Seguenzioidea is a

superfamily SUPERFAMILY is a database and search platform of structural and functional annotation for all proteins and genomes. It classifies amino acid sequences into known structural domains, especially into SCOP superfamilies. Domains are functional, str ...

of minute to medium-sized sea snails, marine gastropod

mollusk Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is es ...

s in the clade

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

.Gofas, S. (2010). Seguenzioidea. In: Bouchet, P.; Gofas, S.; Rosenberg, G. (2010) World Marine Mollusca database. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=224565 on 2011-01-09

Description

The distinctive characteristics of the shells of the Seguenzioidea are: * the nacreous layer (a

plesiomorphic In phylogenetics, a plesiomorphy ("near form") and symplesiomorphy are synonyms for an ancestral character shared by all members of a clade, which does not distinguish the clade from other clades. Plesiomorphy, symplesiomorphy, apomorphy, an ...

character, i.e. a character state that a taxon is inferred to have been retained from its ancestors) This occurs also in the following families: Pleurotomariidae,

Haliotidae ''Haliotis'', common name abalone, is the only genus in the family Haliotidae. This genus once contained six subgenera. These subgenera have become alternate representations of ''Haliotis''. The genus consists of small to very large, edible, h ...

Turbinidae Turbinidae, the turban snails, are a family of small to large marine gastropod molluscs in the superfamily Trochoidea.Bouchet, P. (2014). Turbinidae Rafinesque, 1815. Accessed through: World Register of Marine Species at http://www.marinespec ...

Trochidae The Trochidae, common name top-snails or top-shells, are a family of various sized sea snails, marine gastropod molluscs in the subclass Vetigastropoda. This family is commonly known as the top-snails because in many species the shell resembles ...

, and possibly in the Skeneidae. * the

protoconch A protoconch (meaning first or earliest or original shell) is an embryonic or larval shell which occurs in some classes of molluscs, e.g., the initial chamber of an ammonite or the larval shell of a gastropod. In older texts it is also calle ...

has a trochoid shape. * usually with one or more labral sinuses. This character is also found is several other superfamilies such as Neomphaloidea, Pleurotomarioidea,

Fissurelloidea Fissurellidae, common name the keyhole limpets and slit limpets, is a taxonomic family of limpet-like sea snails, marine gastropod molluscs in the clade Vetigastropoda.Rosenberg, G. (2012). Fissurellidae. Accessed through: World Register of Marin ...

, and

Scissurelloidea Scissurelloidea is a taxonomic superfamily of minute sea snails, marine gastropod mollusks or micromollusks in the subclass Vetigastropoda. Scissurelloidea is a taxonomic superfamily of minute sea snails, marine gastropod mollusks or micromoll ...

and in the families Siliquariidae and

Turridae Turridae is a taxonomic family name for a number of predatory sea snails, marine gastropod mollusks in the superfamily Conoidea. MolluscaBase (2018). Turridae H. Adams & A. Adams, 1853 (1838). Accessed through: World Register of Marine Specie ...

. Therefore, this characteristic is to be considered autapomorphic. * a unique

radula The radula (, ; plural radulae or radulas) is an anatomical structure used by molluscs for feeding, sometimes compared to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food ...

r formula with an underlying rhipidoglossate ground plan.

Taxonomy

This superfamily was placed in part or in whole previously to 1979 either in the Archaeogastropoda near the superfamily Trochoidea or in the

Caenogastropoda Caenogastropoda is a taxonomic clade, a large diverse group which are mostly sea snails and other marine gastropod mollusks, but also includes some freshwater snails and some land snails. The clade is the most diverse and ecologically succ ...

near the superfamily

Stromboidea The Stromboidea, originally named the Strombacea by Rafinesque in 1815, is a superfamily of medium-sized to very large sea snails in the clade Littorinimorpha.MolluscaBase eds. (2020). MolluscaBase. Stromboidea Rafinesque, 1815. Accessed throug ...

