Michal Mergl

Arenigian chitinozoans from the Klabava formation, Bohemia

Abstract The lower Paleozoic succession in Bohemia progressively emerges as a first-order reference in the international stratigraphical scale. This is the reason why investigations have been carried out on chitinozoans from the Klabava Formation which represents the Arenig Series in the Prague Basin. For this preliminary study seventeen samples were collected so that a stratigraphical control based on Arenigian Bohemian graptolite zones is available (namely the Corymbograptus v. similis, Schizograptus tardibrachitus and Tetragraptus cf. pseudobigsbyi zones). However, for a more accurate biozonation more closely spaced sampling will be necessary. Chitinozoans are lacking in some samples while in others abundant but poorly diversified assemblages are present. Among the key species recorded, Conochitina symmetrica, Tanuchitina achabae, Lagenochitina esthonica, D. (Desmochitina) bulla allow biostratigraphical correlations with the Sahara, Armorican Massif, Scandinavia, the Russian Platform, and Quebec. Yet we must emphasize the absence of the genus Eremochitina which is still unrecorded in the Klabava Formation.

The ‘microcontinent’ Perunica: status and story 15 years after conception

Abstract Central Europe consists of a complex mosaic of more or less independent terranes with varying tectonometamorphic histories, usually also of different lithological compositions and protolith, and thus it is reasonable to suppose that the majority of these blocks have experienced somewhat different palaeogeographical evolution. The present terrane juxtaposition has been interpreted in general as a result of the Variscan collision of peri-Gondwanan and peri-Baltic derived terranes, with Gondwana on one side and Baltica and/or Laurentia on the other side. However, reconstruction of the pre-Variscan development and mutual palaeogeographical relationships remains a major challenge of interpretation.

Mediterranean representatives of the obolellidTrematobolus Matthew (Brachiopoda) and a review of the genus

ZusammenfassungDrei neue Arten der Obolelliden-GattungTrematobolus Matthew,T. splendidus, T. serotinus undT. cleidrius, aus tief-mittelkambrischen Schichten von Marokko werden errichtet. Zusätzliche Beschreibungen und Diskussionen behandeln informell beschriebenes Material derselben Gattung bzw. Familie und die spanische ArtT. simplex. T. bicostatus aus Sibirien wird als eigenständige Art angesehen. Die morphologischen Besonderheiten wie auch die spezifischen Merkmale einiger Arten vonTrematobolus werden diskutiert. Dazu gehört insbesondere die Frage nach einem funktionellen Anus und einer gelenkigen Verbindung der Klappen. Überlegungen und Neubewertungen der Vorkommen führen zu einer Revision der stratigraphischen Reichweite von wichtigen Arten der Gattung.AbstractThree new species of the obolellid genusTrematobolus Matthew,T. splendidus n.sp.,T. serotinus n. sp., andT. cleidrius n. sp., from the Middle Cambrian of Morocco are introduced. Additional descriptions and discussions deal with informal material belonging to the same genus and family, respectively, and with the Spanish speciesT. simplex. T. bicostatus from Siberia is raised to specific level. The morphologic characteristics as well as specific significance of several species ofTrematobolus are discussed together with their bearing on functional considerations as of a functional anus and an articulating mechanism. Reconsideration of stratigraphic occurrences of key taxa ofTrematobolus updates the knowledge of the distribution of this genus.

CAMBRIAN LINGULID AND ACROTRETID BRACHIOPODS FROM THE IGLESIENTE AREA (CAMPO PISANO FORMATION, SOUTHWESTERN SARDINIA)

Cambrian brachiopods from Sardinia are investigated for the first time in this paper. The silicified specimens come from nodular limestones of the late Early to Middle Cambrian Campo Pisano Formation of Gutturu Pala (southwestern Sardinia). The brachiopod fauna consists of lingulids and acrotretids and yields two new acrotretid species, described here as Opisthotreta sardica n.sp. and Vandalotreta proclinis n.sp. Material attributed to the genus Schmidtites is reported here for the first time from both the Middle Cambrian and western Gondwana. The genus Linnarssonella is reported for the first time from the Middle Cambrian and from outside North America. Whereas most brachiopods from Gutturu Pala biostratigraphically indicate a rather undifferenciated Middle Cambrian age, the last mentioned genus points to a late Middle Cambrian age for the uppermost part of the Campo Pisano Formation.

Lingulate brachiopods from the Lampazar Formation (late Cambrian) of the Cordillera Oriental of northwestern Argentina

Abstract The Angosto de Lampazar, a classic locality for the study of lower Paleozoic successions in the Cordillera Oriental, NW Argentina, has yielded a late Cambrian relatively diverse, lingulate brachiopod fauna. Sandy lenses with calcareous cement from the uppermost levels of the Lampazar Formation have yielded abundant remains of articulate and phosphatic brachiopods. Among the latter, the new species Eurytreta harringtoni Mergl and Herrera, Lingulella? melonica Mergl and Herrera, Libecoviella lenticularis Mergl and Herrera, and Schizambon cardonalis Mergl and Herrera, as well as the new genus and species Saltaia lampazarensis Mergl and Herrera are formally introduced. Trilobites and conodonts from the same horizons characterize the Cordylodus proavus Zone, allowing a correlation with Stage 10 of the Furongian Series. Although the information on lingulate brachiopods from the C. proavus Zone is scarce across the world, the composition of the studied association displays a relationship with coeval and slightly younger faunas of Utah and Kazakhstan. The Argentine brachiopods, the first described from the late Cambrian Proto-Andean margin of Gondwana, are more closely related to temperate Laurentian faunas than to those from the high latitude North African margin of Gondwana.

