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Oeufs fossiles des cephalopodes?

100%

Kozlowski R.

Acta Palaeontologica Polonica

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1965

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tom 10

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nr 1

L'auteur essaie d'interpréter la nature des énigmatiques vésicules ordoviciennes qu'il a déorites en 1959 sous le nom de Clistrocystis graptolithophilius Kozł. Il constate leur surprenante ressemblance avec les oeufs de la seiche. Cela suggère l'idée qu'il y puisse s'agir des oeufs d'un Céphalopode ordovicien.

2

The aperture and its closure in an Ordovician conulariid

75%

Sendino C., Zagorsek K., Vyhlasova Z.

Acta Palaeontologica Polonica

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2011

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tom 56

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nr 3

The conulariids, an enigmatic fossil group believed to be of cnidarian (scyphozoan) affinity, have four−sided, acutely pyramidal exoskeletons terminated in apertural closures. To date, three main closure types have been recognised in conulariids (plicated, triangular lappets, and lobate lappets) but the first type is poorly illustrated in the literature. Here we present the first photographic illustration of an unequivocal plicated closure in Metaconularia? anomala, based on study of the rich (1700+ specimens) material from the Upper Ordovician of the Prague Basin. This closure is formed by inwardly folded, triangular lappets centred on each of the four faces, with kite−shaped elements centred on the four corners forming a webbing between the lappets. Plicated closures were evidently rare in conulariids and restricted to a few Ordovician species.

3

Ceratopea [Gastropoda] from Lower Ordovician of South Spitsbergen

75%

Birkenmajer K., Yochelson E. L.

Bulletin of the Polish Academy of Sciences. Earth Sciences

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1998

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tom 46

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nr 3-4

4

Maximizing diductor adhension: An unusual cardinal process in Late Ordovician brachiopods from Estonia

75%

Hints L.

Acta Palaeontologica Polonica

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2004

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tom 49

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nr 4

Cardinal process is a structure on dorsal valve of brachiopods serving for separation or attachment of diductor muscles. A cardinal process with a peculiar folded myophore is described from Late Ordovician “Orthis” kukersiana−group brachiopods assigned to the genus Cyrtonotella (order Orthida). This structure differs from those of other rhynchonelliformean brachiopods and can be considered as a separate type among about twenty varieties of processes described up to now.

5

An enigmatic early ? palaeocope ostracode from the Arenig of NW Russia

75%

Tinn O., Meidla T.

Acta Palaeontologica Polonica

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2002

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tom 47

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nr 4

The ostracode Lavachilina evae gen. et sp. nov. is described from the Arenig of Western Russia. Its carapace possesses a unique discontinuous velum, developed at both ends as a narrow spinose ridge. The systematic position of L. evae is uncertain. Its character set shows mostly palaeocope affinities but also some features of leiocopes. L. evae is tentatively assigned to the palaeocope family Oepikellidae, possibly representing an early member of that family. Although L. evae existed contemporaneously with palaeocopes such as Laccochilina, it does not appear to be closely related to these early eurychilinoids.

6

Ordovician rafinesquinine brachiopods from peri-Gondwana

63%

Colmenar J.

Acta Palaeontologica Polonica

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2016

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tom 61

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nr 2

The study of the strophomenide brachiopods of the subfamily Rafinesquininae present in the main Upper Ordovician sections, representing the Mediterranean margin of Gondwana, has revealed an increase in diversity of the group at the region during that time. The studied collections are from the Moroccan Anti-Atlas, the Iberian and the Armorican massifs, the Iberian Chains, Pyrenees, Montagne Noire, Sardinia, and Bohemia. Two genera of the subfamily Rafinesquininae have been recorded. Of them, the cosmopolitan Rafinesquina is the only one previously reported from the region and Kjaerina is found for the first time outside Avalonia, Baltica, and Laurentia. Additionally, two new subgenera have been described, Kjaerina (Villasina) and Rafinesquina (Mesogeina). Furthermore, the new species Rafinesquina (Mesogeina) gabianensis, Rafinesquina (Mesogeina) loredensis, Kjaerina (Kjaerina) gondwanensis, Kjaerina (Villasina) pedronaensis, Kjaerina (Villasina) pyrenaica, and Kjaerina (Villasina) meloui have been described. In addition, other species of these genera previously known from isolated localities in the region, such as Rafinesquina pseudoloricata, Rafinesquina pomoides, and Hedstroemina almadenensis are revised and their geographic range expanded. The adaptive radiation experienced by the rafinesquinines at the Mediterranean region during middle to late Katian, was probably related to changes in the regime of sedimentation and water temperature caused by the global warming Boda event.

