Search results
Results From The WOW.Com Content Network
Furthermore, unlike the extinct ammonoids, the modern nautilus lacks an aptychus, a biomineralized plate which is proposed to act as an operculum which closes the shell to protect the body. However, aptychus-like plates are known from some extinct nautiloids, and they may be homologous to the fleshy hood of a modern nautilus. [3]
Nautiloids were much more extensive and varied 200 million years ago. The ancestors of all Coleoidea (shell-less Cephalopods) once possessed shells, and many early cephalopod species are only known from shell remains. Following the K-Pg extinction event most nautiloid species went extinct, while members of Coleoidea managed to survive ...
Eridites is an extinct genus of prehistoric nautiloids. The nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species. The nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.
The idea that the Nautilida evolved from straight-shelled ("Orthoceras") nautiloids, as proposed by Otto Schindewolf in 1942, through transitional forms such as the Ordovician Lituites can be rejected out of hand as evolutionarily unlikely. Lituites and the Lituitidae are derived tarphycerids and belong to a separate evolutionary branch of ...
Askeatonolucidum is an extinct genus of prehistoric nautiloids. The nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.
Cyrthoceratites is an extinct genus of prehistoric nautiloids. The nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.
Gyroceras is an extinct genus of prehistoric nautiloids. The nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species. The nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.
Metrioceras is an extinct genus of prehistoric nautiloids. The nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.