''Semicassis'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of medium-sized predatory sea snails, marine gastropod molluscs in the subfamily

Cassinae The Cassidae are a taxonomic family of medium-sized, large, and sometimes very large sea snails commonly called helmet snails or bonnet snails. These are marine gastropod mollusks in the superfamily Tonnoidea and the clade Littorinimorpha.Go ...

within the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Cassidae The Cassidae are a taxonomic family of medium-sized, large, and sometimes very large sea snails commonly called helmet snails or bonnet snails. These are marine gastropod mollusks in the superfamily Tonnoidea and the clade Littorinimorpha.Go ...

, the helmet snails and bonnet snails.WoRMS : Semicassis; accessed: 30 July 2020
/ref>

Species

According to the

World Register of Marine Species The World Register of Marine Species (WoRMS) is a taxonomic database that aims to provide an authoritative and comprehensive list of names of marine organisms. Content The content of the registry is edited and maintained by scientific specialis ...

(WoRMS), the following species with valid names are included within the genus ''Semicassis'': *''

Semicassis adcocki ''Semicassis'' is a genus of medium-sized predatory sea snails, marine gastropod molluscs in the subfamily Cassinae within the family Cassidae, the helmet snails and bonnet snails. Species According to the World Register of Marine Species (W ...

'' (Sowerby III, 1896) *''

Semicassis angasi ''Semicassis'' is a genus of medium-sized predatory sea snails, marine gastropod molluscs in the subfamily Cassinae within the family Cassidae, the helmet snails and bonnet snails. Species According to the World Register of Marine Species (W ...

'' (Iredale, 1927) *''

Semicassis bisulcata ''Semicassis bisulcata'', common name: the Japanese bonnet, is a species of large sea snail, a marine gastropod mollusk in the family Cassidae, the helmet snails and bonnet snails. Description The size of an adult shell varies between 25&n ...

'' (Schubert & Wagner, 1829) *'' Semicassis bondarevi'' Mühlhäusser & Parth, 1993 *'' Semicassis bulla'' Habe, 1961 *'' Semicassis canaliculata'' (Bruguière, 1792) * ''

Semicassis cancellata ''Semicassis'' is a genus of medium-sized predatory sea snails, marine gastropod molluscs in the subfamily Cassinae within the family Cassidae, the helmet snails and bonnet snails. Species According to the World Register of Marine Species (W ...

'' (Lamarck, 1803) *''

Semicassis centiquadrata ''Semicassis'' is a genus of medium-sized predatory sea snails, marine gastropod molluscs in the subfamily Cassinae within the family Cassidae, the helmet snails and bonnet snails. Species According to the World Register of Marine Species (W ...

'' (Valenciennes, 1832) *''

Semicassis craticulata ''Semicassis'' is a genus of medium-sized predatory sea snails, marine gastropod molluscs in the subfamily Cassinae within the family Cassidae, the helmet snails and bonnet snails. Species According to the World Register of Marine Species (W ...

'' (Euthyme, 1885) * ''

Semicassis decipiens ''Semicassis'' is a genus of medium-sized predatory sea snails, marine gastropod molluscs in the subfamily Cassinae within the family Cassidae, the helmet snails and bonnet snails. Species According to the World Register of Marine Species (W ...

'' (Kilburn, 1980) * ''

Semicassis dorae ''Semicassis'' is a genus of medium-sized predatory sea snails, marine gastropod molluscs in the subfamily Cassinae within the family Cassidae, the helmet snails and bonnet snails. Species According to the World Register of Marine Species (W ...

'' (Kreipl & Mühlhäusser, 1996) * ''

Semicassis dougthorni ''Semicassis'' is a genus of medium-sized predatory sea snails, marine gastropod molluscs in the subfamily Cassinae within the family Cassidae, the helmet snails and bonnet snails. Species According to the World Register of Marine Species (W ...

'' Dekkers, 2013 *''

Semicassis faurotis ''Phalium faurotis'' is a species of large sea snail, a marine gastropod mollusk in the family Cassidae The Cassidae are a taxonomic family of medium-sized, large, and sometimes very large sea snails commonly called helmet snails or bonne ...

'' (Jousseaume, 1888) * ''

Semicassis fernandesi ''Semicassis'' is a genus of medium-sized predatory sea snails, marine gastropod molluscs in the subfamily Cassinae within the family Cassidae, the helmet snails and bonnet snails. Species According to the World Register of Marine Species (W ...

'' (Kilburn, 1975) * † ''

Semicassis fibrata ''Semicassis'' is a genus of medium-sized predatory sea snails, marine gastropod molluscs in the subfamily Cassinae within the family Cassidae, the helmet snails and bonnet snails. Species According to the World Register of Marine Species (W ...

'' (P. Marshall & Murdoch, 1920) *''

Semicassis glabrata ''Semicassis'' is a genus of medium-sized predatory sea snails, marine gastropod molluscs in the subfamily Cassinae within the family Cassidae, the helmet snails and bonnet snails. Species According to the World Register of Marine Species (W ...

