Parapuzosia seppenradensis is the largest known species of ammonite.

[1] It lived during the Lower Campanian Epoch of the Late Cretaceous period, in marine environments in what is now Westphalia, Germany.

A specimen, found in Seppenrade near Lüdinghausen, Germany in 1895 measures 1.8 m (5.9 ft) in diameter, although the living chamber is incomplete.

The original fossil is shown in the foyer of the Westphalian Museum of Natural History, Münster, Germany.

[3] However, a study in 2021 estimated the diameter of the largest specimens to be around 2 m (6.6 ft).