Your ammonite probably is...

Metalegoceras

In overall form, Metalegoceras was relatively similar to Gastrioceras, but it had a much more complex suture line that was almost more like a ceratite than a goniatite. Metalegoceras lived in the Permian.

Public Domain, https://commons.wikimedia.org/wiki/File:Metalegoceras_sp_2_Permian_Timor_2.PNG