Cystiscus is a

taxonomic Taxonomy is the practice and science of categorization or classification. A taxonomy (or taxonomical classification) is a scheme of classification, especially a hierarchical classification, in which things are organized into groups or types. ...

genus of minute

sea snail Sea snail is a common name for slow-moving marine gastropod molluscs, usually with visible external shells, such as whelk or abalone. They share the taxonomic class Gastropoda with slugs, which are distinguished from snails primarily by the ...

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 * Marine habitats * Marine life * Marine pollution Military * ...

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 saltwater, from freshwater, and from land. T ...

mollusks or

micromollusk A micromollusk is a shelled mollusk which is extremely small, even at full adult size. The word is usually, but not exclusively, applied to marine mollusks, although in addition, numerous species of land snails and freshwater mollusks also ...

s. This genus was placed in the family

Cystiscidae Cystiscidae is a taxonomic family of minute sea snails, marine gastropod mollusks or micromollusks. Description The shell is minute to large, either white, uniformly colored, or patterned; the surface is smooth, sculptured, or axially costate; ...

by Coovert and Coovert, 1995. Previously the genus was in the family Marginellidae, where it is still placed by many other malacologists.

Diagnosis

Shell minute to small, white, hyaline; spire immersed to low; lip thickened, smooth or weakly denticulate; external varix absent; siphonal notch absent; posterior notch absent; lacking collabral parietal callus ridge; columella multiplicate, with combined usually 2 to 8 plications plus parietal lirae, first plication usually strong and raised.

Mantle A mantle is a piece of clothing, a type of cloak. Several other meanings are derived from that. Mantle may refer to: *Mantle (clothing), a cloak-like garment worn mainly by women as fashionable outerwear **Mantle (vesture), an Eastern Orthodox ve ...

smooth, at least partially extending over external shell surface.

Shell description

Shell minute to small (adult length ). Color white, hyaline; surface smooth, glossy. Shape usually elliptic, obovate, or subtriangular; weakly shouldered. Spire completely immersed to low. Aperture narrow to broad, usually wider anteriorly. Lip slightly to distinctly thickened, flared posteriorly in some species, smooth on inside edge to weakly denticulate, lacking lirae, external varix absent. Shell lacking a siphonal notch and posterior notch. Shell with weak parietal callus wash or weak parietal callus deposits in some species, but lacking collabral parietal callus ridge. Columella multiplicate, with combined total 2 to 8 plications plus parietal lirae, rarely to 17 in which the posteriormost are denticles; one species with only 1 plication. Plications usually occupying less than half the length of the aperture, but most of the aperture in some. Plications excavated just inside aperture in a few species, usually evenly rounded, first plication usually raised and very strong. Shell with cystiscid internal whorls.

Animal anatomy

Internal: Unknown
External: Animal with eyes at side of head, usually on lateral swelling; mantle smooth, at least partially extending onto external shell surface, in some species nearly covering shell; foot relatively narrow, about as wide as shell length; head and mantle usually uniformly colored, often bright red, orange, or yellow, or brown, or black, internal mantle color pattern often showing through translucent shell.

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 ...

: Uniserial, ribbon long, narrow, composed of 80-209 plates. Rachidian plates overlapping, narrow, moderately to strong arched, with 6-14 sharp cusps on posterior edge, the central cusp usually the strongest. The anterior edge of the rachidian plate is strongly concave, resulting in U- or V-shaped plates.

Habitat

Intertidal to .

Fossil record

Eocene of France and Alabama, upper

Oligogene Oligogenic inheritance (Greek ὀλίγος – ''ὀligos'' = few, a little) describes a trait that is influenced by a few genes. Oligogenic inheritance represents an intermediate between monogenic inheritance in which a trait is determined by a ...

and Miocene of Western Atlantic, to Recent.

Remarks

The two halves of the head are capable of closing together at will, thus appearing unsplit. The long siphon usually distinguishes this group from ''Gibberula''. The shell of ''Persicula'' is usually patterned, often has a distinct external varix, and the spire is usually immersed. These conchological features serve to separate the two groups.

Species

''Cystiscus'' contains the following accepted species: *''

Cystiscus angasi ''Cystiscus angasi'' is a species of very small sea snail, a marine gastropod mollusk or micromollusk in the family Cystiscidae. Description The size of the shell attains 1.8 mm. Distribution This marine species was found off Port Jackson ...

'' (

Crosse Crosse is a surname, and may refer to: * Andrew Crosse (1784–1855), British amateur scientist * Charles Crosse, British rugby * Charles G. Crosse, American physician and politician * Edmond Francis Crosse (1858-1941), first Archdeacon of Cheste ...

, 1870) *''

Cystiscus aphanacme ''Cystiscus aphanacme'' is a species of very small sea snail, a marine gastropod mollusk or micromollusk in the family Cystiscidae Cystiscidae is a taxonomic family of minute sea snails, marine gastropod mollusks or micromollusks. Descripti ...

'' ( Tomlin, 1918) *''

Cystiscus aurantius ''Cystiscus aurantius'' is a species of very small sea snail, a marine gastropod mollusk or micromollusk in the family Cystiscidae. Description Distribution This marine species occurs off New Caledonia ) , anthem = "" , image_map = New ...

'' Boyer, 2003 *''

Cystiscus beqae ''Cystiscus beqae'' is a species of very small sea snail, a marine gastropod mollusk or micromollusk in the family Cystiscidae Cystiscidae is a taxonomic family of minute sea snails, marine gastropod mollusks or micromollusks. Description ...

