Conodonts Research Papers - Academia.edu (original) (raw)

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- Conodonts
- by Yong Yi Zhen
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- Evolutionary Biology, Geology, Ecology, Biogeography

Over I6,000 conodonts have been extracted from the upper Dinantian (upper Courceyan to Brigantian stages) and early Namurian (Pendleian Stage) strata of the Craven Lowlands. Seventy three species and subspecies have been identified from 25 genera. One new genus and species, Embsaygnathus asymmetricus and 7 new species, Cloghergnathus cravenus, Clydagnathus? hudsoni, Metalonchodina sp. nov. A, Metalonchodina sp. nov. B, Neoprioniodus discretus, Pseudopolygnathus minutus, Synprioniodina spathata are described. Six local-range biozones and two subzones based on the first appearance of selected species are proposed. The zones and subzones are in ascending order: Pseudopolygnathus minutus Zone, Mestognathus beckmanni-Polygnathus bischoffi Zone (with a Gnathodus texanus pseudosemiglaber Subzone at the top), Gnathodus homopunctatus Zone, Gnathodus commutatus Zone (with a Gnathodus girtyi Subzone at the top), Gnathodus bilineatus Zone and Gnathodus nodosus Zone. Correlations based upon these zones and subzones in the Craven Lowlands indicate that all the sampled horizons in the Swinden and Broughton anticlines are of Chadian age. The base of the Arundian Stage in the Clitheroe Anticline is believed to lie within the Cephalopod Shales and not at the base of the Salt Hill Cap Beds as advocated by George and others ( l 976). Correlations with Belgium indicates that the Tournaisian-Visean boundary in the type area of Dinant, Belgium, may be represented by a non-sequence. Possible non-sequences are also suggested in the Dinantian of Germany and Spain and Portugal.

- by Ian Metcalfe
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- Systematics (Taxonomy), Biostratigraphy, Northern England, Conodonts

Carboniferous conodonts are reported for the first time fromMyanmar (Burma). Conodont faunas representative
of the Scaliognathus anchoralis and Gnathodus typicus–Protognathodus cordiformis conodont zones date the
sampled Taungnyo Group south of Loi Kaw, Kayah State as late Tournaisian confirming a Mississippian (Lower
Carboniferous) age for the sampled part of this stratigraphic unit. The dated strata are stratigraphically just
below the Tournaisian–Visean (T-V) boundary. Tournaisian strata are thus for the first time unequivocally
demonstrated in the Shan Plateau region of Myanmar. Similar conodont faunas from the T-V boundary interval
in SE Asia indicate a complete stratigraphic sequence at this level in shallow-marine sequences on intra-
Tethyan Cathaysian tectonic blocks (South China) and in deep-marine Palaeo-Tethyan sediments (cherts of the
Inthanon suture zone, Thailand). However, in shallow-marine sequences on the Sibumasu Block, located on
the NE margin of Gondwana in the Carboniferous, they demonstrate a non-sequence or unconformity at this
level, also seen elsewhere in Gondwana. Biogeographic links between upper Tournaisian and early Visean
conodonts on the Sibumasu Terrane and Laurentia and Eastern Australian Gondwana support a NW Australian
Gondwana margin position for Sibumasu in the Late Palaeozoic.

- by Ian Metcalfe
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- Myanmar, Conodonts, Gondwana, Carboniferous

Se trata de un trabajo de tesis en el cerro El Santísimo, Arivechi, Sonora, México, estudiando la geología del lugar centrandose en la paleontología de la secuencia de rocas calcáreas del Ordovícico Inferior al Superior mediante la identificación de conodontos y de sus respectivas biozonas, útil para el registro fósil del phylum Chordata en el NW de México.

