<abstract>
<title style='display:none'>Abstract</title>
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.
</abstract>

Heterosporangia in <italic>Isoetes Pantii</italic> (Isoetaceae, Pteridophyta): Revealing the Beginnings of Heterospory and Recalling Paleozoic Ancestors?

<abstract>
<title style='display:none'>Abstract</title>
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.
</abstract>

The Rare Trilobites <italic>Exallaspis</italic> (Odontopleuridae) and <italic>Kosovoproetus</italic>? (Tropidocoryphidae) in the Homerian (Silurian) Of The Prague Basin, Bohemian Massif

<abstract><title style='display:none'>Abstract</title>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.</abstract>

Biostratigraphically 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>The calceolide coral Calceola sandalina (Linné, 1771) has been observed in the Acanthopyge Limestone (Choteč Formation, Eifelian) in the Koněprusy area, Czech Republic. Its presence in the Barrandian area indicates absence of significant palaeogeographic barriers restricting the distribution of this tetracoral in the Middle Devonian. Association of Calceola with a taxonomically diverse ribbed brachiopod faunas attests for two different types of environment on the Koněprusy submarine elevation during deposition of the Acanthopyge Limestone. Calceola-bearing beds represent a high-energy reefal environment different from somewhat deeper and calmer environment characterized by smooth-shelled, small to medium sized spire-bearing brachiopods.</abstract>

The First Occurrence of the Devonian Rugose Coral Calceola Sandalina (Linné, 1771) in the Barrandian Area, Czech Republic

<abstract><title style='display:none'>Abstract</title>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.</abstract>

Lingulate Brachiopods of Tremadocian Age from the Abandoned Gabriela Mine (Krušná Hora, Central Bohemia, Czech Republic)

<abstract>
<title style='display:none'>Abstract</title>
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.
</abstract>

First Record of Podichnus in Byronid Shell from the Lower Devonian (Pragian) of the Prague Basin, Czechia

<abstract>
<title style='display:none'>Abstract</title>
<italic>In the middle Sandbian and lower Katian (Upper Ordovician) rocks of the Barrandian area, the fossil remains of conulariids are relatively abundant. Their thecae were sometimes used as solid surfaces for the attachment of epizoans, mostly craniid brachiopods of the genus</italic> Petrocrania, <italic>more rarely also echinoderms</italic> Hemicystites <italic>and</italic> Agelacrinites, <italic>and bryozoans</italic> Ceramopora <italic>and</italic> Spatiopora. <italic>The orientation of shells of</italic> Petrocrania <italic>suggests that conulariids (mostly belonging to the genus</italic> Archaeconularia) <italic>were dead at the time of the brachiopod attachment, their thecae were partly fragmentary and secondarily replaced. A find of</italic> Pseudoconularia grandissima <italic>attached to the theca of the cystoid</italic> Codiacystis <italic>is also reported.</italic>
</abstract>

Organisms Attached to Conulariid Thecae from the Upper Ordovician of the Barrandian Area (Czech Republic)

<abstract>
<title style='display:none'>Abstract</title>
<italic>As yet undescribed accumulations of shells of orthoconic cephalopods, which are in some aspects comparable to cephalopod limestones known from the Silurian and Lower Devonian of the Barrandian area and other regions of the world, occur in the Letná and Zahořany formations (middle Sandbian and lower Katian stages, Upper Ordovician, central Bohemia). These accumulated shells are often colonized by sessile organisms. Only a small proportion of these organisms could be attached to shells of alive cephalopods; the majority of them used empty shells as solid substrates. The most abundant epizoan is the cystosporate bryozoan of the genus</italic> Ceramopora <italic>that often overgrows the cephalopod shells extensively. Holdfasts of the genus</italic> Sphenothallus <italic>and problematic fossils assigned to the genus</italic> Conchicolites <italic>are common. Rarer epibionts include the bryozoan</italic> Spatiopora, <italic>the cystoid echinoderm</italic> Codiacystis <italic>and the brachiopod</italic> Ptychopeltis. <italic>Varying sizes of bryozoan colonies occurring on the same cephalopod shell point to several recurring attachment events, probably reflecting reproduction cycles.</italic>
</abstract>

Accumulations of Fossil Cephalopod Shells and Attached Epizoans from Some Late Ordovician Localities (Barrandian Area, Czech Republic)

<abstract>
<title style='display:none'>Abstract</title>
<italic>The new material of conulariids is described from the mid-Sheinwoodian “Miraspis Limestone” at the famous Špičatý vrch locality near Loděnice in the Barrandian area. Although poorly preserved, three taxa have been determined, referred to the</italic> Archaeoconularia <italic>cf.</italic> fecunda <italic>(Barrande, 1855)</italic>, Conularia proteica <italic>Barrande, 1854 and</italic> Metaconularia <italic>(?) sp.</italic>
</abstract>

Conulariids of the <italic>Monograptus Belophorus</italic> Zone (Motol Formation, Sheinwoodian, Wenlock) of the Barrandian Area, Czech Republic

<abstract>
<title style='display:none'>Abstract</title>
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.
</abstract>

Seminal 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>
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.
</abstract>

Diminutive Epibionts on Crinoid Stems from the Lower/Middle Devonian Boundary in the Barrandian, Czech Republic

