Polystira Florencae
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''Polystira florencae'' is a
species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
of
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 ...
, a marine
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 ...
in the
family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...
Turridae Turridae is a taxonomic family name for a number of predatory sea snails, marine gastropod mollusks in the superfamily Conoidea. MolluscaBase (2018). Turridae H. Adams & A. Adams, 1853 (1838). Accessed through: World Register of Marine Specie ...
, the turrids.


Description

The length of the shell varies between 17 mm and 30 mm. (Original description) The rather large shell has a fusiform shape. It is, pale brown, excepting the large median keel between summit and suture and a broad area that extends over a little more than half of the posterior part of the
columella Lucius Junius Moderatus Columella (; Arabic: , 4 – ) was a prominent writer on agriculture in the Roman Empire. His ' in twelve volumes has been completely preserved and forms an important source on Roman agriculture, together with the wo ...
, which are white. The tops of the other spiral keels are also a trifle paler than the spaces between them. The first 1.5
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 ...
s of the
protoconch A protoconch (meaning first or earliest or original shell) is an embryonic or larval shell which occurs in some classes of molluscs, e.g., the initial chamber of an ammonite or the larval shell of a gastropod. In older texts it is also called ...
are large, well rounded, and smooth. These are followed by about one half of a turn that is crossed by about 10 slightly retractively curved, axial ribs, which are about one fourth as wide as the spaces that separate them. The postnuclear whorls are marked by very strong spiral keels, of which the most conspicuous one is the second one below the summit, which bears the deeply narrow posterior sinus. The first keel occupies the space almost midway between the summit and this keel. Anterior to the strong keel, there are on each whorl two additional keels, one, the stronger, occupying the periphery of the whorls, another a little nearer to the strong second keel than the peripheral and slightly weaker than the peripheral. A slender spiral thread is present midway between the summit and the first, and between the second and third; and two are present between the third and fourth. The spaces between the keels are decidedly concave, and they are crossed by slender, axial riblets, which are retractively curved posterior to the strong keel and protractively curved anterior to it. In addition to this the whorls are marked by microscopic lines of growth and spiral striations. The base is short and marked by four keels, which grow consecutively weaker anteriorly. In the middle of the broad spaces between these keels is a slender spiral thread. A continuation of the axial
sculpture Sculpture is the branch of the visual arts that operates in three dimensions. Sculpture is the three-dimensional art work which is physically presented in the dimensions of height, width and depth. It is one of the plastic arts. Durable sc ...
of the
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 ...
is present here. The
columella Lucius Junius Moderatus Columella (; Arabic: , 4 – ) was a prominent writer on agriculture in the Roman Empire. His ' in twelve volumes has been completely preserved and forms an important source on Roman agriculture, together with the wo ...
is rather long, slender, and marked by oblique spiral cords, which grow consecutively weaker anteriorly, becoming obsolete toward the anterior tip. This also holds good for the continuation of the axial sculpture, which likewise becomes enfeebled and obsolete. The
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 ...
is narrow and long. The outer
lip The lips are the visible body part at the mouth of many animals, including humans. Lips are soft, movable, and serve as the opening for food intake and in the articulation of sound and speech. Human lips are a tactile sensory organ, and can be ...
is deeply incised to form the narrow sinus of the second keel and scalloped by the rest of the keels and cords. The inner lip is thin, reflected over and appressed to the columella. The parietal wall is covered by a moderately thick callus.


Distribution

''P. florencae'' can be found in Caribbean waters, ranging from the
Bahamas The Bahamas (), officially the Commonwealth of The Bahamas, is an island country within the Lucayan Archipelago of the West Indies in the Atlantic Ocean, North Atlantic. It takes up 97% of the Lucayan Archipelago's land area and is home to ...
south to
Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...
.Tunnell, John W., Jr., Felder, Darryl L., & Earle, Sylvia A., eds. ''Gulf of Mexico Origin, Waters, and Biota, Volume 1: Biodiversity.'' Texas A&M University Press, 2009. 669.


References

* Rosenberg, G.; Moretzsohn, F.; García, E. F. (2009). Gastropoda (Mollusca) of the Gulf of Mexico, Pp. 579–699 in: Felder, D.L. and D.K. Camp (eds.), Gulf of Mexico–Origins, Waters, and Biota. Texas A&M Press, College Station, Texas.


External links

*
Todd J.A. & Rawlings T.A. (2014). A review of the Polystira clade — the Neotropic's largest marine gastropod radiation (Neogastropoda: Conoidea: Turridae sensu stricto). Zootaxa. 3884(5): 445-491
{{DEFAULTSORT:Polystira Florencae florencae Gastropods described in 1934