'' (Dunker, 1852) *''

Semicassis granulata The Scotch bonnet (''Semicassis granulata'') is a medium-sized to large species of sea snail, a marine gastropod mollusk in the subfamily Cassinae, the helmet shells and bonnet shells. The common name "Scotch bonnet" alludes to the general ...

'' (Born, 1778) - synonym: ''Phalium granulatum'' (Born, 1778) * † '' Semicassis grateloupi'' (Deshayes, 1853) *'' Semicassis inornata'' (Pilsbry, 1895) * † '' Semicassis kaawaensis'' (Bartrum & Powell, 1928) *'' Semicassis labiata'' (Perry, 1811) * † '' Semicassis laevigata'' (Defrance, 1817) * †'' Semicassis lilliei'' (C. A. Fleming, 1943) * † '' Semicassis marwicki'' (C. A. Fleming, 1943) *'' Semicassis microstoma'' (Martens, 1903) * † '' Semicassis neumayri'' (Hoernes, 1875) *'' Semicassis paucirugis'' (Menke, 1843) *''

Semicassis pyrum ''Semicassis pyrum'', common name the "pear bonnet" or "common helmet", is a species of large sea snail, a marine gastropod mollusc in the family Cassidae The Cassidae are a taxonomic family of medium-sized, large, and sometimes very lar ...

'' (Lamarck, 1822) *'' Semicassis royana'' (Iredale, 1914) *'' Semicassis saburon'' (Bruguière, 1792) *'' Semicassis semigranosa'' (Lamarck, 1822) *'' Semicassis sinuosa'' (Verco, 1904) * † '' Semicassis skinneri'' (Marwick, 1928) *'' Semicassis sophia'' (Brazier, 1872) * † '' Semicassis subsulcosa'' (Hoernes & Auinger, 1884) * † '' Semicassis szilviae'' Kovács & Vicián, 2018 *'' Semicassis thachi'' Kreipl, Alf & Eggeling, 2006 *'' Semicassis thomsoni'' (Brazier, 1875) *'' Semicassis umbilicata'' (Pease, 1861) * ''

Semicassis undulata ''Semicassis undulata'' is a Mediterranean species of medium-sized sea snail, a marine gastropod mollusc in the subfamily Cassinae, the helmet snails and bonnet snails. Taxonomy This taxon was previously sometimes referred to at subspecies ...

'' (Gmelin, 1791) *'' Semicassis westralis'' Kreipl, 1997 *'' Semicassis whitworthi'' (Abbott, 1968) * '' Semicassis zeylanica'' (Lamarck, 1822) ;Species brought into synonymy: * ''Semicassis cicatricosa'' (Gmelin, 1791): synonym of ''

'' (Born, 1778) * ''Semicassis diuturna'' Iredale, 1927: synonym of ''Semicassis bisulcata'' (Schubert & J. A. Wagner, 1829) * ''Semicassis japonica'' (Reeve, 1848): synonym of ''Semicassis bisulcata'' (Schubert & J. A. Wagner, 1829) * ''Semicassis miolaevigata'' Sacco, 1890: synonym of ''Semicassis saburon'' (Bruguière, 1792) * ''Semicassis obscura'' Habe, 1961: synonym of ''Semicassis bulla'' Habe, 1961 * ''Semicassis pauciruge'': synonym of ''Semicassis paucirugis'' (Menke, 1843) * ''Semicassis persimilis'' Kira, 1955: synonym of ''Semicassis bisulcata'' (Schubert & J. A. Wagner, 1829) * ''Semicassis pila'' (Reeve, 1848): synonym of ''Semicassis bisulcata'' (Schubert & J. A. Wagner, 1829) * ''Semicassis salmonea'' Beu, Bouchet & Tröndlé, 2012: synonym of '' Semicassis bulla'' Habe, 1961 Cassidae - Semicassis rondoletii

Extinct Species

Extinct species within this genus include:Fossilworks
/ref> *''Semicassis aldrichi'' Dall 1890 † *''Semicassis angasi'' Iredale 1927 † *''Semicassis deneseplicata'' Martin 1916 † *''Semicassis harpaeformis'' Lamarck 1803 † *''Semicassis labiata'' Perry 1811 † *''Semicassis monilifera'' Sowerby 1846 † *''Semicassis oligocalantica'' Vredenburg 1925 † *''Semicassis ovulum'' Ortmann 1900 † *''Semicassis pyshtensis'' Addicott 1976 † *''Semicassis reclusa'' Guppy 1873 † Fossils of species within this genus have been found all over the world in sediments from

Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', " ...

to Quaternary (age range: 37.2 to 0.0 million years ago).

References

* Powell A. W. B. (1979). William Collins Publishers Ltd, Auckland . Cassidae Gastropod genera Extant Eocene first appearances {{Cassidae-stub