Porcellioidea is an extinct superfamily

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 of small to large sea snail

Snail

Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...

s, marine

Marine (ocean)

Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...

 gastropod mollusks in the clade Vetigastropoda

Vetigastropoda

Vetigastropoda is a major taxonomic group of sea snails, marine gastropod mollusks that form a very ancient lineage. Taxonomically Vetigastropoda are sometimes treated as an order although they are a clade in Bouchet and Rocroi, 2005....

.

This superfamily dates back to the Paleozoic

Paleozoic

The Paleozoic era is the earliest of three geologic eras of the Phanerozoic eon, spanning from roughly...

. They developed sinistrally (left-handed) or planispirally coiled teleoconchs

Gastropod shell

The gastropod shell is a shell which is part of the body of a gastropod or snail, one kind of mollusc. The gastropod shell is an external skeleton or exoskeleton, which serves not only for muscle attachment, but also for protection from predators and from mechanical damage...

.

Taxonomy

Bouchet & Rocroi based their classification on the study by Bandel, published in 1993. However, the position of the Porcelliidae is unsure, as noted by Peter J. Wagner

Peter J. Wagner

Peter J. Wagner is a paleontologist and curator at the Smithsonian Institution. He received his Ph.D. in Geophysical Sciences from The University of Chicago in 1995, conducted postdoctoral research at the Smithsonian Institution, and served as a curator at the Field Museum of Natural History from...

 in 2002. He has shown that Porcelliidae belongs to the subfamily Gosseletininae of the family Gosseletinidae

Gosseletinidae

Gosseletinidae is an extinct family of sea snails, marine gastropod molluscs in the clade Vetigastropoda .- Genera :Genera within the family Glosseletinidae include: * Balbinipleura...

 in the superfamily Eotomarioidea

Eotomarioidea

Eotomarioidea is an extinct superfamily of small to large sea snails, marine gastropod mollusks in the clade Vetigastropoda.-Taxonomy :* † Family Eotomariidae Wenz, 1938 * † Family Gosseletinidae Wenz, 1938 * † Family Luciellidae Knight, 1956...

.

This superfamily consists of four following families (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005

Taxonomy of the Gastropoda (Bouchet & Rocroi, 2005)

The taxonomy of the Gastropoda as it was revised by Philippe Bouchet and Jean-Pierre Rocroi is currently the most up-to-date overall system for classifying gastropod mollusks...

):

• † family Porcelliidae
  Porcelliidae
  Porcelliidae is an extinct family of gastropods in the clade Vetigastropoda .- Taxonomy :...
  
   Koken, 1895
• † family Cirridae
  Cirridae
  Cirridae is an extinct family of fossil sea snails, marine gastropod mollusks in the superfamily Porcellioidea ....
  
   Cossmann, 1916
• † family Discohelicidae
  Discohelicidae
  Discohelicidae is an extinct family of sea snails with planispiral shells, marine gastropod mollusks in the clade Vetigastropoda .This family has no subfamilies.- Genera :...
  
   Schröder, 1995
• † family Pavlodiscidae
  Pavlodiscidae
  Pavlodiscidae is an extinct family of gastropods in the clade Vetigastropoda .This family has no subfamilies....
  
  Frýda, 1998

(Families that are exclusively fossil are indicated with a dagger †)