7

Graptolodendrum mutabile n.gen., n.sp. - an aberrant dendroid graptolite

63%

Kozlowski R.

Acta Palaeontologica Polonica

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1966

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tom 11

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nr 1

A representative of the order Dendroidea, described as Graptolodendrum mutabile n.gen., n.sp., differs from other dendroid graptolites in its bithecae whose position is not stabilized. Mostly, they occur on one side of the stipe and, rarely, on both sides alternatively which is a rule in the Dendroidea. The fusellar structure of autothecae, mostly irregular in the distal part, is also unstabilized. The position of the pore which pierces the wall of metasicula, as in the Graptoloidea, and not of prosicula, is a fully exceptional character in the representative of the Dendroidea. The material in vestigated has been etched out from the Middle Ordovician erratic boulders of Poland.

8

The youngest ctenocystoids from the Upper Ordovician of the United Kingdom and the evolution of the bilateral body plan in echinoderms

63%

Rahman I. A., Stewart S. E., Zamora S.

Acta Palaeontologica Polonica

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2015

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tom 60

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nr 1

During the early Palaeozoic, echinoderm body plans were much more diverse than they are today, displaying four distinct types of symmetry. This included the bilateral ctenocystoids, which were long thought to be restricted to the Cambrian. Here, we describe a new species of ctenocystoid from the Upper Ordovician of Scotland (Conollia sporranoides sp. nov.). This allows us to revise the genus Conollia, which was previously based on a single poorly-known species from the Upper Ordovician of Wales (Conollia staffordi). Both these species are characterized by a unique morphology consisting of an elongate-ovoid body covered in spines, which clearly distinguishes them from their better-known Cambrian relatives; they are interpreted as infaunal or semi-infaunal burrowers from deep-water environments. This indicates that the ctenocystoid body plan was not fixed early in the evolution of the group, and they most likely modified their structure as an adaptation to a new mode of life in the Ordovician.

9

A review of the endocerid cephalopod Protocyptendoceras from the Floian [Lower Ordovician] of the Eastern Cordillera, Argentina

63%

Cichowolski M.

Acta Palaeontologica Polonica

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2009

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tom 54

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nr 1

99-109

Ordovician cephalopods from Western Gondwana are still poorly known and published data is in need of systematic and stratigraphical revision. In this work, the endocerid proterocameroceratid Protocyptendoceras from the Floian of the Eastern Cordillera of Argentina is revised using new material from La Ciénaga, 5 km upstream from Purmamarca. The species P. corvalani and P. teicherti are considered to be junior synonyms of P. fuenzalidae, which is redescribed in detail and reillustrated. Specimens preserve adapical parts of isolated siphuncles, related here to the presence of endocones in a posterior portion. Evidently P. fuenzalidae had a nektobenthic mode of life in a shallow water environment, oriented horizontally. Its palaeobiogeographical affinities are mainly with Floian proterocameroceratids from Eastern Gondwana, such as Anthoceras decorum and the related genera Lobendoceras, Ventroloboceras, and Notocycloceras.

10

Alleged cnidarian Sphenothallus in the Late Ordovician of Baltica, its mineral composition and microstructure

63%

Vinn O., Kirsimae K.

Acta Palaeontologica Polonica

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2015

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tom 60

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nr 4

Sphenothallus is a problematic fossil with possible cnidarian affinities. Two species of Sphenothallus, S. aff. longissimus and S. kukersianus, occur in the normal marine sediments of the Late Ordovician of Estonia. S. longissimus is more common than S. kukersianus and has a range from early Sandbian to middle Katian. Sphenothallus had a wide paleo-biogeographic distribution in the Late Ordovician. The tubes of Sphenothallus are composed of lamellae with a homogeneous microstructure. The homogeneous microstructure could represent a diagenetic fabric, based on the similarity to diagenetic structures in Torellella (Cnidaria?, Hyolithelminthes). Tubes of Sphenothallus have an apatitic composition, but one tube contains lamellae of diagenetic calcite within the apatitic structure. Sphenothallus presumably had originally biomineralized apatitic tubes. Different lattice parameters of the apatite indicate that biomineralization systems of phosphatic cnidarians Sphenothallus and Conularia sp. may have been different.

