rss_2.0Folia Musei rerum naturalium Bohemiae occidentalis. Geologica et Paleobiologica FeedSciendo RSS Feed for Folia Musei rerum naturalium Bohemiae occidentalis. Geologica et Paleobiologica Musei rerum naturalium Bohemiae occidentalis. Geologica et Paleobiologica Feed in (Isoetaceae, Pteridophyta): Revealing the Beginnings of Heterospory and Recalling Paleozoic Ancestors?<abstract> <title style='display:none'>Abstract</title> <p>The extant plant genus Isoetes (Isoetaceae; lycophyte, quillwort) is important from an evolutionary point of view. Species of this heterosporous genus are small herbs (up to 50 centimeters) and exhibit some morphological, anatomical and embryological features of their Paleozoic arborescent lycopsid ancestors. The species Isoetes pantii produces three kinds of microspores (monolete, alete and trilete) and two types of trilete megaspores in one and the same heterosporangium. We attempt to associate these unusual functional megaspores with various Paleozoic spores described mainly from Devonian barinophytaleans such as Omniastrobus dawsonii, Barinophyton richardsonii, B. citrulliforme and Protobarinophyton pennsylvanicum. These have two kinds of spores in a sporangium and provide the first palynological evidence of heterospory at 405 Ma. The germination of microspores and megaspores and production of gametophytes within the heterosporangia of I. pantii corresponds with that of some of its Paleozoic ancestors. Retention of megaspores within heterosporangia and their germination in situ offers evidence that I. pantii exhibits the probable route of evolution of the seed habit. These observations support the hypothesis that a typical heterosporangium was the cradle for the evolution of heterospory.</p> </abstract>ARTICLEtrue of the Metro Line D in Praha-Pankrác: An Introductory Report About a Unique Opportunity for Study of the Upper Ordovician Fossil Assemblages and Sediments in the Prague Basin (Czech Republic)<abstract> <title style='display:none'>Abstract</title> <p>The construction of the new metro line D in Praha-Pankrác provides a unique opportunity to study different aspects such as lithology, stratigraphy and fossil assemblages from the Upper Ordovician and Silurian of the Prague Basin. Results from the sections in tunnels mined so far allowed detailed information about the succession of fossil assemblages, facies variability and actual thicknesses of the upper part of the Bohdalec Formation, the Králův Dvůr and Kosov formations in this part of Prague Basin. The stratigraphic position of Michle Facies in the Bohdalec Formation was also indicated.</p> </abstract>ARTICLEtrue Earliest (Brachiopoda, Cyrtinidina) in the Devonian of the Barrandian (Czech Republic)<abstract> <title style='display:none'>Abstract</title> <p>The earliest known Cyrtina in the Prague Basin has been discovered in the Kotýs Limestone of the Lochkov Formation (Lochkovian) among a rich brachiopod-coral fauna at Branžovy ridge near Bubovice (Beroun District, Czechia). Rare and imperfectly preserved silicified shells are assigned to Cyrtina praecedens Kozłovski, 1929, a species originally described from Podolia, Ukraine. The species is known also in north-eastern Russia (Tajmyr and Sette-Daban Mts) and likely also in New South Wales, Australia. Its distribution provides evidence of the rapid spread of Cyrtina across the shallow shelves of Laurussia, Siberia and Gondwana in the Early Devonian. The Devonian and Carboniferous distribution of Cyrtina is restricted to the agitated, shallow-water carbonate environment in tropical and temperate climatic belts.