- by Andre Becuar
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- Sedimentary geology and stratigraphy, Conodonts, Ordovician, Sonora
- by M. Cemal Goncuoglu
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- Geology, Turkey, Conodonts
- by M. Cemal Goncuoglu and +1
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- Stratigraphy, Turkey, Geodynamics, Igneous petrology
- by Susan Turner
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- Paleobiology, Earth Sciences, Geology, Philosophy of Science

Neanderthals have a distinctive suite of dental features, including large anterior crown and root dimensions and molars with enlarged pulp cavities. Yet, there is little known about variation in molar root morphology in Neanderthals and other recent and fossil members of Homo. Here, we provide the first comprehensive metric analysis of permanent mandibular molar root morphology in Middle and Late Pleistocene Homo neanderthalensis, and Late Pleistocene (Aterian) and recent Homo sapiens. We specifically address the question of whether root form can be used to distinguish between these groups and assess whether any variation in root form can be related to differences in tooth function. We apply a microtomographic imaging approach to visualise and quantify the external and internal dental morphologies of both isolated molars and molars embedded in the mandible (n = 127). Univariate and multivariate analyses reveal both similarities (root length and pulp volume) and differences (occurrence of pyramidal roots and dental tissue volume proportion) in molar root morphology among penecontemporaneous Neanderthals and Aterian H. sapiens. In contrast, the molars of recent H. sapiens are markedly smaller than both Pleistocene H. sapiens and Neanderthals, but share with the former the dentine volume reduction and a smaller root-to-crown volume compared with Neanderthals. Furthermore, we found the first molar to have the largest average root surface area in recent H. sapiens and Neanderthals, although in the latter the difference between M1 and M2 is small. In contrast, Aterian H. sapiens root surface areas peak at M2. Since root surface area is linked to masticatory function, this suggests a distinct occlusal loading regime in Neanderthals compared with both recent and Pleistocene H. sapiens.

- by Jean-Jacques Hublin
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- Aterian, Conodonts, Dental Morphology, Foraminifers

A B S T R A C T The Eyam Limestone Formation of Steeplehouse Quarry, Wirksworth, Derbyshire, UK yields a diverse assemblage of Lower Carboniferous vertebrate remains. The assemblage is dominated by dermal denticles of the enigmatic selachian Petrodus patelliformis M'Coy, 1848, but also contains teeth of petalodonts, hybodonts and neoselachians. Actinopterygian remains also occur. The assemblage has yielded the earliest Neoselachian, Cooleyella fordi (Duffin and Ward, 1983) and the earliest British lonchidiid, Reesodus wirksworthensis (Duffin 1985). The first occurrence of the enigmatic spiny shark Acanthorhachis (Listracanthidae) is reported from the Viséan, extending its range back some 10 million years. Associated invertebrate remains and sedimentological data indicates a thriving fore-reef environment, deposited in a low energy off-reef setting. The vertebrate remains are well preserved with little abrasion, indicating short transport distances. Conodont elements indicating a late Brigantian age (Early Carboniferous, Viséan) have unusual and extensive euhedral apatite overgrowths.

- by Christopher Duffin
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- Vertebrate Palaeontology, Vertebrate Paleontology, Sharks, Conodonts
- by Tomas Kumpan
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- Geology, Geochemistry, Geophysics, Micropaleontology
- by Silvia Blanco-Ferrera
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- Biostratigraphy, Conodonts, Carboniferous, Cantabrian Mountains geology
- by Silvia Blanco-Ferrera
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- Biostratigraphy, Conodonts, Carboniferous
- by Clive Burrett
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- Conodonts, Ordovician, Ordovician Trilobites, Ordovician Paleoecology
- by M. Cemal Goncuoglu
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- Sedimentology, Paleoclimatology, Turkey, Conodonts

Konodon adalah mikrofosil berfosfat yang sangat kecil dan merupakan unsur-unsur kerangka yang tunggal daripada haiwan menyerupai cacing dan termasuk ke dalam Filum Conodonta yang telah pupus. Mikrofosil tersebut sangat berguna bagi kajian biostratigrafi Kambria hingga Trias. Mikrofosil itu telahpun dipakai sebagai petunjuk sekitaran kuno, iklim kuno, suhu kuno dan bagi penetuan usia mutlak. Kajilidikan konodon di Malaysia sudah membuktikan kegunaannya bagi menerangkan stratigrafi Malaysia dan menggalakkan korelasi serantau yang boleh dipercayai di Asia Tenggara.

