Search

Conodonts of the Kashirian Regional Substage in the Upper Volga region are studied for the first time. A conodont assemblage established in a quarry section near the village of Fedyaikino on the Osuga River, allows the correlation of the dolomite series with interbeds of marls and clays (11.45 m) with the Kashirian Nara Formation assigned to the Neognathodus bothrops Zone. In the section near the village of Mozgovo on the Derzha River, limestones and dolomites with cherts (7 m) are attributed to the upper part of the Kashirian, to the Neognathodus medadultimus Zone, although Member C, unconformably overlying Member B, may be Podolskian. Conodont assemblages are typical of sections of the East European Platform. The deposition took place in an offshore marine environment, while the basin coastline was located far to the west. [ABSTRACT FROM AUTHOR]

This study documents Middle to Late Ordovician conodont faunas primarily from the Billabong Creek Formation exposed in the Gunningbland area located west of Parkes and northwest of Forbes in central New South Wales. Forty-four identifiable conodont species recovered from 105 limestone samples in this area form the basis of the most complete biostratigraphic succession in shallow-water facies known through this interval from Australia. Four conodont biozones are recognised, extending from the middle Darriwilian Histiodella holodentata–Eoplacognathus pseudoplanus and Eoplacognathus suecicus biozones, through the upper Darriwilian Pygodus serra Biozone, to the Pygodus anserinus Biozone spanning the uppermost Darriwilian to basal Sandbian interval. A lower to middle Sandbian carbonate gap coincides with an unzoned interval, followed by the successively younger Belodina compressa, Phragmodus undatus and Taoqupognathus blandus conodont biozones in the upper Sandbian to lower Katian. The T. blandus Biozone directly correlates with the detailed conodont biozonation established in Katian limestones of the Molong Volcanic Belt further east. These age determinations provide much improved precision for correlation within Phases 2 and 3 in the mineral-rich Macquarie Volcanic Province. Analysis of conodont biofacies data supports an enhanced understanding of the geological evolution of the Macquarie Volcanic Province by interpreting the interplay between volcanic activity and carbonate deposition. Conodont studies in the Billabong Creek Formation of the Gunningbland area reveal the only known biostratigraphic succession in Australia that extends continuously from the middle Darriwilian to basal Sandbian. Three Late Ordovician (late Sandbian to early Katian) conodont biozones in the upper Billabong Creek Formation correlate precisely with carbonates of the Molong Volcanic Belt to the east. Revised stratigraphic definitions of the Billabong Creek and Gunningbland formations are provided. [ABSTRACT FROM AUTHOR]

The present paper describes the lower Upper Devonian conodont fauna from the upper units of Muth Formation, Spiti Valley, Himalaya.

Previously unidentified small (up to 1.3 mm in length), gently curved hollow spines composed of calcium phosphate and derived from the upper Famennian (Devonian) of the Holy Cross Mountains in central Poland are described. They are similar to the type species of Phakelodus, but show some distinct morphological differences, therefore, have been included into Phakeloides polonicus gen. et sp. nov. The studied specimens of that species show relatively massive mineral structure characterized by significant porosity with well-preserved major structural features. The outer layer of the spines is, in contrary, fragmentarily preserved, and exposes distinct mosaic-like ornamentation of the surface of the middle layer, which consists of obliquely arranged, shallow furrows. Geochemical analyses of the Devonian Phakeloides polonicus gen. et sp. nov. spines have revealed the presence of a weaker mineralized structure, compared to conodont apatite, composed of a diagenetic phosphate phase. It is characterized by moderate cathodoluminescence intensity, elevated concentrations of iron and sulphur as well as decreased concentrations of strontium, calcium, and phosphorus. The "Orsten" type, early diagenetic phosphatization of the outer layer of the spines is not observed in studied specimens of Phakeloides polonicus gen. et sp. nov., contrary to the previously investigated Furongian (Cambrian) material. This points to the low rate of diagenetic phosphatization, which was likely enabled by very slow sedimentation and long residence time of the spines close to sediment-water interface at varying redox conditions and significant flux of phosphate ions. [ABSTRACT FROM AUTHOR]

Significant advance in the understanding of the Late Triassic evolution of conodonts and their final disappearance has been made recently. However, the relevant information is rather fragmented and inconsistent. Its critical assessment is undertaken in order to synthesise the new lines of evidence. The final disappearance of conodonts, which should be distinguished from their regional disappearances and precedent diversity changes, occurred at the Rhaetian–Hettangian transition. It was not preceded by a gradual decline: conodonts were able to diversify in the Late Triassic and to survive several biotic crises/turnovers. Their diversity dynamics corresponded (at least, partly) to the eustatic fluctuations similarly to how this occurred during the entire history of this fossil group. [ABSTRACT FROM AUTHOR]

