Conodont Research Articles

Lanea carlsiConodont Apparatus Reconstruction and its Significance for Subdivision of the Lochkovian

Slavik, L. 2011. Lanea carlsi conodont apparatus reconstruction and its significance for subdivision of the Lochkovian. Acta Palaeontologica Polonica 56 (2): 313–327.

GUADALUPIAN BRACHIOPODS FROM DJEBEL TEBAGA DE MEDENINE, SOUTH TUNISIA

Here we describe a Guadalupian brachiopod fauna from units III to V of the shallow water carbonate succession cropping out at Djebel Tebaga de Medenine, South Tunisia. The fauna comprises 29 taxa of the orders Productida, Orthotetida, Orthida, Rhynchonellida, Athyridida, Spiriferida and Terebratulida, whose distribution is consistent with the Wordian-Capitanian age suggested by the associated fusulinids and conodonts. Most of the brachiopod taxa are pedicle attached genera or cemented ones and thus were permanently attached, and only two were free living concavo-convex semi-infaunal genera; this indicates that they were mostly living in high energy environmental settings, where the settling strategies require firm attachment to the substrate at shallow depth under the influence of fair-weather waves. The brachiopods from South Tunisia are very similar to the fauna from the allochthonous limestones of Pietra di Salomone, Rupe del Passo di Burgio and Rocca di San Benedetto of Sosio Valley, Sicily, Italy, a fauna which is also dominated by cemented and pediculate taxa. Both regions were located at palaeoequatorial latitudes in the western termination of the Tethyan Gulf during Middle Permian time.

CONODONT DATING OF THE LOWER TRIASSIC SEDIMENTARY ROCKS IN THE EXTERNAL DINARIDES (CROATIA AND BOSNIA AND HERZEGOVINA)

Two Lower Triassic sedimentary successions have been dated by means of conodonts in the External Dinarides: Plavno section near Knin, Croatia and Bosansko Grahovo section in Bosnia and Herzegovina. Deposition in both sections shows similar characteristics, differentiated in three continuously deposited facies. The Siliciclastic facies was previously considered Seis beds and assigned to the lower Lower Triassic, the Mudstone facies, and the Siltstone-mudstone facies (occurring in the upper part of the succession) were formerly considered as Campil beds of the upper Lower Triassic. Vertical succession of Siliciclastic, Mudstone, and Siltstone-mudstone facies of both investigated sequences was interpreted as deepening of the environment envisaged as a transgressive trend in a shallow shelf environment. Facies successions at Plavno (690 m thick) and Bosansko Grahovo (229 m thick) differentiate for the presence of Dolostone facies in the lowest part of the Plavno succession. Conodont fauna of Dolostone facies at Plavno section is represented by isarcicellids, Isarcicella staeschei and I. isarcica (sample 3) that marks the Griesbachian isarcica Zone. The Siliciclastic facies of Plavno and Bosansko Grahovo sections is characterized by shallow-water euryhaline taxa attributed to the Smithian, part of the late Dinerian-Smithian obliqua Zone. This fauna is prevailed by Hadrodontina anceps and Pachycladina obliqua with co-occurrence of Smithian Parachirognathus ethingtoni and very rare presence of Foliella sp. or ?Furnishius sp. Discerned conodont taxa enable us to establish conodont zonation which gives new insight to the range of the so-called Siusi and Campil beds.

Guadalupian brachiopods from western Taurus, Turkey.

