Nautilina
Encyclopedia
The Nautilina is the last suborder of the Nautilida
and the only nautiloids living since the end of the Triassic
. The Nautilina, proposed by Shimanskiy, is basically the Nautilaceae
of Kummel, 1964, defined by Furnish and Glenister, but differs in omitting two families, the Paracenoceratidae and Pseudonautilidae which instead are placed in the Liroceratina.
The Nautilina are derived from the Syringonautilidae
, a family in the Centroceratina (Trigonocerataceae), in the Late Triassic and consists of four families, the Nautilidae, Cymatoceratidae
, Herocoglossidae, and Aturiidae. The Nautilidae which is the root stock of the suborder includes the living Nautilus
The Nautilidae are involute or slightly evolute and generally smooth with straight to sinuous sutures. The Cymatoceratidae which are the most common of the Cretaceous nautiloids are strongly ribbed. The Hercoglossidae are smooth but with differentiated sutures, in some with deep lateral lobes and well-developed saddles. The Aturiidae (Aturia) is similar to the Hercoglossidae except for being more discoidal and having a more complex suture and subdorsal siphuncle.
The Nautilidae gave rise to the Cymatoceratidae and Hercoglossidae during the Jurassic while the Herocoglossidae became ancestral to the Aturiidae near the beginning of the Cenozoic. The Cymatoceratidae and Hercoglossidae became extinct near the end of the Paleogene while the Aturiidae reached into the Neogene. Only the Nautilidae remain.
Nautilida
The Nautilida constitute a large and diverse order of generally coiled nautiloid cephalopods that began in the mid Paleozoic and continues to the present with a single family, the Nautilidae which includes two genera, Nautilus and Allonautilus, with six species...
and the only nautiloids living since the end of the Triassic
Triassic
The Triassic is a geologic period and system that extends from about 250 to 200 Mya . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events...
. The Nautilina, proposed by Shimanskiy, is basically the Nautilaceae
Nautilaceae
The Nautilaceae is one of five superfamilies that make up the Nautilida according to Bernard Kummel , and the only one that survived past the Triassic. The Nautilaceae comprise six families: Nautilidae, Paracenoceratidae, Pseudonautilidae, Cymatoceratidae, Hercoglossidae, and Aturiidae...
of Kummel, 1964, defined by Furnish and Glenister, but differs in omitting two families, the Paracenoceratidae and Pseudonautilidae which instead are placed in the Liroceratina.
The Nautilina are derived from the Syringonautilidae
Syringonautilidae
The Syringonautilidae comprise the last of the Trigonocerataceae and are the source for the Nautilaceae which continued the Nautiloidea through the Mesozoic and into the Cenozoic right down to the recent. The Syringonautilidae, itself, is a strictly Triassic family, derived early in the Triassic...
, a family in the Centroceratina (Trigonocerataceae), in the Late Triassic and consists of four families, the Nautilidae, Cymatoceratidae
Cymatoceratidae
The Cymatoceratidae is a family of Mesozoic and early Cenozoic nautiloid cephalopods and the most abundant of this kind in the Cretaceous. They are characterized by ribbed, generally involute shells of varied form - coiled such that the outer whorl envelops the previous, as with Nautilus, and...
, Herocoglossidae, and Aturiidae. The Nautilidae which is the root stock of the suborder includes the living Nautilus
Nautilus
Nautilus is the common name of marine creatures of cephalopod family Nautilidae, the sole extant family of the superfamily Nautilaceae and of its smaller but near equal suborder, Nautilina. It comprises six living species in two genera, the type of which is the genus Nautilus...
The Nautilidae are involute or slightly evolute and generally smooth with straight to sinuous sutures. The Cymatoceratidae which are the most common of the Cretaceous nautiloids are strongly ribbed. The Hercoglossidae are smooth but with differentiated sutures, in some with deep lateral lobes and well-developed saddles. The Aturiidae (Aturia) is similar to the Hercoglossidae except for being more discoidal and having a more complex suture and subdorsal siphuncle.
The Nautilidae gave rise to the Cymatoceratidae and Hercoglossidae during the Jurassic while the Herocoglossidae became ancestral to the Aturiidae near the beginning of the Cenozoic. The Cymatoceratidae and Hercoglossidae became extinct near the end of the Paleogene while the Aturiidae reached into the Neogene. Only the Nautilidae remain.