Ordovician conodonts representing 28 genera and 28 named and three unnamed species were identified from 740 chert and siliceous siltstone spot samples (>3 000 thin sections) from deep-water turbiditic sequences of the Lachlan Orogen in central and southern New South Wales, Australia. Based on these faunas, a new conodont biozonal scheme has been established to divide the Ordovician turbiditic successions of the Lachlan Orogen into 12 superbiozones and biozones. They are (in ascending order) the Paracordylodus gracilis Superbiozone (including the Prioniodus oepiki Biozone), Periodon flabellum Superbiozone (including the Oepikodus evae Biozone in the lower part), Periodon hankensis Biozone, Periodon aculeatus Superbiozone (including the Histiodella labiosa, Histiodella holodentata, Histiodella kristinae, Pygodus serra and Pygodus anserinus biozones) and the Periodon grandis Biozone. The Pygodus anserinus Biozone is divided further into the lower and upper subbiozones. This new conodont biozonation scheme spanning the upper Tremadocian to middle Katian interval permits precise age-dating and correlation of deep-water siliciclastic rocks that characterize the Ordovician Deep-Sea Realm regionally and internationally. [ABSTRACT FROM AUTHOR]

The present study of Anisian (Middle Triassic) conodonts from the Kocaeli Peninsula (western Turkey) encompasses over 10 species of the families Gondolellidae and Gladigondolellidae, providing Early and Middle Triassic time constraints, Chiosella timorensis (Nogami, 1968); Cornudina oezdemirae Gedik, 1975; Gladigondolella tethydis (Huckriede, 1958); Neostrachanognathus tahoensis Koike, 1998; Paragondolella aegaea (Bender, 1970); Paragondolella bulgarica Budurov and Stefanov, 1975; Nicoraella kockeli (Tatge, 1956); P. hanbulogi (Sudar and Budurov, 1979), and Gladigondolella sp. A. Newly established are Paragondolella hirschii n. sp. Kılıç and Budurov; P. praecornuta n. sp. Kılıç, Budurov, Petrunova and Mir0103uţ0103; and P. ebruae n. sp. Kılıç. The Kocaeli Anisian conodonts show a faunal affinity with Bulgaria. The present Anisian fauna is characteristic of the Tethys. The strong homeomorphy that characterizes the Anisian in western North America is discussed. [ABSTRACT FROM AUTHOR]

The conodont fauna of the Rotelliforme, Meeki, Occidentalis and lower Subasperum zones of Nevada (Humboldt Range) is here described. The first three zones represent, by means of the American authors, the Upper Anisian of North America, while at the base of the Subasperum Zone is located the Anisian/Ladinian boundary. Three species—groups of conodonts have been emended and revised, they are: Gondolella constricta Mosher & Clark, Gondolella mombergensis mombergensis Tatge and Gondolella mombergensis longa (Budurov & Stefanov). Comparisons with the possible coeval faunas of epicontinental sequences from Europe have been discussed. Within the conodont fauna, the main change has been noted at the base of the Occidentalis Zone. On the base of the conodont fauna, the Anisian/ Ladinian boundary at the base of the Occidentalis Zone seems to be the most supported in Nevada.

The preserit paper describes Upper Devonian conodont fauna from the black and bluish limestone succession lying immediately above the Muth Quartzite exposed near the village Tanze, Luneak valley, Ladakh.

The Bellerophon (Late Permian) and Werfen (Lower Triassic) Formations were investigated on the basis of conodonts. Fifteen sections were sampled from Carnic Alps and Dolomites area in the Southern Alps. Ten were productive. The Bellerophon Formation yielded a few specimens of Hindeodus typicalis, Ellisonia agordina and Ellisonia sp. In the Werfen Formation were collected Hindeodus typicalis, Ellisonia agordina, E. triassica, Hadrodontina anceps, Xaniognathus gradatus, Isarcicella isarcica, Pachycladina obliqua, Ellisonia delicatula, Neospathodus triangularis. In describing the conodont fauna, multielement taxonomy is applied. Ellisonia agordina is a new species found at the top of the Bellerophon Formation and from the Tesero to the Siusi Members of the Werfen Formation, i, e. at the Permian — Triassic boundary and in the Lower Triassic. The apparatus of this new species is described. In the Southern Alps the range of Hindeodus typicalis, previously known in the Werfen Formation, extends down into the uppermost Bellerophon Formation. All species confirm the ranges found elsewhere in the world. On the basis of only the conodont fauna, it is not possible as yet to recognize the position of the Permian — Triassic boundary more precisely in the Bellerophon/Werfen Formations in the Southern Alps. It is obvious, however, that the recovery of Isarcicella isarcica allows the certain identification of the Triassic.