- by Ian Metcalfe
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- Malaysia, Biostratigraphy, Palaeobiology, Conodonts

Late Permian (late Changhsingian), possible Early Triassic Induan (Dienerian), and early Olenekian (Smithian) conodonts have been recovered from the Hovea Member of the Kockatea Shale in the exploration well Corybas 1, northern Perth Basin, Western Australia. Placement of the biostratigraphic Permian – Triassic boundary is in the lower part of the Sapropelic Interval of the Hovea Member. The Australian endemic Protohaploxypinus microcorpus palynofloral Zone is confirmed to be of late (but not latest) Changhsingian age. The Permian – Triassic boundary, based on international calibration using conodonts, carbon-isotope stratigraphy and new radio-isotopic dating, is placed in the lower part of the Kraeuselisporites saeptatus and Lunatisporites pellucidus Zones of western and eastern Australia, respectively, which corresponds approximately to the basal part of the Rewan Group and equivalents in eastern Australia.

- by Ian Metcalfe
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- Australia, Conodonts, Permian-Triassic transition, Permian Triassic Boundary

The article presents new results of biostratigraphic and isotopic analyses for the Upper Famennian - Lower Tournaisian deep-water deposits of the Syvyu River section. Ostracode and conodont faunal changes, interpretation of lithological particularities and O and C isotopic variations enabled description of the boundary of the Systems, and identify stratigraphic equivalents of the Hangenberg Shale.

- by Artem Plotitsyn
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- Conodonts, Famennian, Devonian-Carboniferous boundary, Ostracoda
- by Peter Koenigshof
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- Facies Analysis, Conodonts
- by Apsorn Sardsud and +1
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- Geology, Paleontology, Conodonts
- by Silvia Blanco-Ferrera
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- Conodonts, Carboniferous, Pyrénées

The Jerus Limestone, Cheroh, Pahang, previously considered part of the Raub Group and of Carboniferous or Permian age, has yielded rich conodont faunas of Lower Triassic (late Dienerian) and Middle Triassic age. The Lower Triassic, until recently unrecognised in western Pahang, appears to be predominantly of carbonate facies, including channel filling conglomeratic limestones derived from nearby active fault scarps.

- by Ian Metcalfe
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- Biostratigraphy, Conodonts, Triassic, SE Asia Regional Geology
- by Ana Karina Scomazzon and +2
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- Paleoecology, Biostratigraphy, Conodonts, Pennsylvanian

Limestones exposed at Gunong Keriang, Kedah. have yielded conodonts representative of the Early Permian (Wolfcampian) Neogondolella bissel!i-Sweetognathus whitei and the Early Triassic (Smithian) Neospathodus waageni Zones.
The Kodiang Limestone exposed at Bukit Hantu near Kodiang, Kedah has yielded conodonts representative of the Late Permian (Capitanian) Neogondolella rosenkrantzi-Neospathodus divergens Zone and species of Neospathodus characteristic of the Early Triassic. The PermianTriassic boundary is for the first time recognised in exposed sections in Malaysia. Since the Kodiang Limestone is shown to extend down into the Permian it is considered probable that it is continuous with the underlying Chuping Limestone.
The Middle and Late Permian appear to be absent at Gunong Keriang, being cut out by an unconformity or non-sequence.

- by Ian Metcalfe
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- Conodonts, Triassic, Peninsular Malaysia
- by Masatoshi Sone
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- Evolutionary Biology, Palaeogeography, Geology, Ecology
- by Tatiana Kulashova
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- Paleontology, Scolecodonts, Conodonts, Annelida
- by Axel Munnecke
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- Evolutionary Biology, Geology, Paleoecology, Ecology
- by Jiří Kalvoda
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- Geology, Geochemistry, Geophysics, Tectonics

Late Permian conodonts are for the first time reported from Vietnam. Pa, Sa, Sb, Sc and M elements of the
Changhsingian conodont species Hindeodus julfensis (Sweet) are reported from a 40 cm thick limestone in
the middle part of the Yenduyet Formation near Son La, NW Vietnam. The occurrence of H. julfensis indicates
a Changhsingian age that is consistent with an interpreted early Changhsingian age for a brachiopod
fauna slightly higher in the sampled section. The Son La section is located in the Song Da Rift Zone and
overlies basaltic volcanics considered equivalent to the Emeishan large igneous province basalts that are
plume related. The Permian–Triassic boundary in Vietnam is yet to be precisely located biostratigraphically
but proxy chemostratigraphic data indicate its likely position in sections at Nhi Tao and Lung Cam,
N. Vietnam and correlation with the Global Stratotype Section and Point at Meishan, South China. The
recovered conodonts have a Conodont Colour Alteration Index of 5 and have been heated to c. 600 C
but they do not show any evidence of textural alteration due to regional metamorphism such as
micro-folding or stretching that would indicate any direct effects of the compressional Indosinian
Orogeny.