<abstract><title style='display:none'>Abstract</title>The late Paleozoic deposits in several basins in the Czech Republic are well
 known for their abundance of silicified stems. Despite the fact they have been
 known since 19th century, there are few modern works of this material. The stems
 have been known to occur at several stratigraphic levels. During the course of
 recent field work such material has been found at additional levels. Most of
 them belong to the genus <italic>Agathoxylon</italic>, divided here into two
 types: cordaitalean plants and conifers. Based on previous data from Intra
 Sudetic and Pilsen Basins, and new material from Krkonoše Piedmont and
 Kladno-Rakovník Basins, this work compiles and compares the occurrence,
 anatomical features and taxonomy of silicified Agathoxylon-type of stems through
 four studied areas. The various cordaitalean - conifer ratio among all basins
 reflect different palaeoenvironment in each of them.</abstract>

Municipal Museum Nová Paka, F.F. Procházky
                    70, 50901 Nová Paka, Czech Republic

Charles University in Prague, Faculty of Science,
                    Albertov 6, 128 43 Praha 2, Czech Republic

Palaeontology Department, West Bohemian Museum in Pilsen,
                    Kopeckého sady 2, 30100 Plzeň Czech Republic;

Summary of Occurrence and Taxonomy of Silicified
 <italic>Agathoxylon</italic>-Type of Wood in Late Paleozoic Basins of the
 Czech Republic

<abstract><title style='display:none'>Abstract</title>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.</abstract>

Vertebrate Microremains from the Pragian, Emsian and Eifelian of the Prague Basin (Czech Republic)

<abstract><title style='display:none'>Abstract</title>Typification of Sydneia manleyi Pšenička et al. 2003 is based
 entirely on fertile foliage. Of late, attached sterile-fertile segments have
 been found which are illustrated and described, together with cutic-ular
 preparations. A new subfamily, Sydneideae subfam. nov. is erected for the
 monotypytic species. The synangial chemistry is compared with marattialean
 synangia/sporangia from the Czech Republic and from Canada.</abstract>

Palaeontological Department, West Bohemian Museum in
                    Pilsen, Kopeckého sady 2, 30100 Pilsen, Czech Republic

Palaeobiology Laboratory, Cape Breton University Sydney,
                    Nova Scotia, B1P 6L2, Canada

IANIGLA-CCT-CONICET and Área de Química,
                    Instituto de Ciencias Básicas, Universidad Nacional de Cuyo, Centro
                    Universitario - M5502JMA - Mendoza, Argentina

Sterile Foliage of Fertile <italic>Sydneia Manleyi</italic> and
 Synangial Chemistry (Eusporangiate Fern, Late Asturian, Canada): A New Subfamily
 Sydneideae

<abstract><title style='display:none'>Abstract</title> The temporarily exposed rocks of the Dobrotivá Formation (Middle Ordovician, upper Darriwilian) accessible, due to lower water levels, in Džbán water reservoir (Praha-Vokovice area) have produced common fauna. The newly obtained trilobite-dominated fossil associations enable a more detailed discussion of faunal changes in the lower and lower-middle portions of the Dobrotivá Formation - a transition from the Placoparia Association to the newly recognized Degamella-Zeliszkella Association, dominated by mesopelagic forms.</abstract>

Česká geologická služba, Klárov 3, 118 21 Praha 1,

Complementary Description of the Middle Ordovician Trilobite Associations at Praha-Vokovice

<abstract><title style='display:none'>Abstract</title> The Pennsylvanian flora from the Alpe Logone/Val Sanagra locality in the Western Lombardy (Southern Alps, Italy) last underwent a taxonomic study in the mid 20th century. The main problem is generally poor preservation of the plant remains, which makes their identification problematic. Despite this, the authors have identified 43 fossil species from this locality. Based on the sedimentary context of this paleoflora, we assume that the Val Sanagra sediments were deposited in a continental setting, in a fluvial environment with a well-developed and vegetated floodplain where where clastic substrates would locally and occasionally change into peat swamp. The common presence of rhytidolepis and sub-rhytidolepis sigillarias, as well of Eusphenopteris neuropteroides, Lobatopteris miltonii, Mariopteris latifolia, Paripteris linguaefolia, Pecopteris microphylla, Alethopteris sp. (cf. grandinii) indicates that the flora from the Val Sanagra locality spans the interval between the Duckmantian and Bolsovian (middle Moscovian), and thus represents one of the oldest Pennsylvanian floras of the Southern Alps.</abstract>

Palaeontology Department, West Bohemian Museum in Pilsen, Kopeckého sady 2, 30100 Plzeň, Czech Republic

Charles University in Prague, Faculty of Science, Albertov 6, 128 43 Praha 2, Czech Republic

Dipartimento di Scienze della Terra e dell’Ambiente, Universita di Pavia, Via Ferrata 1, 27100 Pavia, Italy

Czech Geological Survey, Klárov 3/131, 118 21 Praha 1, Czech Republic

Revision of the Pennsylvanian Flora from Val Sanagra in Western Part of the Southern Alps (Italy)

<abstract><title style='display:none'>Abstract</title>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.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.</abstract>

The Cuticles of (?) Thylacocephalan Arthropod from the Basal Choteč Event (Choteč Formation, Eifelian; Barrandian Area, Czech Republic)

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