Multielement Species Research Articles

Origin and evolution of the Early Ordovician conodont genus Prioniodus Pander, 1856 — New evidence from South China

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.

Middle-Upper Ordovician conodonts from the Ffairfach and Golden Grove groups in South Wales, United Kingdom

ABSTRACT The conodont fauna of the reference succession of the regional British Llandeilian Stage of the Llanvirn Series was first described in a classical study by Rhodes more than 65 years ago using single element (form) taxonomy. Although several subsequent authors have recorded a substantial number of conodont taxa from the Llandeilo area, the present study is the first to present a modern taxonomic review of these late Darriwilian-early Sandbian faunas that include approximately 20 multielement species. Most prominent are representatives of Amorphognathus, Baltoniodus, Eoplacognathus, and Plectodina. The study faunas have their own biogeographical character. The distinctive genera Complexodus, Protopanderodus, and Pygodus, which are common in coeval Baltoscandic faunas, are not present, but the occurrence of Amorphognathus, Baltoniodus, and Eoplacognathus provides a link to age equivalent Baltoscandic faunas. The presence of abundant specimens of Plectodina and less common representatives of Erismodus and Icriodella are reminiscent of North American Midcontinent faunas. This type of faunal assemblage is in some respects similar to those of the early Caradoc Series of the Welsh Borderland. Biostratigraphically diagnostic species indicate that the Llandeilo study succession ranges from the Eoplacognathus lindstroemi Subzone of the Pygodus serra Zone to the Baltoniodus variabilis Subzone of the Amorphognathus tvaerensis Zone.

ACRITARCHS AND CONODONTS FROM THE CAMBRO - ORDOVICIAN FURUHÄLL (KÖPINGSKLINT) SECTION (ÖLAND, SWEDEN)

Cambrian to Lower Ordovician acritarchs and Lower Ordovician conodont species have been recorded from the Furuhäll Section at Köpingsklint on Öland, Sweden. The acritarchs are represented by three different microfloras. The first is found at the base of the section investigated and is characterized by the association of Cristallinium cambriense with Eliasum llaniscum, Retisphaeridium dichamerum and R. howellii. This microflora has been recorded in strata previously referred to the Paradoxides paradoxissimus trilobite Superzone.
 The second microflora includes Timofeevia lancarae, T. pentagonalis and T. phosphoritica and it has been found in layers dated to the Upper Cambrian Agnostus pisiformis trilobite Zone.
 The third microflora comprises Of several species among which Aremoricanium ? grootaertii, Athabascaella playfordii, Dasydiacrodium tremadocum, Stelliferidium furcatum which are indicative of a Tremadocian age. This association includes taxa which usually occur in different bioprovinces, thus it allows transprovincial correlations. This microflora has been recorded in Lower Ordovician (Tremadocian) strata Of the Dictyonema flabelliforme s.l. - Clonograptus heres graptolite Zones.
 The new species Adara (Middle Cambrian) and Cristallinium aciculatum (Upper Cambrian) are described.
 The conodont species are referable to Tremadocian Paltodus deltifer Zone and Paroistodus proteus, Prioniodus elegans and Oepikodus evae conodont Zones Of the Arenigian. The fauna is typical Baltic, but includes elements of Tropodus and Tropodus sweeti which otherwise are known from the midcontinent conodont faunal province.
 The composition of the multielement species Baltonidius ? deltatus, B. crassulus, Oistodus aff. O. lanceolatus, Paltodus deltifer, P. peracutus and P. subaequalis is revised.
 The sequence of Furuhäll is characterized by several hiata, some of which can be related to eustatic sea level lows. The most extensive hiatus is from the Upper Cambrian Leptoblastus trilobite Zone into the early Tremadocian Dictyonema flabilliforme s.l. Zone. Barren interzones have been recorded at the base and at the top of Hunnebergian Substage. The lower barren inter-zone corresponds to the Tremadocian - Arenigian stage boundary or the Paltodus deltifer - Paroistodus proteus zonal boundary. The upper barren interzone coincides With Paroistodus proteus and Prioniodus elegans zonal boundary.