. In 1987 Salvini-Plawén and Haszprunar changed its status to the suborder Seguenziina, based on the

r formula that they considered to be intermediate between "rhipidoglossate" and "taenioglossate". At about the same time in 1987 Goryachev elevated the superfamily to ordinal status Seguenziiformes in the superorder

Littorinimorpha Littorinimorpha is a large order of snails, gastropods, consisting primarily of sea snails ( marine species), but also including some freshwater snails ( aquatic species) and land snails ( terrestrial species).Bouchet P. & Rocroi J.-P. (Ed.); Fr ...

, based on the taenioglossal radula.

2005 taxonomy

2005 taxonomy according to Bouchet & Rocroi, 2005. (Families that are exclusively

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

are indicated with a dagger †.) :Superfamily Seguenzioidea ::Family

Seguenziidae Seguenziidae is a family of very small deepwater sea snails, marine gastropod mollusks in the superfamily Seguenzioidea (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005).Bouchet, P. (2012). Seguenziidae. Accessed through ...

::Family Chilodontaidae ::† Family

Eucyclidae Eucyclidae is a family of gastropods in the superfamily Seguenzioidea (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005). This family has no subfamilies. Genera Genera within the family Eucyclidae include: * '' Amberl ...

::† Family Laubellidae

2007–2009 taxonomy

Kano et al. (2009)Kano Y., Chikyu E. & Warén A. (2009) "Morphological, ecological and molecular characterization of the enigmatic planispiral snail genus '' Adeuomphalus'' (Vetigastropoda: Seguenzioidea)". ''Journal of Molluscan Studies'' 75: 397-418. . elevated the subfamily Calliotropinae to the family level as the

Calliotropidae Eucyclidae is a family of gastropods in the superfamily Seguenzioidea (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005). This family has no subfamilies. Genera Genera within the family Eucyclidae include: * '' Amberley ...

, and the subfamily Cataeginae to family level as the Cataegidae. The superfamily Seguenzioidea consists of six families:WoRMS : Seguenzioidea; accessed : 1 October 2010
/ref> * Cataegidae McLean & Quinn, 1987 * Chilodontaidae Wenz, 1938 *

Choristellidae Choristellidae is a family of gastropods in the superfamily Seguenzioidea Seguenzioidea is a superfamily of minute to medium-sized sea snails, marine gastropod mollusks in the clade Vetigastropoda.Gofas, S. (2010). Seguenzioidea. In: Bouchet, ...

Bouchet & Warén, 1979 *

Koken, 1896 * † Eucycloscalidae Gründel, 2007 *

Eudaroniidae Eudaroniidae is a family of gastropods belonging to the order Seguenziida. The family consists of only one genus: ''Eudaronia'' Cotton, 1945. References Eudaroniidae Gastropod families Taxa described in 2004 {{seguenzioidea-stub ...

Gründel, 2004 * † Eunemopsidae Bandel, 2010 * †

Lanascalidae Lanascalidae is an extinct family of sea snails, marine Marine is an adjective meaning of or pertaining to the sea or ocean. Marine or marines may refer to: Ocean * Maritime (disambiguation) * Marine art * Marine biology * Marine debris * Mar ...

Bandel, 1992 *† Laubellidae Cox, 1960 *

Pendromidae Pendromidae is a family of gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from salt ...

Warén, 1991 * † Pseudoturcicidae Bandel, 2010 * † Sabrinellidae Bandel, 2010 *

Verrill, 1884 *

Trochaclididae Trochaclididae, common name the false top snails,A Guide to the Marine Mollu ...

Thiele, 1928 ;Unassigned to a family: ** '' Adeuomphalus'' Seguenza, 1876 ** '' Aequispirella'' Finlay, 1924 ** '' Akritogyra'' Warén, 1992 ** '' Anekes'' Bouchet & Warén, 1979 ** '' Benthobrookula'' A. H. Clarke, 1961 **'' Brookula'' Iredale, 1912 **''

Eudaronia ''Eudaronia'' is a genus of sea snails, marine gastropod mollusks in the family Eudaroniidae within the superfamily Seguenzioidea. Species Species within the genus ''Eudaronia'' include: * ''Eudaronia aperta'' (Sykes, 1925) * '' Eudaronia bicon ...

