Fossil ammonite

Fossil ammonite
Simbirskites nepaulensis

Ammonites were a type of marine cephalopod mollusc, a group that today includes octopuses, cuttlefish and squid. They first appeared in the Devonian period, over 400 million years ago, and were widespread in the Mesozoic era until their extinction at the end of the Cretaceous period about 66 million years ago. Many other life forms also became extinct at this time, including the non-avian (or non-bird) dinosaurs.

Upper Jurassic, 163–145 million years ago, Papua New Guinea