Here we describe 41 brachiopod species belonging to the orders Productida, Orthotetida, Orthida, Rhynchonellida, Athyridida, Spiriferida, Spiriferinida, and Terebratulida coming from the Guadalupian lower-middle part of the Pamucak Formation at Curuk Dað, Antalya (Western Taurus, Turkey). Associated conodonts are also reported and illustrated. The brachiopod taxa are either pedicle attached genera, with one genus also stabilized by penetration of its elongate umbo, or free living concavo-convex semi-infaunal genera; this indicates that the energy of the environment was never very high, as in settings just below the fair weather wave-base or in a back-reef, more protected inner platform. The brachiopods from the Pamucak Formation are very similar to the Wordian fauna of southeastern Oman, and they are similar to the Guadalupian assemblages of Chios, North Iran, South Thailand, and Salt Range. In comparison they share only a few taxa with the Guadalupian faunas of Central Afghanistan and Karakorum. Therefore the biotic affinity of the Guadalupian brachiopods of the Pamucak Formation is clearly peri-Gondwanan. The brachiopod record at Curuk Dað has implications for understanding the pattern of the end-Guadalupian (pre-Lopingian) biotic crisis. The pre-Lopingian crisis assemblages are quite diverse and nearly totally consist of Guadalupian genera and species except for a single Lopingian incomer. Their stratigraphic range terminates rather abruptly and the following 120 metres of shallow water limestones are barren of brachiopods, after which there is the first occurrence of Lopingian brachiopod taxa, which show a much lower biodiversity. This pattern is different from that observed in South China and it shows that the end-Guadalupian crisis is not only characterized by taxonomic selectivity, but also by a strong local control on the extinction/recovery pattern of some groups.

1003 The first occurrence of Griesbachian conodonts in Japan

1003 The first occurrence of Griesbachian conodonts in Japan

Litho-biostratigraphy and the conodonts of Palaeozoic/Triassic deposits in Albania

Litho-biostratigraphy and the conodonts of Palaeozoic/Triassic deposits in Albania

The nature and age of the Suroyam clinopyroxenite massif (Middle Urals)

The Suroyam alkaline ultrabasitesyenite (mainly pyroxenite) massif, including the Suroyam apatitetita� nomagnetite deposit, is a part of the Nyazepetrovsk structural-formational zone located on the western slope of the Middle Urals, within the Ufimskii promon� tory of the East European Platform. The Nyazepetrovsk complex tectonically overlaps the sedimentary shelf and bathyal deposits of the mar� gin of the Paleozoic continent (Fig. 1) and is the uppermost tectonic sheet developed here. The com� plex is made of volcanogenic-sedimentary and intru� sive rocks of Ordovician-Early Devonian age, approximately correlated with the Early and Late islandarc oceanic formations of the Tagil zone (1). According to the chemical composition and metallo� genic features, the Suroyam massif located in the area of these formations can be compared with massifs of a palladiumbearing "branch" of the Platinum belt (Ural PGEbearing belt) in the Urals. The Rb-Sr iso� chrone age of the massif is 415.2 ± 1.1 Ma. Recent data obtained provide confirmation of the allochthonous origin of the Suroyam massif and its positional con� nection with the Tagil zone. The stratigraphic section of the Nyazepetrovsk zone is represented by volcanic and volcanogenic- sedimentary formations with subordinate siliceous rocks, siltstone, and sandstones. The section is distin� guished into three formations (from ancient to young): basalt, basalt-andesitebasalt, and trachybasalttra� chyte. Based on rare findings of radiolarians, con� odonts, and macrofauna, the age of the formations is regarded as Ordovician-Early Devonian. The Suroyam massif is located in the southern area of the axial part of the Nyazepetrovsk zone, and it is mainly composed of apatitetitanomagnetite clinopy� roxenites, subjected to strong superimposed potassium and sodium metasomatism, connected with manifes� tations of alkaline magmatism (2). The nature of the massif is under discussion. There were ideas expressed in (3, 4) about its platform origin, but more convincing evidence is needed. We have identified, however, sim� ilarities of the Suroyam massif with some specific mas� sifs of the Platinum belt with titanomagnetite mineral� ization. In particular, among the most widespread types in the Suroyam massif (Fig. 2) are highferrugi� nous clinopyroxenites, green and dark green rocks, characterized by fine to coarse grained structure, as well as pegmatoid structure. The main rockforming minerals are clinopyroxene, titanomagnetite, apatite, and phlogopite. The quantitative ratios of these miner� als vary greatly. The central part of the Suroyam massif is composed of coarsegrained titanomagnetite cli� nopyroxenites (like kosvites) with a titanomagnetite content of 6-25%; the marginal part is characterized mainly by apatitetitanomagnetite types of rocks, con� taining 2.9-19.5% of apatite. The undeformed rocks have sideronitic and granoblastic texture. Clinopyroxene forms short and long prismatic grains. According to the chemical composition, cli� nopyroxene is represented by diopsidehedenbergite, containing 25-30% of the hedenbergite molecule. The iron content in pyroxene ranges from 14 to 26% (20 at. % on average). There was noted a high content of alumina (2.49-5.05%) with variations in the augite content from 6 to 11%. The titanomagnetite is lowtitanium, and it is rep� resented by xenomorphic grains with sideronitic tex� ture. In addition it forms finegrained, platy, den� dritic, and dropshaped inclusions in clinopyroxene. In general, titanomagnetite is distributed uniformly in the rock. However, there are sections with a banded distribution of ore minerals. In titanomagnetite there are inclusions of xenomorphic clinopyroxene and prismatic apatite. Sometimes, the ore mineral forms

