Xenophoridae, commonly called carrier shells, is a

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 ...

of medium-sized to large

sea snails 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 ...

, 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 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 ...

s in the

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

Littorinimorpha Littorinimorpha is a large order of snails, gastropods, consisting primarily of sea snails (marine species), but also including some freshwater snails ( aquatic species) and land snails ( terrestrial species).Bouchet P. & Rocroi J.-P. (Ed.); Frý ...

. According to the taxonomy of the Gastropoda by Bouchet & Rocroi (2005) the family Xenophoridae has no subfamilies.

Distribution

The Xenophorids live on sand and mud bottoms of the

continental shelves A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an island ...

and the continental slopes of the

subtropical The subtropical zones or subtropics are geographical zone, geographical and Köppen climate classification, climate zones to the Northern Hemisphere, north and Southern Hemisphere, south of the tropics. Geographically part of the Geographical z ...

and

tropical The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred to ...

seas and range from very shallow water to depths of more than 1,400 meters.Kreipl, K. & Alf, A. (1999): ''Recent Xenophoridae''. 148 pp. incl. 28 color plts. ConchBooks, Hackenheim, .

Shell description

Xenophorids are unusual in that in many of the species the animal cements small stones or shells to the edge of 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 o ...

as it grows, thus the shells of those species are sometimes humorously referred to as "shell-collecting shells". The genus name ''

Xenophora ''Xenophora'', commonly called carrier shells, is a genus of medium-sized to large sea snails, marine gastropod mollusks in the family Xenophoridae, the carrier snails or carrier shells. WoRMS (2012). Xenophora. Accessed through: World Regist ...

'' comes from two ancient Greek words and means "bearing (or carrying) foreigners". The shells are small to rather large (diameter of base without attachments 19–160 mm; height of shell 21–100 mm), depressed to conical, with narrow to wide, simple to spinose peripheral edge or flange separating

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 ...

from base.

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 ...

large, base broad, rather flattened, often umbilicate. Periostracum very thin or wanting.

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 ...

depressed-conical, multispiral (in one species paucispiral).

Teleoconch The gastropod shell is part of the body of a gastropod or snail, a kind of mollusc. The shell is an exoskeleton, which protects from predators, mechanical damage, and dehydration, but also serves for muscle attachment and calcium storage. Some ...

usually with foreign objects attached in spiral series to peripheral flange and, sometimes, remainder of dorsum, at least on early

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 ...

. Operculum horny, yellowish to brown, nucleus lateral, with simple growth lamellae, sometimes with conspicuous radial striae or hollow radial ribs.

Genera

Genera within the family Xenophoridae include: *''

Onustus ''Onustus'' is a genus of large sea snails, marine gastropod mollusks in the family Xenophoridae, the carrier shells. Description Shells medium-sized to large (diameter of base without attachments 80–160 mm; height of shell 42–100& ...

'' Swainson, 1840 - synonyms: ''Trochotugurium'' Sacco, 1896; ''Tugurium'' Fischer in Kiener, 1879 *'' Stellaria'' Möller, 1832 - synonym: ''Haliphoebus'' Fischer in Kiener, 1879; ''Xenophora'' (''Stellaria'') Schmidt, 1832 *''

'' Fischer von Waldheim, 1807WoRMS (2010). ''Xenophora'' Fischer von Waldheim, 1807. In: Bouchet, P.; Gofas, S.; Rosenberg, G. (2010) World Marine Mollusca database
on 2010-08-07 Accessed through: World Register of Marine Species
/ref> - type genus

References

External links

{{Taxonbar, from=Q4053381