11

Crinoid ancestry without blastozoans

63%

Guensburg T. E., Blake D. B., Sprinkle J., Mooi R.

Acta Palaeontologica Polonica

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2016

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tom 61

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nr 2

At present, a debate in the paleontologic literature focuses on whether or not the immediate ancestry of the Crinoidea lies in an unidentified member of the Blastozoa, which includes eocrinoids and an assemblage known variously as the “cystoids”. Those proposing to derive crinoids from within the blastozoans have recently argued for homologies in the construction of the oral region of certain derived taxa from both groups. An opposing viewpoint, outlined here, finds evidence that aside from plesiomorphies, proposed similarities are superficial and homoplastic. We suggest these superficialities represent convergent adaptive strategies. Earliest crinoids express ambulacral traits unlike any blastozoan but that are expressed in the only other pentaradial echinoderms with a known record early enough to be considered in the context of crinoid origins, edrioasteroids and edrioasteroid-like stem echinoderms.

12

Graptolite-like fibril pattern in the fusellar tissue of Palaeozoic rhabdopleurid pterobranchs

63%

Mierzejewski P., Kulicki C.

Acta Palaeontologica Polonica

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2001

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tom 46

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nr 3

The fusellar tissue of Palaeozoic rhabdopleurid pterobranchs has been studied using the SEM techniques. The fibrillar material of Ordovician Kystodendron ex gr. longicarpus and Rhabdopleurites primaevus exhibits a distinct dimorphism, comprising: (1) thinner, wavy and anastomosing/branching fusellar fibrils proper, producing a tight three-dimensional meshwork; and (2) long, more or less straight and unbranched cortical fibrils, sometimes beaded, and arranged in parallel. These fibrils are similar to the fusellar and cortical fibrils of graptolites, respectively. Until now, dimorphic fibrils and their arrangement within fusellar tissue were regarded as unique characters of the Graptolithina. In general, the fibrillar material of these fossils is partially preserved in the form of flaky material (new term) composed of flakes (new term). Flakes are interpreted as flattened structures originating from the fusion of several neighbouring tightly packed fibrils. A Permian rhabdopleurid, referred to as Diplohydra sp., reveals a fabric and pattern of fusellar tissue similar to that of both Ordovician rhabdopleurids but devoid (?) of cortical fibrils. The results presented here question views that: (1) substantial differences in fabric and pattern of fusellar tissue exist between fossil pterobranchs and graptolites; and (2) the ultrastructure of pterobranch periderm has remained unchanged at least since the Ordovician. The Palaeozoic rhabdopleurids investigated are closer ultrastructurally to graptolites than to contemporary pterobranchs. The pterobranchs and the graptolites should be treated as members of one class - the Graptolithoidea.

13

Significance of the genus Thysanotos Mickwitz 1896 for the Ordovician stratigraphy of East-Central Europe

63%

Bednarczyk W. S.

Bulletin of the Polish Academy of Sciences. Earth Sciences

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1999

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tom 47

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nr 1

14

Aspects of life mode among Ordovician asteroids: Implications of new specimens from Baltica

63%

Blake D. B., Rozhnov S.

Acta Palaeontologica Polonica

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2007

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tom 52

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nr 3

A new genus and species of Asteroidea (Echinodermata), Estoniaster maennili, is described from the Upper Ordovician (Caradocian) of Estonia; it is similar to the western European genus Platanaster and the North American Lanthanaster and an as yet unpublished new genus. Specimens of Urasterella? sp. and Cnemidactissp. are recognized from the Middle Ordovician of northwest Russia; although similar to known species, incomplete preservation precludes more precise taxonomic assessment. Asteroids are important in many existing marine communities, and in spite of a meager fossil record, diversity suggests they were important in the early Paleozoic as well. Some debate has centered on arm flexibility in early asteroids, which bears on their roles in their communities. Parallels in ambulacral series arrangement between Ordovician and extant species and presence of an ambulacral furrow indicate similar broad ranges of motion and therefore potentially parallel ecologic roles. Many factors might have contributed to the differences between ancient and extant ambulacral articulation, including changes in positioning of a part of the water vascular system, changes in predation and bioturbation pressures, and taphonomic events that obscure skeletal details.

