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The Triassic to Recent fossil record of the dinoflagellates is represented overwhelmingly by geologically resistant, organic‐walled, non‐motile resting cysts; such cysts are formed following the sexual phase in the life cycle. Very few confirmed records exist of the motile stage being preserved in the fossil record. This paper reports the occurrence of two very unusual dinoflagellate taphofacies, one developed in bituminous shales and the other in micrites, from the Oligocene fossil Lagerstätte at Sieblos, Hesse, Germany. A new dinoflagellate taxon, Sieblososphaera martini sp. nov. has been identified through analysis of dissociated skeletal elements in the bituminous shales and external moulds and casts in the micrites. The unique preservation of these fossils confirms them not only as primary biogenically silicified motile thecate cells, but also indicates that there was a much greater range of tabulation present within the subfamily Lithoperidiniaceae than has hitherto been recognized. [ABSTRACT FROM AUTHOR]

The family Gavelinellidae was one of the most widespread and abundant groups of benthic foraminifers in the Cretaceous. This group evolved in the Early Cretaceous and became dominant in the Aptian and Albian together with some other families of Rotaliina. The reasons for this evident evolutionary success are unclear, and even the taxonomy and palaeoecology of the group are still a matter of debate. This paper goes ‘back to basics’ and begins by adjusting the terminology, description and evaluation of gavelinellid species identified during high-resolution studies of the Albian Kirchrode borehole in the Lower Saxony Basin. This is the type area of Reuss' classical (1863) monograph on foraminifera from north German Hils and Gault. In order to avoid terminological misunderstandings, a new definition of test orientation applied to gavelinellids is used. The ventral side is described here as the side that bears the aperture or its extension along the margin, and the dorsal side is the opposite side of the test. The interpretative relationship of the test to the substrate is, therefore, avoided. Albian gavelinellids from the Kirchrode II borehole are represented by two genera, Berthelina and Lingulogavelinella, and six species. The morphology of most gavelinellids, including all documented taxa, is indistinct, which is the main reason for their confusing taxonomy. Species often show strongly overlapping characters, and variability within the species may be comparable or even higher than the variability between different taxa. Morphological details are usually the only features enabling the identification of species. The detailed description and photographic documentation of identified gavelinellid taxa presented herein is based on investigations of over 14 000 individuals augmented by comparative studies of various archival collections. Several diagnostic characters of gavelinellid tests, useful for taxonomic identification, are discussed and compared. [ABSTRACT FROM AUTHOR]

Fossil amoebae are very rare, although their evolutionary history extends back into the Proterozoic. The Cenomanian amber of Schliersee (southern Germany) is very rich in micro-organisms and contains the highest diversity of fossil freshwater rhizopods (Gymnamoebia and Testacealobosia) yet discovered. Altogether seven testate amoebae and one gymnamoebian species are recorded from this Mesozoic amber. The four newly discovered taxa described in this paper can be assigned to the extant species Centropyxis delicatula, Centropyxis hirsuta, Phryganella acropodia and Phryganella paradoxa. Over 200 individuals of Phryganella paradoxa are preserved. Together with their syninclusions, the amoebae are species of limnetic or limnetic–terrestrial microcoenoses. The presence of 100-myr-old fossils with extant representatives suggests evolutionary stasis of these freshwater amoebae. However, not all modern testacean families have been recorded from Mesozoic limnetic habitats. Our experimental studies verify that naked and testate amoebae can be embedded in resins. [ABSTRACT FROM AUTHOR]