Primeira ocorrência dos gêneros Ellisonia, Gondolella e Ubinates (Conodonts) para a Formação Itaituba, Pensilvaniano da Bacia do Amazonas, Brasil

This paper analyzes and describes a fi rst occurrence of the conodonts Ellisonia, Gondolella and Ubinates in Amazonas Basin, North of Brazil. The recovered material comes from two outcrops along the Tapajos River and from a limestone quarry of Itaituba Formation, whose levels are included in the Itaituba Formation, with a Pennsylvanian age. Those conodonts are relevant paleoecological indicators of water depth, salinity and environmental energy and have implications in the Late Carboniferous to Triassic biostratigraphy. The fossil remains represent M and S conodont elements, associated to Pa elements of the Idiognathodus, Idiognathoides, Neognathodus, Adetognathus, Hindeodus and Diplognathodus genus . Key words: conodonts, Amazonas Basin, Itaituba Formation, Pennsylvanian.

The Earliest Known Venomous Animals Recognized Among Conodonts

Conodonts, a large group of tiny extinct marine animals ranging in age from the Late Cambrian to Late Triassic (ca. 500 to 200 Mya), are usually considered as jawless vertebrates. Their only commonly occurring fossilized remains are minute, phosphatic, teeth-like elements of their feeding apparatuses. In most of the early conodonts the elements were conical and strongly elongated. Many of them are characterized by possession of a deep, longitudinal groove, usually associated with sharp edges or ridges. A comparative study of the grooved elements and venomous teeth and spines of living and extinct vertebrates strongly suggests that the groove in conodonts was also used for delivery of venom. Structural convergence of the conodont apparatus Panderodus with the grasping apparatus of chaetognaths, a group of extant, venomous invertebrate predators of similarly ancient origin, provides additional support for this conclusion.

FAMENNIAN CONODONTS FROM KAL-E-SARDAR SECTION, EASTERN TABAS, CENTRAL IRAN

Sixty-three conodont species and subspecies from the Kal-e-Sardar section indicate that the strata span early to late Famennian. Contrary to most of the sections measured in the Shishtu Formation, the icriodid-polygnathid biofacies is restricted to the lower part of Kal-e-Sardar Famennian succession. Palmatolepid and bispathodid-dominated biofacies in the middle and upper part of section represent a deep shelf to mid-continental slope marine environment. The currently accepted ranges of P. tichonovitchi, P. tenellus and P. inconcinnus are early Famennian, late Frasnian-early Famennian, and early to middle Famennian, respectively, together with middle to late Famennian for P. nodoundatus. Two new species, Polygnathus sardarensis and P. yazdii, are proposed.

Holothurian sclerites of Carnian strata in the Mežica area, Slovenia

The paper presents holothurian sclerites from the 2nd clastic horizon of the "Raibl Beds" in the Mežica area. The fauna is dominated by genus Theelia, represented by T. immisorbicula Mostler, T. planorbicula Mostler and T. ex gr. variabilis Zankl in association with species Priscopedatus ploechingeri Mostler. Julian age of the holothurian-bearing bed is defined by conodont apparatus Nicoraella ? budaensis Kozur & Mock.

