Aptychopsid plates ‐ jaw elements or protective operculum

Publisher Website
Google Scholar
Abstract
The 3 plates characteristic of Aptychopsis have been described as a jaw apparatus in this orthocone cephalopod as well as an operculum for it. Due to the limited material, interpretations have in various cases been made from photographic illustrations and those results are discussed. The area of the aptychopsid plates is compared with the apertural area of the cephalopod and a great similarity is seen. Arguments for and against soft parts outside the aptychopsid plates are discussed as well as the position of the plates. Material from a Silurian shale in southern Sweden is described.