</p> </abstract>ARTICLEtrue Epibionts on Crinoid Stems from the Lower/Middle Devonian Boundary in the Barrandian, Czech Republic<abstract> <title style='display:none'>Abstract</title> <p>Diminutive crinoid holdfasts and cemented tests of the foraminifers Psammosphaera and Tolypammina were observed on coarse bioclasts in weathered limestones of the Daleje-Třebotov Formation. Specimens were obtained in 1984 by washing so called “white beds” at a temporary locality in Praha- Barrandov. A few millimeter sized bioclasts with epibionts were freed from hard limestone beds of the Třebotov Limestone near the Lower/Middle Devonian boundary by long-term weathering. Many of the crinoid holdfasts attached to pluricolumnals provoked a stereomic response of the host crinoid. Also the growth orientation of the crinoid epibiont is not random and indicates some crinoid-epibiont to crinoidhost interaction. Reaction of host stereome and non-random stem orientation offer direct evidence of epibiont larval settlement and subsequent growth on the stem of a living crinoid host. The extensive growth of the host stereome ended by partial to total engulfing of the epibiont holdfast. This indicates advancing and finally successful defence of the host crinoid against the epibiont. The holdfast gives evidence that the small host crinoids offered a somewhat higher tier for even smaller epibiont crinoids. However, other observed holdfasts indicate fixation of larva and growth over loose bioclasts lying on a sea bed. Location of foraminifer test on bioclasts confims that foraminifers cemented and grew on loose echinodermal and brachiopod remains and preferred crevices and similar protected sites with concave profiles. This is clear evidence that diverse bioclasts (brachiopod shells, pelmatozoan ossicles) provided the hard substrate suitable for epibiont life on a sea bed.</p> </abstract>ARTICLEtrue Rare Trilobites (Odontopleuridae) and ? (Tropidocoryphidae) in the Homerian (Silurian) Of The Prague Basin, Bohemian Massif<abstract> <title style='display:none'>Abstract</title> <p>The deep-water Aulacopleura koninckii Assemblage in the lower Homerian (T. testis Sub-Biozone) “Aulacopleura shales“ strata at the classical ‘Barrande’s pits’ locality on the Černidla hillside at Loděnice in the Prague Basin is supplemented by the addition of two new trilobite taxa, viz. Exallaspis? perunicana sp. n. and Kosovoproetus? aff. praecursor (Přibyl &amp; Vaněk 1987). The palaeogeographic distribution of Exallapis Ramsköld &amp; Chatterton, 1991 is extended by the occurrence of Exallaspis? perunicana sp. n. and the younger Exallaspis sp. in the upper Homerian (the P. parvus – G. nassa Biozone) of the Prague Basin, reflecting the faunal migration between the southern shelf of the Baltica palaeocontinent and the Perunica microcontinent accross the Rheic Ocean. The small dimensions of the K.? aff. praecursor exoskeletons compared to those of K.? praecursor in the bordering shallow-water Liolalax–Sphaerexochus– Cheirurus Assemblage represent another example of adaptive nanism in trilobites of the Aulacopleura-Raphiophorus Biofacies.</p> </abstract>ARTICLEtrue Insights Concerning the Variety of Sidertic Structures and Variable Genesis and of Sideritic Occurrences: An Unexplored Source of Palaeontological Information (Sydney Coalfield, Middle Pennsylvanian, Canada)<abstract> <title style='display:none'>Abstract</title> <p>Reported are descriptions of twelve samples representing a variety of sideritic structures, including nodules mostly from roof shale of the Middle Pennsylvanian Sydney Coalfield, Canada. The co-occurrence of fossiliferous nodules and compression fossils in the shaley roof rocks at Point Aconi enhance greatly palaeontological information. Newly discovered in a coal seam, and part of the sample, is a 40 mm thick continuous sheet-like layer of siderite with abundant permineralized-like-compressed small to micron-sized structures in a rather evenly-sized sideritic matrix, probably indicating a genetic origin different from that of the nodules. Methods include some thin-section, and two X-Ray analysis. However, large systematic sampling is a prerequisite to explore that situation, which additionally could provide faunal information for Euromerican correlation.