A detailed structural mapping and geometrical analysis of distinct bedding-(sub)perpendicular and bedding-parallel quartz veins has been performed in the northeastern part of the High-Ardenne slate belt (Rursee, North Eifel, Germany), with the aim to reconstruct the local fracturing/veining history. The structural relationship of these two types of veins as well as their relationship with cleavage, folds and faults allows attributing a pre- to early-Variscan age to these veins. The first type of veins is oriented (sub)perpendicular to bedding and consists of several, mutual cross-cutting generations, which clearly predate Variscan deformation. The second type of veins, bedding-parallel veins, post-dates the bedding-(sub)perpendicular veins and reflects bedding-parallel thrusting at the onset of Variscan deformation, predating folding. Subsequently, during progressive Variscan compression both types of veins were passively folded within characteristic, NW-vergent, overturned folds. Locally, due to flexural slip folding, reactivation along the bedding-parallel veins may have taken place.
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The taxonomic affinities of fossils from theFrasnian succession of Be lgium previously described asphyllopod and phyllocarid crustacean shields are discussed.The rediscovery of the holotype of Ellipsocaris dewalquei,the type species of the genus Ellipsocaris Woodward inDewalque, 1882, allows to end the discussion on the taxo-nomic assignation of the genus Ellipsocaris. It is removedfrom the phyllopod crustaceans as interpreted originally andconsidered here as an ammonoid anaptychus. Furthermore, itis considered to be a junior synonym of the genus SidetesGiebel, 1847. Similarly, Van Straelen’s (1933) lower to middleFrasnian record Spathiocaris chagrinensis Ruedemann, 1916,is also an ammonoid anaptychus. Although ammonoids canbe relatively frequent in some Frasnian horizons of Belgium,anaptychi remain particularly scarce and the attribution to thepresent material to peculiar ammonoid species is not possible.
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RBINS Staff Publications 2017
Crocodilian remains from the late Palaeocene continental locality of Mont de Berru (Marne, France) offer the opportunity to reassess the taxonomic identity of the oldest diplocynodontid from Europe. Owing to significant morphological differences from previously described species of Diplocynodon, which include the presence of a splenial symphysis, a new species, Diplocynodon remensis sp. nov., is erected here. Its inclusion in a phylogenetic framework for Eusuchia leads to its positioning as a derived member of diplocynodontids. Diplocynodontidae are viewed as a basal alligatoroid taxon, and, because morphological affinities with the Late Cretaceous−early Eocene North American genus Borealosuchus were mentioned in earlier studies, a comparison amongst D. remensis sp. nov., Leidyosuchus, and Borealosuchus spp. is presented. Although D. remensis sp. nov. is the geologically oldest diplocynodontid, according to our results, it is not the phylogenetically most primitive. Other morphological discrepancies are highlighted, indicating that the topology recovered here is only tentative. From a biogeographical point of view, the appearance of Diplocynodon in Europe prior to the Palaeocene/Eocene boundary indicates that it did not disperse with North American taxa that reached Europe around the time of the Palaeocene-Eocene thermal maximum (PETM). Therefore, a pre-PETM dispersal from North America at the same times as other vertebrates with clear North American affinities also occurring in the Palaeocene of Europe cannot be excluded. The description of D. remensis sp. nov. adds substantial new, albeit conflicting, information, highlighting the need for a better phylogenetic framework with a revision of other critical taxa (Menatalligator, Borealosuchus) from the Palaeocene of Europe and North America.
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