- by Ian Metcalfe
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- Vietnam, Conodonts, Permian, Permian-Triassic transition
- by Ladislav Slavik and +1
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- Pyrenees, Conodonts, Correlation, Zonation

The article presents new information concerning taxonomic composition of the biota of the Upper Devonian deposits of the River Sharyu. By studying a collection of conodonts and brachiopods the stratigraphic position of the section was clarified. The fauna propagation analysis revealed that the boundary between Frasnian and Famennian stages is opened twice in this outcrop. This fact is explained by complex tectonics of the Chernyshev swell.

- by Artem Plotitsyn
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- Stratigraphy, Conodonts, Brachiopods, Frasnian Fammenian Boundary

The present study reports upon the conodont fauna of the Upper Serpukhovian through Lower Moscovian of the Donets Basin, Ukraine. Three new species are described: Declinognathodus? pseudolateralis, Idiognathodus praedelicatus and Idiognathoides postsulcatus. The relatively continuous, rhythmic succession of shales, siltstones and sandstones, with limestone interlayers and coal seams contains a wide variety of fossils: foraminifers, conodonts, brachiopods, ostracods, corals, gastropods, ammonoids, crinoids, bivalves, bryozoans, plant remains etc. It is therefore the key or standard sec-tion for interregional and intercontinental correlations. Additionally, the Bashkirian Stage is signifi-cant in Late Carboniferous conodont evolution as during this interval all of the Late Carboniferous and Early Permian genera originated. At the Mid-Carboniferous boundary almost all of the Early Carboniferous conodont genera became extinct. The descendants of the Early Carboniferous genus Gnathodus a...

- by Tamara Nemyrovska
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- Western Europe, Eastern Europe, Southeast Asia, Biostratigraphy
- by Elena Sokiran and +1
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- Sea Level, Brachiopods (Biology), Conodonts, Primary Production

Diamictites occurring in the Raub area, Pahang are interpreted as an olisthostrome associated with normal faults which were active along the western margin of the developing central graben of Peninsular Malaysia. Conodonts fran clasts in the diamictite and fron bedded limestone matrix sugest a late Farly Triassic age for these deposits and penecontanporaneous erosion and redeposition of Permian and early Triassic sediments. The early Triassic conodonts fran Raub belong to the Tethys Province and suggest that Malaya was unlikely to have been marginal to Gondwana in the early Triassic.

- by Ian Metcalfe
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- Sedimentology, Malaysia, Biostratigraphy, Conodonts

Conodonts representative of the Lower, Middle and Upper Triassic are now known in the Malay Peninsula and all the Triassic Stages except the Rhaetian are represented. The best known sequence of Triassic conodonts occurs in the Kodiang Limestone of Kedah but there are still significant gaps in the known conodont succession. In particular, Griesbachian and Dienerian conodonts are poorly known and conodonts representative of the Upper Spathian, Lower Ladinian, Middle and Upper Norian and Rhaetian are unknown. New data from the Kodiang Limestone of Bukit Mulong and Bukit Kepelu help to fill some of these gaps in the Carnian and Norian conodont succession. The Chuping Limestone of Perlis has also recently yielded some Lower Norian conodonts which implies a correlation with the Kodiang Limestone to the south. Other recent discoveries include early Late Triassic (Lower Carnian) conodonts from the Chert Member of the Semanggol Formation, Kedah, Early Triassic (Spathian) conodonts from north-west Pahang and Early Triassic (upper Dienerian) and Middle Triassic (upper Anisian) conodonts from the Jerus Limestone, Cheroh, west Pahang.

- by Ian Metcalfe
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- Malaysia, Biostratigraphy, Conodonts, Triassic

Interbedded siltstones, mudstones and limestones of the "Raub Group" exposed at the Raub Gold Mine, Raub, Pahang have yielded the conodont Nagondolella rosenkrantzi (Bender & Stoppel) which indicates a Late Permian (either Guadalupian or Dzhulfian) age. The sedimentary rocks at the Raub Gold mine are tightly to isoclinally folded and comparison of the structural style with that of the Middle-Upper Triassic Semantan Formation suggests a structural discontinuity which may correspond to the age of suturing of the Sibumasu and East Malaya tectonic blocks.

