''Fusiturricula armilda'' is a

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 ...

Drilliidae The Drilliidae are a taxonomic family of small predatory sea snails with high-spired shells. They are classified as marine gastropod mollusks in the superfamily Conoidea. This family has no subfamilies. It consists of about 30 genera and approxi ...

Description

The size of an adult shell varies between 17 mm and 60 mm. (Original description) The small, delicate shell is fleshy white, obscurely banded with brown, a pale belt on the body whorl just in front of the periphery. It contains 8

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 excluding 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 calle ...

. 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 acute, slightly shorter than 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 ...

including 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 ...

. The whorls show a conspicuous shoulder, above which a slightly concave spirally striate anal fasciole extends to the appressed suture, which on the last whorl or two shows indications of a marginal thickening. 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 ...

consists of (on the body whorl, about fifteen) protractive short riblets with subequal or slightly shorter interspaces apparently confined to the periphery: these are crossed by t\ro strong spiral threads, the posterior largest and forming oblong tumid nodules at the intersections. The anterior thread is also but less conspicuously nodulous or undulated. The rest of the surface is covered with fine spiral threads, of which there are three between the two large ones above mentioned. The base of the body whorl has fourteen coarse spiral threads with one to three finer intercalary threads. 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 very deep and wide The thin 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 sharp and much produced. 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 ...

is smooth, twisted and obliquely attenuated in front with an impervious axis. The siphonal canal lis ong, moderately narrow and slightly recurved. This species differs from ''

Fusiturricula fusinella ''Fusiturricula fusinella'' is a species of sea snail, a marine gastropod mollusk in the family Drilliidae.Bouchet, P. (2015). Fusiturricula fusinella (Dall, 1908). In: MolluscaBase (2015). Accessed through: World Register of Marine Species at h ...

'' by the obliquity of the ribs and the disparity in size between the peripheral spiral cords, which are quite equal and equally nodulous in ''F. fusinella''. W.H. Dall (1908): Reports on the Dredging Operations off the West Coast of Central America to the Galapagos, to the West Coast of Mexico, and in the Gulf of California, in charge of Alexander Agassiz, carried on by the U. S. Fish Commission Steamer "Albatross," during 1891, Lieut. Commander Z. L. Tanner, U. S. N., Commanding. XXX VII. Reports on the Scientific Results of the Expedition to the Eastern Tropical Pacific, in charge of Alexander Agassiz, by the U. S. Fish Commission Steamer "Albatross," from October, 1904, to March, 1905, Lieut. Commander L. M. Garrett, U. S. N., Commanding. XIV. The Mollusca and the Brachiopoda; Bulletin of the Museum of Comparative Zoology at Harvard v. 43 p. 275 (1904)
/ref>

Distribution

This species occurs in the

demersal zone The demersal zone is the part of the sea or ocean (or deep lake) consisting of the part of the water column near to (and significantly affected by) the seabed and the benthos. The demersal zone is just above the benthic zone and forms a laye ...

of the Eastern Pacific Ocean off the Galapagos Islands and from the

Gulf of California The Gulf of California ( es, Golfo de California), also known as the Sea of Cortés (''Mar de Cortés'') or Sea of Cortez, or less commonly as the Vermilion Sea (''Mar Bermejo''), is a marginal sea of the Pacific Ocean that separates the Baja C ...

, Western Mexico, to

Panama Panama ( , ; es, link=no, Panamá ), officially the Republic of Panama ( es, República de Panamá), is a transcontinental country spanning the southern part of North America and the northern part of South America. It is bordered by Co ...

References

Tucker, J.K. 2004 ''Catalog of recent and fossil turrids (Mollusca: Gastropoda)''. Zootaxa 682:1–1295

External links

* {{DEFAULTSORT:Fusiturricula Armilda armilda Gastropods described in 1908