Baltoniodus

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Baltoniodus
Temporal range: Dapingian–Sandbian
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Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Class: Conodonta
Family: Balognathidae
Genus: Baltoniodus
Lindström, 1971 [1]
Species
  • Baltoniodus alobatus
  • Baltoniodus cooperi
  • Baltoniodus gerdae
  • Baltoniodus medius
  • Baltoniodus navis
  • Baltoniodus norrlandicus
  • Baltoniodus prevariabilis
  • Baltoniodus triangularis
  • Baltoniodus variabilis

Baltoniodus is an extinct genus of conodonts.

Use in stratigraphy

The base of the Dapingian, the third stage of the Middle Ordovician, is defined as the first appearance of Baltoniodus triangularis.

Contents

The Whiterock Stage refers mainly to the early Middle Ordovician in North America, it is often used in the older literature in a global sense. The Whiterock Stage is given a range from 471.8 (ca. 472) to 462 m.y.a., spanning close to 10 million years. Officially its start is defined by the potentially lowest occurrence of the conodont Protoprioniodus aranda or Baltoniodus triangularis.

B. gerdae has been found in the early Sandbian Bromide Formation, in Oklahoma, USA.

Related Research Articles

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The Tremadocian is the lowest stage of Ordovician. Together with the later Floian stage it forms the Lower Ordovician epoch. The Tremadocian lasted from 485.4 to 477.7 million years ago. The base of the Tremadocian is defined as the first appearance of the conodont species Iapetognathus fluctivagus at the Global Boundary Stratotype Section and Point (GSSP) section on Newfoundland.

The Furongian is the fourth and final series of the Cambrian. It lasted from 497 to 485.4 million years ago. It succeeds the Miaolingian series of the Cambrian and precedes the Lower Ordovician Tremadocian stage. It is subdivided into three stages: the Paibian, Jiangshanian and the unnamed 10th stage of the Cambrian.

The Darriwilian is the upper stage of the Middle Ordovician. It is preceded by the Dapingian and succeeded by the Upper Ordovician Sandbian stage. The lower boundary of the Darriwilian is defined as the first appearance of the graptolite species Undulograptus austrodentatus around 467.3 million years ago. It lasted for about 8.9 million years until the beginning of the Sandbian around 458.4 million years ago.

In the geological timescale, the Llandovery epoch occurred at the beginning of the Silurian period. The Llandoverian epoch follows the massive Ordovician-Silurian extinction events, which led to a large decrease in biodiversity and an opening up of ecosystems.

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The Canadian is the Lower or Early Ordovician in North America. The term is common in the older literature and has been well understood for more than a century. However it has no official recognition by the International Commission on Stratigraphy (ICS) and has been superseded by the more recently defined Ibexian series of western Utah.

The Dapingian is the third stage of the Ordovician and the first stage of the Middle Ordovician. It is preceded by the Floian and succeeded by the Darriwilian. The top of the Floian is defined as the first appearance of the conodont species Baltoniodus triangularis which happened about 470 million years ago. The Dapingian lasted for about 2.7 million years until about 467.3 million years ago.

The Whiterockian, often referred to simply as the Whiterock, is an earliest or lowermost stage of the Middle Ordovician. Although the Whiterockian or Whiterock Stage refers mainly to the early Middle Ordovician in North America, it is often used in the older literature in a global sense.

Periodon is a genus of conodonts which existed in what is now Canada, Iran, Argentina, China, Russia, and the United States during the Ordovician Period. It was described by Hadding in 1913, and the type species is P. aculeatus.

Westergaardodina is a species-rich genus of spine, U or W-shaped paraconodont known from Middle Cambrian to Lower Ordovician strata.

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Appalachignathus is a genus of multielement conodonts from the Middle Ordovician of North America.

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Microzarkodina is an extinct genus of conodonts mainly from the Middle Ordovician of Baltoscandia. 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.

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References

  1. Vom Anfang, Hochstand und Ende eines Epikontinentalmeeres. Maurits Lindström, Geologische Rundschau, March 1971, Volume 60, Issue 2, pages 419-438, doi:10.1007/BF02000464