The article presents the results of a study of Wenlock-Ludlow boundary sediments in the river Padimeytyvis basin at Chernov uplift using paleontological, lithological and chemostratic methods. The results of paleontological studies allowed attributing to the Wenlock the carbonate stratum of the upper part of the section along the stream Bezymjannyi and establishing Wenlock-Ludlow boundary only in the section of the river Padimeytyvis. The results of studying the isotope δ13Ccarb. in Wenlock-Ludlow boundary sediments are also presented. In the upper part of the section along the stream Bezymyanny a positive C-isotopic shift of the curve which possibly marks the late Wenlock global biotic event of Mulde was observed. Keywords: Ludlow, Wenlock, conodonts, brachiopods, Arctic region, Timan-Northern Ural region, isotope δ13Ccarb. [ABSTRACT FROM AUTHOR]

A new upper Tournaisian (Lower Carboniferous) siphonodellid conodont species Siphonodella carinata n. sp. is described. The material comes from the shallow-water carbonate sediments of the Pechora Swell (Timan-Pechora region or NE of European Russia). The co-occurrence of conodonts Hindeodus cristulus (Youngquist & Miller), Bispathodus stabilis (Branson & Mehl) Morphotype 1, Polygnathus longiposticus Branson & Mehl and Pseudopolygnathus nodomarginatus (Branson) suggests the late Tournaisian (Lower Siphonodella crenulata Zone) age of the deposits. Morphologically the new species is similar to Siphonodella semichatovae Kononova & Lipnjagov and S. ludmilae Zhuravlev & Plotitsyn, but differs in possessing three rostral ridges at the late stages of ontogeny and Class III symmetry. The presence of the shallow-water siphonodellids Siphonodella bella Kononova & Migdisova and S. quasinuda Gagiev, Kononova & Pazuhin in the upper part of the Tournaisian is detected for the first time.

A new morphometric approach was developed to study morphological variation within P1 elements commonly referred to as Idiognathodus simulator, which was selected to be the biostratigraphic marker for the base of the global Gzhelian Stage (Carboniferous). This new approach combines landmark-based geometric morphometrics with eigen analyses to analyze shape variation within P1 elements of the I. simulator group, and could be used to analyze shape variation in other morphologically similar conodont groups. Specimens analyzed were obtained from three sections of the early Gzhelian Heebner Shale of the Oread cyclothem in the North American Midcontinent region, the cyclothem from which I. simulator was originally named. This analysis shows that the I. simulator group comprises a set of at least five species with asymmetrical P1 element pairs, relatively short adcarinal ridges, and a variably developed eccentric groove. Species discrimination is based on the presence of caudal and rostral lobes, character of the adcarinal ridges, and platform shape. The species I. simulator is restricted to P1 elements with a caudal adcarinal ridge that is isolated from the caudal platform margin. Idiognathodus lateralis sp. nov. is erected to include P1 elements with a caudal adcarinal ridge that is not isolated from the caudal platform margin.

The paper is devoted to the Upper Cambrian and Tremadocian organophosphatic microfossils which were hitherto treated as conodonts and assigned mainly to the genera Coelocerodontus and Viirodus. Individual elements of the fossils, similarly to the elements of conodonts, belonged originally to the multi-element apparatuses. Present studies, based mainly on the collections from Sweden, Poland (core sections), Estonia and Kazakhstan, show that despite the similarities of their individual elements to conodonts, they significantly differ from them in the inner structure, as well as in the construction of the apparatuses composed of them. Elements of their apparatuses are matched in shape to each other and certainly functioned in conjunction, while those belonging to the euconodont apparatuses are usually differentiated in shape and usually functioned in separation. All fossils of this group are provisionally named coelocerodonts in this paper. Their individual elements, as well as the apparatuses composed of them, are similar in construction to those of the genus Phakelodus, which is an ancestor of chaetognaths.

A conodont fauna of late Tremadocian to early Floian age (Early Ordovician) is documented from the Yinchufu Formation of Zhejiang Province, South China. It is characterized by the occurrence of two species of Prioniodontidae, a new species of Prioniodus and Acodus triangularis. Prioniodus antiquus sp. nov. may represent the most primitive species of Prioniodus , which is one of the earliest conodont genera with a ramiform—pectiniform apparatus. Based on the review of nearly 200 species originally assigned to Prioniodus , six multielement species are confirmed to belong to this genus. Morphological changes of these six species shows that they form an evolutionary lineage directly evolved from an adentate species, likely Acodus triangularis which has been reported from South China, Australia and from the Precordillera of western Argentina. Origination of the ramiform—pectiniform apparatuses as represented by the appearances of Prioniodus through late Tremadocian to Floian of the Early Ordovician might be a major response of the 'conodont animals' to occupy and adapt to the increasingly diversified environments in the shelf and slope settings. The biofacies distribution of the six Prioniodus species indicates that Prioniodus might have originated in deep-water slope settings and progressively spread into distal and then interior shelves in the late Tremadocian and diversified in the Floian, with Prioniodus amadeus possibly representing a relict species that survived into the Middle Ordovician and was restricted to shallow water environments. • A case study investigates the origination of the ramiform—pectiniform apparatus. • The grouping of the six Prioniodus species and their evolutionary relationships are discussed. • Prioniodus probably originated in deep-water environments and progressively spread into distal and then interior shelves. [ABSTRACT FROM AUTHOR]

In the present paper, the conodont fauna from three detailed sections surveyed in the Lower Triassic sequence of Central Dolpo, Nepal (Tarap-Atali area) is illustrated. Combining faunas from the three sections, it was possible to recognize a succession of faunal events that covers most of the Scythian and the Lower Anisian. In the whole, 11 faunas have been recognized and discussed.

