Liroceratidae is an extinct family of nautilids

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...

, shelled marine molluscs

Siphuncle

The siphuncle is a strand of tissue passing longitudinally through the shell of a cephalopod mollusk. Only cephalopods with chambered shells have siphuncles, such as the extinct ammonites and belemnites, and the living nautiluses, cuttlefish, and Spirula...

, belonging to the Clydonautilaceae

Clydonautilaceae

The Clydonautilaceae is a superfamily within the nautiloid order Nautilida characterized by smooth, generally globular, shells with nearly straight sutures, in early forms but developing highly differentiated sutures in some later forms...

, consisting of generally smooth, involute, nautiliconic forms with a small umbilicus. The whorl section is usually depressed and broadly rounded, the suture only slightly sinuous, and the siphuncle

Siphuncle

The siphuncle is a strand of tissue passing longitudinally through the shell of a cephalopod mollusk. Only cephalopods with chambered shells have siphuncles, such as the extinct ammonites and belemnites, and the living nautiluses, cuttlefish, and Spirula...

 usually more or less central.

The Liroceratidae range from the Mississippian well into the Triassic and may even extend down into the upper Devonian.

The Liroceratidae are probably derived from the Rutoceratidae

Rutoceratidae

The Rutoceratidae are the prototypical nautilids, derived probably from either the Brevicoceratidae or Acleistoceratidae of the Oncocerida early in the Devonian...

 and form the root stock of the Clydonautilaceae. They also provide the basis for the name for Shimankiy's Lirocerina, a suborder mostly equivalent to the Clydonautilaceae. The Liroceratidae gave rise to the Ephippioceratidae

Ephippioceratidae

Ephippioceratidae is a family of clydonatilacean nautilids with shells as in the Liroceratidae but with sutures that have deep ventral and dorsal saddles...

 early in the Mississippian, which extend well into the Permian, and to the Clydonautilidae

Clydonautilidae

The Clydonautilidae are Middle and Upper Triassic nautiloid cephalopods, which are derivatives of the clydonautlicean family Liroceratidae, that have generally smooth, involute, globular to compressed shells, characterized by a suture with prominent lobes and saddles...

, Gonionautilidae

Gonionautilidae

Gonionautilidae is a family in the nautilid superfamily Clydonautiliaceae that contains only the genus Gonionautilus, known from the Upper Triassic of Europe and North America....

, and Siberionautilidae

Siberionautilidae

Siberionautilidae is a family in the nautilid superfamily Clydonautilaceae that contains only the genus Siberionautilus, which comes from the Upper Triassic of Siberia, Russia....

in the Triassic.

References

• Bernhard Kummel, 1964. Nautiloidea -Nautilida; Treatise on Invertebrate Paleontology, Part K. Geol Soc of America and Univ of Kansas press, R.C. Moore (ed) -- Liroceratidae K444 -K447.
• J. Tuck, R Mapes, & S. Arnoff, 1978. New Coiled Nautiloids from the Wewok Formation (Pennsylvanian) of Oklahoma. Jour Paleo V.52, N.1, pp67–72. Jan. 1978