</p> </abstract>ARTICLEtrue of K-Feldspars and Kaolinitization in Arkoses of West and Central Bohemian Continental Permo–Carboniferous<abstract> <title style='display:none'>Abstract</title> <p>The examined K-feldspars in arkoses of the continental Upper Carboniferous – Lower Permian of the West and Central Bohemian basins originated in the whole bed sequence (Duckmantian to Autunian; 314.2–297.1 Ma) from one source, which were so-called mountain granites of the older intrusive complex (OIC) of the Krušné hory Mts, as confirmed by the X-ray and geochemical analyses. The presence of feldspar clasts from other granitoids (Merklín and Louny massifs) was found only in the straight transgreding basal Carboniferous rocks. While other arkoses underwent synsedimentary and/or post-sedimentary kaolinization, in the deposits of Kaznějov and Horní Bříza (Nýřany Member of the Kladno Formation) pre-sedimentary kaolinization (sedimentation of sandstones and conglomerates with kaolinitic cement) occurred.</p> </abstract>ARTICLEtrue Record of Podichnus in Byronid Shell from the Lower Devonian (Pragian) of the Prague Basin, Czechia<abstract> <title style='display:none'>Abstract</title> <p>Brachiopod etching trace Podichnus, typically with centrifugally arranged clusters of holes or slits, has hitherto been known only in calcium carbonate substrates. The similar etching trace is newly described on calcium phosphate substrate. The trace Podichnus isp. in a wall of a phosphatic byronid test was observed in the lower Devonian Vinařice Limestone (Pragian) in the Koněprusy area of the Prague Basin in the Barrandian area, the Czech Republic. The trace is smaller that majority of described species of this fixichnia, and displays a smooth central disc surrounded by two circlets of holes or pits. Some holes penetrate through wall of byronid test without any biotic response of a byronid. The maker of Podichnus isp. is uknown but among the associated fossils are eligible candidates including rhynchonellids, orthids and terebratulids. It is rare direct evidence of etching activity of the pedicle in the Lower Palaeozoic and the first finding of Podichnus in the Devonian in the Prague Basin. The emended diagnosis of the ichnogenus is presented herein.</p> </abstract>ARTICLEtrue Chemometric Model Simulating the Acitheca Polymorpha Frond: Implications for Reconstructing Carboniferous Ferns (Marattiales, Canada)<abstract> <title style='display:none'>Abstract</title> <p>Reported are results of an initial approximate imitation of a Carboniferous fern frond, i.e., marattialean Acitheca polymorpha (Schimper), Middle Pennsylvanian Sydney Coalfield, Canada. The simulation experiment is based on the analysis of 14 infrared spectra obtained by means of Fourier Transform Infrared spectroscopy from four detached fragments of sterile polymorphic penultimate-pinna compressions. The calculated relative, semi-quantitative, chemical data from the infrared spectra are the input for principal component analysis deriving a 3D (three-dimensional) chemometric model. To interpret it, the four specimens are placed in hypothetical-frond positions simulating a tripinnate frond, based on diminishing penultimate-rachial widths from 1-mm (distal) to 10-mm (proximal). Hypothetical conclusions include position-dependent chemistries, specifically that of opposing trends of aromaticity vs. aliphaticity in pinnules-rachises. This, in turn, would suggest potential for (i) fern-frond reconstruction, and (ii) for determination of a most likely frond position of fragmentary specimens by “chemical classification”; the predictive aspect. However, further experimental refinement is necessary particularly based on larger frond segments to confirm or disconfirm the overall hypothetical results.</p> </abstract>ARTICLEtrue Adhesive Pad of a Climbing Pteridosperm from Permian Peat-Forming Forest (Wuda, Inner Mongolia)<abstract><title style='display:none'>Abstract</title><p>Certain pteridosperm tendril adhesive pads are depicted from the Cathaysian flora of the Early Permian Taiyuan Formation of Wuda Coal-field in Inner Mongolia China. Specimens contain elliptical or rounded pads situating at the swollen tip of pinnule lobe tendrils which are highly comparable to those of the extant Parthenocissus tricuspidata in the way that both of them are similar in form and function. Specifically, information we have gained suggested that pteridosperms from the Permian might have performed a similar