15

A spinose appendage fragment of a problematic arthropod from the Early Ordovician of Morocco

63%

Van R. P., Tetlie O. E.

Acta Palaeontologica Polonica

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2006

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tom 51

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nr 2

A highly spinose fragment of a possibly raptorial appendage from the Arenig (Early Ordovician) of the Upper Fezouata Formation north of Zagora, southeastern Morocco is described as the arthropod Pseudoangustidontus duplospineus gen. et sp. nov. The single fragmentary specimen displays a unique morphology, carrying at least 39 pairs of spines (i.e., 78 spines) of very regularly alternating lengths. Pseudoangustidontus gen. nov. shows some similarities to a number of spinose arthropod appendages and appendage parts, most notably to the spine−bearing podomeres of the third prosomal appendage of megalograptid eurypterids and the problematic and incompletely known genus Angustidontus. However, megalograptids and Angustidontus both have a lower spine count, while the latter also carries only a single row of spines. Because no known arthropod displays a morphology closely comparable to that of Pseudoangustidontus gen. nov., the affinities of the new fossil within Arthropoda remain uncertain.

16

The morphology and fine structure of the Ordovician Cephalodiscus-like genus Melanostrophus

63%

Mierzejewski P., Urbanek A.

Acta Palaeontologica Polonica

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2004

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tom 49

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nr 4

The holotype and a new specimen from the type locality, as well as a few new specimens of Melanostrophus fokini Öpik, 1930, an enigmatic invertebrate from the Ordovician of the Baltic region, have been examined using combined LM, SEM and TEM techniques. This form is reinterpreted as a ?cephalodiscid hemichordate. Its skeleton or coenecium is an encrusting assemblage of uniform zooidal tubes, forming a circular or subcircular palisade−like structure.The zooidal tubes are long (up to 50 mm) and slender, similar to zooidal tubes of the extant pterobranch hemichordate Cephalodiscus (Orthoecus). The fine structure of the skeleton wall is similar to that in graptolites and four components have been recognized within periderm: (i) thick, outer cortical layer, (ii) very thin fusellar layer, constructed of annular growth bands, with their oblique sutures arranged randomly, resembling the fusellar layer of some pterobranchs and primitive graptolites, (iii) inner cortical layer, and (iv) thin, enamel−like inner lining. The periderm is abundantly perforated by pits and holes of different diameters; some of them were probably caused by saprophytic or parasitic borers, but the largest ones (up to 100 µm) are probably primary and mark a tube bifurcation. It is concluded that cortex formation is not a synapomorphy for graptolites.

17

Late Ordovician brachiopods from the Selety River basin, North Central Kazakhstan

63%

Nikitin I. F., Popov L. E., Bassett M. G.

Acta Palaeontologica Polonica

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2003

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tom 48

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nr 1

A medium−diversity fauna of late Ordovician rhynchonelliformean brachiopods occurs in the Tauken Formation (upper Caradoc–lowermost Ashgill) of north Central Kazakhstan.It demonstrates close similarity to the approximately contemporaneous faunas characteristic of shallow clastic shelves (BA 2–3) of the Chingiz and Chu−Ili ranges (both in Kazakhstan) and South China, but is characterized by a high proportion of endemic new species, including Tetraphalerella bestiubensis sp.nov., Glyptomena kaskolica sp.nov., Dinorthis taukensis sp.nov., Rhynchotrema seletensis sp.nov., and Nalivkinia (Pronalivkinia)zvontsovisp.nov.The abundance of Rhynchotrema is somewhat unusual by comparison with faunas from other Kazakhstanian terranes, where rhynchonellides of the family Ancistrorhynchidae are usually dominant in near−shore biofacies.The occurrence of the atrypides Sulcatospira and early Nalivkinia demonstrates a clear biogeographical linkage with approximately contemporaneous faunas of South China.

