''Littorina'' is a

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 small

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, 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 ...

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

s 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 ...

Littorinidae, the winkles or periwinkles.WoRMS (2011). Littorina Férussac, 1822. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=138135 on 2011-04-15 These small

snails A snail is a shelled gastropod. The name is most often applied to land snails, terrestrial molluscs, terrestrial pulmonate gastropod molluscs. However, the common name ''snail'' is also used for most of the members of the molluscan class Gas ...

live in the tidal zone of rocky shores.

Overview

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

there are about nine species in this genus, one of which is the rough periwinkle, ''

Littorina saxatilis ''Littorina saxatilis'', common name the rough periwinkle, is a species of small sea snail, a marine (ocean), marine gastropod mollusc in the family Littorinidae, the winkles or periwinkles. First identified in the 1700s, it has been misidentifie ...

'' (Olivi, 1792). Another closely related (supposed) species ''Littorina tenebrosa'' (Montagu 1802) was thought to be distinct because of its different ecological requirements, but current studies have shown that it is not at all clear whether the two are indeed separate species or whether ''L. tenebrosa'' is perhaps merely an ecotype (an ecological form) of ''L. saxatilis''.Gosling, E.M. (2002). ''The periwinkle as a model in biodiversity studies: a geneticist's view.'' in Marine Biodiversity in Ireland and Adjacent Waters. Ulster Museum. publication no. 8 ''Littorina'' has given its name to the

Littorina Sea Littorina Sea (also Litorina Sea) is a geological brackish water stage of the Baltic Sea, which existed around 8500–4000 Before Present, BP and followed the Mastogloia Sea (initial Littorina Sea), a transitional stage from the Ancylus Lake. ...

, the geologic precursor of the

Baltic Sea The Baltic Sea is an arm of the Atlantic Ocean that is enclosed by the countries of Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia, Sweden, and the North European Plain, North and Central European Plain regions. It is the ...

Distribution

The periwinkles are found on the seashore in the

littoral zone The littoral zone, also called litoral or nearshore, is the part of a sea, lake, or river that is close to the shore. In coastal ecology, the littoral zone includes the intertidal zone extending from the high water mark (which is rarely flood ...

and sublittoral zone in all parts of the world. In the Baltic they live within the influence of freshwater, and frequently become distorted in consequence.

Description

The thick, pointed shell is turbinated and has few whorls. The aperture is rounded. The outer lip is acute. 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 ...

is rather flattened and imperforate. The operculum is paucispiral. The lingual teeth are hooked and trilobed. The uncini (small teeth on the radula) are hooked and dentated.

Species

The type species:''Turbo littoreus''

Linnaeus Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...

, 1758 restricts the species in this genus to the northern hemisphere, moderate and cold zones. The tropical species belong in other genera of the same family Bandel, K. & D. Kadolsky (1982). Western Atlantic Species of Nodolittorina (Gastropda: Prosobranchia): comparative morphology and its functional, ecological, phylogenetic and taxonomic implications. Veliger 25 (1): 1-42. Species in the genus ''Littorina'' include * '' Littorina aleutica'' Dall, 1872 * '' Littorina arcana'' Hannaford-Ellis, 1978 * '' Littorina brevicula'' (Philippi, 1844) * '' Littorina compressa'' Jeffreys, 1865 * '' Littorina fabalis'' (Turton, 1825) * '' Littorina horikawai'' Matsubayashi & Habe in Habe, 1979 * '' Littorina islandica'' Reid, 1996 † * '' Littorina kasatka'' Reid, Zaslavskaya & Sergievsky, 1991 * '' Littorina keenae'' Rosewater, 1978 * '' Littorina littorea'' (

, 1758), Common periwinkle * '' Littorina mandshurica'' (Schrenk, 1861) * '' Littorina natica'' Reid, 1996 * '' Littorina obtusata'' (

, 1758), flat periwinkle * '' Littorina petricola'' Arnold, 1908 † * '' Littorina plena'' Gould, 1849 * '' Littorina remondii'' Gabb, 1866 † * ''

'' (Olivi, 1792), rough periwinkle * '' Littorina scutulata'' Gould, 1849, checkered periwinkle * '' Littorina sitkana'' Philippi, 1846 * '' Littorina sookensis'' Clark & Arnold, 1923 † *'' Littorina squalida'' Broderip & Sowerby, 1829 * '' Littorina subrotundata'' (Carpenter, 1864) * '' Littorina varia'' * '' Littorina zebra'' ;Species brought into synonymy: * ''Littorina aestuarii'' Jeffreys, 1865: synonym of ''Littorina obtusata'' (Linnaeus, 1758) * ''Littorina affinis'' d'Orbigny, 1839: synonym of '' Tectarius striatus'' (King & Broderip, 1832) * ''Littorina angulifera'' is a synonym for '' Littoraria angulifera'' (Lamarck, 1822) * ''Littorina arenica'' Jay, 1839: synonym of '' Tectarius striatus'' (King & Broderip, 1832) * ''Litorina arenica'' Dunker, 1845: synonym of '' Tectarius striatus'' (King & Broderip, 1832) * ''Littorina canariensis'' d'Orbigny, 1839: synonym of '' Tectarius striatus'' (King & Broderip, 1832) * ''Littorina cingulifera'' R. W. Dunker, 1845: synonym of '' Littoraria cingulifera'' R. W. Dunker, 1845 * ''Litorina globosa'' Dunker, 1845: synonym of '' Tectarius striatus'' (King & Broderip, 1832) *'' Littorina granularis'' Gray, 1839: synonym of '' Echinolittorina miliaris'' (Quoy & Gaimard, 1833) * ''Littorina lamellosa'' Souverbie, 1861: synonym of '' Fossarus lamellosus'' (Souverbie, 1861) * ''Littorina marnat'' Potiez & Michaud, 1838: synonym of '' Echinolittorina punctata'' (Gmelin, 1791) * ''Littorina obesa'' (G.B. Sowerby, 1832): synonym of '' Littoraria coccinea'' (Gmelin, 1791) * ''Littorina petraeus'' (Montagu, 1803): synonym of '' Melarhaphe neritoides'' (Linnaeus, 1758) * ''Littorina planaxis'' G.B. Sowerby I, 1844: synonym of '' Tectarius striatus'' (King & Broderip, 1832) * ''Littorina saxatilis jugosa'' Montagu, 1803: synonym of ''Littorina saxatilis'' (Olivi, 1792) * ''Littorina saxatilis nigrolineata'' Gray, 1839: synonym of ''Littorina saxatilis'' (Olivi, 1792) * ''Littorina striata'' is a synonym for '' Tectarius striatus'' (King & Broderip, 1832) * ''Littorina undulata'' Gray, 1839: synonym of '' Littoraria undulata'' (Gray, 1839) * ''Littorina unifasciata antipodum'': synonym of '' Austrolittorina antipodum'' (Philippi, 1847) * ''Littorina ziczac'' is a synonym for '' Echinolittorina ziczac'' (Gmelin, 1791) * ''Littorina zonaria'' Bean, 1844: synonym of ''Littorina saxatilis'' (Olivi, 1792)

References

* Reid D.G. (1996). ''Systematics and evolution of Littorina''. The Ray Society 463p {{Authority control Gastropod genera Littorinidae