Pragian

The Pragian is one of three faunal stages in the Early Devonian Epoch. It lasted from 410.8 ± 2.8 million years ago to 407.6 ± 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. It is named after the city of Prague.^[7] The GSSP is located within the Prague Formation at Velká Chuchle, Prague.

Pragian
410.8 ± 2.8 – 407.6 ± 2.6 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Chronology
−420 — – −415 — – −410 — – −405 — – −400 — – −395 — – −390 — – −385 — – −380 — – −375 — – −370 — – −365 — – −360 — – Paleozoic S Devonian C M Přídolí Early Mid Late EM Lochkovian Pragian Emsian Eifelian Givetian Frasnian Famennian Tournai.           ← Rhynie chert^[1] ← Hangenberg event, Famennian glaciation ← Kellwasser event (Late Devonian extinction)^[2] ← Widespread^[3] shrubs & trees ← Hunsrück fauna Subdivision of the Devonian according to the ICS, as of 2021.^[4] Vertical axis scale: millions of years ago.
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°00′53″N 14°22′21″E / 50.0147°N 14.3726°E / 50.0147; 14.3726
Lower GSSP ratified	1989^[5]
Upper boundary definition	FAD of the conodont Polygnathus kitabicus
Upper boundary GSSP	Zinzil'ban Gorge, Uzbekistan 39°12′00″N 67°18′20″E / 39.2000°N 67.3056°E / 39.2000; 67.3056
Upper GSSP ratified	1995^[6]

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

Pragian life

Main page: Category: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]

References

1. Parry, S. F.; Noble, S. R.; Crowley, Q. G.; Wellman, C. H. (2011). "A high-precision U–Pb age constraint on the Rhynie Chert Konservat-Lagerstätte: time scale and other implications". Journal of the Geological Society. London: Geological Society. 168 (4): 863–872. doi:10.1144/0016-76492010-043.
2. Kaufmann, B.; Trapp, E.; Mezger, K. (2004). "The numerical age of the Upper Frasnian (Upper Devonian) Kellwasser horizons: A new U-Pb zircon date from Steinbruch Schmidt(Kellerwald, Germany)". The Journal of Geology. 112 (4): 495–501. Bibcode:2004JG....112..495K. doi:10.1086/421077.
3. Algeo, T. J. (1998). "Terrestrial-marine teleconnections in the Devonian: links between the evolution of land plants, weathering processes, and marine anoxic events". Philosophical Transactions of the Royal Society B: Biological Sciences. 353 (1365): 113–130. doi:10.1098/rstb.1998.0195.
4. "Chart/Time Scale". www.stratigraphy.org. International Commission on Stratigraphy.
5. Chlupac, Ivo; Oliver, William (June 1989). "Decision on the Lochkovian-Pragian Boundary Stratotype (Lower Devonian)" (PDF). Episodes. 12 (2): 109–114. doi:10.18814/epiiugs/1989/v12i2/014. Retrieved 18 December 2020.
6. Yolkin, E.; Kim, A.; Weddige, K.; Talent, J.; House, M. (December 1997). "Definition of the Pragian/Emsian Stage boundary". Episodes. 20 (4): 235–240. doi:10.18814/epiiugs/1997/v20i4/005. Retrieved 18 December 2020.
7. "Pragian stage". Encyclopedia Britannica. Retrieved 2 October 2019.
8. 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.