The Nautilaceae form one of five superfamilies that make up the

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 ''Allonauti ...

according to Bernard Kummel (1964), and the only one that survived past the

Triassic The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period ...

. The Nautilaceae comprise six families:

Nautilidae The nautilus (, ) is a pelagic marine mollusc of the cephalopod family Nautilidae. The nautilus is the sole extant family of the superfamily Nautilaceae and of its smaller but near equal suborder, Nautilina. It comprises six living species ...

Paracenoceratidae The Paracenoceratidae are an extinct family of prehistoric nautiloids. The cephalopods lived during the Jurassic and Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the thi ...

, Pseudonautilidae, Cymatoceratidae,

Hercoglossidae Hercoglossidae is a family of Nautilid in the superfamily Nautilaceae. It was established by Spath in 1927 for smooth, involute nautiloids characterized by a suture with differentiated elements, known from the Upper Jurassic to the Oligocene. ...

, and Aturiidae. Shimanskiy (1957) separated the Paracenoceratidae and Pseudonautilidae from his near equivalent

Nautilina 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 ...

and added them to the Lyroceratina, expanding the equivalent Clydonautilaceae and bringing it into the Jurassic. The Nautilaceae are represented by ''

Nautilus The nautilus (, ) is a pelagic marine mollusc of the cephalopod family Nautilidae. The nautilus is the sole extant family of the superfamily Nautilaceae and of its smaller but near equal suborder, Nautilina. It comprises six living species in t ...

'' and ''

Allonautilus The genus ''Allonautilus'' contains two species of nautiluses, which have a significantly different morphology from those placed in the sister taxon ''Nautilus''. ''Allonautilus'' is now thought to be a descendant of ''Nautilus'', rendering the l ...

'', genera included in the Nautilidae. Species in the Nautilaceae are generally smooth and involute with straight to strongly sinuous sutures and a small siphuncle. Some groups have sinuous plications or ribs. The Nautilaceae began in the Late Triassic with '' Cenoceras'', a globular to discoidal genus derived from the Syringonautilidae and possibly from '' Syringonautilus''. ''Cenoceras'', the earliest member of the Nautilaceae and Nautilidae, is the only nautiloid known to have crossed the upper Triassic boundary and the only one known from the Lower Jurassic. All six families of the Nautilaceae, except for the Aturiidae (''Aturia''), are derived from the ''Cenoceras'' complex in the Middle Jurassic or from ''

Eutrephoceras ''Eutrephoceras'' is an extinct genus of nautilus from the Late Jurassic to the Miocene (around 161 to 5 million years ago). They are characterized by a highly rounded involute shell with slightly sinuous suture patterns. Description ''Eutrep ...

'' which immediately followed. The Cenozoic '' Aturia'' seems sufficiently derived to warrant familial distinction from its source, the Hercoglossidae.

References

*Kummel B. 1964. Nautiloidea-Nautilida; Treatise on Invertebrate Paleontology Part K, Teichert & Moore (eds) Geological Society of America and University of Kansas Press. {{Taxonbar, from=Q16986221 Nautiloids Mollusc superfamilies Extant Late Triassic first appearances