Recalibration of the Tethyan shallow-benthic zonation across the Paleocene-Eocene boundary : the Egyptian record

The Galala Mountains in Egypt provide an excellent platform-basin transect with deposits spanning the Paleocene/ Eocene (P/E) boundary. These interfingering deposits enable a recalibration between platform and open marine biostratigraphic schemes. We investigated 18 sections from a shallow-water carbonate platform margin, dominated by larger benthic foraminifera, to basinal marls with pelagic and deep marine biota. The Late Paleocene to Early Eocene development of larger foraminifera is well recorded in the Galala transect, in particular the Tethyan evolutionary event known as the larger foraminifera turnover (LFT). This turnover distinguishes Paleocene assemblages dominated by glomalveolinids, miscellanids and ranikothalids typical for shallow benthic Zone 4 (SBZ4) from those of SBZ5, dominated by alveolinids, nummulitids, and orbitolitids. Our data agree with previous studies that suggested that the larger foraminifera turnover (LFT) coincides with the Paleocene/ Eocene boundary, delineated by the carbon isotopic excursion (CIE) and that it correlates with the boundary between calcareous nannofossils subzones NP9a/b, the benthic extinction event in smaller benthic foraminifera and the boundary between planktic foraminifera Biozones P5/E1

Late Maastrichtian-Early Paleocene sea level and climate changes in the Antioch Church Core (Alabama, Gulf of Mexico margin, USA): a multi-proxy approach

The Antioch Church core from central Alabama, spanning the Cretaceous-Paleogene (K-P) boundary, was investigated by a multi-proxy approach to study paleoenvironmental and sea level changes within the wellconstrained sequence stratigraphic setting of the Gulf of Mexico margin. The Antioch Church core comprises the Maastrichtian calcareous nannoplankton Zone CC25 and the Danian Zones NP1 to NP4 corresponding to the Maastrichtian planktonic foraminifera Zones CF3 and the Danian Zones P1a to P2. Facies shifts from a Maastrichtian siliciclastic to a mixed siliciclastic-carbonate depositional system during the late Danian. Sedimentary proxies indicate that depositional settings changed between littoral (foreshore) and inner and middle neritic (offshore transition zone). Four sedimentary sequences, each encompassing LST, TST, and HST were identified. Estimated water depths by using benthic foraminiferal assemblages were not exceeding 20-40 m for the Maastrichtian and 0-40 m for the Danian sequences. The succession of facies shifts within systems tracts can be very well disentangled by major and trace element data as well as by various element ratios including Zr/Rb, (Zr+Rb)/Ca, and Sr/Ca. By applying element stratigraphy, the ambiguities of the natural gamma ray log -with peaks associated either with maximum flooding surfaces or with silty lag deposits ("placer silts") during the late regressive HST- are resolved. In addition, the Zr/Rb ratio provides a good proxy for monitoring grain size distribution and sorting effects. According to the Antioch Church core data, the K-P boundary is associated with a sandstone event bed that includes ejecta spherules from the Chicxulub impact. However, the genesis of the K-P event bed, whether lowstand, tempestite- or tsunami-related, cannot be resolved from this core. In terms of clay mineralogy, the studied interval is characterized by a steady increase in smectite that parallels a decrease in kaolinite with the latter disappearing about two My after the K-P boundary during Biozone NP2. This change in the clay mineral assemblage, which is almost independent of lithology, may suggest a long-term shift from stable, tropical warm and humid climates during the latest Maastrichtian to warm climate with alternating humid and arid seasons in the middle Danian

The evolution of late Paleocene-early Eocene carbonate platforms of the Tethys

Abstrac

The upper Eocene-Oligocene carnivorous mammals from the Quercy Phosphorites (France) housed in Belgian collections

The Quercy Phosphorites Formation in France is world famous for its Eocene to Miocene faunas, especially those from the upper Eocene to lower Oligocene, the richest of all. The latter particularly helped to understand the ‘Grande Coupure’, a dramatic faunal turnover event that occurred in Europe during the Eocene-Oligocene transition. Fossils from the Quercy Phosphorites were excavated from the middle 19th century until the early 20th century in a series of sites and became subsequently dispersed over several research institutions, while often losing the temporal and geographical information in the process. In this contribution, we provide an overview and reassess the taxonomy of these barely known collections housed in three Belgian institutions: the Université de Liège, KU Leuven, and the Royal Belgian Institute of Natural Sciences. We focus our efforts on the carnivorous mammals (Hyaenodonta and Carnivoramorpha) and assess the stratigraphic intervals covered by each collection. These fossils are derived from upper Eocene (Priabonian), lower Oligocene (Rupelian), and upper Oligocene (Chattian) deposits in the Quercy area. The richness of the three collections (e.g., the presence of numerous postcranial elements in the Liège collection), the presence of types and figured specimens in the Leuven collection, and some identified localities in the RBINS collection make these collections of great interest for further studies on systematics and the evolution of mammals around the ‘Grande Coupure’

