Your ammonite probably is...

Kosmoceras

Kosmoceras had lots of radial ribs along its flanks. It had a flat, narrow venter and probably was a deep-water swimmer. It lived in the Mid Jurassic and is found worldwide. Some specimens have a long spine protruding from the aperture.

CC0, https://commons.wikimedia.org/wiki/File:Kosmoceras_jason_-_Naturhistorisches_Museum,_Braunschweig,_Germany_-_DSC05122.JPG