Protorthacean brachiopods from the Middle Cambrian of Morocco

Protorthacean brachiopods from the Middle Cambrian of the Moroccan Atlas regions are described in terms of morphology and systematic affinities. The superfamily Protorthacea is revised to include both Protorthidae and Bohemiellidae. Newly introduced is the protorthid genus Saesorthis, the morphologic characteristics as well as the significance of which are discussed in detail together with their bearing on early phylogeny of the Orthacea. A reinvestigation of Brahimorthis antiqua led to the recognition of additional morphologic peculiarities and enhances understanding of its stratigraphic occurrence. Additional descriptions and discussions deal with informally described protorthid and bohemiellid species. Bohemiella and Jamesella are reported from Africa for the first time. J. Paleont., 71(5), 1997, pp. 791-812 Copyright ? 1997, The Paleontological Society 0022-3360/97/0071-0791

Divaricate patterns in Cambro-Ordovician obolid brachiopods from Gondwana

03.00

Schizocrania (Brachiopoda, Discinoidea): taxonomy, occurrence, ecology and history of the earliest epizoan lingulate brachiopod

Abstract A new brachiopod species, Westonia mardini, from the Furongian of Turkey and a new occurrence of Westonia urbiona from the Cambrian Series 3 of Iberian Peninsula are reported. These new finds of ‘westoniids’ collected in Gondwana allow the discussion of the functional morphology of their terrace ridges. This structure enabled an effective and rapid reburrowing and allowed the occupation of the shallow marine unstable sands and silts in the shoreface environments. This burrowing mechanism, with their pedicle directed downwards, was unknown before the Cambrian Series 2 and was abandoned chiefly in the Early Ordovician. Here we also review the distribution of ‘westoniids’ in space and time to analyse the diversification, decline and replacement of this important group of brachiopods. They became a significant part of the semi-infaunal marine associations beginning with the Cambrian Series 2 and proliferated in shallow arenaceous shelves during the Cambrian Series 3 and during the Furongian in most palaeocontinents. The acme of ‘Westoniid’ obolids associations was in the Furongian, but locally relict associations were present in high-latitude Gondwana until the Tremadocian. Decline of westoniid associations began during the Tremadocian, being replaced by very diverse smooth-shelled obolid associations with a novel burrowing mechanism and deeper lifestyle. http://zoobank.org/urn:lsid:zoobank.org:act:4D74A740-34FD-4E3A-89BA-F80128800C0E

Index of Fossiliferous Localities of the Olešná Member, Klabava Formation (Lower Ordovician of the Prague Basin, Czech Republic)

The lingulate brachiopod Schizocrania (Trematidae, Discinoidea) is reviewed. Ptychopeltis is definitively synonymized with Schizocrania, because new data indicate that convexity of the shell, profile of the anterior margin commissure, density of the dorsal valve costellation, ornamentation of the ventral valve and shape of the pedicle notch are worthless for separation of these genera. Four Ordovician species of Schizocrania are reported from the Barrandian area: S. multistriata (Darriwilian), S. hornyi (Sandbian), S. incola (Sandbian) and the new species S. equestra sp. nov. (Katian). Occurrence of Schizocrania striata is confirmed for the first time around the S/D boundary in the Barrandian area. Schizocrania has a wide geographic range with mid-Ordovician to early Devonian occurrences in Laurentia, Avalonia, West Gondwana and the Silurian occurrence in Baltica. Schizocrania was the earliest lingulate brachiopod adhering to floating objects in an open sea (both living cephalopods and their empty drifting shells), but it was highly opportunistic, and used any vacant hard surface on the sea floor (conulariids, strophomenid brachiopods, trilobites) as a suitable substrate for settlement of the larva. Decline of the genus coincided with disappearance of planktic graptolites, and might have been caused by competition of rapidly evolving planktic dacryoconarids, increased predation pressure, and rebuilding of the trophic structure in the early Devonian seas.

Fenestrate Bryozoans in the Acanthopyge Limestone (Eifelian) in the Barrandian Area (Czech Republic)

Abstract Thirty-two fossiliferous localities of the Olešná Member, a distinct unit of the Klabava Formation, are described. As we are able to find they represent all fossil sites of this unit ever been mentioned in publications. Fossil taxa from relevant papers are summarized and the historical names used for the localities are listed. Updated lists of fauna are compiled for each locality; based on them an overall list for the member is completed.