Cystiscus
Encyclopedia
Cystiscus is a taxonomic genus
of minute sea snail
s, marine
gastropod mollusks or micromollusk
s.
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.
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
smooth, at least partially extending over external shell surface.
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.
of France
and Alabama
, upper Oligogene and Miocene
of Western Atlantic, to Recent.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of minute 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 or micromollusk
Micromollusk
A micromollusk is a descriptive term for 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 reach adult size at very small...
s.
This genus was placed in the family Cystiscidae
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; the spire is flat to immersed, or low to tall; the...
by Coovert and Coovert, 1995. Previously the genus was in the family Marginellidae
Marginellidae
Marginellidae, or the margin shells, are a taxonomic family of small, often colorful, sea snails, marine gastropod molluscs in the clade Neogastropoda.- Taxonomy :...
, where it is still placed by many other malacologists.
Diagnosis
Shell minute to small, white, hyaline; spireSpire (mollusc)
A spire is a descriptive term for part of the coiled shell of mollusks. The word is a convenient aid in describing shells, but it does not refer to a very precise part of shell anatomy: the spire consists of all of the whorls except for the body whorl...
immersed to low; lip thickened, smooth or weakly denticulate; external varix
Varix (mollusc)
A varix is an anatomical feature of the shell of certain sea snails, marine gastropod molluscs.It is a thickened axial ridge in the shell of some families of gastropods. A varix is located at intervals around the whorl, and is formed by considerable thickening of the outer lip at a resting stage...
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
Mantle (mollusc)
The mantle is a significant part of the anatomy of molluscs: it is the dorsal body wall which covers the visceral mass and usually protrudes in the form of flaps well beyond the visceral mass itself.In many, but by no means all, species of molluscs, the epidermis of the mantle secretes...
smooth, at least partially extending over external shell surface.
Type species
The type species of this genus is Cystiscus capensis Stimpson, 1865Shell description
Shell minute to small (adult length 1–6 mm). 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: UnknownExternal: 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
Radula
The radula is an anatomical structure that is used by molluscs for feeding, sometimes compared rather inaccurately to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food enters the esophagus...
: 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.
Fossil record
EoceneEocene
The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...
of France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
and Alabama
Alabama
Alabama is a state located in the southeastern region of the United States. It is bordered by Tennessee to the north, Georgia to the east, Florida and the Gulf of Mexico to the south, and Mississippi to the west. Alabama ranks 30th in total land area and ranks second in the size of its inland...
, upper Oligogene and Miocene
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
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 alternans Pritchard & Gatliff, 1899
- Cystiscus angasi Crosse, 1870
- Cystiscus aphanacme (Tomlin, 1918)
- Cystiscus bucca Tomlin, 1916
- Cystiscus capensis Stimpson, 1865 T
- Cystiscus connectans May, 1911
- Cystiscus cratericula Tate & May, 1900
- Cystiscus cymbalum Tate, 1878
- Cystiscus flindersi Pritchard & Gatliff, 1899
- Cystiscus freycineti May, 1915
- Cystiscus goubini Bavay, 1922
- Cystiscus halli Pritchard & Gatliff, 1899
- Cystiscus huna Kay, 1979
- Cystiscus incerta May, 1919
- Cystiscus indiscreta May, 1911
- Cystiscus japonicus (Nomura & Hatai, 1940)
- Cystiscus jucundus (Turton, 1932)
- Cystiscus melwardi Laseron, 1957
- Cystiscus minusculusCystiscus minusculusCystiscus minusculus is a species of very small sea snail, a marine gastropod mollusk or micromollusk in the family Cystiscidae....
Lussi & Smith, 1998 - Cystiscus minutissima Tenison Woods, 1876
- Cystiscus obesula May, 1919
- Cystiscus ocellus (Dall, 1927)
- Cystiscus opima Laseron, 1957
- Cystiscus peelaeCystiscus peelaeCystiscus peelae is a species of very small sea snail, a marine gastropod mollusk or micromollusk in the family Cystiscidae....
Lussi & Smith, 1998 - Cystiscus problematica Gatliff & Gabriel, 1916
- Cystiscus pseustes (E.A.Smith, 1904)
- Cystiscus sandwicensis (Pease, 1860)
- Cystiscus subauriculata May, 1916
- Cystiscus thouinensis May, 1916
- Cystiscus tomlini Bavay, 1917
- Cystiscus tomliniana May, 1917
- Cystiscus vidae DellRichard DellDr Richard Kenneth Dell was a New Zealand malacologist. He was born in Auckland. As a young boy, he took an interest in shells, collecting them from the shores of Waitemata Harbour. He even managed to start a "museum" in his backyard...
, 1956