Plesiocystiscus is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of minute

predatory Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...

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 ...

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 e ...

s 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 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; ...

Etymology

The genus name is derived from the

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

''plesios'', near, in the sense of plesiomorphic, of characters near the ancestor, combined with ''Cystiscus'' the name of another closely related genus. This indicates the relationship to the genus ''Cystiscus'', type genus of the family. The gender of the name is masculine.

Taxonomy

Sometimes this

is simply left in the larger family

Marginellidae Marginellidae, or the margin shells, are a Taxonomy (biology), taxonomic family (biology), family of small, often colorful, sea snails, Marine (ocean), marine gastropod molluscs in the clade Neogastropoda. Taxonomy The higher classification of ...

. The type species is ''Marginella jewettii'' Carpenter, 1857. (Note: Gastropod

taxonomy 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. ...

has been in flux for more than half a century, and this is especially true currently, because of new research in

molecular A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and bioche ...

phylogeny A phylogenetic tree (also phylogeny or evolutionary tree Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA.) is a branching diagram or a tree showing the evolutionary relationships among various biological spec ...

. Because of all the ongoing changes, different reliable sources can yield very different classifications).

Shell description

Shell Shell may refer to: Architecture and design * Shell (structure), a thin structure ** Concrete shell, a thin shell of concrete, usually with no interior columns or exterior buttresses ** Thin-shell structure Science Biology * Seashell, a hard ou ...

minute to small (adult length 1,5 to 6.0 mm). Color white, hyaline; surface smooth, glossy. Shape cylindrical, elliptic, or obovate; weakly to distinctly shouldered. Suture rapidly descending on last half of last whorl, then abruptly sweeping upward just before lip, giving characteristic shape to adult shell.

Spire A spire is a tall, slender, pointed structure on top of a roof of a building or tower, especially at the summit of church steeples. A spire may have a square, circular, or polygonal plan, with a roughly conical or pyramidal shape. Spires are ...

nearly flat to low.

Aperture In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane. An opt ...

moderately narrow, broader anteriorly. Lip thin anteriorly, gradually thickening tower shoulder, smooth, lacking denticulation or

lira Lira is the name of several currency units. It is the current currency of Turkey and also the local name of the currencies of Lebanon and of Syria. It is also the name of several former currencies, including those of Italy, Malta and Israe ...

e, external

varix A varix (pl. varices) is an abnormally dilated vessel with a tortuous course. Varices usually occur in the venous system, but may also occur in arterial or lymphatic vessels. Examples of varices include: * Varicose veins, large tortuous veins usua ...

absent. Siphonal notch and posterior notch absent. Shell often with a weak parietal callus wash or weak parietal callus deposits. Columella multiplicate, with combined total of 3-8 plications, usually occupying less than half to slightly more than half the aperture length. Shell with cystiscid internal

whorl A whorl ( or ) is an individual circle, oval, volution or equivalent in a whorled pattern, which consists of a spiral or multiple concentric objects (including circles, ovals and arcs). Whorls in nature File:Photograph and axial plane floral ...

Anatomy

The triserial radula, found in many other cystiscids, is the most primitive in this family. This is the only genus of marginelliform gastropods with a triserial

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 ...

. This group is considered to be the most primitive in the family based on the radula and type of animal. The radular and shell features, including the presence of odontophoral cartilage hoods, possession of cystiscid internal whorls, and lack of an external varix, place this group in the Cystiscidae.

Ecology

Habitat

This genus lives from the

intertidal zone The intertidal zone, also known as the foreshore, is the area above water level at low tide and underwater at high tide (in other words, the area within the tidal range). This area can include several types of habitats with various species o ...

to 80 m in depth.

Fossil record

This genus is found in the

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

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...

, the

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...

and

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...

, and the

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

, to the Recent.

Species

Species within the genus ''Plesiocystiscus'' include: * ''

Plesiocystiscus abbotti ''Plesiocystiscus abbotti'' is a species of sea snail, a marine gastropod mollusk, in the family Cystiscidae Cystiscidae is a taxonomic family of minute sea snails, marine gastropod mollusks or micromollusks. Description The shell is minut ...

'' (de Jong & Coomans, 1988) * ''

Plesiocystiscus alfiopivai ''Plesiocystiscus alfiopivai'' is a species of very small sea snail, a marine gastropod mollusk or micromollusk in the family (biology), family Cystiscidae. Description Distribution References External links

* Cystiscidae Gastropo ...

