''Odostomia'' is the most speciose

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of minute

sea snail Sea snails are slow-moving marine (ocean), marine gastropod Mollusca, molluscs, usually with visible external shells, such as whelk or abalone. They share the Taxonomic classification, taxonomic class Gastropoda with slugs, which are distinguishe ...

s, pyramidellid

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. This genus is placed in the

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 ...

Pyramidellidae Pyramidellidae, common name the pyram family, or pyramid shells, is a voluminous taxonomic family of mostly small and minute ectoparasitic sea snails, marine heterobranch gastropod molluscs. The great majority of species of pyrams are micromol ...

in the subfamily

Odostomiinae Odostomiinae, ''Odostomia'' snails and their allies, is a taxonomic subfamily of minute parasitic sea snails. These are marine heterobranch gastropod mollusks, or micromollusks, in the family Pyramidellidae. Taxonomy The subfamily Odostomiinae ...

. There are several hundred species in this diverse genus (

Schander Carl Fredrik Christoffer Schander (21 May 1960 – 21 February 2012) was a professor in marine biology at the University of Bergen, Norway. He was also a thematic leader at the Centre of Excellence in Geobiology. His doctoral thesis (1997, Uni ...

et al. 1999) Bouchet, P.; Gofas, S. (2011). Odostomia Fleming, 1813. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=138413 on 3 June 2012 Most of the description of species in the genus ''Odostomia'' was carried out by Dall & Bartsch in 1909. Many of the described species are however suspected of being synonyms, or are proven synonyms. The genus ''Odostomia'' Fleming, 1813 was used by 19th century authors, particularly in the European literature, for most of the smaller

. It is still a catchall for most small pyramidellids lacking both axial and spiral sculpture. Some authors, e.g. Høisæter (2014), Peñas, Rolán & Swinnen (2014) and Giannuzzi-Savelli et al. (2014) who are here followed have attempted to redistribute some of the species, but there are still many species remaining unduly under ''Odostomia''. For these, the database

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

has refrained from making new combinations not backed by (or implicit from) a published source but, unless otherwise noted, the species that were already "accepted" under a subgenus now raised to full genus have been marked as "accepted" under that full genus. The European and American species of ''Odostomia'' differ in several anatomical and shell characteristics. They are therefore likely to be assigned to different genera.

Distribution

The genus ''Odostomia'' is common in all oceans from the tropics to the polar regions. It is mainly known from coastal areas and sandy shores, and is less common in the

deep sea The deep sea is broadly defined as the ocean depth where light begins to fade, at an approximate depth of or the point of transition from continental shelves to continental slopes. Conditions within the deep sea are a combination of low tempe ...

Description

There is little known about their life histories. Most species are only known from their shells. Most species have a white of yellowish, minute, conical to ovate-conical shell, usually between 2 mm and 5 mm. The

apex The apex is the highest point of something. The word may also refer to: Arts and media Fictional entities * Apex (comics) A-Bomb Abomination Absorbing Man Abraxas Abyss Abyss is the name of two characters appearing in Ameri ...

is rather obtuse or nipple-shaped, sinistrally or dextrally oriented to the teloconch. The

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 " ...

is usually deeply immersed in the first of the succeeding turns. The shells are variously sculptured, usually with a microsculpture. The

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 ...

contains in most cases between 4 and 6

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

s. The

body whorl The body whorl is part of the morphology (biology), morphology of the gastropod shell, shell in those gastropod mollusks that possess a coiled shell. The term is also sometimes used in a similar way to describe the shell of a cephalopod mollusk ...

is usually large, comprising 50-60% of the total length. The

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 ...

is suboval to ovate with the

peristome Peristome (from the Greek language, Greek ''peri'', meaning 'around' or 'about', and ''stoma'', 'mouth') is an anatomical feature that surrounds an opening to an organ or structure. Some plants, fungi, and shelled gastropods have peristomes. In mo ...

incomplete behind. There is usually a tooth-like fold on the

columella Lucius Junius Moderatus Columella (, Arabic: ) was a prominent Roman writer on agriculture in the Roman Empire. His in twelve volumes has been completely preserved and forms an important source on Roman agriculture and ancient Roman cuisin ...

. The shells usually have a small

umbilicus Umbilicus may refer to: *The navel or belly button *Umbilicus (mollusc), a feature of gastropod, Nautilus and Ammonite shell anatomy *Umbilicus (plant), ''Umbilicus'' (plant), a genus of over ninety species of perennial flowering plants *Umbilicus ...

or none at all.

Life habits

The members of ''Odostomia'' are

ectoparasite Parasitism is a Symbiosis, close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the Host (biology), host, causing it some harm, and is Adaptation, adapted str ...

s on other molluscs, and polychaetes. First they pierce the body wall with the buccal stylet and then feed on them by sucking blood with their buccal pump. They have become a pest of

oyster Oyster is the common name for a number of different families of salt-water bivalve molluscs that live in marine or brackish habitats. In some species, the valves are highly calcified, and many are somewhat irregular in shape. Many, but no ...

mussel Mussel () is the common name used for members of several families of bivalve molluscs, from saltwater and Freshwater bivalve, freshwater habitats. These groups have in common a shell whose outline is elongated and asymmetrical compared with other ...

scallop Scallop () is a common name that encompasses various species of marine bivalve molluscs in the taxonomic family Pectinidae, the scallops. However, the common name "scallop" is also sometimes applied to species in other closely related famili ...

s and

slipper limpet The Calyptraeidae are a family of small to medium-sized marine prosobranch gastropods.MolluscaBase. Calyptraeidae Lamarck, 1809. Accessed through: World Register of Marine Species at: http://www.marinespecies.org/aphia.php?p=taxdetails&id=141 on ...

s. Most of the Odostomia species are host-specific, only a few are not. ''Odostomia scalaris'' MacGillivray, 1843 is an ectoparasite on a wide range of hosts but especially known as a pest of mussels. ''Odostomia turrita'' Hanley, 1844 has been found on the European lobster ''Homarus gammarus'' (Linnaeus, 1758).Sneli, J.-A. (1972). Odostomia turrita found on Homarus gammarus Nautilus: Maandblad van het Koninklijk Belgisch Zeemanscollege = Nautilus: Revue mensuelle du Collège Royal Maritime Belge 86(1): 23

Species

References

* * * Fretter, V. M., and A. Graham. 1949. The structure and mode of life of the Pyramidellidae, parasitic opisthobranchs. J. Mar. Biol. Assoc. U.K. 28: 493-532 * Boss, K. J., and A. S. Merrill. 1965. Degree of host specificity in two species of ''Odostomia'' (Pyramidellidae: Gastropoda). Proc. Malacol. Sot. London 36: 349–355. * Vaught, K.C. (1989). ''A classification of the living Mollusca''. American Malacologists: Melbourne, FL (USA). . XII, 195 pp * Gofas, S.; Le Renard, J.; Bouchet, P. (2001). Mollusca, in: Costello, M.J. et al. (Ed.) (2001). ''European register of marine species: a check-list of the marine species in Europe and a bibliography of guides to their identification''. Collection Patrimoines Naturels, 50: pp. 180–213 * Spencer, H.; Marshall. B. (2009). ''All Mollusca except Opisthobranchia''. In: Gordon, D. (Ed.) (2009). New Zealand Inventory of Biodiversity. Volume One: Kingdom Animalia. 584 pp

External links

To Discoverlife

To GenBank

To ITIS

To World Register of Marine Species
{{Use dmy dates, date=May 2017 Pyramidellidae Gastropod genera