infrajurensis sp. nov. (b...

Abstract Reconstructing dinosaur trophic structure prior to the Cretaceous–Paleogene (K–Pg) boundary may provide information about ecosystem organization and evolution. Using calcium isotopes, we investigate preserved biogenic isotope compositions in a set of teeth from three continental formations Alberta, Canada, assess latest Cretaceous food web structure. Tooth enamel δ44/42Ca values are pr...

How does the choice of size metric, specimen selection, and taxonomic level affect the results of macroevolutionary or ecological analyses? Four molluscan data sets are used to address this question as follows. First, the relationships among various size metrics are examined using a morphometric data set of Late Cretaceous–Oligocene veneroid bivalves. Second, the relationship between the size o...

Introduction: The Wetumpka Structure is an ~7-8 km diameter impact in Alabama of Late Cretaceous (80-83 Ma) age. The structure was originally reported by [1-2]; subsequent work including drilling has been discussed by [3-10]. An earlier gravity survey [11] indicated that the structure exhibited an annular gravity high gravity over the crystalline rock ridge and low gravity within the interior a...

T paper examines how the understanding of the prospectivity of the Liberia-Sierra Leone Basin has developed over the last 40 years largely due to improvements in seismic data over this period. A series of basins developed between major transform fault zones associated with the opening of the South Atlantic Ocean from the early Cretaceous onward. The Liberia-Sierra Leone Basin forms part of the ...

[1] Paleomagnetic data from the Internal Sierras unravel the kinematic relationship between basement (Guarga, Gavarnie, Bielsa) and cover thrusts (LarraMonte Perdido). The new data come from an area of 100 km along strike and 5–15 km across strike of the southwestern Pyrenees. The area covers a variety of structural positions that range from cover to basement thrusts. From 84 sites located in U...

BACKGROUND Central Patagonia, Argentina, preserves an abundant and rich fossil record. Among vertebrate fossils from the Upper Cretaceous Bajo Barreal Formation of Patagonia, five individuals of the small, non-avian theropod dinosaur Aniksosaurus darwini were recovered. Group behavior is an important aspect of dinosaur paleoecology, but it is not well-documented and is poorly understood among n...

An ornithurine bird, Hongshanornis longicresta gen. et sp. nov., represented by a nearly complete and articulated skeleton in full plumage, has been recovered from the lacustrine deposits of the Lower Cretaceous Jehol Group in Inner Mongolia, northeast China. The bird had completely reduced teeth and possessed a beak in both the upper and lower jaws, representing the earliest known beaked ornit...