- by Ian Metcalfe
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- Biostratigraphy, Gold Mineralization, Conodonts, Permian

Four new species of the conodont genus Hindeodus, Hindeodus eurypyge sp. nov., Hindeodus inflatus sp. nov., Hindeodus sp. nov. A and Hindeodus sp. nov. B, are described from the Permian-Triassic transition in South China. Our study confirms the first appearance of Hindeodus parvus at the GSSP level, base of Bed 27c at Meishan. However, at Shangsi the first occurrence of H. parvus is about 4.5 m above the event boundary. Analysis of conodont biostratigraphy of the Meishan D section and the Shangsi section suggest significant differences between the two sections. These include the absence of H. changxingensis Wang from the Shangsi section and the approximately 4.5 m of the Shangsi section that contains H. priscus (Kozur), H. latidentatus (Kozur) and H. eurypyge n.sp. below the first occurrence of H. parvus. These differences may be accounted for most easily by suggesting that there is a minor depositional hiatus at the Permian-Triassic boundary GSSP level as based on the first appearance of the conodont Hindeodus parvus in Meishan section D. Taxonomic re-evaluation of Hindeodus Pa elements indicates that species of the genus can be broadly separated into two groups based on the morphology of the posterior portion of the element and on growth patterns. The stable Pa element morphology of Hindeodus, first developed in the Carboniferous, was replaced by a complex of rapid evolutionary change in the latest Permian and Early Triassic with as many as 11 valid species of the genus in the Permian – Triassic boundary interval which are probably descendants of only two species, H. typicalis and H. n.sp. B. We suggest that the dramatic change in conodont biofacies observed at the P-T boundary in South China from Neogondolella-dominated faunas to Hindeodus-dominated faunas was caused by the introduction a high component of silt, beginning in bed 27 at Meishan and bed 28 at Shangsi, that tipped the environmental balance in favor of Hindeodus and Isarcicella over Neogondolella (Clarkina) species. We contend that Hindeodus species were adaptable to higher levels of turbidity than Neogondolella (Clarkina) species and hence at Meishan and Shangsi it was not a matter of a drastic increase in the abundance of Hindeodus, but an exclusion of Neogondolella.

- by Ian Metcalfe
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- Taxonomy, China, Conodonts, Permian Triassic Boundary
- by James Barrick
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- Conodonts, Permian, Texas

The Upper Devonian — Lower Carboniferous stratigraphic interval of the North of Urals and Urals Foredeep is promising for search of hydrocarbons and other mineral deposits. So urgent is the establishment of a detailed stratigraphic framework and the identification of levels with the high correlation potential. Conodont biostratigraphic boundaries (expansa, praesulcata, sulcata, duplicata, sandbergi, quadruplicata, and isosticha zones) and global events (Dasberg, Hangenberg, and Lower Alum Shale) in the Upper Famennian — Tournaisian of the North Urals and Chernyshev Swell (Kozhim River section, Syvyu River section, Izyael River section and Malaya Usa River section) are characterized. As a result the levels having the highest correlation potential (base of the sulcata Zone, base of the quadruplicata Zone, transgressive phases of the Hangenberg Event and Lower Alum Shale Event) are identified. Detailed studies of the distribution of conodonts in the Devonian-Carboniferous boundary interval revealed that taxa Polygnathus purus Voges and Pseudopolygnathus primus Branson et Mehl begin its spread on the level of the first appearance of Siphonodella sulcata (Huddle). Consequently, they are on a par with Siphonodella sulcata (Huddle) can determine the position of the boundary between the systems in the sections of the North Urals and Chernyshev Swell.