The Ordovician zone index conodont <i>Amorphognathus ordovicicus</i> Branson & Mehl, 1933 from its type locality and the evolution of the genus <i>Amorphognathus</i> Branson & Mehl, 1933

Abstract. The 2003 rediscovery of the long ‘lost’ Ozora, Missouri classical conodont locality of Branson & Mehl (1933b), from which the world’s first Late Ordovician conodont fauna was described, has made it possible to obtain topotype specimens of the several important conodont species introduced by Branson and Mehl from this site. A taxonomic reassessment of the Ozora conodont fauna indicates that it includes at least 14 multi-element species, eight of which were previously known from this locality. Several specimens of the taxonomically diagnostic M element of the biostratigraphical key species Amorphognathus ordovicicus were recovered. This element was previously not known from the type locality of the species at Ozora. A general review of the evolution of the genus Amorphognathus shows that some elements, particularly the M and Pa elements, exhibit relatively rapid gradual morphological changes that are helpfull for distinguishing a series of biostratigraphically useful species through the Upper Ordovician (Sandbian–Hirnantian) interval. No ancestor of Amorphognathus has yet been identified but currently available data suggest that the genus appeared in the latest Darriwilian or earliest Sandbian and went extinct in the late Hirnantian. None of the Early Silurian platform genera appears to be closely related to Amorphognathus.

Rhipidognathid conodonts from the Early Ordovician Honghuayuan Formation of Guizhou, South China

The two oldest species of rhipidognathid conodonts, Rhipidognathus yichangensis and Bergstroemognathus extensus, are described and illustrated from the Early Ordovician Honghuayuan Formation of Guizhou, South China. Both species are interpreted to consist of a septimembrate apparatus. The form species Bergstroemognathus hubeiensis is regarded as a junior synonym of B. extensus. As currently defined, the multi-element species B. hubeiensis includes elements belonging to both B. extensus and R. yichangensis, and hence can no longer be regarded as a valid species.

LATE ORDOVICIAN JAWED POLYCHAETE FAUNAS OF THE TYPE CINCINNATIAN REGION, U.S.A

Abstract Late Ordovician jawed polychaete (Annelida) faunas from the type Cincinnatian region in the tri-state area of Indiana, Ohio, and Kentucky, North America, are discussed on the basis of an extensive and unique collection of more than 50,000 well-preserved scolecodonts. Approximately 40 to 50 multi-element species belonging to a dozen families are identified. Scolecodonts of polychaetes with prionognath, and particularly labidognath, type of jaw apparatus markedly dominate, whereas those of placognath and ctenognath taxa are very rare. The most common and/or characteristic genera include Oenonites Hinde, 1879; Kettnerites Žebera, 1935; Atraktoprion, Kielan-Jaworowska, 1962; Ramphoprion Kielan-Jaworowska, 1962; Protarabellites Stauffer, 1933a; Kalloprion, Kielan-Jaworoska, 1962; Leptoprion, Kielan-Jaworowska, 1966; Hadoprion Eriksson and Bergman, 1998; Mochtyella Kielan-Jaworowska, 1961; and Tetraprion? Kielan-Jaworowska, 1966. Members of the family Polychaetaspidae, particularly Oenonites species, g...

Late Ordovician jawed polychaete faunas of the type Cincinnatian region, U.S.A.