Conodont faunas from the limestone pebbles of the Upper Paleozoic Conglomerate at Praprotno, Slovenia demonstrate the presence of two faunas. The older fauna, marked by Palmatolepis surecta and Polygnathus decorosus is indicative of the Frasnian stage (Upper Devonian). The younger fauna is dominated by Gnathodus bilineatus and contains Lochriea commutata and L. nodosa. This fauna is characteristic of the Late Visean-Namurian (Lower Carboniferous).

The stratigraphical data collected during four geological expeditions to the Northern Karakorum (1996,1991,1992a,1992b) are discussed. The sedimentary succession has been classified by 9 formations, here formalised, and subdivided into members and lithozones. The biochronology has been established on fusulinids, brachiopods, and conodonts. Several plates illustrate the most significant fossil species as well as the litho- and microfacies. The sedimentary succession may be roughly subdivided into three parts. The lower part consists of terrigenous rocks, mostly pelitic and less frequently arenaceous(quartzarenites with thick arkose intervals during the latest Asselian-early Sakmarian). They are evidence of a continental to coxtal environment, with short term marine ingressions. The second part begins with the Sakmarian, when the marine environment spread over most of the studied area. Bioclastic sand bars with brachiopods and crinoids at the base are followed by huge fusulinid packages. In Hunza oolitic bars and dolostone peritidal cycles also follow. The carbonate ramp is often polluted by terrigenous sediments, especially westwards. Temporary arenaceous spillovers (quartzarenites), often linked to minor sedimentation gaps, occur both westwards in the Baroghil area, and eastwards in the Hunza-Shimshal area. In the centre, in the Upper Karambar valley, a large gap most probably occurs, with reappearance of the sedimentation only with the dolostones of the Upper Permian. These erosional episodes with arenaceous spillovers are interpreted as being linked to rifting events of the Neotethys opening, active southwards. The third part of rhe succession concerns the Late Permian. Towards the end at the Murgabian or at the beginning of the Midian, the Northern Karakorum is subdivided into two major areas. To the west, after a transgressive episode with ironstone deposition, a wide peritidal carbonate platform spread over from Baroghil to Chillinji in Karambar and the Pasu area in Hunza. This palaeogeographic pattern extends up to the Triassic. However, biostratigraphic control is poor. Instead to the north-east, a progressive sinking of the slope is observed, with spreading of deeper environments and cherty limestone deposition. The down-warping is activated by block-faulting resulting in huge megabreccia bodies interbedded with the cherty limestones. During the Dzhulfian, significant clay inputs dilute the carbonate mud accumulation and shales are dominant around the Permian-Triassic boundary. Pelagic carbonate sedimentation gradually recovers from the Smithian onward. The Permian of the Karakorum is the sedimentary evidence of the passive margin of a lithospheric block, detached from the Gondwana continent during the Permian, that will later migrate towards the centre of the Paleo-Tethys, along with other lithospheric blocks of the Mega Lhasa plate.

The conodont succession in the Upper Devonian facially different sections of northeastern European Russia (Chernyshev Ridge, Subpolar and Polar Urals, Pai-Khoi) are studied. The sections are subdivided and correlated taking into account the global standards for stages. The Frasnian Montagne Noire zonation (Klapper, 1989) is used for the first time for northeastern European Russia; the authors correlated this zonation with the scale of Ziegler and Sandberg (1990). Famennian deposits are subdivided using scale of Ziegler and Sandberg (1984) and miospore zonation. The age of local geological units (formations) is specified; the formations of different regions of northeastern European Russia are correlated to each other and to the regional subdivisions of EEP and Southern Urals. A total of 93 species of Ancyrodella, Mesotaxis, Palmatolepis, Polygnathus, and Zieglerina are described. Two new species Ctenopolygnathus parallelus sp. nov. and Polygnathus masonae sp. nov. are distinguished and five species are described in the open nomenclature. Special chapter is devoted to the phylomorphogenesis of Ancyrodella. [ABSTRACT FROM AUTHOR]

A new upper Tournaisian (Lower Carboniferous) siphonodellid conodont species Siphonodella carinata n. sp. is described. The material comes from the shallow-water carbonate sediments of the Pechora Swell (Timan-Pechora region or NE of European Russia). The co-occurrence of conodonts Hindeodus cristulus (Youngquist & Miller), Bispathodus stabilis (Branson & Mehl) Morphotype 1, Polygnathus longiposticus Branson & Mehl and Pseudopolygnathus nodomarginatus (Branson) suggests the late Tournaisian (Lower Siphonodella crenulata Zone) age of the deposits. Morphologically the new species is similar to Siphonodella semichatovae Kononova & Lipnjagov and S. ludmilae Zhuravlev & Plotitsyn, but differs in possessing three rostral ridges at the late stages of ontogeny and Class III symmetry. The presence of the shallow-water siphonodellids Siphonodella bella Kononova & Migdisova and S. quasinuda Gagiev, Kononova & Pazuhin in the upper part of the Tournaisian is detected for the first time. [ABSTRACT FROM AUTHOR]