- by Artem Plotitsyn
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- Stratigraphy, Conodonts, Devonian-Carboniferous boundary, Urals

We describe a new Early Triassic (Griesbachian)
succession of conodont faunas from a high-resolution sampling
of the basal Early Triassic microbial limestone and the
base of the overlying unit at the Wuzhuan section (Nanpanjiang
Basin, Guangxi, South China). The microbial limestone
records the earliest phase of the Early Triassic biotic
recovery after the end-Permian mass extinction. For the first
time, rich conodont faunas are reported from within the microbialite.
The faunas from Wuzhuan are largely dominated
by anchignathodontids, including several Isarcicella species,
which were previously documented only from strata above
the microbialite. A total of 14 conodont species assigned to
three genera is recorded from the Wuzhuan section. Starting
from the base of the microbialite upwards, several species
are sequentially added to the conodont assemblage. The
alpha diversity peaks at the top of the microbialite. The
conodont record in the considered microbialite interval at
Wuzhuan is presumably unaffected by local ecological
changes. It therefore more likely represents an evolutionary
rather than an ecological pattern. We compare the Wuzhuan’s
conodont record with a well-supported phylogenetic
model and suggest that the sequence of first occurrences at
Wuzhuan is the closest to the ‘true’ sequence of evolutionary
events that took place during this Griesbachian radiation of
anchignathodontids. Based on comparisons with the GSSP
section at Meishan, we suggest further that the first occurrence
of Hindeodus parvus in Meishan does not correspond
to its first appearance datum.

- by Morgane Brosse and +2
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- Biostratigraphy, Conodonts, Microbialites, Permian Triassic Boundary
- by Ian Metcalfe
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- Biogeography, Paleoclimate, Conodonts, Gondwana
- by Fabio Marco Dalla Vecchia
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- Conodonts, Triassic, Epigondolella Slovakensis, Dolomia Di Forni
- by Valeri Sachanski
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- Geology, Paleontology, Stratigraphy, Palynology
- by Aymon Baud
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- Evolutionary Biology, Geology, Ecology, Biostratigraphy

Conodonts are a clade of chordates and are valuable indicator fossils for biostratigraphy. The segmini-planate (neogondolelliform) conodonts represent a major morphological group ranging from upper Carboniferous to Upper Triassic marine sediments. However, the morphological similarity of segminiplanate P 1 elements generates problems for taxonomy, especially in the Permian and Triassic clades. This paper represents the first study of morphological variation in Triassic segminiplanate conodonts using a geometric morphometric approach. The laminar microstructures observed in conodont cross-sections indicate that, within our analysed specimens, smaller conodonts with fewer laminae are generally from an earlier ontogenetic stage while larger conodonts with more laminae are from a later stage of onto-geny. Using linear regressions between relative warp scores from both upper and lateral views and conodont length, we demonstrate strongly allometric growth patterns for the species Paragondolella bifurcata Budurov & Stefanov. Our results indicate that the species-group taxon Pg. praeszaboi bystrickyi (Kovacs et al.) is an early growth stage of Pg. bifurcata and thus synonymous. We suggest that the allometry of con-odonts should be considered seriously, especially when there are numerous transitional morphologies between large-and small-sized conodonts. Reconstructing the ontogenetic series and using larger-sized conodonts within the numerous transitional morphologies in the population of a rock sample for the definition of new species are suggested for future studies.

- by Yanlong Chen and +1
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- Morphometrics, Geometric Morphometrics, Taxonomy, Conodonts
- by LUIS Sanchez de Posada
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- Evolutionary Biology, Geology, Taxonomy, Ecology
- by Robert Nicoll
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- Geology, Geochemistry, Geophysics, Taxonomy

The conodont color alteration index (CAI) was determined in elements from core samples of the Frasnian
Barreirinha Formation (one well) and of the PennsylvanianePermian Tapajos Group (twenty three wells
and one limestone quarry) in the Amazonas Basin. The thermal history of the basin is analyzed using the
CAI value distribution represented in maps and stratigraphic sections through correlation schemes, and
in conjunction with previously published data. The pattern of palaeotemperatures for CAI values of 1.5e3
is coincident with organic matter maturation under a sedimentary overburden providing diagenetic
conditions in the oil/gas window. Locally, conodonts show metamorphism (CAI value of 6e7) in relation
to the intrusion of diabase bodies in beds including high geothermal gradient evaporites. Microtextural
alteration on the surface conodonts commonly shows several types of overgrowth microtextures
developed in diagenetic conditions. Locally, recrystallization in conodonts with a high CAI value is
congruent with contact metamorphism in relation to Mesozoic intrusions. The CAI values of 1.5 or 2
observed close to the surface in several areas of the basin may be interpreted in relation to a high thermal
palaeogradient derived from the magmatic episode or/and to the local denudation of the upper part of
the Paleozoic succession prior to this thermal event.

- by valesca lemos and +1
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- Conodonts