Description

About Neochetoceras steraspis Jurassic ammonite Neochetoceras steraspis

Physical Description

Neochertoceras steraspis is an small ammonite reaching to about 7 cm in diameter. It is preserved different than most other ammonites it is more 2D than 3D. It is believed that the animal inside an ammonite shell had many tentacles for grabing prey and motion. I’m saying this, as up till this day ,no soft tissue imprint of these tentacles has been found yet! Maybe soon, who knows. To protect it self it has a aptychus, two plates or lids so to say to close the entrance of its shell.

Age and Distribution

N. steraspis is from the Upper Jurassic of Germany. This ammonite lived approximately 150 million years ago. At the time this area was full of small athols and lagoons, which covered most what is now southern Germany. At this time it was nearer the equator. Neochertoceras steraspis co-inhabited the athols with one of the most famous animals of that time: the Archaeopteryx. Besides them flying overhead, there were also flying reptiles like: Pterodactylus, Rhamphorhynchus, Anurognathus and a few others. In the warm waters  one could encounter  marine reptiles like the Ichthyosaurus, Cricosaurus, fishes, sharks, cephalopods and crustaceans and many more. There are about 800 or so known fauna of the Solnhofen area.

About the Oppeliidae Jurassic ammonite Neochetoceras steraspis

Evolutionary Significance

The first ammonites can be found in Lower Devonian fossil beds. The Oppeliidae family members are found from the Middle Jurassic untill the Upper Cretaceous. Like all Ammonites they died out at / near the end of the Cretaceous period. Ammonites were more closely related to squid, octopuses and cuttlefishes than with a nautilus (which looks more like them)

Taxonomy

Neochertoceras steraspis belongs to the Streblitinae which is a subclass of the Oppeliidae ammonites. There are nine discribed sub families of Oppeliidae, of which others can be found in southern Germany.