Plesiocystiscinae is a

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end botanical subfamily names with "-oideae", and zo ...

of minute sea

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 ...

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

micromollusk 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 infraorder

Neogastropoda Neogastropoda is an order of aquatic snails, both freshwater and marine gastropod molluscs. Description The available fossil record of Neogastropoda is relatively complete, and supports a widely accepted evolutionary scenario of an Early Cre ...

. The genus name on which this subfamily name is based is derived from the Greekword ''plesios'', near, in the sense of plesiomorphic, in other words having characters close to those of the ancestor, combined with ''Cystiscus'' the name of a closely related genus. Sometimes the single

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 ...

in this subfamily 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 ...

. (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, white, hyaline; last

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 ...

rapidly expanded then lip abruptly swept posteriorly giving characteristic shape;

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 ...

flat to low; lip thickened posteriorly, smooth, lacking

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 or denticulation, 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 absent; posterior notch absent; columella multiplicate with combined total of 3-8 plications plus parietal lirae; internal

s cystiscid type.

Description of soft parts

Animal

tentacle In zoology, a tentacle is a flexible, mobile, and elongated organ present in some species of animals, most of them invertebrates. In animal anatomy, tentacles usually occur in one or more pairs. Anatomically, the tentacles of animals work main ...

s and siphon are moderately long. The mantle is translucent, and in some species it is not readily extended over the external shell surface. The foot is relatively narrow. The internal anatomy is unknown.

Genus

Genus in this subfamily: * ''

Plesiocystiscus Plesiocystiscus is a genus of minute predatory sea snails, marine gastropod molluscs or micromolluscs in the family Cystiscidae. Etymology The genus name is derived from the Greek ''plesios'', near, in the sense of plesiomorphic, of characters ...

'' Coovert and Coovert, 1994

References

* Coovert G. A. & Coovert H. K. (1995). "Revision of the Supraspecific Classification of Marginelliform Gastropods". ''The Nautilus'' 109(2-3): 43–110. {{Taxonbar, from=Q7204651 Cystiscidae