'' Espinosa & Ortea, 2002 * '' Plesiocystiscus alfredensis'' (Bartsch, 1915) * '' Plesiocystiscus aphanospira'' (Tomlin, 1913) * '' Plesiocystiscus atomus'' (E.A. Smith, 1890) * '' Plesiocystiscus bavayi'' Boyer, 2003 * ''

Plesiocystiscus bubistae ''Plesiocystiscus bubistae'' is a species of very small sea snail, a marine gastropod mollusk or micromollusk in the family (biology), family Cystiscidae. Description The shell size varies between 1.5 mm and 2.3 mm. Distribution Thi ...

'' (Fernandes, 1988) * '' Plesiocystiscus buzio'' Ortea, Moro & Espinosa, 2020 * '' Plesiocystiscus cinereus'' (Jousseaume, 1875) * '' Plesiocystiscus consanguineus'' (E.A. Smith, 1890) * '' Plesiocystiscus elzae'' Bozzetti, Da Costa & T. Cossignani, 2010 * '' Plesiocystiscus fabioi'' T. Cossignani & Lorenz, 2020 * '' Plesiocystiscus franki'' Espinosa & Ortea, 2019 * '' Plesiocystiscus genecoani'' Espinosa & Ortea, 2000 * '' Plesiocystiscus gutta'' (Gofas & Fernandes, 1987) * '' Plesiocystiscus irinae'' Bozzetti, Da Costa & T. Cossignani, 2010 * '' Plesiocystiscus jansseni'' (de Jong & Coomans, 1988) * '' Plesiocystiscus janzeni'' Espinosa & Ortea, 2019 * '' Plesiocystiscus jardonae'' Ortea & Espinosa, 2016 * '' Plesiocystiscus jewettii'' (Carpenter, 1857) * '' Plesiocystiscus josephinae'' (Fernandes & Rolan, 1991) * '' Plesiocystiscus larva'' (Bavay, 1922) * '' Plesiocystiscus leonorae'' Bozzetti, Da Costa & T. Cossignani, 2010 * '' Plesiocystiscus luiscarlosi'' Bozzetti, Da Costa & T. Cossignani, 2010 * '' Plesiocystiscus luteopunctatus'' Ortea, Moro & Espinosa, 2020 * '' Plesiocystiscus mariae'' (Espinosa & Ortea, 2014) * '' Plesiocystiscus mongei'' Espinosa & Ortea, 2019 * '' Plesiocystiscus ovatus'' Lussi & Smith, 1998 * '' Plesiocystiscus palantirulus'' (Roth & Coan, 1968) * '' Plesiocystiscus politulus'' ( Dall, 1919) * '' Plesiocystiscus pseudogranulina'' Lussi & Smith, 1998 * '' Plesiocystiscus thalia'' (Turton, 1932) * '' Plesiocystiscus tomlini'' (Bavay, 1917) * '' Plesiocystiscus valae'' Lussi & Smith, 1998 * '' Plesiocystiscus variegatus'' Lussi & Smith, 1998 * '' Plesiocystiscus violaceus'' Rolán E. & Gori S. 2014 * '' Plesiocystiscus watanuensis'' Cossignani, 2001 ;Synonyms: * ''Plesiocystiscus bocasensis'' (Olsson & McGinty, 1958): synonym of ''Plesiocystiscus larva'' (Bavay, 1922)

References

Footnotes

* Espinosa & Ortea (2000). "Descripción de un género y once especies nuevas de Cystiscidae y Marginellidae (Mollusca: Neogastropoda) del Caribe de Costa Rica". ''Aviccenia'' 12/13: 95-114. * Espinosa & Ortea (2002). "Nuevas especies de margineliformes de Cuba, Bahamas y el Mar Caribe de Costa Rica". ''Avicennia'' 15: 101-128. * Bozzetti L., Da Costa D. & Cossignani, T. (2010) ''Quattro nuovi Plesiocystiscus dal Mozambico (Gastropoda: Prosobranchia, Cystiscidae).'' Malacologia Mostra Mondiale 69:16-18.

External links

Coovert G.A. & Coovert H.K. (1995) Revision of the supraspecific classification of marginelliform gastropods. The Nautilus 109(2-3): 43-110
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