Late Ordovician jawed polychaete (Annelida) faunas from the type Cincinnatian region in the tri-state area of Indiana, Ohio, and Kentucky, North America, are discussed on the basis of an extensive and unique collection of more than 50,000 well-preserved scolecodonts. Approximately 40 to 50 multi-element species belonging to a dozen families are identified. Scolecodonts of polychaetes with prionognath, and particularly labidognath, type of jaw apparatus markedly dominate, whereas those of placognath and ctenognath taxa are very rare. The most common and/or characteristic genera include Oenonites Hinde, 1879; Kettnerites Žebera, 1935; Atraktoprion, Kielan-Jaworowska, 1962; Ramphoprion Kielan-Jaworowska, 1962; Protarabellites Stauffer, 1933a; Kalloprion, Kielan-Jaworoska, 1962; Leptoprion, Kielan-Jaworowska, 1966; Hadoprion Eriksson and Bergman, 1998; Mochtyella Kielan-Jaworowska, 1961; and Tetraprion? Kielan-Jaworowska, 1966. Members of the family Polychaetaspidae, particularly Oenonites species, generally dominate in abundance and number of species. The second most abundant family typically is either Ramphoprionidae or Paulinitidae. Overall, the taxonomic diversity seems to increase from the deeper water, shale-dominated, Edenian Kope Formation and upward in the succession to the shallower water, limestone-dominated, Richmondian Whitewater Formation. Five more or less distinct scolecodont associations were identified that are of potential biostratigraphic utility. Most families and genera identified have intercontinental distribution and can be identified also in approximately coeval strata of the Baltic paleocontinent. However, the faunal composition differs between these regions, especially at the species level.

Species-specific isotope-ratio measurements of volatile tin and antimony compounds using capillary GC-ICP-time-of-flight MS.

The analytical performance of an axial inductively-coupled-plasma time-of-flight mass spectrometer (ICP-TOFMS) as a detector for fast transient chromatographic signals resulting from the coupling to capillary gas chromatography (CGC) was investigated. A cryotrapping GC-ICP-TOFMS method for the determination of volatile metal(loid) compounds (VOMs) in gases was used and the suitability of the TOF mass analyzer for multielemental speciation analysis and multi-isotope ratio determinations was studied in terms of accuracy and precision. Isotope ratios 118Sn/120Sn and 121Sb/123Sb have been determined in in-house gas standard atmospheres in Tedlar bags at two different levels (100 pg and 1 ng) for different elemental species (SnH4, MeSnH3, Me2SnH2, Me3SnH, BuSnH3, SbH3, and MeSbH2). A limitation arising from counting statistics in both detection modes could be shown. A solution containing rhodium (10 ng mL(-1)) and cadmium (40 ng mL(-1)) was introduced simultaneously to the GC outlet. Rhodium acts as a continuous internal standard and Cd is used for mass-bias correction (by measuring the 111Cd/113Cd ratio). The detection system in both pulse counting and analog mode was examined. The best attainable precision was established for Me2SnH2 (analog mode, 12 replicates, 1 ng, RSD 0.34%, accuracy 0.31%) whereas most other species ranged between 0.4 and 0.5% RSD if higher concentrations were used. The limitations of the pulse counting system are clearly seen, with peak heights of more than 2000 counts reaching saturation (for an integration time of 100 ms), which reduces the accuracy of isotope ratio determinations. A dozen VOM could be detected in an aged landfill gas sample; several unidentified Sn compounds were present. Although their isotope ratios are within the confidence value of the standards, it is not yet clear if the acquired precision is good enough to identify isotopic fractionation of metal(loid)s through biovolatilization processes. With the precision achieved, the combination of cryotrapping GC and ICP-TOFMS is a powerful tool for monitoring volatile multi-element species in multi-tracer experiments and isotope dilution methodology.

Conodont micropalaeontology of mid-Ordovician aged limestone clasts from Lower Old Red Sandstone conglomerates, Lanark and Strathmore basins, Midland Valley, Scotland

Abstract. Mid-Ordovician limestone clasts in the Lower Old Red Sandstone conglomerates of the Lanark and Strathmore basins of the Midland Valley, Scotland, were derived from a cryptic carbonate platform, now hidden beneath the Southern Uplands Allochthon. These have yielded 17 multi-element species of conodonts, which are systematically described herein and include the eponymous biozonal species Pygodus serra and Pygodus anserinus. The fauna represents an outer shelf-ocean margin biofacies, found only in Upper Ordovician conglomerates in the Southern Uplands and the Malopolska Terrane, Poland.