18

Outline of palaeozoic geology of the Southern Lublin Region

63%

Pawlowski S.

Bulletin of the Polish Academy of Sciences. Earth Sciences

|

1992

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tom 40

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nr 2

19

A new graptolite, intermediate between the Tuboidea and the Camaroidea

63%

Mierzejewski P.

Acta Palaeontologica Polonica

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2001

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tom 46

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nr 3

A new tuboid graptolite, Camarotubus graptocamaraeformis gen. et sp.n., is described from a calcareous erratic boulder of middle Ordovician (Caradoc?) age from Poland. This encrusting form combines characters of both the tuboid and the camaroid graptolites, and is regarded as a purely morphological intermediate between them. This finding supports Kozłowski's (1949) concept of a close phylogenetic relationship between the orders Tuboidea and Camaroidea.

20

Lingulate brachiopods from Lower Ordovician [Tremadoc] chalcedonites, Holy Cross Mountains, Poland

63%

Holmer L. E., Biernat G.

Acta Palaeontologica Polonica

|

2002

|

tom 47

|

nr 1

Lingulate brachiopods from chalcedonites of Tremadoc age are redescribed based on new material from the Holy Cross Mountains, Poland. The fauna includes 18 species, of which Elliptoglossa polonica and Siphonotretella popovi are new. The enigmatic Orbiculoidea? subovalis Biernat is redescribed as a species of the recently erected aberrant paterulids Diencobolus Holmer, Popov, Koneva, and Bassett. The fauna includes also Acrotreta dissimilis (Biernat), ?Ditreta dividua Biernat, Semitreta maior Biernat, Eurytreta minor Biernat, Mamatia retracta (Popov), Orbithele ceratopygarum (Brøgger), Siphonobolus uralensis (Lermontova), Alichovia analogica Biernat, Pomeraniotreta sp., Akmolina sp., Rowellella sp., Acanthambonia sp. A, Acanthambonia? sp. B, Leptembolon cf. lingulaeformis (Mickwitz), and the earliest known species of Eoconulus. Most of the recorded lingulate species are endemic, but a significant number are now known also from eastern Kazakhstan and the South Urals, as well as from the Tremadoc of Sweden and Norway.

Ograniczanie wyników

Oeufs fossiles des cephalopodes?

The aperture and its closure in an Ordovician conulariid

Ceratopea [Gastropoda] from Lower Ordovician of South Spitsbergen

Maximizing diductor adhension: An unusual cardinal process in Late Ordovician brachiopods from Estonia

An enigmatic early ? palaeocope ostracode from the Arenig of NW Russia

Ordovician rafinesquinine brachiopods from peri-Gondwana

Graptolodendrum mutabile n.gen., n.sp. - an aberrant dendroid graptolite

The youngest ctenocystoids from the Upper Ordovician of the United Kingdom and the evolution of the bilateral body plan in echinoderms

A review of the endocerid cephalopod Protocyptendoceras from the Floian [Lower Ordovician] of the Eastern Cordillera, Argentina

Alleged cnidarian Sphenothallus in the Late Ordovician of Baltica, its mineral composition and microstructure

Crinoid ancestry without blastozoans

Graptolite-like fibril pattern in the fusellar tissue of Palaeozoic rhabdopleurid pterobranchs

Significance of the genus Thysanotos Mickwitz 1896 for the Ordovician stratigraphy of East-Central Europe

Aspects of life mode among Ordovician asteroids: Implications of new specimens from Baltica

A spinose appendage fragment of a problematic arthropod from the Early Ordovician of Morocco

The morphology and fine structure of the Ordovician Cephalodiscus-like genus Melanostrophus

Late Ordovician brachiopods from the Selety River basin, North Central Kazakhstan

Outline of palaeozoic geology of the Southern Lublin Region

A new graptolite, intermediate between the Tuboidea and the Camaroidea

Lingulate brachiopods from Lower Ordovician [Tremadoc] chalcedonites, Holy Cross Mountains, Poland