Plesiocystiscus
Encyclopedia
Plesiocystiscus is a genus
of minute sea predatory sea snail
s, marine
gastropod mollusks or micromollusk
s in the family Cystiscidae
.
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.
is simply left in the larger family Marginellidae
. The type species is Marginella jewettii Carpenter, 1857.
(Note: Gastropod taxonomy
has been in flux for more than half a century, and this is especially true currently, because of new research in molecular phylogeny. Because of all the on-going changes, different reliable sources can yield very different classifications).
nearly flat to low. Aperture
moderately narrow, broader anteriorly. Lip thin anteriorly, gradually thickening tower shoulder, smooth, lacking denticulation or lirae, external varix
absent. Siphonal notch and poterior 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
s.
. 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.
of France
, the Miocene
and Pliocene
of Florida
, and the Pleistocene
of California
, to the 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 predatory 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 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...
.
Etymology
The genus name is taken is derived from the GreekGreek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
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 genusGenus
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...
is simply left in the larger 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 :...
. The type species is Marginella jewettii Carpenter, 1857.
(Note: Gastropod taxonomy
Taxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...
has been in flux for more than half a century, and this is especially true currently, because of new research in molecular phylogeny. Because of all the on-going changes, different reliable sources can yield very different classifications).
Shell description
Shell 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. 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...
nearly flat to low. Aperture
Aperture (mollusc)
The aperture is an opening in certain kinds of mollusc shells: it is the main opening of the shell, where part of the body of the animal emerges for locomotion, feeding, etc....
moderately narrow, broader anteriorly. Lip thin anteriorly, gradually thickening tower shoulder, smooth, lacking denticulation or lirae, 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 and poterior 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
Whorl (mollusc)
A whorl is a single, complete 360° revolution or turn in the spiral growth of a mollusc shell. A spiral configuration of the shell is found in of numerous gastropods, but it is also found in shelled cephalopods including Nautilus, Spirula and the large extinct subclass of cephalopods known as the...
s.
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 radulaRadula
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...
. 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.
Fossil record
This genus is found in the 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...
, the 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...
and Pliocene
Pliocene
The Pliocene Epoch is the period in the geologic timescale that extends from 5.332 million to 2.588 million years before present. It is the second and youngest epoch of the Neogene Period in the Cenozoic Era. The Pliocene follows the Miocene Epoch and is followed by the Pleistocene Epoch...
of Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
, and the Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
of California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
, to the Recent.
Species
Species within the genus Plesiocystiscus include:- Plesiocystiscus abbotti (de Jong & Coomans, 1988)
- Plesiocystiscus alfiopivaiPlesiocystiscus alfiopivaiPlesiocystiscus alfiopivai is a species of very small sea snail, a marine gastropod mollusk or micromollusk in the family Cystiscidae....
Espinosa & Ortea, 2002 - Plesiocystiscus alfredensisPlesiocystiscus alfredensisPlesiocystiscus alfredensis, common name the blue oval marginella, is a species of very small sea snail, a marine gastropod mollusk in the family Cystiscidae.This species occurs throughout the Indo-Pacific Oceans. It prefer to live in sheltered areas....
(Bartsch, 1915) - Plesiocystiscus aphanospira (Tomlin, 1913)
- Plesiocystiscus atomus (E.A. Smith, 1890)
- Plesiocystiscus bavayiPlesiocystiscus bavayiPlesiocystiscus bavayi is a species of very small sea snail, a marine gastropod mollusk or micromollusk in the family Cystiscidae....
Boyer, 2003 - Plesiocystiscus bubistae (Fernandes, 1988)
- Plesiocystiscus cinereus (Jousseaume, 1875)
- Plesiocystiscus consanguineus (E.A. Smith, 1890)
- Plesiocystiscus elzae Bozzetti, Da Costa & T. Cossignani, 2010
- Plesiocystiscus genecoaniPlesiocystiscus genecoaniPlesiocystiscus genecoani is a species of very small sea snail, a marine gastropod mollusk or micromollusk in the family Cystiscidae....
Espinosa & Ortea, 2000 - Plesiocystiscus guttaPlesiocystiscus guttaPlesiocystiscus gutta is a species of minute sea snail, a marine gastropod in the family Marginellidae, sometimes instead placed in the eponymous family Cystiscidae.This species is sometimes known simply as "Cystiscus gutta....
(Gofas & Fernandes, 1987) - Plesiocystiscus irinae Bozzetti, Da Costa & T. Cossignani, 2010
- Plesiocystiscus jansseni (de Jong & Coomans, 1988)
- Plesiocystiscus jewettiiPlesiocystiscus jewettiiPlesiocystiscus jewettii is a species of minute predatory sea snail, a marine gastropod mollusk in the family Cystiscidae....
(Carpenter, 1857) - Plesiocystiscus josephinaePlesiocystiscus josephinaePlesiocystiscus josephinae is a species of minute sea snail, a marine gastropod mollusk in the family Marginellidae, sometimes placed in the family Cystiscidae. This species is sometimes known as Cystiscus 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 ovatusPlesiocystiscus ovatusPlesiocystiscus ovatus is a species of very small sea snail, a marine gastropod mollusk or micromollusk in the family Cystiscidae....
Lussi & Smith, 1998 - Plesiocystiscus palantirulus (Roth & Coan, 1968)
- Plesiocystiscus politulus (Dall, 1919)
- Plesiocystiscus pseudogranulinaPlesiocystiscus pseudogranulinaPlesiocystiscus pseudogranulina is a species of very small sea snail, a marine gastropod mollusk or micromollusk in the family Cystiscidae.-External links:*...
Lussi & Smith, 1998 - Plesiocystiscus thalia (Turton, 1932)
- Plesiocystiscus valaePlesiocystiscus valaePlesiocystiscus valae is a species of very small sea snail, a marine gastropod mollusk or micromollusk in the family Cystiscidae....
Lussi & Smith, 1998 - Plesiocystiscus variegatusPlesiocystiscus variegatusPlesiocystiscus variegatus is a species of very small sea snail, a marine gastropod mollusk or micromollusk in the family Cystiscidae....
Lussi & Smith, 1998 - Plesiocystiscus watanuensisPlesiocystiscus watanuensisPlesiocystiscus watanuensis is a species of very small sea snail, a marine gastropod mollusk or micromollusk in the family Cystiscidae....
Cossignani, 2001