Search results for "Conodont"
showing 10 items of 44 documents
Morphologic variation in the P1 element of Mississippian species of the conodont genus Pseudognathodus
2018
A revision of the Austin Conodont Collection at the Natural History Museum, London, has revealed a diverse assemblage of P1 elements of Pseudognathodus . Pseudognathodus homopunctatus, Ps. lineatus, Ps. mermaidus and Ps. symmutatus are di?erentiated and a new species, Ps. posadachaconae , is de?ned from material from North Wales. The systematic of these species is updated. A revised diagnosis is provided for the genus Pseudognathodus , as well as for the species Ps. lineatus and Ps. symmutatus . The types of Ps. symmutatus cannot be differentiated from immature specimens of Ps. homopunctatus . The evolutionary relationships of Pseudognathodus species are discussed. Stratigraphic distributio…
New biostratigraphic data from the Ladinian pelagic limestones of Pizzo di Sant’Otiero - Madonie Mountains, Sicily
2014
New biostratigraphic data, based on conodont investigations, were collected from the Ladinian limestones recently described at Sant’Otiero, a locality near the Village of Petralia Sottana in the Madonie Mountains (Central-Northern Sicily). At this locality a new calcareous succession lying at the base of a major tectonic unit of the Maghrebian chain is described. This succession consists of a lower massive part formed by a carbonate megabreccia, the elements of which are shallow water extraclasts with dasycladalean algae (Diplopora annulatissima Pia), benthic foraminifers, “Tubiphytes” and problematic organisms commonly described from Anisian carbonate platforms. Upward a well-bedded succes…
Middle Triassic conodont apparatus architecture revealed by synchrotron X-ray microtomography
2018
Abstract The composition of conodont apparatuses is crucial for understanding the feeding mechanisms of these early vertebrates. However, the multielement apparatus reconstructions of most species remain equivocal because they have been inferred from loose element collections, guided by knowledge from rare articulated ‘bedding plane assemblages’ and fused clusters, often from distantly related taxa. Even these natural assemblages can be difficult to interpret because the component elements can be closely juxtaposed or embedded in matrix, making it hard to discern the morphology of each element and their relative positions within the architecture of the feeding apparatus. Here we report five…
A database of Triassic conodonts from a comprehensive revisión of literature
2013
The revision of a comprehensive amount of bibliography has made possible the development of a database containing the stratigraphic ranges of the conodont species from the uppermost Permian and the Triassic, with a total of 336 species in 52 genera. This database is aimed at biostratigraphy and studies related to biological, evolutional and palaeodiversity dynamics. La revisión de una amplia cantidad de bibliografía ha hecho posible el desarrollo de una base de datos en la que figuran los rangos estratigráficos de las especies de conodontos presentes desde el Pérmico superior y el Triásico, con un total de 336 especies y 52 géneros. Esta base de datos está dirigida a la bioestratigrafía y a…
New insights into the diversity dynamics of Triassic conodonts
2013
International audience; In this paper, we examine the diversity trends and the evolutionary patterns of Triassic conodonts through a newly powered large-scale data-set compiled directly from the primary literature. Paleodiversity dynamics analyses have been undertaken by working at the species level and using a system of time units based on biozone subdivisions for a fine temporal level resolution. The role of heterogeneous duration of taxa in diversity estimates has been evaluated through the probabilistic profiles. Results reveal three different stages in the diversity behaviour of Triassic conodonts from standing metrics delimited by two inflections at the mid-Anisian and mid-Carnian. Su…
Middle Triassic conodonts from northeastern Spain: biostratigraphic implications
2000
The facies development of the Spanish Triassic corresponds to the typical three-fold subdivision of the Germanic Facies: Buntsandstein, Muschelkalk and Keuper. Two intervals interpreted as epeiric carbonate platforms: lower Muschelkalk (Anisian) and upper Muschelkalk (Ladinian) are recognized during the Middle Triassic of northeastern Spain. These carbonate intervals are separated by one siliciclastic/evaporitic interval interpreted as sabbkha and saline deposits: middle Muschelkalk facies (Lower Ladinian). In northeastern Spain (Catalonian Coastal Ranges), two Middle Triassic sections comprising lower Muschelkalk facies have yielded the following conodont taxa: Paragondolella bulgarica, P.…
On the ontogeny and orientation of the Triassic Conodont P1-element in Pseudofurnishius murcianus Van den Boogaard, 1966
2010
Successive growth stages of P1-elements in the Middle to early Late Triassic species Pseudofurnishius murcianus allows the observation of a detailed ontogeny. Besides the gradual enlargement of its curved blade and the growing number of its denticles, a small internal platform develops, eventually followed by an external one, both bearing denticles. The number of denticles on the blade and internal platform increases from five and one in the smallest specimens, respectively, to 14 and 9 in fully developed ones, whereby the distribution pattern of platform-denticles, on the inner one in particular, is of great morphological variety. For the orientation of the P1-element of P. murcianus, the …
Upper Givetian and Frasnian (Middle and Upper Devonian) conodonts from Ampriú (Aragonian Pyrenees, Spain): global correlations and palaeogeographic r…
2012
This report describes for the first time a part of the Middle and Upper Devonian conodont sequence of the Sierra Negra Subfacies in the Aragonian Pyrenees (Spain), establishing the basis for further sound correlations both across the distinct Pyrenean facies and subfacies and on other relevant world areas. The description of 20 conodont taxa and their stratigraphical distribution permits recognition of two separate time intervals. The older one corresponds to the lower Upper Givetian (Middle Devonian), hermanni to crista- tus ectypus zones. The younger interval is uppermost Lower Frasnian to lower Middle Frasnian (Upper Devonian) and is equivalent to MN4-MN6 zones. The combination of litho-…
A long-snouted late Eifelian arthrodire from Aragon (Spain)
2021
Carolowilhelmina geognostica Carls, 1995 is a large arthrodire (Placodermi) from the Tortodus kockelianus Conodont Zone, late Eifelian, in the Eastern Iberian Cordillera in southern Aragon. The somewhat incomplete but articulated skull is preserved, showing a long tubular rostral plate, very small postnasal plates, low toothless inferognathals, and a small, slender and flat parasphenoid. Supraorbital and central sensory lines meet their antimeres at the midline of the skull, forming a straight double line. Lines along the ventral surface of the rostral plate probably belong to the suborbital branches of the infraorbital sensory lines. The combination of characters of Carolowilhelmina points…
Magnetostratigraphy and biostratigraphy of the Carnian/Norian boundary interval from the Pizzo Mondello section (Sicani Mountains, Sicily)
2001
The 146.5 m-thick Upper Triassic limestone section at Pizzo Mondello in the Sicani Mountains of western Sicily is characterized by high quality of exposure, accessibility, and stratigraphic continuity. Magnetostratigraphic results delineate 12 normal and reverse polarity magnetozones, labelled successively from the base upwards as PM1n, PM1r, PM6n, PM6r. The Carnian/Norian boundary, based on conodont biostratigraphy, falls somewhere in the PM3n to PM5n interval which corresponds to the E14n to E16n magnetozone interval in the Newark reference sequence of polarity reversals. Comparison of magnetobiostratigraphic data from the Newark basin, Pizzo Mondello and other Late Triassic marine sectio…