Xenophoridae, commonly called carrier shells, is a

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

of medium-sized to large

sea snails Sea snails are 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 absence of a visibl ...

, marine

gastropod Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and fro ...

mollusk Mollusca is a phylum of protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant species of molluscs are recognized, making it the second-largest animal phylum after Arthropoda. The ...

s in the

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

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

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 immediately to the Northern Hemisphere, north and Southern Hemisphere, south of the tropics. Geographically part of the Ge ...

and

tropical The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

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 Science Biology * Seashell, a hard outer layer of a marine ani ...

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 Register ...

'' 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. Spire ...

from base.

Aperture In optics, the aperture of an optical system (including a system consisting of a single lens) is the hole or opening that primarily limits light propagated through the system. More specifically, the entrance pupil as the front side image o ...

large, base broad, rather flattened, often umbilicate.

Periostracum The periostracum ( ) is a thin, organic coating (or "skin") that is the outermost layer of the shell of many shelled animals, including molluscs and brachiopods. Among molluscs, it is primarily seen in snails and clams, i.e. in gastropods an ...

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 many gastropods, including snails, 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 ...

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). In nature File:Photograph and axial plane floral diagram ...

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

Classification

Xenophoridae belongs to the superfamily

Stromboidea The Stromboidea, originally named the Strombacea by Rafinesque in 1815, is a superfamily of medium-sized to very large sea snails in the clade Littorinimorpha.MolluscaBase eds. (2020). MolluscaBase. Stromboidea Rafinesque, 1815. Accessed through ...

, which also includes the true conchs (

Strombidae Strombidae, common name, commonly known as the true conchs, is a Taxonomy (biology), taxonomic family (biology), family of medium-sized to very large sea snails in the superfamily (zoology), superfamily Stromboidea, and the Epifamily Neostromboid ...

). It had previously been placed in a monotypic superfamily, Xenophoroidea, but placement in Stromboidea is supported by behavioral, anatomical, and genetic data. Within Stromboidea, Xenophoridae appears to be most closely related to

Aporrhaidae Aporrhaidae is a family of sea snails commonly called the "pelican's foot snails." The taxonomy of the Gastropoda by Bouchet & Rocroi, 2005Bouchet P. & Rocroi J.-P. (Ed.); Frýda J., Hausdorf B., Ponder W., Valdes A. & Warén A. 2005. ''Classif ...

and

Struthiolariidae Struthiolariidae is a family (biology), family of small to medium-sized sea snails, marine (ocean), marine gastropod molluscs in the superfamilia, superfamily Stromboidea.Bouchet, P.; Rosenberg, G. (2014). Struthiolariidae Gabb, 1868. Accessed th ...

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

Genera

Genera within the family Xenophoridae include: * † '' Acanthoxenophora'' Perrilliat & Vega, 2001 * '' Aspidophoreas'' Nappo, Bini & Santucci, 2022 *'' Onustus'' Swainson, 1840 - synonyms: ''Trochotugurium'' Sacco, 1896; ''Tugurium'' Fischer in Kiener, 1879 * '' Ponderiana'' Nappo, Bini & Santucci, 2022 *''

Stellaria ''Stellaria'' is a genus of about 190 species of flowering plants in the family Caryophyllaceae, with a cosmopolitan distribution. Common names include starwort, stitchwort and chickweed. Description ''Stellaria'' species are relatively small ...

'' 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

Behavior

Like other stromboids, xenophorids move in a "leaping" manner. '' Xenophora conchyliophora'' has been found to move an average of 233.5 cm per day, with its speed during short-duration "sprints" averaging 1.44 cm per minute and reaching a maximum speed of 5.5 cm per minute. Xenophorids incorporate shells, coral, and other objects into their shells as they grow. Several different hypotheses have been proposed to explain this behavior.

References

External links

Family: Xenophoridae (Carrier Shells)

Troschel, F. H. (1852). Bericht über die Leistungen im Gebiete in der Naturgeschichte der Mollusken während des Jahres 1851. Archiv für Naturgeschichte. 18(2): 257-307

Gray, J. E. (1840). Shells of molluscous animals, pp. 105-152. in: Synopsis of the contents of the British Museum. ed. 42. G. Woodfall. London. 370 pp.

Adams, H. & Adams, A. (1853-1858). The genera of Recent Mollusca; arranged according to their organization. London, van Voorst. Vol. 1: xl + 484 pp.; vol. 2: 661 pp.; vol. 3: 138 pls.

Ladd, H.S. (1977). Cenozoic fossil mollusks from western Pacific islands; Gastropods (Eratoidae through Harpidae). U.S. Geological Survey Professional Paper. 533: i–iv, 1–84, pls 1–23

Ponder W.F. (1983). A revision of the Recent Xenophoridae of the World and of the Australian Fossil Species (Mollusca : Gastropoda). Memoir 17. The Australian Museum Sydney, Australia
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