''Homalopoma luridum'', with the common name: Dall's dwarf turban, 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 small

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 ...

with

calcareous Calcareous () is an adjective meaning "mostly or partly composed of calcium carbonate", in other words, containing lime or being chalky. The term is used in a wide variety of scientific disciplines. In zoology ''Calcareous'' is used as an adje ...

opercula, a

marine Marine is an adjective meaning of or pertaining to the sea or ocean. Marine or marines may refer to: Ocean * Maritime (disambiguation) * Marine art * Marine biology * Marine debris * Marine habitats * Marine life * Marine pollution Military * ...

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

Colloniidae Colloniidae is a family of small sea snails with calcareous opercula, marine gastropod mollusks in the clade Vetigastropoda.MolluscaBase eds. (2020). MolluscaBase. Colloniidae Cossmann, 1917. Accessed through: World Register of Marine Species at ...

.Rosenberg, G. (2012). ''Homalopoma luridum'' (Dall, 1885). Accessed through:

World Register of Marine Species The World Register of Marine Species (WoRMS) is a taxonomic database that aims to provide an authoritative and comprehensive list of names of marine organisms. Content The content of the registry is edited and maintained by scientific specialist ...

at http://www.marinespecies.org/aphia.php?p=taxdetails&id=528071 on 2013-02-10

Description

The height of the shell varies between 6 mm and 10 mm. Its color is red, ashen or purple. The small, globose shell is very solid and imperforate. 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 conic, more or less depressed. The suture is moderately impressed. There are five

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. These are slightly convex, the last decidedly deflected toward 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 ...

, encircled by about fifteen subequal spiral lirae, separated by interstices about as wide as the ridges. The incremental striae are generally strongly developed, causing the liree to appear nodose or somewhat irregular, and the interstices to appear pitted. The oblique

is pearly white within. It measures about half the length of shell. 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 ...

is arcuate. The base of the shell is obsoletely uni- bi- or tri-dentate. The rounded oval operculum is nearly smooth and slightly concave in the middle.G.W. Tryon (1888), Manual of Conchology X; Academy of Natural Sciences, Philadelphia
(described as ''Leptothyra carpenteri'')

Distribution

This species occurs in abundant numbers in the Pacific Ocean under rocks and an shale at low tide from

Sitka russian: Ситка , native_name_lang = tli , settlement_type = Consolidated city-borough , image_skyline = File:Sitka 84 Elev 135.jpg , image_caption = Downtown Sitka in 1984 , image_size ...

, Alaska to Northern

Baja California Baja California (; 'Lower California'), officially the Free and Sovereign State of Baja California ( es, Estado Libre y Soberano de Baja California), is a state in Mexico. It is the northernmost and westernmost of the 32 federal entities of Mex ...

, Mexico.

References

External links

To Biodiversity Heritage Library (3 publications)

To Encyclopedia of Life

To USNM Invertebrate Zoology Mollusca Collection

To ITIS

To World Register of Marine Species
* {{Taxonbar, from=Q3736942 Colloniidae Gastropods described in 1885