''Turris selwyni'' is an extinct

species In biology, a species is the basic unit of Taxonomy (biology), 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 ...

of sea snail, a marine gastropod

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 es ...

in the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

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.MolluscaBase eds. (2022). MolluscaBase. Turris selwyni (Pritchard, 1904) †. Accessed through: World Register of Marine Species at: https://www.marinespecies.org/aphia.php?p=taxdetails&id=1394762 on 2022-12-29

Description

The length of the shell varies between 28 mm and 38 mm. (Original description) The shell has a tumidly fusiform or biconic shape. It is of medium size and build, with a comparatively broad body whorl rapidly tapering to a very acute

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 ...

, with an

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 ...

only slightly less than half the length of the shell, and a well-marked sinus on the keel. 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 calle ...

is small, smooth, with an obtuse nucleus composed of about two

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 flo ...

s gradually merging into the whorls of the spire. The spire contains eight whorls, with a somewhat irregular and ascending overlap, giving rise to a canaliculate suture. The whorls are convex and furnished medially with two spiral lirae which mark exactly the position of the sinus. A third spiral thread is usually visible just above the anterior suture, and a fourth weak one just below the posterior suture on the earlier spire whorls, while a fifth makes its appearance on the penultimate and antepenultimate whorls and the posterior sutural thread becomes stronger. On the body whorl below the sinus threads there are eight or nine stronger spiral lirae, and the space between the suture and the keel is strongly concave. The whole shell surface is finely spirally striate, the striae tending to be slightly undulatory owing to irregularities of growth, and increasing in strength towards the anterior of the shell. The spiral sculpture is crossed transversely by sinuated growth lines and striae of unequal strength. The sinus is broad and deep, and distinctly margined by the lirae forming the keel. The

is large, pyriform, and extending- to a short, broad, open, slightly bent

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 ...

. 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 thin and strongly arched at the middle, crenulate internally in conformity with the stronger spiral threads. 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 ...

margin is smooth and slightly enamelled. Pritchard (1904), Contributions to the palaeontology of the Older Tertiary of Victoria. Gastropoda. Part II; Proceedings of the Royal Society of Victoria 17 p. 326 pl. 19 fig. 1
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Distribution

Fossils of this marine species were found in

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recent" ...

strata in

Victoria Victoria most commonly refers to: * Victoria (Australia), a state of the Commonwealth of Australia * Victoria, British Columbia, provincial capital of British Columbia, Canada * Victoria (mythology), Roman goddess of Victory * Victoria, Seychelle ...

, Australia.

References

* Finlay, H. J. (1927). New specific names for Austral Mollusca. Transactions of the New Zealand Institute. 57: 488-533.

External links

A.W.B. Powell, The family Turridae in the Indo-Pacific. Part 1. The subfamily Turrinae
{{DEFAULTSORT:Turris Selwyni selwyni Gastropods described in 1904 Extinct gastropods