C. H. Pander's introduction to conodonts, 1856

C. H. Pander's introduction to conodonts, 1856

Late Ordovician (Hirnantian) scolecodont clusters from the Soom Shale Lagerstätte, South Africa

Abstract. More than 20 partial scolecodont clusters were recovered from the Soom Shale Lagerstätte, South Africa. The specimens were found in association with chitinozoans, algae, conodont apparatuses and the enigmatic needle-like fossil Siphonacis. The Family Xanioprionidae is identified and the species Xanioprion? n. sp. is distinguished. The Family Mochtyellidae is also identified and the new genus Synaptogenys and new species S. rietvleiensis are described. The specimens represent the first described scolecodonts from South Africa and the first apparatus-based taxonomic study of specimens from Gondwana.

LATE DEVONIAN CONODONTS FROM THE HOJEDK SECTION, KERMAN PROVINCE, SOUTHEASTERN IRAN

Conodonts (34 species and subspecies) from the Hojedk section north of Kerman span the late Givetian to early Famennian. The new data suggest that Devonian biostromes in central and eastern Iran were deposited on differing levels, and that the currently accepted ranges of Icriodus excavatus, Polygnathus subincompletus and P. mosquensis are late Givetian - late Frasnian, early to late Frasnian, and middle to late Frasnian. Polygnathus ashourii n. sp. is proposed.

Morphofunctional analysis of Late Paleozoic conodont elements and apparatuses

Five functional types are recognized among Late Paleozoic conodont elements; they are distinguished by morphological and histological characteristics: grasping-holding, filtering, cutting, crushing, and grinding. Combinations of functional types of elements form functional types of conodont apparatuses, the main of which are filtering, grasping-cutting, grasping-pressing, grasping-cutting-grinding, and grasping-cutting-crushing apparatuses.

AGE AND GEOCHEMISTRY OF MIDDLE TO LATE CARNIAN BASALTS FROM THE ALAKIRÇAY NAPPE (ANTALYA NAPPES, SW TURKEY): IMPLICATIONS FOR THE EVOLUTION OF THE SOUTHERN BRANCH OF NEOTETHYS

The geochemical features of spilitic basalts and the radiolarian fauna of associated pelagic sediments have been studied from two different sections of the Alakircay Nappe of the Antalya Nappes, SW Turkey. The first section in Cukurkoy is located in the eastern part of the Antalya Gulf and includes thick spilitic basalts, overlain by an alternation of mudstone, marl and pelagic cherty limestone. Radiolarian data from the cherty limestone in this unit reveals a middle Carnian age for this section. The second section in Yaylakuzdere is situated in the western part of the Antalya Gulf. In this section, thick pillow basalts are overlain by a succession of limestone/cherty limestone and shale beds. The age of the limestones interlayered with the pillow basalts was assigned to the late Carnian, whereas the basal part of the overlying cherty limestones was dated as latest Carnian/earliest Norian by conodont and radiolarian faunas. The pillow lavas in the Cukurkoy and Yaylakuzdere regions consist of within-plate type alkaline basalts and display multi-element pattern similar to typical oceanic island basalts (OIB). Low La/Yb, Zr/Y and La/Nb < 1 ratios are also indicative for an OIB-like deep mantle source. These alkaline basalts have not suffered interactions with a subducted slab and/or continental crust due to presence of high HFSE abundance, the lack of depletion in Nb and Ta that are characteristics of subduction and/or crustal contamination processes. Based on this data, it can be concluded that alkaline volcanism in these two regions of the Antalya Nappes have been probably generated by a small OIBtype mantle plume during the middle - late Carnian time interval, in the advanced stages of rifting of the Antalya Nappes successions in the southern branch of Neotethys. This data reveals the generation of a rift basin before middle Carnian for this ocean.

