Nautiloids are a group of marine cephalopods (Mollusca) which originated in the Late Cambrian and are represented today by the living Nautilus and Allonautilus...

is the long, cone-shaped shell belonging to several species of ancient nautiloid cephalopod—the prehistoric ancestors of today's marine cephalopod mollusks...

coleoids (i.e., octopuses, squid and cuttlefish) than they are to shelled nautiloids (such as the living Nautilus). The earliest ammonoids appeared during...

Orthoceras is a genus of extinct nautiloid cephalopod restricted to Middle Ordovician-aged marine limestones of the Baltic States and Sweden. This genus...

chambers enclosed between two adjacent septa in the phragmocone of a nautiloid or ammonoid cephalopod molluscus. These can be seen in cross-sections...

Multiceratoidea is a major subclass or superorder of Paleozoic nautiloid cephalopods. Members of this group can be characterized by nautilosiphonate connecting...

became dominant during the Ordovician period, represented by primitive nautiloids. The class now contains two, only distantly related, extant subclasses:...

This list of nautiloids is a comprehensive listing of all genera that have ever been included in the subclass Nautiloidea, excluding purely vernacular...

be the upper surface. All cephalopods with external shells except the nautiloids became extinct by the end of the Cretaceous period 65 million years ago...

Ward, P.D. & W.B. Saunders 1997. Allonautilus: a new genus of living nautiloid cephalopod and its bearing on phylogeny of the Nautilida. Journal of Paleontology...