|Belemnites photo by Wilson44691, Mark A. Wilson|
(Department of Geology, The College of Wooster),
donated to public domain
Belemnites appeared during the late Triassic but proliferated in the Jurassic. Since they survived the major extinction at the end of the Triassic, and because they were likely important elements in the marine food chain, the evolution of belemnites may be related to the evolution of marine reptiles too. When numbers of prey expand, that can help the numbers of predators expand as well.
Although belemnites looked very much like modern squids, fossils that preserve their soft parts do reveal some differences. They did have ten grasping arms like modern squids, but they did not have the pair of specialized tentacles modern squids have. Belemnites went extinct at the end of the Cretaceous.
|Eryon photo by Didier Descouens,|
used under Creative Commons license
—Richard I. Gibson
Late Triassic belemnites
Eryon photo by Didier Descouens, used under Creative Commons license
Belemnites photo by Wilson44691, Mark A. Wilson (Department of Geology, The College of Wooster), donated to public domain