type of physiological process by producing some chemical substances which assisted them in climbing. The Wuda pteridosperm likely to climbed on Cordaites or Sigillaria trees. Moreover, physical principles such as the pressure difference between inside and outside of the pads also seems to play an important role in assisting climbing. The new finding indicates that some pteridosperms in the Permian Cathaysian flora possessed climbing growth habit as well as those in the Late Carboniferous Euramerica Flora, where climbing/scrambling growth habit is well known in the coal swamp forests. This finding shows one of the several earliest climbing habits in Cathaysia Flora and thus remarkably promotes our understanding of the growth habit of pteridosperm and the change in plant community structure in that area.</p></abstract>ARTICLEtrue Cuticles of (?) Thylacocephalan Arthropod from the Basal Choteč Event (Choteč Formation, Eifelian; Barrandian Area, Czech Republic)<abstract><title style='display:none'>Abstract</title><p>Small fragments of phosphatic cuticle have been observed in dark limestone of the early Eifelian age (Choteč Formation) in the interval of the Basal Choteč Event. The cuticle is two-layered, primarily folded, with a chamber between outer and inner walls. Fragments likely represent small cuticle pieces from the margins of the carapace. The exterior of the cuticle is nearly smooth bearing irregular network of wrinkled polygons or shallow pits. Low conical mound-like to high thorn-like spines with annular structure extend from both outer and inner surface of cuticle. Wrinkled and folded bases of these spines indicate moderate flexibility of cuticle. Spines are hollow, the higher ones often with apical opening. The inner surface of carapace carries smaller spines or is nearly smooth. Chamber walls inside the cara-pace are with folds and other structures supporting stiffness of the cuticle. The internal walls of the cuticle are covered by polygonal bumps. These uniformly sized and shaped bumps are about 1 μm sized and likely represents imprints of the epithelial cells adjoined to the basal membranous layer of endocuticle.</p><p>Biological affinity of cuticle fragments is unclear. They surely represent pieces of the arthropod cara-pace, the most probably a thylacocephalan. Associated fossils indicate a deeper marine environment. Bloom of prasinophytes, abundance of dacryoconarids and organophosphatic brachiopods, and striking rarity and diminutive size of other fauna indicate eutrophic conditions in a neritic sea, likely with hypoxic bottom water. Nectonic mode of life in open sea can be suggested for an animal bearing this cuticle.</p></abstract>ARTICLEtrue Biology of the Arborescent Seed-Fern : Implications for Taxonomy (Medullosales, Late Pennsylvanian Sydney Coalfield, Canada)<abstract><title style='display:none'>Abstract</title><p>A shaley slab (65 x 45 x 7 cm) from the Sydney Coalfield, Canada, Cantabrian age, on splitting apart revealed 2 – 3 layers each entombing thousands of abscised pinnules of Linopteris obliqua and eight dispersed compound-synangial structures. The campanulary-ventral-sporal micromorphology of the best preserved structure of these compares sufficiently well with previously reported structures from the Sydney Coalfield named Potoniea krisiae. Earlier studies involving larger sampling suites furthermore contributed to the observation that Hexagonocarpus sp. (female organ) and P. krisiae (male organ) usually co-occur with abscised L. obliqua pinnules; however, these two organs do not co-occur on isochronous bedding planes. In the absence of confirmatory organic attachments, the presented data provide as yet the strongest support for the hypothesis of the organs’ connectivity, but whether female-male trees existed or not, and the mode of attachment of the organs remain unknown. Hypothesized for the latter is pinnate attachment.