Perisphinctes

Perisphinctes is an extinct genus of ammonite cephalopod. They lived during the Jurassic Period and serve as an index fossil for that time period.[3]

The Perisphinctes boweni ammonite was named after the English chemist and geologist E. J. Bowen (1898–1980).

Distribution
Shells of species belonging to this genus have been found in the Jurassic of Antarctica, Argentina, Cuba, Ethiopia, France, Germany, India, Iran, Italy, Madagascar, Poland, Portugal, Russia, Saudi Arabia, Spain, Switzerland, the United Kingdom and Yemen.