The conodont apparatus of Zieglerodina eladioi (Valenzuela Rios, 1994)

Zieglerodina eladioi (Valenzuela-Ríos) è una specie di conodonti ozarkodinidi documentata dalla parte più alta del Přídolí (Siluriano superiore) al Lochkoviano medio (Devoniano Inferiore). La specie è stata istituita nei Pirenei spagnoli e fino a ora è documentata in diverse aree del nord Gondwana (Marocco, Alpi Carniche, Sardegna, Repubblica Ceca e Turchia). L’apparato di Zieglerodina eladioi viene ricostruito basandosi su ritrovamenti in Marocco, Sardegna e nelle Alpi Carniche; esso comprende sei elementi (P1, P2, M, S0, S1 e S2) in cui gli elementi ramiformi sono caratterizzati da una denticolazione alternata con denticoli aghiformi. La morfologia dell’apparato conferma l’attribuzione della specie al genere Zieglerodina.Zieglerodina eladioi (Valenzuela-Ríos) is a small ozarkodinid from the latest Přídolí (Silurian) and the Lochkovian (Lower Devonian), up to now documented only in areas of North Gondwana. Material from Morocco, the Carnic Alps, and Sardinia provide the basis for the seximembrate reconstruction of this conodont species’ apparatus (consisting of P1, P2, M, S0, S1, and S2 elements). The ramiform elements of Zieglerodina eladioi are characterised by an alternate denticulation with spike-like denticles, further confirming the attribution of the species to the genus Zieglerodina

Running across the Silurian/Devonian Boundary along Northern Gondwana: A Conodont Perspective

The Global Stratotype Section and Point (GSSP) of the Silurian/Devonian boundary, Lower Devonian Series and Lochkovian Stage was formally placed in 1977 at Klonk, in the Czech Republic, at the first appearance of the graptolite Uncinatograptus uniformis uniformis (Přibyl). However, since then, correlation of this limit has been often hampered in carbonate facies where graptolites are uncommon or totally absent. A large calcareous deposition occurred at the Silurian/Devonian boundary along the northern and peri-Gondwana margin, thus representing an ideal location to select and test a possible additional biostratigraphic marker of the limit among conodonts. The first appearance of Caudicriodus hesperius almost simultaneously at the base of the Devonian in Bohemia, the Carnic Alps, Sardinia, Morocco and elsewhere indicates that this taxon is the conodont that best approximates the beginning of the Period. The first or last appearance of other species (e.g., Ozarkodina confluens, Zieglerodina klonkensis, Z. remscheidensis and Caudicriodus woschmidti) may help to recognise the boundary as well

Stars in the Silurian sky : Echinoderm holdfasts from the Carnic Alps, Austria

A small collection of echinoderm holdfasts from the Ludlow Cardiola Formation of the Carnic Alps (Austria) contains a wide range of morphologies as a response of environmental adaptation. In general, the holdfasts have a globous and massive dome-like profile with several processes arranged in a sub-radial disposition, so to create a sort of 'star-like' outline. A small central depression is common but not present on all specimens. The distinctive holdfasts are preserved in an iron-rich phase, documenting a substitution that has also affected other non-echinoderm calcareous material

Pramosio e Avostanis

Vengono descritti gli aspetti geologici, paleontologici, mineralogici e naturalistici dellìarea di Pramosio-Avostanis nelle Alpi Carnich

First documentation of the Polygnathoides siluricus conodont Zone (Ludfordian) in South America (Argentina) and the stratigraphic significance of the younger species of Kockelella (Conodonta)

The coquinoid beds from the middle part of the Los Espejos Formation at the Poblete creek section (Talacasto Creek) yielded abundant conodonts. The genus Kockelella (Walliser) represents the most relevant biostratigraphical genus in this conodont fauna. The co-occurrence of Kockelella maenniki Serpagli and Corradini, Kockelella variabilis ichnusae Serpagli and Corradini, K. variabilis Walliser, Kockelella ortus sardoa (Serpagli & Corradini), and Kockelella ortus absidata (Barrick & Klapper) allow us to record for the first time the Polygnathoides siluricus Zone in South America, which suggests the Ludfordian Stage (late Ludlow). We also propose an accurate correlation of the Los Espejos Formation with the lower Ludfordian deposits from the Carnic Alps, Sardinia, Morocco, Czech Republic, Gotland, and North America.Fil: Gomez, Maria Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Centro de Investigaciones de la Geosfera y Biosfera. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones de la Geosfera y Biosfera; ArgentinaFil: Mestre, Ana Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Centro de Investigaciones de la Geosfera y Biosfera. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones de la Geosfera y Biosfera; ArgentinaFil: Garcias Paez, Yanina Vanesa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Centro de Investigaciones de la Geosfera y Biosfera. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones de la Geosfera y Biosfera; ArgentinaFil: Corradini, Carlo. Università degli Studi di Cagliari; Itali

The new genus Walliserognathus and the origin of Polygnathoides siluricus (Conodonta, Silurian)

The new Genus Walliserognathus is described to host the species posthamata (Walliser). The genus is monospecific. The shape of P1 and P2 elements of Walliserognathus posthamatus, characterized by a small platform along the whole elements, and its stratigraphic distribution limited to the A. ploeckensis Zone suggest that the species may have been the bridge in the phylogenesis from Wurmiella to Polygnathoides

A Pridoli-Lochkovian conodont zonation in Sardinia and the Carnic Alps: implications for a global zonation scheme

The main conodont zonation schemes for the Pridoli and the Lochkovian presents some problems that make difficult their use in several geographical areas. Data from several sections in Sardinia and the Carnic Alps not only allow to built a regional zonation scheme for these areas, but also suggest possible solutions of global validity. In the Carnic Alps and Sardinia, the P\u159\ueddol\ued is subdivided into three zones: Eosteinhornensis s.l., Lower and Upper detortus. The latter results after the subdivision of the former detortus Zone on the basis of the Last Appearance Datum of some coniform species (Dapsilodus obliquicostatus, Coryssognathus dubius and Panderodus recurvatus) that became extinct almost simulta-neously in the latest P\u159\ueddol\ued. Daps. obliquicostatus is chosen as the marker, being the most common and easily identifi-able species. In the Lochkovian six zones are discriminated: Hesperius, carlsi, transitans, eleanorae, trigonicus and pan-dora \u3b2. The hesperius Zone, which includes the postwoschmidti subzone in its upper part, is expanded to include most of the eurekaensis zone of the "global" scheme, because the marker Oz. eurekaensis is not present. The carlsi Zone corre-sponds to the upper part of the eurekaensis Zone and to the lower part of the former mid-Lochkovian delta Zone (= omoalpha Zone). The rest of the Middle Lochkovian is subdivided into the three zones (transitans, eleanorae and trigonicus) already proposed in Nevada and Spain, followed by the pandora \u3b2 Zone. All the zones are discussed and checked for their applicability in other palaeogeographical regions

Ontogeny of Ancyrodelloides carlsi (Boersma) and comments on its generic attribution (Conodonta, Lower Devonian)

The ontogeny of the Lochkovian conodont species Ancyrodelloides carlsi (Boersma) is demonstrated thanks to a rich population from Morocco. The studied sample includes elements at various growth stages from juvenile to gerontic. The data are confirmed by several elements in collections from several localities in the Carnic Alps (Italy and Austria). The absence of terraces at every stage of growth and the presence of a strong denticulated lateral process confirms the generic attribution of the species to genus Ancyrodelloides. Comments on the apparatus are provided. The geographical distribution of the species, limited to Europe and the Mediterranean region, challenges its stratigraphic value for long distance correlations