</p></abstract>ARTICLEtrue Sclerites Eurytholia from the Lower and Middle Devonian of the Czech Republic<abstract><title style='display:none'>Abstract</title><p>Problematic phosphatic sclerites Eurytholia are reported for the first time from the Middle Devonian. Unequivocal sclerites were observed in limestones of Emsian to late Eifelian age in six localities of the Barrandian area of the Central Bohemia of the Czech Republic. Formerly observed size and shape variations of Eurytholia sclerites prevent formal description of a new species on few specimens of Emsian and Eifelian age. Therefore the new specimens are identified as Eurytholia aff. bohemica. Their presence indicates longer time range of the Eurytholia animal, covering not only the Ordovician, the Silurian and the earliest Devonian as known formerly, but also late Lower Devonian and the Middle Devonian. Similar features in morphology and histology of Eurytholia indicate relationship to a conodont Pseudooneotodus and a support suggestion about the vertebrate origin of Eurytholia sclerites.</p></abstract>ARTICLEtrue of the Art of “Amphibian” Localities of the Letovice Subbasin (Boskovice Basin, Czech Republic)<abstract><title style='display:none'>Abstract</title><p>This paper provides a summary of localization of Permian historical sites in the Boskovice Basin, which yielded amphibians of the family Discosauriscidae. Most of these sites have not been previously precisely localized. Our investigation is focused mainly on so-called “Špinar’s localities” named after Prof. Z. Špinar and described in his work. Several sites were also described by A. Stehlík, J. Zajíc &amp; S. Štamberg and J. Augusta. The reason for the localization of these locations is that more than 3,000 samples from these sites are stored at the Chlupáč’s Museum of Earth History of the Charles University in Prague. Most localities are situated around the village of Bačov, where carbonization is the dominant type of preservation of Palaeozoic amphibian skeletons.</p></abstract>ARTICLEtrue Brachiopods of Tremadocian Age from the Abandoned Gabriela Mine (Krušná Hora, Central Bohemia, Czech Republic)<abstract><title style='display:none'>Abstract</title><p>Lingulate brachiopods are described from a lithic sandstone referred to the upper part of the Třenice Formation. Loose blocks were sampled from a dump of abandoned Gabriela Mine in Krušná Hora Hill near Beroun, Central Bohemia. Apart of the Acrotreta aff. grandis Klouček, 1919, genera Teneobolus, Rosobolus, Broeggeria, Rowellella and Siphonobolus are distinguished. Comments to their ontogeny, affinity, stratigraphical and spatial occurrences and taphonomy are discussed.</p></abstract>ARTICLEtrue Important Findings of Two Index Trilobites from the Jince Formation (Cambrian, Drumian) of the Příbram-Jince Basin (Barrandian Area, Czech Republic)<abstract><title style='display:none'>Abstract</title><p>Litavkaspis rejkovicensis Fatka, Kordule et Šnajdr from the Příbram-Jince Basin has been known to occur in a roughly 30 m thick eponymous Taxon-range Zone situated in the lower parts of the Jince Formation (Cambrian, Drumian), within the Eccaparadoxides pusillus Interval Zone. A unique finding of a cranidium of Litavkaspis sp. at the locality Jince-Vystrkov, described in this report, comes from the middle parts of the Paradoxides gracilis Taxon-range Zone, lying roughly 250 m higher than the hitherto known biostratigraphically youngest occurrence of the index taxon. Specimens of Dawsonia bohemica (Šnajdr) from the Jince Formation have been collected exclusively in about 1 m thick deposits of the eponymous Taxon-range Zone situated stratigraphically at the base of the Onymagnostus hybridus Interval Zone. The findings of Dawsonia cf. bohemica presented herein come from the localities Rejkovice – Potůček in the Litavkaspis rejkovicensis Taxon-range Zone, and Rejkovice – Ve žlutých in the Acadolenus snajdri Interval Zone. Their stratigraphic positions are therefore 30–50 m lower than the typical occurrence of Dawsonia bohemica (Šnajdr) in the eponymous Taxon-range Zone.