Parapuzosia

Parapuzosia seppenradensis is the largest known species of ammonite. It lived during the Lower Cretaceous, in marine environments in what is now Germany. 
A specimen found in Germany in 1895 measures in diameter. The front chamber where the animal lived is damaged. Presumably, a large predator bit the end off and the living ammonite taken with it. Almost all ammonite fossils have this damage to the 'living chamber'.
If complete, this specimen would have had a diameter of about or even . The total live mass has been estimated at , of which the shell would be about .