Pragian

System/
Period		 Series/
Epoch		 Stage/
Age		 Age (Ma)
Carboniferous Mississippian Tournaisian younger
Devonian Upper/
Late		 Famennian 358.9 372.2
Frasnian 372.2 382.7
Middle Givetian 382.7 387.7
Eifelian 387.7 393.3
Lower/
Early		 Emsian 393.3 407.6
Pragian 407.6 410.8
Lochkovian 410.8 419.2
Silurian Pridoli no faunal stages defined older
Subdivision of the Devonian system
according to the ICS, as of 2017.[1]

The Pragian is one of three faunal stages in the Early Devonian epoch. It lasted from 411.2 ± 2.8 million years ago to 407 ± 2.8 million years ago. It was preceded by the Lochkovian stage and followed by the Emsian stage. The most important lagerstätte of the Pragian is Rhynie chert in Scotland.

In North America the Pragian Stage is represented by Siegenian or Deerparkian time.

Palaeontology

Ammonoidea

The first ammonoids (order Agoniatitida) appeared in later parts of this stage (at the lower boundary of the Zlichovian stage as it was known in Siberian representations). They were descended from bactritoid nautiloid ancestors, which also appeared in this stage before experiencing evolutionary radiations in the next stage.[2]

Agnathans

Agnathans of the Pragian
Taxa Presence Location Description Images
Lochkovian-Emsian Hunsrück Slate Formation, Germany among others in Europe
Lochkovian-Emsian Wayne Hereford Quarry, England & Podolia, Ukraine
Lochkovian-Emsian Britain & Belgium

References

  1. ↑ http://www.stratigraphy.org/index.php/ics-chart-timescale
  2. ↑ Kröger, Björn (2009). "Nautiloids before and during the origin of ammonoids in a Siluro-Devonian section in the Tafilalt, Anti-Atlas, Morocco". Special Papers in Palaeontology. 79. ISBN 978-1-405-18770-1.


This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.