Copyright of Paläontologische Zeitschrift is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A new morphometric approach was developed to study morphological variation within P1 elements commonly referred to as Idiognathodus simulator, which was selected to be the biostratigraphic marker for the base of the global Gzhelian Stage (Carboniferous). This new approach combines landmark-based geometric morphometrics with eigen analyses to analyze shape variation within P1 elements of the I. simulator group, and could be used to analyze shape variation in other morphologically similar conodont groups. Specimens analyzed were obtained from three sections of the early Gzhelian Heebner Shale of the Oread cyclothem in the North American Midcontinent region, the cyclothem from which I. simulator was originally named. This analysis shows that the I. simulator group comprises a set of at least five species with asymmetrical P1 element pairs, relatively short adcarinal ridges, and a variably developed eccentric groove. Species discrimination is based on the presence of caudal and rostral lobes, character of the adcarinal ridges, and platform shape. The species I. simulator is restricted to P1 elements with a caudal adcarinal ridge that is isolated from the caudal platform margin. Idiognathodus lateralis sp. nov. is erected to include P1 elements with a caudal adcarinal ridge that is not isolated from the caudal platform margin. [ABSTRACT FROM AUTHOR]

The collection of the Department of Palaeontology and Geology of the Hungarian Natural History Museum was enriched by a microfossil material which is scientifically greatly important and unique in Hungary. In 2010, when Sándor Kovács passed away, his conodont collection was moved to the Department of Palaeontology of the Eötvös Loránd University. Following years of classification and partly processing, the material was donated to the museum. Conodonts are known from marine beds of the Palaeozoic and the Triassic and they are highly significant from the stratigraphical point of view. Due to their rapid evolution, conodont elements are used worldwide for correlating different successions, despite their uncertain systematic affinities. Beside conodonts, other microfossil groups can also be found in the collection that contains thousands of fossils. The material is mostly from Hungary, but localities from other countries are represented as well. [ABSTRACT FROM AUTHOR]

A prioniodontid conodont Arianagnathus jafariani gen. et sp. nov. from the late Llandovery part of the Niur Formation of the Derenjal Mountains, East Central Iran had an apparatus bearing 3 pairs of P elements. Pa elements of its apparatus are closest to those of Icriodella sandersi (Llandovery-Wenlock boundary interval, Wales, Great Britain) in the weak development of an icrion. Due to the small sample size not all S-elements have been identified but those present are similar to those described in the Icriodella and Icriognathus apparatuses. Based on similarities with previously described apparatus Notiodella we suggest that Arianagnathus jafariani gen. et sp. nov. probably had an apparatus of 17 elements. Arianagnathus is therefore an important additional example that has potential for aiding the future revision of the palaeobiological arrangement of elements within and the phylogeny of conodont apparatuses with 3 P elements, one of which is icrion bearing. The completely known apparatus of associated Ozarkodina derenjalensis sp. nov. shows similarity to some unnamed Ozarkodina from Wales, Great Britain. Many of the conodonts found in the Llandovery part of the studied section are cosmopolitan; the new conodont species seem to have their possible closest relatives in Avalonia. [ABSTRACT FROM AUTHOR]

Pseudofurnishius is a late Anisian (Pelsonian)--early Carnian (Cordevolian) conodont genus of gondolellid stock, characteristic for the Sephardic Province and restricted to the "Southern Tethys" region of the northern margin of Gondwana. Its most commonly found species, Pseudofurnishius murcianus, appears at the base of the Ladinian (Fassanian). The Ladinian material of Spain reveals its ontogeny characterised by initial lateral protrusions from the carina that may develop first mono-platform and later bi-platform units, finally evolving into elaborated multi-denticulated forms. The late Anisian-- early Carnian phylogenesis of Pseudofurnishius priscus → P. shagami → P. murcianus is proposed. At the end of the Ladinian, Pseudofurnishius expanded to the entire "Southern Tethys" shelf and into Cimmerian terranes that drifted away from northern Gondwana, now accreted to Eurasia, such as the Sibumasu terrane (Southwest China--Malayan Peninsula). [ABSTRACT FROM AUTHOR]

The paper is devoted to the Upper Cambrian and Tremadocian organophosphatic microfossils which were hitherto treated as conodonts and assigned mainly to the genera Coelocerodontus and Viirodus. Individual elements of the fossils, similarly to the elements of conodonts, belonged originally to the multi-element apparatuses. Present studies, based mainly on the collections from Sweden, Poland (core sections), Estonia and Kazakhstan, show that despite the similarities of their individual elements to conodonts, they significantly differ from them in the inner structure, as well as in the construction of the apparatuses composed of them. Elements of their apparatuses are matched in shape to each other and certainly functioned in conjunction, while those belonging to the euconodont apparatuses are usually differentiated in shape and usually functioned in separation. All fossils of this group are provisionally named coelocerodonts in this paper. Their individual elements, as well as the apparatuses composed of them, are similar in construction to those of the genus Phakelodus, which is an ancestor of chaetognaths. [ABSTRACT FROM AUTHOR]

