Plesiocystiscus is a

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

predatory Predation is a biological interaction in which 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 ...

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 ...

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

s or

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

s in the family

Cystiscidae Cystiscidae is a taxonomic family of small 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 costat ...

Etymology

The genus name is derived from the

Greek Greek may refer to: 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 of all kno ...

''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 taxonomic family of small, often colorful, sea snails, marine gastropod molluscs in the clade Neogastropoda. Taxonomy The higher classification of the family Marginellidae has long been in a state o ...

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

taxonomy image:Hierarchical clustering diagram.png, 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 o ...

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 that are held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions that satisfy this criterion. In quantum physics, organic chemistry, ...

phylogeny A phylogenetic tree or phylogeny is a graphical representation which shows the evolutionary history between a set of species or Taxon, taxa during a specific time.Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, M ...

. 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 Science Biology * Seashell, a hard outer layer of a marine ani ...

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. Spire ...

nearly flat to low.

Aperture In optics, the aperture of an optical system (including a system consisting of a single lens) is the hole or opening that primarily limits light propagated through the system. More specifically, the entrance pupil as the front side image o ...

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 Turkish lira, currency of Turkey and also the local name of the Lebanese pound, currencies of Lebanon and of Syrian pound, Syria. It is also the name of several former currencies, ...

e, external

varix A varix (: varices) is an abnormally dilated blood 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 ...

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). In nature File:Photograph and axial plane floral diagra ...

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 (; : radulae or radulas) is an anatomical structure used by mollusks 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 enters ...

. 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 or foreshore is the area above water level at low tide and underwater at high tide; in other words, it is the part of the littoral zone within the tidal range. This area can include several types of habitats with various ...

to 80 m in depth.

Fossil record

This genus is found in the

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

France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

, the

Miocene The Miocene ( ) is the first epoch (geology), 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 mea ...

and

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58Florida Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...

, and the

Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

, to the Recent.

Species

Species within the genus ''Plesiocystiscus'' include: * '' Plesiocystiscus abbotti'' (de Jong & Coomans, 1988) * '' Plesiocystiscus alfiopivai'' Espinosa & Ortea, 2002 * '' Plesiocystiscus alfredensis'' (Bartsch, 1915) * '' Plesiocystiscus aphanospira'' (Tomlin, 1913) * '' Plesiocystiscus atomus'' (E.A. Smith, 1890) * ''

Plesiocystiscus bavayi ''Plesiocystiscus bavayi'' is a species of very small sea snail, a marine gastropod mollusc or micromollusc in the family Cystiscidae. Description Distribution This marine species occurs off New Caledonia New Caledonia ( ; ) is a grou ...

'' Boyer, 2003 * ''

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

'' (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
{{Taxonbar, from=Q3138357 Gastropod genera