Tetrapleuroceras is an extinct prehistoric nautiloid from the Lower Permian

Permian

The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...

 of the Urals in Russia.

Tetrapleuroceras is one of two genera that Shimianky combined as the Neptunoceratidae in 1957, the other being Neptunoceras

Neptunoceras

Neptunoceras is an extinct genus of prehistoric nautiloid. The nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.-References:...

. The Neptunoceratidae, according the Rousseau Flower (1963) is doubtfully distinct from the Scyphoceratidae, a family from the Lower Permian included in the Aipocerataceae

Aipocerataceae

The Aipocerataceae is a superfamily within the Order Nautilida characterized by rapidly expanding, smooth to ribbed, cyrtoconic to coiled shells with rounded or sometimes dorsally flattened or impressed whorls, nearly straight sutures, and a ventral and marginal siphuncle. Septal necks are...

.(Kummel 1964.

The Scyphoceratidae, to which Tetrapleuroceras is assigned (Flower 1963) are cyrtoconic or possibly loosely coiled nautilids with smooth or ribbed shell, generally short phragmocone

Phragmocone

The phragmocone is the chambered portion of the shell of a cephalopod. It is divided by septa into camerae.In most nautiloids and ammonoids, the phragmocone is a long, straight, curved, or coiled structure, in which the camarae are linked by a siphuncle which determines buoyancy by means of gas...

s, and slightly expanded 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...

 segments. Nautilids are a type of nautiloid, a subclass of shelled cephalopods that were once diverse and numerous but now represented by only general 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...

and Allonautilus

Allonautilus

The genus Allonautilus contains two species of nautiluses, which differ significantly in terms of morphology from those placed in the sister taxon Nautilus. Allonautilus is now thought to be a descendant of Nautilus and the latter paraphyletic.-External links:*...

See also

• Nautiloid
  Nautiloid
  Nautiloids are a large and diverse group of marine cephalopods belonging to the subclass Nautiloidea that began in the Late Cambrian and are represented today by the living Nautilus. Nautiloids flourished during the early Paleozoic era, where they constituted the main predatory animals, and...
  
  
• List of nautiloids