The Alum Shale Formation exposed at the Degerhamn quarry road section, southern Öland, Sweden, contains a diversified assemblage of euconodonts, paraconodonts and protoconodonts, the majority of which have ranges confined to the Furongian Series (Cambrian). The first occurrence (FO) of the cosmopolitan euconodont speciesProconodontus muelleriis recorded in the uppermost part of theCtenopyge spectabilistrilobite Zone and the first appearance datum ofCordylodus?andresiis in the upper part of theParabolina lobatatrilobite Zone. Three new successive paraconodont associations are introduced: (1) theFurnishinaAssociation, (2) theProoneotodusAssociation and (3) theWestergaardodinaAssociation, which, respectively, correspond to deeper marine, deep marine and shallow marine conditions. The genusStenodontusChen & Gong is revised in multielement taxonomy. New species formally named areFurnishina holmiandWestergaardodina asinina;Furnishinasp. A andFurnishinasp. B are described in open nomenclature. [ABSTRACT FROM AUTHOR]

Two global isotopic events, the early Sheinwoodian (early Wenlock) and that at the Silurian-Devonian transition, have been comprehensively studied in representative carbonate successions at Kytayhorod and Dnistrove, respectively, in Podolia, Ukraine, to compare geochemistry and biotic changes related correspondingly to the Ireviken and Klonk events. These two large-scale isotope excursions reveal different regional ecosystem tendencies. The well-defined increasing trend across the Llandovery-Wenlock boundary in siliciclastic input, redox states and, supposedly, bioproductivity, was without strict correlative relations to the major 13C enrichment event. The environmental and biotic evolution was forced by eustatic sea-level fluctuations and two-step climate change toward a glaciation episode, but strongly modified by regional epeirogeny movements due to location near the mobile Teisseyre-Törnquist Fault Zone. Thus, the global early Sheinwoodian biogeochemical perturbation was of minor depositional significance in this epeiric sea, as in many other Laurussian domains. Conversely, the Podolian sedimentary record of the Klonk Event exhibits temporal links to the abrupt δ13C anomaly, overprinted by a tectonically driven deepening pulse in the crucial S-D boundary interval. This carbon cycling turnover was reflected in the regional carbonate crisis and cooling episodes, paired with a tendency towards eutrophication and recurrent oxygen deficiency, but also with major storms and possible upwelling. Faunal responses in both Podolian sections follow some characters of the Silurian pattern worldwide, as manifested by conodont changeover prior to the major early Sheinwoodian isotopic/climatic anomaly. This contrasts with the relative brachiopod and chitinozoan resistances in the course of the Ireviken Event. Also, during the Klonk Event, a moderate faunal turnover, both in benthic and pelagic groups, occurred only near the very beginning of the prolonged 13C-enriched timespan across the system boundary, possibly due to progressive dysoxia and temperature drop. The characters point to a peculiarity of the Klonk Event by comparison with the Silurian global events, and some similarity already to the succeeding Devonian transgressive/anoxic episodes. [ABSTRACT FROM AUTHOR]

In the Podolian Dniester Basin (southwestern Ukraine) the Lower Devonian marine deposits are represented by about 530 m thick continuous sequence of interlaminated carbonate and schale outcrops at several localities. Conodonts occur in most of the carbonate layers of the whole Lochkovian but are not abundant and their ramiform elements are mostly broken or lacking. Therefore, only the pectiniform, Pa elements of twenty five stratigraphically important conodont species occurring in the region are discussed and two new species, Caudicriodus schoenlaubi and Pandorinellina? parva are proposed. The hypothetical phyletic relationships within the main representatives of the icriodontid and spathognathodontid genera, Caudicriodus, Zieglerodina, and Pandorinellina? are traced. Comparison of the previously published and newly obtained data revealed discrepancies in the hitherto used interpretation of some of the conodont taxa and their stratigraphic ranges. Contrary to the earlier reports, Caudicriodus postwoschmidti does not occur in the lower Lochkovian but only in the middle part of the Chortkiv Formation, high above the Monograptus uniformis Zone. Based on new material and verification of the previous determinations, a modified scheme of the Lochkovian conodont zonation in Podolia is proposed. Conodont zones: Caudicriodus hesperius, C. transiens, C. postwoschmidti, C. serus, and ?Caudicriodus steinachensis are distinguished. The zones are correlated with conodont zonations in other regions--Barrandian, Cantabrian Mountains, Pyrenees, and Nevada. Biostratigraphy of the Siluro-Devonian transition and Lochkovian is integrated with the carbon isotope stratigraphy. [ABSTRACT FROM AUTHOR]

