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.
In North America the Pragian Stage is represented by Siegenian or Deerparkian time.Ammonoidea
The first ammonoids appeared in later parts of this stage. They were descended from bactritoid nautiloid ancestors, which also appeared in this stage before experiencing evolutionary radiations in the next stage.Agnathans