Uppermost Cambrian and Lower Ordovician conodont biostratigraphy of the Survey Peak Formation (Ibexian/Tremadoc), Wilcox Pass, Alberta, Canada

The Survey Peak Formation (350 m thick) consists of calcareous shale, mudstone, siltstone, and limestone-pebble conglomerate, and is formally divided into four revised members, successively: Basal Silty Member, Putty Shale Member, Middle Carbonate Member, and Upper Carbonate Member. The Wilcox Pass section, Jasper National Park, Alberta, provides a standard stratigraphic section for the southern Canadian Rocky Mountains and yielded over 4,500 conodonts from 87 samples which are of high species diversity, moderately well preserved, with a conodont Color Alteration Index (CAI) value of 3. Over 50 multielement species representing some 20 genera are identified, and most are illustrated. Conodont zones recognized in the four members include: Basal Silty Member—Eoconodontus notchpeakensis, Cordylodus proavus, C. caboti, C. intermedins, and C. lindstromi; Putty Shale Member—lower C. angulatus; Middle Carbonate Member—upper C. angulatus and coeval Rossodus manitouensis, Colaptoconus priscus (new) and Scolopodus cf. S. rex; Upper Carbonate Member—Striatodontus lanceolatus-S. striatus. In total, ten conodont lineage and assemblage zones are recognized within the Survey Peak Formation. Most can now be precisely correlated with trilobite faunas and acritarch microfloras described from this section, and with conodont zones established for the Great Basin area, Utah-Nevada, and for western Newfoundland. The Survey Peak Formation is of uppermost Cambrian to lower Ibexian (Tremadoc) in age with the Cambrian-Ordovician boundary placed between 26 and 29 m above the base of the formation in the Basal Silty Member.

Conodont paleoecology of the Lower Ordovician St. George Group, Port au Port Peninsula, western Newfoundland

The St. George Group in western Newfoundland is nearly 600 m thick and is subdivided into the Watts Bight, Boat Harbour, Catoche, and Aguathuna Formations. The group is a nearly complete Lower Ordovician succession representing about 15–20 m.y. The depositional environment of the St. George Group is represented by three main lithofacies (supratidal, peritidal, and subtidal), expressed as two first-order cycles and five second-order cycles.In the study of St. George Group conodonts, over 70 multielement species are represented in 45,000 conodont specimens from 432 samples of 10 sections. Computer cluster analysis of most of those samples on the basis of similarity of conodont species was used to determine conodont community structure. Both the principal coordinate analysis (PCA) partitioning method and the agglomerative method (UPGMA with Bray-Curtis) were chosen for the statistical analysis. The four lithological formations and five secondary lithological cycles in the St. George Group emerge as distinct entities when the samples are clustered together on the basis of conodont data for analysis of first-order and second-order variations in community composition.Two deeper water, five shallow-water, and five intermediate communities through this time interval are recognized. The majority of conodonts from these communities are of Midcontinent Realm affinities, but some species represent strong North Atlantic Realm influxes during the transgressive periods.

Early Ordovician conodonts from the Dumugol Formation in the Baegunsan Syncline, eastern Yeongweol and Samcheog areas, Kangweon-Do, Korea

