The belemnites are a diverse order of widespread cephalopod mollusks from the Late Triassic-Late Cretaceous of the entire world. They, as a whole, were named in 1895 by Karl Alfred von Zittel. They were very similar to modern squid and cuttlefish; however, they also had some unique traits.
Physiology[]
Belemnites were very similar to modern squid, with mid-sized tentacles, large eyes, a small, keratinous beak hiding between their circular rows of tentacles, and a long, finned body held together by a large mantle (or guard, in this case). However, they did have a few differences; they lacked the specialized arms present in modern squid, having hooks on their tentacles instead. Their bodies would have been covered in smooth skin.
Diet[]
Belemnites were predators, feeding on fish and crustaceans. Their tentacles would have been used to get a hold of struggling prey, while their beaks would have been used to crush them and tear them into pieces.
Belemnite genera (note that those are not all the ones that exist)[]
Belemnotheutis[]
Belemnotheutis is a belemnotheutid belemnite from the Middle-Late Jurassic of the United Kingdom, Poland, and Germany. It was named in 1842 by Joseph Chaning Pearce. It lived the generic belemnite lifestyle, swimming around in large groups and catching fish with their hooked tentacles; as well as this, it often serves as an index fossil for the Jurassic, similar to Perisphinctes.
Acanthoteuthis[]
Acanthoteuthis is a belemnotheutid belemnite from the Late Jurassic-Early Cretaceous of Germany. It was named in 1839 by Richard Wagner and Georg zu Munster. Due to having cartilaginous and muscular support systems that strengthened the connection between the head and the mantle, it would have been a very fast swimmer.
Belemnitella[]
Belemnitella is a belemnitellid belemnite from the Late Cretaceous of the United States of America, Germany, the Netherlands, Belgium, Russia, Sweden, Denmark, and Bulgaria. It was named in 1840 by Alcide d'Orbigny. It was one of the latest surviving belemnites (since the belemnites started to decline after the Early Cretaceous); as well as this, it lived the generic belemnite lifestyle.