'' Cotton, 1945 ** ''

Granigyra ''Granigyra'' is a genus of sea snails, marine (ocean), marine gastropod mollusks, unassigned in the superfamily (biology), superfamily Seguenzioidea. Species Species within the genus ''Granigyra'' include: * ''Granigyra arenosa'' Warén, 1993 ...

'' Dall, 1889 ** ''

Lissotesta ''Lissotesta'' is a genus of minute sea snails or micromolluscs, marine gastropod molluscs, unassigned in the superfamily Seguenzioidea.Rosenberg, G.; Gofas, S. (2012). Lissotesta. Accessed through: World Register of Marine Species at http://www ...

'' Iredale, 1915 ** '' Lissotestella'' Powell, 1946 ** ''

Microcarina ''Microcarina'' is a genus of sea snails, marine gastropod mollusks, unassigned in the superfamily Seguenzioidea.Rosenberg, G. (2012). ''Microcarina''. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php ...

'' Laseron, 1954 **''

Moelleriopsis ''Moelleriopsis'' is a genus of sea snails, marine gastropod mollusks unassigned in the superfamily Seguenzioidea. Description The small shell of these deep-water species is relatively thin. It is white under a golden brown or olive brown epider ...

'' Bush, 1897 ** '' Notosetia'' Iredale, 1915 ** ''

Palazzia ''Palazzia'' is a genus of sea snails, marine gastropod mollusks, unassigned in the superfamily Seguenzioidea. Species Species within the genus ''Palazzia'' include: * '' Palazzia ausonia'' (Palazzi, 1988) * '' Palazzia nautiliformis'' (Powell, ...

'' Warén, 1991 ** '' Putilla'' A. Adams, 1867 ** ''

Retigyra ''Retigyra'' is a genus of sea snails, marine gastropod mollusks, unassigned in the superfamily Seguenzioidea. Species Species within the genus ''Retigyra'' include: * '' Retigyra granulosa'' (Sykes, 1925) * '' Retigyra iheringi'' (Dautzenberg ...

'' Warén, 1989 ** ''

Trenchia ''Trenchia'' is a genus of sea snails, marine gastropod mollusks, unassigned in the superfamily Seguenzioidea.Rosenberg, G. (2012). ''Trenchia'' Knudsen, 1964. Accessed through: World Register of Marine Species at http://www.marinespecies.or ...

'' Knudsen, 1964 ** '' Ventsia'' Warén & Bouchet, 1993 ** ''

Vetulonia Vetulonia, formerly called Vetulonium ( Etruscan: ''Vatluna''), was an ancient town of Etruria, Italy, the site of which is probably occupied by the modern village of Vetulonia, which up to 1887 bore the name of Colonnata and Colonna di Buriano: t ...

'' Dall, 1913 ** '' Wanganella'' Laseron, 1954 ** ''

Xyloskenea ''Xyloskenea'' is a genus of sea snails, marine gastropod molluscs, unassigned in the superfamily Seguenzioidea. Species Species within the genus ''Xyloskenea'' include: * '' Xyloskenea consors'' B. A. Marshall, 1988 * '' Xyloskenea costulifer ...

'' B. A. Marshall, 1988 ;Unassigned genera brought into synonymy: * ''

Abyssogyra ''Moelleriopsis'' is a genus of sea snails, marine gastropod mollusks unassigned in the superfamily Seguenzioidea. Description The small shell of these deep-water species is relatively thin. It is white under a golden brown or olive brown epi ...

'' A.H. Clarke, 1961: synonym of ''

'' Bush, 1897 * ''Intortia'' Egorova, 1972: synonym of ''

'' Iredale, 1915 * ''Molleriopsis'' : synonym of ''

'' Bush, 1897

References

* Kano, Y. 2008: ''Vetigastropod phylogeny and a new concept of Seguenzioidea: Independent evolution of copulatory organs in the deep-sea habitats.'' Zoologica Scripta 37: 1-21
James F. Quinn Jr., (1991), ''Systematic Position of Basilissopsis and Guttula, and a Discussion of the Phylogeny of the Seguenzioidea (Gastropoda: Prosobranchia)'', Bulletin of Marine Science, Volume 49, Numbers 1-2, September 1991 , pp. 575-598(24)
{{Taxonbar, from=Q2285470 Vetigastropoda