</p></abstract>ARTICLEtrue from Compressed Medullosalean Plant Fossils: Chemical and Morphological Studies (Late Pennsylvanian Sydney Coalfield, Canada)<abstract><title style='display:none'>Abstract</title><p>Fragmented compression specimens of medullosalean fronds have been voluminously described over the past 200 years. However, the literature on rodlets is scarce. We addressed the questions (i) of common occurrence in these fronds, (ii) what made the fronds so strong to bear such a biomassive load, and (iii) what is the chemical make up of rodlets that expressed as striae and ridges (medullosalean hallmark) occur on these fronds? Recovered were soluble and insoluble, black, round and flat, opaque or translucent rodlets that are up to 5 mm long and ca. 10-111 μm wide, and are typed as (i) transparent, (ii) insoluble, or (iii) soluble in Schulze’s solution. In situ insoluble rodlets can be distinguished from associate coal and cuticle-free compression foliage and rachides by relatively high aromaticity and low aliphatics, although their chemical composition is unknown. Rodlets are presumably related to sclerenchymatous tissue in support of strength/stability of these sizeable medullosalean fronds.</p></abstract>ARTICLEtrue Microremains from the Pragian, Emsian and Eifelian of the Prague Basin (Czech Republic)<abstract><title style='display:none'>Abstract</title><p>The vertebrate faunas in limestone samples of the Early and Middle Devonian ages (Pragian, early Emsian, late Emsian, and latest Eifelian) which were collected from five localities in the Barrandian area, Bohemia, include scales, tesserae, bones, and teeth of acanthodians, placoderms, chondrichthyans, and sarcopterygians. Although the vertebrate remains are not abundant the assemblages are significant in being dominated by particular taxa. Apart from undetermined microremains the genera <italic>Cheiracanthoides, Laliacanthus, Nostolepis</italic>, and <italic>Tassiliodus</italic> were determined.</p></abstract>ARTICLEtrue from Pennsylvanan Marattialean Fern (C. Presl in Sternberg) Němejc from Pilsen Basin (Czech Republic) and Sydney Coalfield (Canada)<abstract><title style='display:none'>Abstract</title><p>Pennsylvanian fossil-fern cuticles are notoriously difficult to extract, little can be found in the palaeobotanical literature, yet they can supply significant taxonomic/systematic, phytostratigragphic, and palaeoenvironment information. This is demonstrated for cuticles from “Pecopteris” polypodioides of the coal basins in the Czech Republic and Canada. “Pecopteris” polypodioides is a marattialean tree fern which was part of the peat-forming flora, growing in a wet environment. Due to this fact, cuticles are generally very thin, and we assume that their major function was to reduce the ability of fungal spores to germinate and bacterial to grow, thereby reducing the possibility of these agents to cause disease. The secondary function was to be a major barrier to water loss and reducing the wettability of pinnules.</p></abstract>ARTICLEtrue Geological, Palaeobotanical and Palynological Evidence of the Carboniferous from Brandov (Krušné Hory Mts., Czech Republic)<abstract><title style='display:none'>Abstract</title><p>Gas-pipeline construction around Brandov (Czech Republic) exposed pre Quaternary strata allowing more precise understanding of the regional geology. The crystalline rocks in the basement, near the Brandov Carboniferous Relict, belong to Sayda Dome rather than to the Hora Svaté Kateřiny (Katharinaberg) Dome. The lower Carboniferous unit (Westphalian – Moscovian) is of greater extent than previously estimated. In contrast, the upper unit, which is correlated with Stephanian (Kasimovian or Gzhelian) strata, is arealy less extensive than previously estimated and is devoid of fossil remains. An anthracite seam, in the lower unit, was discovered in the “North depth” some 1–1.3 km to the North from old mining activity of the “South depth”. The seam was accompanied by a flora dominated by cordaitaleans and sphenopsids (calamitaleans), and common lycopsids and ferns. Palynomorphs were isolated from mudstones for the first time and 36 genera and 51 species of miospores could be determined. A humic clayey layer was discovered in the Quaternary deposits whose palynological age is 500 – 100 years old.</p></abstract>ARTICLEtrue