'' Wakefield & McCleery, 2006 *''

Cystiscus boucheti ''Cystiscus boucheti'' is a species of very small sea snail, a marine gastropod mollusk or micromollusk in the family Cystiscidae. Description Distribution This marine species occurs off New Caledonia ) , anthem = "" , image_map = New C ...

'' Boyer, 2003 *''

Cystiscus bougei ''Cystiscus bougei'' is a species of very small sea snail, a marine gastropod mollusk or micromollusk in the family Cystiscidae. Description The size of the shell attains 1.45 mm. Distribution This marine species occurs off New Caledonia ...

'' ( Bavay, 1917) *''

Cystiscus bucca ''Cystiscus bucca'' is a species of very small sea snail, a marine gastropod mollusk or micromollusk in the family Cystiscidae Cystiscidae is a taxonomic family of minute sea snails, marine gastropod mollusks or micromollusks. Description ...

'' ( Tomlin, 1916) *''

Cystiscus caeruleus ''Cystiscus caeruleus'' is a species of very small sea snail, a marine gastropod mollusk or micromollusk in the family Cystiscidae. Description The shell is a smooth, semi-translucent white with a slit-like opening along one side. Distribution ...

'' Boyer, 2003 *''

Cystiscus camelopardalis ''Cystiscus camelopardalis'' is a species of very small sea snail, a marine gastropod mollusk or micromollusk in the family Cystiscidae. Description The length of the shell attains 1.3 mm. Distribution This marine species occurs off New ...

'' Boyer, 2003 *''

Cystiscus carinifer ''Cystiscus carinifer'' is a species of very small sea snail, a marine gastropod mollusk or micromollusk in the family Cystiscidae. Description The size of the shell attains 1.56 mm. Distribution This marine species occurs off the Tuamotu Arc ...

'' Wakefield & McCleery, 2005 *''

Cystiscus connectans ''Cystiscus connectans'' is a species of very small sea snail, a marine gastropod mollusk or micromollusk in the family Cystiscidae Cystiscidae is a taxonomic family of minute sea snails, marine gastropod mollusks or micromollusks. Descr ...

'' (May, 1911) *'' Cystiscus cooverti'' Boyer, 2003 *''

Cystiscus cratericula ''Cystiscus cratericula'' is a species of very small sea snail, a marine gastropod mollusk or micromollusk in the family Cystiscidae Cystiscidae is a taxonomic family of minute sea snails, marine gastropod mollusks or micromollusks. Desc ...

'' (Tate & May, 1900) *'' Cystiscus cymbalum'' (Tate, 1878) *''

Cystiscus cystiscus ''Cystiscus connectans'' is a species of very small sea snail, a marine gastropod mollusk or micromollusk in the family Cystiscidae Cystiscidae is a taxonomic family of minute sea snails, marine gastropod mollusks or micromollusks. Descript ...

'' (Redfield, 1870) *''

Cystiscus deeae ''Cystiscus deeae'' is a species of very small sea snail, a marine gastropod mollusk or micromollusk in the family Cystiscidae. Description The size of the shell attains 1.23 mm. Distribution This marine species occurs off Kenutu Island, ...

'' Wakefield & McCleery, 2006 *''

Cystiscus deltoides ''Cystiscus deltoides'' is a species of very small sea snail, a marine gastropod mollusk or micromollusk in the family Cystiscidae. Description The size of the shell attains 1.5 mm. Distribution This marine species occurs off New Caledonia ...

'' Boyer, 2003 *''

Cystiscus flindersi ''Cystiscus flindersi'' is a species of very small sea snail, a marine gastropod mollusk or micromollusk in the family Cystiscidae Cystiscidae is a taxonomic family of minute sea snails, marine gastropod mollusks or micromollusks. Descri ...

'' (Pritchard & Gatliff, 1899) *''

Cystiscus freycineti ''Cystiscus freycineti'' is a species of very small sea snail, a marine gastropod mollusk or micromollusk in the family Cystiscidae Cystiscidae is a taxonomic family of minute sea snails, marine gastropod mollusks or micromollusks. Descr ...

'' (May, 1915) *'' Cystiscus garretti'' Wakefield & McCleery, 2006 *''

Cystiscus gorii ''Cystiscus gorii'' is a species of very small sea snail, a marine gastropod mollusk or micromollusk in the family Cystiscidae Cystiscidae is a taxonomic family of minute sea snails, marine gastropod mollusks or micromollusks. Description ...

'' Boyer, 2018 *''

Cystiscus goubini ''Cystiscus goubini'' is a species of very small sea snail, a marine gastropod mollusk or micromollusk in the family Cystiscidae Cystiscidae is a taxonomic family of minute sea snails, marine gastropod mollusks or micromollusks. Description ...

'' ( Bavay, 1922) *''

Cystiscus halli ''Cystiscus halli'' is a species of very small sea snail, a marine gastropod mollusk or micromollusk in the family Cystiscidae. References Cystiscidae Gastropods described in 1899 Halli Halli may refer to: * Halli Airport, a military ai ...

'' (Pritchard & Gatliff, 1899) *''

Cystiscus havannensis ''Cystiscus havannensis'' is a species of very small sea snail, a marine gastropod mollusk or micromollusk in the family Cystiscidae Cystiscidae is a taxonomic family of minute sea snails, marine gastropod mollusks or micromollusks. Desc ...

'' Wakefield & McCleery, 2006 *'' Cy