''Pleurotomella parella'' is a species 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 in the family

Raphitomidae Raphitomidae is a family of small to medium-sized sea snails, marine gastropod mollusks in the superfamily Conoidea.Bouchet P. & Rocroi J.-P. (Ed.) (2005). "Classification and nomenclator of gastropod families". ''Malacologia'' 47(1-2). . 39 ...

Description

The length of the shell attains 41 mm, its diameter 13.5 mm. (Original description) The large, thin shell is elongate-fusiform. it is white with a very thin translucent periostracum. It contains about eight

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 exclusive of the (lost)

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 ...

. The spire rather is acute. The suture is slightly appressed. The whorl in front of it is polished and slightly constricted. The margin of the whorl here and there is obscurely plicate by the incremental lines. The surface of the fasciole here and there is marked by obscure, irregular, short, oblique, fine ridges at right angles to the lines of growth. In front of the fasciole are (on the penultimate whorl fourteen) low, feeble, protractively oblique ribs, with much wider shallow interspaces, hardly reaching the suture in front on the spire or the periphery on the

body whorl The body whorl is part of the morphology of the shell in those gastropod mollusks that possess a coiled shell. The term is also sometimes used in a similar way to describe the shell of a cephalopod mollusk. In gastropods In gastropods, the b ...

. The spiral sculpture is confined to the whorl in front of the fasciole and consists of (on the penultimate whorl about fifteen) fine, sharp incised lines, on the body of the whorl rather distant, the interspaces flat and often unequal but toward 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 ...

closer and more regular. The aperture is semilunar. The

anal sulcus The anal sulcus, also called the anal sinus or anal canal, in Gastropods is a notch, a shelly tube at the top of the aperture In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and fo ...

is near the suture, wide, shallow. The outer lip is very thin, sharp, simple. The body is polished. The columella is straight, gyrate, obliquely truncate in front. The axis is pervious. The siphonal canal is short, wide, in front slightly flaring.W.H. Dall (1908) Reports on the Mollusca and Brachiopoda, Bulletin of the Museum of Comparative Zoology at Harvard College. vol. 43
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Distribution

This marine species occurs off Ecuador and off Malpelo Island, South of, Colombia, North Pacific Ocean at a depth of 2070 m.

References

External links

*
Gastropods.com: ''Pleurotomella (Pleurotomella) parella''
{{DEFAULTSORT:Pleurotomella Parella parella Gastropods described in 1908