Samples from the Dumugol Formation were collected from eight measured sections and two cores in the so-called Baegunsan Syncline, located between eastern Yeongweol and Samcheog areas, Kangweon-Do, South Korea. A total of 7,813 identifiable conodonts were recovered from 146 samples. They are classified into 24 multielement species referable to 16 genera, and 37 form species belonging to 17 genera; six species are newly described:Distacodus dumugolensis, Parapanderodus acontiformis, Scolopodus longibasis, Scolopodusn. sp. A,Triangulodus dumugolensis, andOistodus(?) sp. The Dumugol Formation is divided biostratigraphically into four conodont zones, viz,Chosonodina herfurthi-Rossodus manitouensis, Glyptoconus quadraplicatus, Paracordylodus gracilis, andTriangulodus dumugolensiszones in ascending order. These zones are correlated with those of the early Ordovician conodont faunas of North America, northern Europe, China, Australia, and Iran. The Dumugol Formation ranges from late Tremadocian to early Arenigian in age. The boundary between these two series lies between 70 and 100 m above the base of the Dumugol Formation in each of the sections.

A major conodont extinction event during the early Ordovician within the Midcontinent realm

The major change in the Lower Ordovician conodont faunas of the Midcontinent Realm was recognized by earlier workers. Our recent intense study of Midcontinent conodonts from the St. George Group, Port au Port Peninsula, western Newfoundland, has shown that seven major conodont lineages, involving some 33 multielement species, completely terminate in the late Tremadoc Series, within an interval of a few metres, at a level between the Lower Ordovician conodont Fauna C and Fauna D. The extinction event occurs during the peak of a regressive phase within the deposition of the St. George Group and at a time of apparent global eustatic fall at or slightly below the Tremadoc-Arenig series boundary. This important extinction bioevent has been recognized throughout the Midcontinent Realm in North America.

Stoichiometric considerations in multicomponent aqueous stability diagrams

Aqueous stability diagrams are frequently used to assist in interpreting the chemical mechanism of many hydrometallurgical systems. It has been found that, for multi-element diagrams, when chemical species containing more than one element, other than oxygen or hydrogen, are stable, more than one diagram is required to describe the system. The structure of multi-element diagrams was found to be primarily dependent on restrictions placed on the relative quantities of the component elements. The restrictions are determined by the stoichiometry of stable, multi-element species. Aqueous stability diagrams, calculated by the CSIRO-Monash Thermochemistry System for the iron-sulfur-water system at 523.15 K, and including a representation of the pyrrhotite solid-solution phase, are used to illustrate these features. Use of these diagrams in the interpretation of the mechanism of hydrometallurgical processes is discussed.

Quantification of outlines in Frasnian (Upper Devonian) platform conodonts

The outline of the platform in Pa elements of conodont genera such as Palmatolepis is commonly one of the most heavily weighted taxonomic characters. But a taxonomy based only on visual discrimination of Pa elements of Frasnian species of Palmatolepis has resulted in widespread misidentification. Although their Pa elements can be confused, Palmatolepis subrecta, Palmatolepis hassi, and related species from the Frasnian of the Montagne Noire and Iowa can be separated consistently by use of features displayed by other elements of the apparatus, especially the Pb and M elements. To determine if significant differences exist among the Pa elements of these multielement species, digitized outlines of the Pa elements were analyzed using an orientation function similar to the tangent-angle function of F. L. Bookstein. A multielement classification based on the Pb and M elements was tested by a discriminant analysis of the outlines of the Pa elements. The results show that there is close agreement between the two procedures and that systematic differences exist among the Pa elements of groupings based on the Pb and M elements. Unquestionably, quantification of the outlines of platform conodonts will substantially improve taxonomic methods, with consequent enhancement of biostratigraphy.

Lower Ordovician conodonts from Washington Land, western North Greenland

Early Canadian (Lower Ordovician) conodonts have been recorded from loose slabs which were collected by J. C. Troelsen in 1941 at Kap Clay, Washington Land, western North Greenland. The samples probably derived from the Cape Clay Formation which is exposed in the steep coastal cliff. The macrofauna of the samples includes Symphysurina sp. of Early Ordovician age. The conodont fauna comprises "Paltodus" bassleri Furnish, Utahconus oneotensis (Furnish}, "Oistodus" triangularis Furnish, and species of Cordylo­dus Pander and "Acontiodus" Pander. The fauna correlates with Fauna C of the North American Mid­continental Faunal succession and with the Cordylodus angulatus Zone of the Baltic-Scania succession. Locally, it correlates with the conodont fauna recorded from the Cape Clay formation of Southern Devon Island, Canadian Arctic Archipelago. The conodont fauna is described applying multielement taxonomy. In all 314 specimens, representing 20 multielement species, were recorded. Some species are new, but they are referred to only in open no­menclature because of the unsettled stratigraphical status of the loose blocks.

