This large aptychi was found on the beach at Lyme Regis in 2024 and most likely comes from a large arnioceras ammonite. It isn’t certain exactly what the function of aptychi were in ammonites, but the two leading theories is that this is either the jaw apparatus (mandibles) of the ammonite, or an ‘opercula’ - a structure which closes the aperture of the ammonite in order to protect the ammonite inside it’s shell. Aptychi this size and preservation are rare and provide a good insight into the lives of ammonites in the jurassic oceans and how they might have behaved. The piece has a cut-base so it can be displayed without the need of a stand.
Approximately 195 million years old.
Fossil dimensions: 18mm across at widest point.
Rock dimensions: 40mm x 40mm
This large aptychi was found on the beach at Lyme Regis in 2024 and most likely comes from a large arnioceras ammonite. It isn’t certain exactly what the function of aptychi were in ammonites, but the two leading theories is that this is either the jaw apparatus (mandibles) of the ammonite, or an ‘opercula’ - a structure which closes the aperture of the ammonite in order to protect the ammonite inside it’s shell. Aptychi this size and preservation are rare and provide a good insight into the lives of ammonites in the jurassic oceans and how they might have behaved. The piece has a cut-base so it can be displayed without the need of a stand.
Approximately 195 million years old.
Fossil dimensions: 18mm across at widest point.
Rock dimensions: 40mm x 40mm