Conodont faunal dynamics and high-resolution biostratigraphy in the lithologically and faunally anomalous ‘Täljsten’ succession, which spans the Darriwilian Lenodus variabilis–Yangtzeplacognathus crassus Zone boundary, were investigated in a 2·5 m-thick section on Mt Kinnekulle that includes an interval yielding fossil meteorites and extraterrestrial chromite. The previous interpretation that this interval reflects a regression is consistent with the occurrence and abundance patterns of some conodont taxa. The disappearance of e.g., Periodon, suggests that the regression began prior to the deposition of the grey ‘Täljsten’. The transition from red to grey limestone coincides with a conspicuous faunal re-arrangement. The lower half of the ‘Täljsten’ reflects a gradual shallowing favourable for some taxa, such as Lenodus, and the immigration of Microzarkodina cf. ozarkodella and Histiodella holodentata. In the middle of the ‘Täljsten’ interval, coinciding with the appearance of abundant cystoids, conditions became less hospitable for conodonts, resulting in a low diversity and low abundance fauna, which occurs to the top of the interval. The overlying red limestone, apparently deposited during a deepening event, marks a return to pre-‘Täljsten’ conditions with a re-organised fauna. The close correlation between the lithologic shifts and conodont faunal changes demonstrates the usefulness of conodonts as environmental indicators. [ABSTRACT FROM PUBLISHER]

A graptolite biostratigraphy is erected for the upper Telychian (upper crenulata Biozone) to lower Sheinwoodian (riccartonensisor dubiusBiozone) strata of the Jabalón River section, Spain. Two unconformities are recognized in the section: one between the lapworthiand murchisonibiozones; the other between the murchisoniand riccartonensisbiozones. These unconformities coincide with intervals of lowered eustatic sea-level. Graptolite assemblages include both cosmopolitan taxa and some which have been recorded previously from Morocco and/or other Spanish sections. At some stratigraphical levels Pristiograptusor Euroclimacisspecies are abundant; Monoclimacis, Streptograptusand Mediograptusspecies are generally uncommon. Conodonts were examined from the upper spiralisthrough to lower murchisoniBiozone; the occurrences of Pterospathodus amorphognathoidesare consistent with the species' known range elsewhere. Four new graptolite species are described: Euroclimacis jabalonensis, E. hamata, Monoclimacis flexaand Stimulograptus pradoi. [ABSTRACT FROM AUTHOR]

Microzarkodina is a genus of mainly Middle Ordovician conodonts that has its centre of distribution in Baltoscandia, and much less commonly occurs in southern China, Australia, Argentina and Laurentia. In Baltica a series of species, Microzarkodina russica n. sp., M. flabellum, M. parva, M. bella, M. hagetiana and M. ozarkodella, established themselves successfully. The succession of species ranges from just below the base of the Middle Ordovician (M. russica) to the upper part of the Middle Ordovician (M. ozarkodella). The species are frequently used for biostratigraphical purposes. The largely contemporaneous species Microzarkodina bella and M. hagetiana probably both evolved from M. parva and mostly occurred in separate areas. Microzarkodina ozarkodella probably evolved from M. hagetiana. This present investigation is based on a total of 94,208 elements, collected from 20 sections and one drill-core site in Sweden, one drill-core site and one outcrop in Estonia and two sections in the St Petersburg area in Russia. The Microzarkodina apparatus probably consisted of 15 or 17 elements: four P, two or four M and nine S elements. The S elements include different Sa, Sb1, Sb2, and Sc element types. [ABSTRACT FROM PUBLISHER]

Abstract: The Çetmi accretionary melange is cropping out in the Biga Peninsula of northwest Turkey. It is characterised by an isolated position, relatively far from the accretion complexes of the nearest suture zones, which raises the question of its lateral correlations. A detailed biostratigraphic investigation of the limestone and radiolarite blocks and the matrix of the Çetmi melange allowed to propose a solution for this palaeogeographic problem. Scarce red nodular limestones in the Han Bulog facies represent the oldest lithology in the melange. Their Late Scythian–Ladinian age is based on Chiosella gondolleloides, the co-occurrence of Gladigondolella sp. and Nicoraella cf. kockeli, and Paragondolella fuelopi. Light grey limestone blocks are a characteristic feature of the Çetmi melange. They occur in two distinct facies. Facies A consists of packstone to grainstone, and is characterised by unsorted and poorly washed pelbiosparites. Facies B consists of wackestone to packstone, and is characterised by poorly washed biopelmicrites to biopelsparites. The foraminiferal assemblage of Facies A, containing Triasina hantkeni, is of Late Norian to Rhaetian age. The foraminiferal assemblage of Facies B never contains T. hantkeni, and is characteristic of a Late Triassic (Carnian? to Norian–Rhaetian) age. Radiolarian cherts are widely distributed in the Çetmi melange. They record fully pelagic sedimentation from the Upper Bajocian to the Aptian. The matrix of the Çetmi melange consists of brown to black shales, sometimes silty or siliceous, intercalated with dark grey greywackes. Palynomorphs of one sample of brownish silty shale yielded an Early to Middle Albian age, based on the co-occurrence of several dinoflagellate cysts. The age of the matrix, representing the youngest lithology within the melange, and of the unconformable overlaying section (latest Albian–Cenomanian) indicate that the melange-forming process stopped between the Early Albian and the latest Albian–Cenomanian. At a regional scale, the Çetmi melange has little in common with the melanges from the İzmir–Ankara and Intra–Pontide sutures of northwestern Turkey precluding a direct correlation. On the other hand, the Çetmi melange shares several characteristics with the melange-like units of the eastern Rhodope Zone (Bulgaria and Greece), like a major Cenomanian transgression, the reworking of Triassic limestones and Middle Jurassic–Lower Cretaceous radiolarians, and the absence of Jurassic–Cretaceous passive margin lithologies. The occurrence of Rhodopian units on the Biga Peninsula suggests that the studied units represent an isolated fragment of the Rhodope Zone in NW Turkey. [Copyright &y& Elsevier]

