A restudy of PASTIELS (1948) dinoflagellate cysts from the Early Eocene of Belgium

The Early Eocene (Ypresian) dinoflagellate cyst assemblage described by PASTIELS (1948) is reassessed, on the basis of an examination of surviving type material. At least twenty-eight different taxa are recognized. The new species Cannosphaeropsis williamsii and the new combinations Nematosphaeropsis reticulensis (PASTIELS, 1948) and Tityrosphaeridium exilimurum (DAVEY and WILLIAMS, 1966a) are proposed. Emended diagnoses are formulated for the families Deflandreaceae EISENACK, 1954 and Wetzeliellaceae VOZZHENNIKOVA, 1961 and for the species N. reticulensis, Glaphyrocysta exuberans (DEFLANDRE and COOKSON, 1955) and G. pastielsii (DEFLANDRE and COOKSON, 1955). A neotype is selected for G. exuberans and a lectotype for N. reticulensis. The morphology of Polysphaeridium belgicum SARJEANT in DAVEY et al, 1969, and the problems presented by the generic separation of Polysphaeridium and Dapsilidinium, as comprehended by BUJAK et al., 1980b, are discussed. It is shown that, whereas there is great uniformity in Early Eocene assemblages between northeast Europe and the Grand Banks, offshore eastern Canada, the assemblages of the latter region differ in detailed composition from those of the Labrador and Scotian Continental Shelves (herein termed the "Bujak" and "Brideaux" Associations) and vary markedly from those recorded in other parts of the world

Restudy of some smaller dinoflagellate cysts from the Upper Cretaceous of Belgium

An account is presented of the restudy of seven forms of small dinoflagellate cysts from Upper Cretaceous flints of Belgium. The new genus Rhiptocorys is erected for forms having a hypotract much larger than the epitract, showing an unequal development of high crests and having an epitractal archaeopyle; the diagnosis for its type species, Rhiptocorys veligera (Deflandre), is emended. The new combination Druggidium fourmarierii (Lejeun-Carpentier) is proposed and a former variety elevated to specific status, as Druggidium leave (Lejeune-Carpentier). Emended diagnoses are proposed for both these taxa and for Dinogymnium avellana (Lejeune-Carpentier). Forms attributed by Lejeune-Carpentier (1951) to Phanerodinium cayeuxi Deflandre are reconsidered and one is redescribed as ?Phanerodinium sp. Photographs of all these forms are presented for the first time and interpretative drawings, many redrawn from the first author's original figures, supplement the text

Zbadanie holotypu Dinoflagellata opisanego w XIX w. z górnej jury Polski

Results are presented of a re-examination of the holotype of Xanthidium penicillatum, a species of dinoflagellate cyst first reported by Ehrenberg (1843) from the Corallian of Poland and validly published by him in 1854. It is shown to correspond exactly in morphology with Systematophora fasciculigera (Klement, 1960), from the Upper Jurassic of Germany. The new combination Systematophora penicillata (Ehrenberg, 1854) is proposed and S. fasciculigera is rejected as a subjective junior synonym.Zbadano na nowo holotyp Xanthidium penicillum, gatunku cysty Dinoflagellata notowanego przez Ehrenberga (1843) z oksfordu Polski i opisanego przez tego autora w 1854 roku. Morfologicznie odpowiada on Systematophora fasciculigera Klement, 1960 z górnej jury niemieckiej. Zaproponowano nową kombinację: Systematophora penicillata (Ehrenberg, 1854), a nazwę: S. fasciculigera odrzucono, jako młodszy synonim

Dinosaurs and the Cretaceous Terrestrial Revolution

The observed diversity of dinosaurs reached its highest peak during the mid- and Late Cretaceous, the 50 Myr that preceded their extinction, and yet this explosion of dinosaur diversity may be explained largely by sampling bias. It has long been debated whether dinosaurs were part of the Cretaceous Terrestrial Revolution (KTR), from 125–80 Myr ago, when flowering plants, herbivorous and social insects, squamates, birds and mammals all underwent a rapid expansion. Although an apparent explosion of dinosaur diversity occurred in the mid-Cretaceous, coinciding with the emergence of new groups (e.g. neoceratopsians, ankylosaurid ankylosaurs, hadrosaurids and pachycephalosaurs), results from the first quantitative study of diversification applied to a new supertree of dinosaurs show that this apparent burst in dinosaurian diversity in the last 18 Myr of the Cretaceous is a sampling artefact. Indeed, major diversification shifts occurred largely in the first one-third of the group's history. Despite the appearance of new clades of medium to large herbivores and carnivores later in dinosaur history, these new originations do not correspond to significant diversification shifts. Instead, the overall geometry of the Cretaceous part of the dinosaur tree does not depart from the null hypothesis of an equal rates model of lineage branching. Furthermore, we conclude that dinosaurs did not experience a progressive decline at the end of the Cretaceous, nor was their evolution driven directly by the KTR