''Urosalpinx mengeana'' is an extinct

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 ...

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 ...

Muricidae, the murex snails or rock snails.

Description

The length of the shell attains 25 mm, its maximum diameter 18 mm. (Original description) The shell has a small, smooth, bulbous

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 ...

of 1½

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, followed by about six sculptured, rapidly enlarging later whorls. The protoconch is usually lost with the first one or two following whorls, so that the apex (as in our figure) seems somewhat blunt, but when perfect, though short, it is quite acute. The

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 ...

consists of 12-15 transverse rounded ribs, beginning at or near the suture and continuing over the periphery, becoming obsolete on the base of the whorl. The incremental lines are also somewhat alternated in strength and quite distinct. The spiral sculpture consists of (on the body whorl ten or twelve) sharp, even ridges, which override the ribs and descend into the interspaces, and each of which is usually accompanied by a pair of very fine, sharp threads parallel to it in the separating grooves. The ridges are usually very even in strength, but on the

siphonal canal The siphonal canal is an anatomical feature of the shells of certain groups of sea snails within the clade Neogastropoda. Some sea marine gastropods have a soft tubular anterior extension of the mantle called a siphon through which water is ...

vary, being sometimes weaker or even oalmost absent there. The suture is distinct, undulated by the ribs, not channelled The whorls are full and rounded, the last constricted at the base. 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 rather elongated, differentiated from the siphonal canal. The throat is strongly lirate, with 8-10 elevated threads ending a little way within the edge of the outer lip, which is crenulated by the sculpture. The columella is simple, with a thin callus. The siphonal canal is narrow, deepand somewhat recurved. The siphonal fasciole is strong, enclosing with the reflected columella a moderate, not very deep umbilical pit. W.H. Dall, Transactions of the Wagner Free Institute of Science of Philadelphia v.3:pt.1-3 (1890-1895)
/ref>

Distribution

Fossils were found in

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 ...

strata of

Florida 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 ...

, USA.

References

External links

A. P. Brown and H. A. Pilsbry. 1911. Fauna of the Gatun Formation, Isthmus of Panama. Proceedings of the Academy of Natural Sciencesof Philadelphia 63(2):336-373
{{DEFAULTSORT:Urosalpinx mengeana mengeana Gastropods described in 1890 Pleistocene gastropods