The hypothesis that conodonts are vertebrates rests solely on evidence of soft tissue anatomy. This has been corroborated by microstructural, topological and developmental evidence of homology between conodont and vertebrate hard tissues. However, these conclusions have been reached on the basis of evidence from highly derived euconodont taxa and the degree to which they are representative of plesiomorphic euconodonts remains an open question. Furthermore, the range of variation in tissue types comprising the euconodont basal body has been used to establish a hypothesis of developmental plasticity early in the phylogeny of the clade, and a model of diminishing potentiality in the evolution of development systems. The microstructural fabrics of the basal tissues of the earliest euconodonts (presumed to be the most plesiomorphic) are examined to test these two hypotheses. It is found that the range of microstructural variation observed hitherto was already apparent among plesiomorphic euconodonts. Thus, established histological data are representative of the most plesiomorphic euconodonts. However, although there is evidence of a range in microstructural fabrics, these are compatible with the dentine tissue system alone, and the degree of variation is compatible with that seen in clades of comparable diversity. [ABSTRACT FROM AUTHOR]

Biostratigraphical study of the early to mid-Ordovician conodont fauna from ribbon-banded radiolarian cherts of the middle Burubaital Formation in Central Kazakhstan reveals an almost complete succession of conodont biozones from the late Tremadocian to the early Darriwilian. During this interval, biosiliceous sediments were deposited in basinal environments, inhabited by lingulate brachiopods, sponges, pterobranchs and caryocaridids in conditions of high fertility and primary productivity of surface water. The community structure of taxonomically diverse conodont assemblages typifying open oceanic environments is not significantly different from that of epicratonic basins of the North Atlantic conodont province. The regional increase of oxygenated bottom waters at the base of the Oepikodus evae Biozone is possibly related to considerable changes in palaeo-oceanographical circulation patterns. The finds of three natural clusters of Prioniodus oepiki (McTavish) enable us to propose an emended diagnosis of this species. [ABSTRACT FROM AUTHOR]

The elements of many conodont taxa exhibit a polygonal surface micro-ornamentation. Four main types are recognized (striation, linear texture, regular (idiomorphic) texture and granular texture) and their distribution over the conodont elements of different morphology is considered. The intraspecific (ontogenetic and ecological) and interspecific (phylogenetic) causes of the reticulation texture variations are also considered. [ABSTRACT FROM AUTHOR]

Conodonts, one of the longest-lived early groups of vertebrates, have a very complete fossil record ranging from the late Cambrian to the end of the Triassic and persisted through many global climatic and biotic events. In this paper, we analyse a large dataset harvested from the Paleobiology Database to compute global diversity curves at the generic level and explore patterns of conodont paleogeographic distribution. Our results partly confirm the most prominent findings of earlier studies including the occurrence of an Ordovician acme, a Permian nadir and a short-lived Triassic recovery. Major peaks of origination were found in the Early Ordovician and Early Triassic, while major extinctions occurred in the Upper Ordovician and Pennsylvanian. Paleogeographical extent of conodonts was impacted by i) the position of paleo-continents (notably impacting the latitudinal gradient of diversity), ii) the available continental shelf area and iii) ice sheets expansion. Diversity trends were mostly impacted by transitions between hothouse and icehouse ages, with major glaciations and associated marine regressions co-occurring with major extinctions. The influence of global sea level was less marked than that of temperature. However, the final demise of conodonts at the end of the Triassic did not coincide with either a major glaciation or marine regression. This supports the view that extinction of the group was mostly due to biotic factors such as competition with 'Mesozoic' taxa. • Conodont biodiversity was significantly impacted by sea-level and sea temperature; • Hit by end-Ordovician and end-Carboniferous extinction peaks; • Major extinctions were related to glaciation and sea-level drop; • Abiotic context of final extinction was different, suggesting biotic effects. [ABSTRACT FROM AUTHOR]