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An argillaceous, monothalamous foraminifera Tolypammina vagans (Brady) adapted to live in sponges, was found in the water system of numerous siliceous sponges collected from Oxfordian marls and limestones of Central and Southern Poland. Individual variability of T. vagans was traced and it was found that most species of Tolypammina Rhumbler should be classified within this species. The occurrence of T. vagans in sponges was commensal in character and dependend on: 1) dynamics of water circulation in sponges, 2) presence of sufficient quantity of terrigenous quartz in silt fraction in water. The role of occurrence of T. vagans in successively changing sponge assemblages for the reconstruction rate of silt sedimentation in the Oxfordian Basin of Poland is pointed out.
A number of Devonian and Carboniferous microfossils generally referred to as non-radiosphaerid calcispheres or parathuramminid foraminifera are identified as poor preservations of the Devonian volvocacean alga Eovolvox silesiensis. The cell walls are decomposed and embedded in a calcareous matrix of combined early and late diagenetic origin. The main stages of the complex preservational history of the Devonian volvocaceans are discussed and each results in the formation of microfossils known so far as Vicinesphaera Antropov, Polyderma Dervillé, Palaeocancellus Dervillé, Pachysphaerina Conil & Lys, and Archaesphaera Suleimanov. These microfossils have a world-wide distribution and are particularly common in certain Upper Devonian and Lower Carboniferous limestones. They are often associated with radiosphaerid calcispheres and in the Devonian sometime with Amphipora. The presence of autochthonous and abundant volvocacean algae in sediments, up till now interpreted as marine or restricted marine deposits, probably indicates brackish (oligohaline) or fresh-water depositional environments similar to modern strongly eutrophized lakes. Volvocacean calcispheres appear to be a very sensitive paleoenvironmental indicator.
The results of studies on the structure and palaeoecology of the brachiopod Horridonia horrida (Sowerby) from Lower Zechstein of the Holy Cross Mountains (Góry Świętokrzyskie) are discussed in the present paper. The life position preserved in some individuals, allowed the author to elucidate the adaptative character of several morphological elements of the shell and the range of their variability.
First fossil representatives of the modern fresh-water algae from the family Volvocaceae - Eovolvox silesiensis gen. et sp. nov. - have been discovered in the Frasnian Amphipora-calcisphaere limestone of Upper Silesia, Poland. The abundant appearance of these algae indicates a very low salinity gradient of the depositional environment, probably close to that of modern eutrophic lacustrine conditions. The algae have been preserved due to rapid carbonate permineralization during preburial and/or early burial stage.
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The results of the author's studies on the morphology, function and taxonomic value of astrorhizae in the Palaeozoic Stromatoporoidea are presented. In contradistinction to previous views according to which astrorhizae were considered as structure formed by stolons or zooids of the Stromatoporoidea, the author concludes that they are traces of foreign organisms associated with the Stromatoporoidea. The relationships between both organisms were probably commensal or mutualistic in character. On the basis of associations observed in Recent sponges and coelenterates, the author has discussed the possibility of a plant (algae) or animal (non-skeletal coelenterates) nature of the organisms which were associated with the Stromatoporoidea. Depending on the manner of connecting astrorhizae with the skeletal tissue of the coenosteum, two types of these structures, i.e. a) integrated and b) separated, have been distinguished and their morphological and growth interpretation attempted. The new interpretation of astrorhizae allows one to eliminate these structures as diagnostic features of the Stromatoporoidea which may to a considerable extent simplify the taxonomy of this group.
Common enigmatic fossils called stromatoporoids are recognized as calcareous stromatolitic structures build by coccoid cyanobacteria (= Cyanophyta). The diversified internal structures of stromatoporoids reflect various growth patterns of cyanobacterial cell aggregates or colonies preserved due to a rapid in situ calcification. Stromatoporoid stromatolites are evolutionary advanced descendants of early precamprian stromatolites generated by weakly differentiated stratiform mats of coccoid cyanobacteria. The presence of stromatoporoid stromatolites in ancient subtidal environments, often in association with normal marine biota, is a non-actualistic phenomenon which needs to be explained in other than present-day ecological terms.
We present discoveries of internal bodies in problematic Silurian and Devonian organic−walled microfossils classified traditionally as polygonomorph, acanthomorph, sphaeromorph, and herkomorph acritarchs. These bodies are comparable with reproductive structures (autoand/or aplanospores) of modern unicellular green algae (Chlorococcales). Our findings suggest that many of these microfossils may represent asexually reproducing (sporulating) vegetative cells of chlorococcalean algae. The presence of spore−like bodies in the studied acritarchs supports earlier suggestions, based on ultrastructural and biomarker studies, that some acritarchs can be affined with green algae.
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On two Ordovician calcareous algae

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Organic thalli of Ordovician calcareous algae Vermiporella fragilis Stolley and Palaeoporella variabilis Stolley found for the first time are studied. The structure of V. fragilis is shown to be fundamentally different from that previously described by various authors. Its thallus consists of a central stem and lateral branches of three orders, arranged in regular whorls. Spores are preserved in stem segments, which are separated by septa. Morphologically they resemble the oospores of a Recent alga Sphaeroplea Fritsch. The structure of previously unknown filamentous central parts of thallus of P. variabilis is studied and their relation to subcortical and cortical threads penetrating the calcareous sheath are described. Revised diagnoses of Vermiporella Stolley and Palaeoporella Stolley and of their type species are given.
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