Pragian
Second stage of the Devonian
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The Pragian is one of three faunal stages in the Early Devonian Epoch. It lasted from 413.02 ± 1.91 million years ago to 410.62 ± 1.95 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. It is named after the city of Prague.[7] The GSSP is located within the Prague Formation at Velká Chuchle, Prague.
| Pragian | |||||||||||||||||
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| Chronology | |||||||||||||||||
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| Etymology | |||||||||||||||||
| Name formality | Formal | ||||||||||||||||
| Name ratified | 1985[5] | ||||||||||||||||
| Usage information | |||||||||||||||||
| Celestial body | Earth | ||||||||||||||||
| Regional usage | Global (ICS) | ||||||||||||||||
| Time scale(s) used | ICS Time Scale | ||||||||||||||||
| Definition | |||||||||||||||||
| Chronological unit | Age | ||||||||||||||||
| Stratigraphic unit | Stage | ||||||||||||||||
| Time span formality | Formal | ||||||||||||||||
| Lower boundary definition | FAD of the conodonts Eognathodus sulcatus and Latericriodus steinachensis Morph beta | ||||||||||||||||
| Lower boundary GSSP | Velká Chuchle quarry, Prague, Czech Republic 50.0147°N 14.3726°E | ||||||||||||||||
| Lower GSSP ratified | 1989[5] | ||||||||||||||||
| Upper boundary definition | FAD of the conodont Polygnathus kitabicus | ||||||||||||||||
| Upper boundary GSSP | Zinzil'ban Gorge, Uzbekistan 39.2000°N 67.3056°E | ||||||||||||||||
| Upper GSSP ratified | 1995[6] | ||||||||||||||||
In North America the Pragian Stage is represented by Siegenian or Deerparkian time.
Pragian life
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.[8]
