''Ptychobela lavinia'', common name the lavinia turrid, 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

Pseudomelatomidae Pseudomelatomidae is a family of predatory sea snails, marine gastropods included in the superfamily Conoidea (previously Conacea) and part of the Neogastropoda ( Bouchet & Rocroi, 2005). In 1995 Kantor elevated the subfamily Pseudomelatomina ...

, the turrids and allies.

Description

The length of the shell varies between 35 mm and 50 mm. (Original description) the shell is rather coarse with about a dozen

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. The color of the shell is yellowish or light brown. 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 ...

is smooth and slightly bulbous. The suture is strongly appressed with a spiral cord in front of it. The whorls are moderatelyshouldered. The anal fasciole is somewhat concave and spirally striate. The axial sculpture consists of (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 ...

about 12) protractively oblique rounded ribs with subequal interspaces, prominent on the periphery, attenuated on the base and not reaching 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 ...

. The incremental lines are sharp, sometimes almost threadlike. The spiral sculpture consists of (from three to five on the spire, about 10 on the body whorl) strong, rounded cords overriding the ribs and not swollen at the intersections. The interspaces are subequal and sometimes with an intercalated smaller thread. Lastly the surface is finely minutely spirally striate in the intervals between the larger threads and cords. The aperture is narrow. 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 close to the suture, short and rounded, with a subsutural callus. The outer lip is produced, thin edged, more or less crenulate from the spiral sculpture and smooth within. The inner lip and the columella show a rather thick layer of callus with a slightly raised outer edge. The columella is straight. The siphonal fasciole is feeble. The

is short, wide and recurved. Dall (1919) Descriptions of new species of Mollusca from the North Pacific Ocean; Proceedings of the U.S. National Museum, vol. 56 (1920)

Distribution

This species occurs in the Pacific Ocean between Mexico and Peru

References

External links

*
Gastropods.com: ''Ptychobela lavinia''
{{DEFAULTSORT:Ptychobela Lavinia

lavinia In Roman mythology, Lavinia ( ; ) is the daughter of Latinus and Amata, and the last wife of Aeneas. Creation It has been proposed that the character was in part intended to represent Servilia Isaurica, Emperor Augustus's first fiancée. Stor ...

Gastropods described in 1919