On the morphology of the astragalus and calcaneus of the amphicyonids (Carnivora, Mammalia) from the Paleogene of Europe: implications for the ecology of the European bear-dogs

peer reviewedThe Paleogene mammals of Europe are rarely known from partial or complete skeletons. As a result, their systematics and ecology are often solely based on dental characters and postcranial remains, when available, are usually neglected. This explains why the locomotion of mammals of the Eocene-Oligocene transition, the “Grande Coupure”, is poorly known. The aim of this study is to describe the tarsal bones (astragali and calcanei) and characterize the locomotion of amphicyonid carnivorans, one of the most abundant mammalian predator groups from the Phosphorites du Quercy (France) sites. The identification of taxa and the characterization of both posture and locomotion were carried out using four criteria: relative abundance (in comparison with dental data), morphology, size, and body mass. Seven morphotypes, four among astragali and three among calcanei, are identified as Amphicyonidae and show various postures: plantigrade, semi-digitigrade, and digitigrade. One morphotype of the astragalus and one of the calcaneus are identified as Cynodictis lacustris Gervais, 1852, which exhibits a digitigrade posture. The study of postcranial bones, such as tarsals, allows for a better understanding of the ecology of these animals and deserves more interest in future morphological and phylogenetic studies

Molecular characterization and identification of proteins regulated by Hfq in Neisseria meningitidis

Hfq is a highly conserved pleiotropically acting prokaryotic RNA-binding protein involved in the post-transcriptional regulation of many stress-responsive genes by small RNAs. In this study, we show that Hfq of the strictly human pathogen Neisseria meningitidis is involved in the regulation of expression of components involved in general metabolic pathways, iron metabolism and virulence. A meningococcal hfq deletion strain (H44/76Δhfq) is impaired in growth in nutrient-rich media and does not grow at all in nutrient-limiting medium. The growth defect was complemented by expression of hfq in trans. Using proteomics, the expression of 28 proteins was found to be significantly affected upon deletion of hfq. Of these, 20 proteins are involved in general metabolism, among them seven iron-responsive genes. Two proteins (PilE, TspA) are involved in adherence to human cells, a step crucial for the onset of disease. One of the differentially expressed proteins, GdhA, was identified as an essential virulence factor for establishment of sepsis in an animal model, studied earlier. These results show that in N. meningitidis Hfq is involved in the regulation of a variety of components contributing to the survival and establishment of meningococcal disease

The Global Stratotype Sections and Points for the bases of the Selandian (Middle Paleocene) and Thanetian (Upper Paleocene) stages at Zumaia, Spain

The global stratotype sections and points for the bases of the Selandian (Middle Paleocene) and Thanetian (Upper Paleocene) stages have been defined in the coastal cliff along the Itzurun Beach at the town of Zumaia in the Basque Country, northern Spain. In the hemipelagic section exposed at Zumaia the base of the Selandian Stage has been placed at the base of the Itzurun Formation, ca. 49 m above the Cretaceous/ Paleogene boundary. At the base of the Selandian, marls replace the succession of Danian red limestone and limestone-marl couplets. The best marine, global correlation criterion for the basal Selandian is the second radiation of the important calcareous nannofossil group, the fasciculiths. Species such as Fasciculithus ulii, F. billii, F. janii, F. involutus, F.pileatus and F. tympaniformis have their first appearance in the interval from a few decimetres below up to 1.1 m above the base of the Selandian. The marker species for nannofossil Zone NP5, F. tympaniformis, first occurs 1.1 m above the base. Excellent cyclostratigraphy and magnetostratigraphy in the section creates further correlation potential, with the base of the Selandian occuring 30 precession cycles (630 kyr) above the top of magnetochron C27n. Profound changes in sedimentology related to a major sea-level fall characterize the Danian-Selandian transition in sections along the margins of the North Atlantic. The base of the Thanetian Stage is placed in the same section ca. 78 m above the Cretaceous/Paleogene boundary. It is defined at a level 2.8 m or eight precession cycles above the base of the core of the distinct clay-rich interval associated with the Mid-Paleocene Biotic Event, and it corresponds to the base of magnetochron C26n in the section. The base of the Thanetian is not associated with any significant change in marine micro-fauna or flora. The calcareous nannofossil Zone NP6, marked by the first occurrence of Heliolithus kleinpelli starts ca. 6.5 m below the base of the Thanetian. The definitions of the global stratotype points for the bases of the Selandian and Thanetian stages are in good agreements with the definitions in the historical stratotype sections in Denmark and England, respectively