''Vertigo milium'',

common name In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often contrast ...

the blade vertigo, is a

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 ...

of minute air-breathing

land snail A land snail is any of the numerous species of snail that live on land, as opposed to the sea snails and freshwater snails. ''Land snail'' is the common name for terrestrial gastropod mollusks that have shells (those without shells are known as ...

, a

terrestrial Terrestrial refers to things related to land or the planet Earth. Terrestrial may also refer to: * Terrestrial animal, an animal that lives on land opposed to living in water, or sometimes an animal that lives on or near the ground, as opposed to ...

pulmonate Pulmonata or pulmonates, is an informal group (previously an order, and before that a subclass) of snails and slugs characterized by the ability to breathe air, by virtue of having a pallial lung instead of a gill, or gills. The group includ ...

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

Vertiginidae Vertiginidae, common name the whorl snails, is a family of minute, air-breathing land snails, terrestrial pulmonate gastropod molluscs or micromollusks in the superfamily Pupilloidea. Distribution The distribution of the Vertiginidae is in the ...

, the whorl snails. MolluscaBase eds. (2023). MolluscaBase. Vertigo milium (A. Gould, 1840). Accessed through: World Register of Marine Species at: https://www.marinespecies.org/aphia.php?p=taxdetails&id=1065107 on 2023-02-10 The variety ''Vertigo milium var. antillarum'' Pilsbry, 1934 is a taxon inquirendum.

Shell description

The

shell Shell may refer to: Architecture and design * Shell (structure), a thin structure ** Concrete shell, a thin shell of concrete, usually with no interior columns or exterior buttresses ** Thin-shell structure Science Biology * Seashell, a hard ou ...

is small, subcylindrical, smooth shining. Growth lines are very fine, a little oblique.

Apex The apex is the highest point of something. The word may also refer to: Arts and media Fictional entities * Apex (comics), a teenaged super villainess in the Marvel Universe * Ape-X, a super-intelligent ape in the Squadron Supreme universe *Apex ...

is smooth. The color of the shell is dark chest-nut. The shell has 5 rounded

whorls 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 d ...

, that are somewhat regularly increasing and decreasing to a bluntly rounded apex. Sutures are impressed. 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 obscurely semicircular, lateral and truncated above. The "circumference" of the aperture is "made up of two curves of different radius uniting in the peristome, where the junction causes an angle projecting inwards, the smaller curve comprising about one-fourth part and forming the superior portion of the peristome. The aperture has six teeth as follows: two sharp, projecting teeth of about equal size placed on the parietal wall and dividing that region into three nearly equal parts; one on 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 wo ...

, large, massive, broad; a third placed on the outer lip above or at the junction of the two radii, long, curved, ridge-like, pointing directly between the two parietal teeth; a fourth on the base of the lip, small, conical, tubercular; and one large, entering, elevated, long lamina, which begins on the base of the lip and curves backward until it disappears behind the columella tooth (this is the "gular lamina" of Sterki). Peristome is white or brownish-white, reflected, the terminations separated, but joined by a prominent callus. The umbilicus is well marked, open, deep. Base of the shell is rounded. The width of the shell is 0.80–0.90 mm. The height of the shell is 0.90–1.40 mm. The height of aperture is 0.25–0.30 mm.

Anatomy

The animal is similar in form to the other species of ''Vertigo''. The color is dirty white, darker on the upper surface. The foot is very broad, posterior of the center, from whence it tapers rapidly to a point. The foot is thick and fleshy and well able to support the light shell. Eye-peduncles are of medium length, somewhat enlarged at the tips, where the eyes are placed. The jaw is very slightly arcuate, the ends a trifle rounded. Concave margin is notched and anterior surface lightly striated. The jaw is of equal width throughout its length. The formula of the

radula The radula (, ; plural radulae or radulas) is an anatomical structure used by molluscs for feeding, sometimes compared to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food ...

is like this: ₂ ⁷ ₇ + + + + ₂ ⁷ ₇ Teeth are as in the other members of the genus. There are four perfect lateral teeth and the first marginal tooth is similar but with a second outer cusp. From this point the marginals become wider, the inner cusp remains always the larger, and the outer cusp develops from five to seven small cusps or denticles.

Distribution

Distribution of ''Vertigo milium'' include

Illinois Illinois ( ) is a U.S. state, state in the Midwestern United States, Midwestern United States. Its largest metropolitan areas include the Chicago metropolitan area, and the Metro East section, of Greater St. Louis. Other smaller metropolita ...

Maine Maine () is a state in the New England and Northeastern regions of the United States. It borders New Hampshire to the west, the Gulf of Maine to the southeast, and the Canadian provinces of New Brunswick and Quebec to the northeast and north ...

Minnesota Minnesota () is a state in the upper midwestern region of the United States. It is the 12th largest U.S. state in area and the 22nd most populous, with over 5.75 million residents. Minnesota is home to western prairies, now given over to ...

Ontario Ontario ( ; ) is one of the thirteen provinces and territories of Canada.Ontario is located in the geographic eastern half of Canada, but it has historically and politically been considered to be part of Central Canada. Located in Central Ca ...

and

Quebec Quebec ( ; )According to the Canadian government, ''Québec'' (with the acute accent) is the official name in Canadian French and ''Quebec'' (without the accent) is the province's official name in Canadian English is one of the thirtee ...

, Canada, to

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 ...

and

Texas Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...

,Kathryn E. Perez. (last edited September 12, 2006
''Land Snail List for Texas''
. accessed 25 June 2009. USA.

Habitat

Baker (1902) described habitat like this: "Gregarious. Found plentifully under leaves, stones and sticks, in moist situations."

References

This article incorporates public domain text from reference. Baker F. C. (25 April) 1902
''The Mollusca of the Chicago Area''
Part II. ''Gastropoda''. Bulletin No. III. of the Natural History Survey, The Chicago Academy of Sciences, 418 pp. 33 plates, pag
241
��242. * Gould, A. A. (1840). Monograph of the species of Pupa found in the United States; with figures. Boston Journal of Natural History. 3(3): 395-404, plate 3. * Thompson, F. G. (2011). An annotated checklist and bibliography of the land and freshwater snails of México and Central America. Florida Museum of Natural History Bulletin. 50(1): 1-299 * Rosenberg, G. & Muratov, I. V. (2006). Status report on the terrestrial Mollusca of Jamaica. Proceedings of the Academy of Natural Sciences of Philadelphia. 155: 117-161; Erratum: 156: 401 (2007).

External links

photos of shells of ''Vertigo milium''
*

Manual of Conchology George Washington Tryon Jr. (20 May 1838 – 5 February 1888) was an American malacologist who worked at the Academy of Natural Sciences in Philadelphia. Biography George Washington Tryon was the son of Edward K. Tryon and Adeline Savidt. ...

, volume 25
plate 13
figures 1–7.
Pilsbry, H. A. (1900). Land snails of Cape May, New Jersey. The Nautilus. 14(7): 73-75

Pilsbry, H. A. (1911). Land shells of Atlantic City, New Jersey. The Nautilus. 25(3): 34-35
{{DEFAULTSORT:Vertigo Milium milium Molluscs of Canada Molluscs of the United States Gastropods described in 1840 Taxa named by Augustus Addison Gould