NEW LADINIAN AMMONOIDS FROM MT. SVILAJA (EXTERNAL DINARIDES, CROATIA)

A small collection of Ladinian ammonoids from Mt. Svilaja (External Dinarides) is here described for the first time. The ammonoids were collected from a thick succession, which yielded in its lower part the classic Lower Triassic ammonoid faunas of Muae, known since the XIX century. The collection comes from an interval yielding conodonts of the hungaricus Assemblage zone, and is composed of leiostraca ( Proarcestes ) and trachyostraca ammonoids. The latter consists of the new genus Alkaites , and the new species A. dinaricus , Detoniceras svilajanus and Argolites trinodosus . Alkaites n. gen. is characterised by involute coiling, v-shaped ventral side and five spiral rows of nodes. D. svilajanus n. sp. is distinguished by flat ventral side, and four rows of nodes with peculiar ratio 1:1:2:2 between perimbilical,1st lateral, 2nd lateral, and ventrolateral nodes. A. trinodosus n. sp. is characterised from any other species of Argolites by three rows of nodes. At the present the new genus Alkaites and the three new species are known only from the study area. The dating of the new taxa is done by indirect correlations based on the distribution of Detoniceras and Argolites in other sections of the Southern Alps, as well as on the calibration of the hungaricus Assemblage zone with the ammonoid standard scale. The inferred age is Gredleri Zone (Lower Ladinian).

Upper Devonian-Lower Carboniferous conodonts from Chiang Dao cherts, Northern Thailand

In Northern Thailand, radiolarites (radiolarian cherts) are very common and their study provides an important tool to understand the regional geology and moreover to localise the suture zone(s). Some of these deep and distal oceanic series yield conodonts which provide to obtain precise age datings. The present work is focused on the Upper Devonian and Lower Carboniferous conodonts from the Chiang Dao area (Chiang Mai province). The conodont faunas from these oceanic cherts display juvenile characters which are interpreted to be a result from a constraining environment.

THE LOWER TRIASSIC SHALLOW MARINE SUCCESSION IN GORSKI KOTAR REGION (EXTERNAL DINARIDES, CROATIA): LITHOFACIES AND CONODONT DATING

The paper aims to present Lower Triassic lithofacies definition and first conodont fauna of Gorski Kotar region, Croatia. The depositional environment is envisaged as shallow marine realm of a passive continental margin. Sedimentary complex differentiates in predominantly carbonate sedimentation that characterises the beginning of deposition with upward increasing trend of terrigeneous influx. Lithofacial units have been defined as oolitic bar facies, lagoonal facies, shoreface-offshore facies, ooid-sandy shoal facies, restricted bay facies and flat-pebble conglomerate facies.The following conodont taxa were collected: Ellisonia sp., Foliella gardenae, Hadrodontina sp., Hindeodus parvus, Hindeodus sp., Pachycladina obliqua, ?Parachirognathus sp., Platyvillosus costatus and Pl. hamadai. The oldest strata yield Hindeodus parvus marking lowermost Triassic. The biostratigraphical data enable recognition of the parvus-isarcicella zones, obliqua Zone and Platyvillosus Subzone. The finds of Hindeodus parvus, Platyvillosus costatus and Pl. hamadai represent their first records in the External Dinarides and enable correlation of the Early Triassic conodont faunas of the Western Tethyan realm.

BRACHIOPODS FROM THE UPPER TRIASSIC REEF HABITATS OF THE NORTHERN CALCAREOUS ALPS (DACHSTEIN LIMESTONE, HOCHSCHWAB, AUSTRIA)

Upper Triassic brachiopods from 2 localities in the reef Dachstein Limestone of the SE Hochschwab massif in Styria, Austria are systematically described and illustrated. About 900 variably preserved specimens belong to 28 species, representing thus the most diverse brachiopod fauna known from the North Alpine Dachstein Limestone. This indicates that brachiopods were common inhabitants of reef habitats during the Alpine Norian. Oxycolpella , Sinucosta and Aulacothyropsis are dominant. Seven brachiopod species are known from the Kossen Formation (Rhaetian). Adygella biplicata (Dagys) and Ladinian Hungarispira loretzi (Bittner) are the newcomers in the Nordalpine Dachstein Limestone. In addition to brachiopods, only some fragments of bivalves were found. Conodonts of the species Epigondolella triangularis (Budurov 1972) indicate the Early Norian age.