Conodonts from the Cape Clay Formation (Lower Ordovician), southern Devon Island, Arctic Archipelago

As part of a program involving the Ordovician conodont faunas of southern Devon Island, Northwest Territories, 22 samples were processed from the Cape Clay Formation and lowest Nadlo Point Formation near Dundas Harbour. The Cape Clay Formation is 85 m thick and composed of bluff-forming mottled limestone and dolomitic limestone. A small but diverse conodont fauna of 229 elements was recovered in which 23 form and multielement species are represented. Several new taxa are described in open nomenclature, and multielement Utahconus? bassleri (Furnish) is discussed. The fauna is considered to represent Fauna C of the North American Midcontinent Faunal Province and is indicative of a late Tremadocian age. This fauna, in a unit with few macrofossils, indicates correlation of the Cape Clay Formation near Dundas Harbour with the upper Turner Cliffs Formation of the Foxe Basin, with the upper Copes Bay and (or) lower Baumann Fiord formations of Cornwallis, northwest Devon, and Ellesmere Islands of the Canadian Arctic, and with some portion of Ross–Hintze trilobite Zones A – lower D of the Great Basin.

A spathognathodont lineage of Mississippian conodonts

Evolutionary lineages of conodont elements and of some apparatuses are gradually being documented to increase the value of these fossils in stratigraphic interpretation and to further our understanding of conodont taxonomy. The well-documented faunas from Mississippian strata of the Illinois Basin and type Mississippian beds provide a great deal of information for the recognition of phylogenies. The disjunct element genus Spathognathodus is part of a basic and long-ranging type of conodont apparatus from which a number of other forms have been derived, and some of its Mississippian disjunct element species can now be placed in multielement species. A lineage involving spathognathodont Pa elements recognized in the Mississippian, then, is the basis of the present study. The phylogeny recognized started with Synprioniodina? crassidentata, and includes S.? regularis, S.? pulchra, S.? coalescens, S.? spicula, Hinduodus cristula, and H. minutus in the Mississippian. Aputiignathus scitulus and A. penrscitulus apparently represent a separate line, which also might include disjunct element Spathognathodus rexroadi.

Middle Devonian Conodonts from the Harrogate Formation, Southeastern British Columbia

A fauna of Middle Devonian conodonts from the Harrogate Formation is described. The conodont evidence favors a middle to late Eifelian age rather than a Givetian age for this unit. A new form species of Icriodus, I. stelcki s.f., a new multielement species of Polygnathus, P. parawebbi, and a new multielement species of Coelocerodontus, C. Klapperi are described. A discussion of some of the problems of applying multielement taxonomy to conodont faunas is included.

Notes on Some Upper Silurian Multielement Conodonts

Seventeen types of conodont elements, fifteen previously described as form species, have been grouped into three multielement species. The type species of the form genera Ozarkodina Branson and Mehl, 1933, Plectospathodus Branson and Mehl, 1933, Spathodus Branson and Mehl, 1933 (non Boulenger, 1900), and Spathognathodus Branson and Mchl, 1941 are all elements of the same conodont apparatus. Hindeodella Bassler, 1925 is probably the oldest generic name applicable to this type of multielement species. The apparatuses of the multielement species investigated appear to consist of five or six different types of elements that can readily be homologized from species to species. This fact appears to offer a most useful basis for the continued grouping of form species into multielement species within the genera Hindeodella. and Ligonodina.