Cystiscus is a

taxonomic 280px, Generalized scheme of taxonomy Taxonomy is a practice and science concerned with classification or categorization. Typically, there are two parts to it: the development of an underlying scheme of classes (a taxonomy) and the allocation ...

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of minute

sea snail Sea snails are slow-moving marine (ocean), marine gastropod Mollusca, molluscs, usually with visible external shells, such as whelk or abalone. They share the Taxonomic classification, taxonomic class Gastropoda with slugs, which are distinguishe ...

s, marine

gastropod Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and fro ...

mollusk Mollusca is a phylum of protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant species of molluscs are recognized, making it the second-largest animal phylum after Arthropoda. The ...

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

Diagnosis

Exoskeleton, Shell minute to small, white, hyaline; Spire (mollusc), spire immersed to low; lip thickened, smooth or weakly denticulate; external Varix (mollusc), 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 (mollusc), Mantle 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: 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 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'' (Joseph Charles Hippolyte Crosse, Crosse, 1870) *''Cystiscus aphanacme'' (John Read le Brockton Tomlin, Tomlin, 1918) *''Cystiscus aurantius'' Boyer, 2003 *''Cystiscus beqae'' Wakefield & McCleery, 2006 *''Cystiscus boucheti'' Boyer, 2003 *''Cystiscus bougei'' (Arthur René Jean Baptiste Bavay, Bavay, 1917) *''Cystiscus bucca'' (John Read le Brockton Tomlin, Tomlin, 1916) *''Cystiscus caeruleus'' Boyer, 2003 *''Cystiscus camelopardalis'' Boyer, 2003 *''Cystiscus carinifer'' Wakefield & McCleery, 2005 *''Cystiscus connectans'' (May, 1911) *''Cystiscus cooverti'' Boyer, 2003 *''Cystiscus cratericula'' (Tate & May, 1900) *''Cystiscus cymbalum'' (Tate, 1878) *''Cystiscus cystiscus'' (Redfield, 1870) *''Cystiscus deeae'' Wakefield & McCleery, 2006 *''Cystiscus deltoides'' Boyer, 2003 *''Cystiscus flindersi'' (Pritchard & Gatliff, 1899) *''Cystiscus freycineti'' (May, 1915) *''Cystiscus garretti'' Wakefield & McCleery, 2006 *''Cystiscus gorii'' Boyer, 2018 *''Cystiscus goubini'' (Arthur René Jean Baptiste Bavay, Bavay, 1922) *''Cystiscus halli'' (Pritchard & Gatliff, 1899) *''Cystiscus havannensis'' Wakefield & McCleery, 2006 *''Cystiscus hernandezi'' Boyer, 2018 *''Cystiscus incertus'' (May, 1920) *''Cystiscus indiscretus'' (May, 1911) *''Cystiscus iota'' (Hedley, 1899) *''Cystiscus jucundus'' (W. Turton, 1932) *''Cystiscus mainardii'' Cossignani, 2009 *''Cystiscus maloloensis'' Wakefield & McCleery, 2006 *''Cystiscus manceli'' (Jousseaume, 1875) *''Cystiscus marshalli'' Boyer, 2003 *''Cystiscus maskelynensis'' Wakefield & McCleery, 2006 *''Cystiscus matoensis'' Wakefield & McCleery, 2006 *''Cystiscus melwardi'' (Laseron, 1957) *''Cystiscus microgonia'' (Dall, 1927) *''Cystiscus minor'' Boyer, 2003 *''Cystiscus minusculus'' Lussi & G. Smith, 1998 *''Cystiscus minutissimus'' (Tenison Woods, 1876) *''Cystiscus montrouzieri'' (Arthur René Jean Baptiste Bavay, Bavay, 1922) *''Cystiscus mosaica'' Wakefield & McCleery, 2005 *''Cystiscus nebulosa'' Wakefield & McCleery, 2005 *''Cystiscus obesulus'' (May, 1920) *''Cystiscus pardus'' Boyer, 2003 *''Cystiscus peelae'' Lussi & G. Smith, 1998 *''Cystiscus politus'' (Carpenter, 1857) *''Cystiscus problematicus'' (Gatliff & Gabriel, 1916) *''Cystiscus pseudoaurantius'' Boyer, 2003 *''Cystiscus pseustes'' (E. A. Smith, 1904) *''Cystiscus punctatus'' Boyer, 2003 *''Cystiscus pusillus'' Wakefield & McCleery, 2006 *''Cystiscus rendai'' Boyer, 2018 * ''Cystiscus robini'' Boyer, 2018 * † ''Cystiscus rotunda'' (May, 1922) May, W.L. (1922) New species of fossil shells from Table Cape. Papers and Proceedings of the Royal Society of Tasmania, 1921, 9–12, pl. 4.
/ref> *''Cystiscus sandwicensis'' (Pease, 1860) *''Cystiscus subauriculatus'' (May, 1915) *''Cystiscus thouinensis'' (May, 1915) *''Cystiscus tomlinianus'' (May, 1918) *''Cystiscus triangularis'' Cossignani, 2008 *''Cystiscus tricinctus'' Boyer, 2003 *''Cystiscus truncatus'' (Dall, 1927) *''Cystiscus vavauensis'' Wakefield & McCleery, 2006 *''Cystiscus viaderi'' Boyer, 2004 *''Cystiscus vidae'' (Dell, 1956) *''Cystiscus viridis'' Boyer, 2003 *''Cystiscus vitiensis'' Wakefield & McCleery, 2006 *''Cystiscus wakefieldi'' T. Cossignani, 2001 *''Cystiscus yasawaensis'' Wakefield & McCleery, 2006

References

* 2005. Classification and Nomenclator of Gastropod Families. Malacologia 47(1-2):1-397. * Laseron, C. F. (1957). A new classification of the Australian Marginellidae (Mollusca), with a review of species from the Solanderian and Dampierian zoogeographical provinces. Australian Journal of Marine and Freshwater Research. 8(3): 274-311

External links

Stimpson W. 1865. On certain genera and families of zoophagous gasteropods. American Journal of Conchology, 1: 55-64, pl. 8-9

Coovert G.A. & Coovert H.K. (1995) Revision of the supraspecific classification of marginelliform gastropods. The Nautilus 109(2-3): 43-110
{{Taxonbar, from=Q5201224 Cystiscus, Taxa named by William Stimpson Cystiscidae