Littorina obtusata

Littorina obtusata
Littorina obtusata
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
Subclass:	Caenogastropoda
Order:	Littorinimorpha
Family:	Littorinidae
Genus:	Littorina
Species:	L. obtusata
Binomial name
Littorina obtusata (Linnaeus, 1758)
Synonyms
Litorina arctica Møller, 1842 Litorina ioides Menke, 1845 Litorina obtusata (Linnaeus, 1758) Litorina obtusata var. fasciata Menke, 1845 Litorina obtusata var. unicolor Menke, 1845 Litorina obtusata var. zonata Menke, 1845 Littorelaea pultneyii Leach in Gray, 1847 Littorina arctica (Møller, 1842) Littorina arctica var. angulata M. Sars, 1851 Littorina arctica var. eliator M. Sars, 1851 Littorina groenlandica var. laevior Mørch, 1857 Littorina obtusata f. elatiorangulata Middendorff, 1849 Littorina obtusata f. globosa Middendorff, 1849 Littorina obtusata f. magnei Sacchi, 1961 Littorina obtusata f. torquata Sacchi, 1963 Littorina obtusata littoralis var. albescens Dautzenberg & P. Fisher, 1925 Littorina obtusata littoralis var. alternata Dautzenberg & P. Fisher, 1915 Littorina obtusata littoralis var. fusca Dautzenberg & P. Fisher, 1915 Littorina obtusata littoralis var. inversicolor Dautzenberg & P. Fisher, 1915 Littorina obtusata littoralis var. olivacea Dautzenberg & P. Fisher, 1915 Littorina obtusata littoralis var. rhabdota Dautzenberg & P. Fisher, 1915 Littorina obtusata littoralis var. rubens Dautzenberg & P. Fisher, 1915 Littorina obtusata lutea Dautzenberg & P. Fisher, 1915 Littorina obtusata var. aestuarii Jeffreys, 1869 Littorina obtusata var. albida Schlesch, 1930 Littorina obtusata var. ambigua Dautzenberg & P. Fisher, 1915 Littorina obtusata var. aurantia Dautzenberg, 1893 Littorina obtusata var. balteata Dautzenberg & P. Fisher, 1915 Littorina obtusata var. castanea Dautzenberg & P. Fisher, 1915 Littorina obtusata var. citrina Dautzenberg, 1893 Littorina obtusata var. lineolata Dautzenberg & P. Fisher, 1915 Littorina obtusata var. orana Norman, 1888 Littorina obtusata var. ornata Jeffreys, 1865 Littorina obtusata var. pulchra Schlesch, 1930 Littorina obtusata var. tessellata Dautzenberg & P. Fisher, 1915 Littorina obtusata var. virescens Schlesch, 1930 Littorina palliata Say, 1821 Littorina palliata var. auricularia Schlesch, 1916 Littorina palliata var. carinata Schlesch, 1916 Littorina preconica S. Smith, 1860 Littorina tenebrosa f. elatiorcrassa Middendorff, 1849 Littorina tenebrosa var. obtusataea Middendorff, 1849 Nerita litoralis Turton, 1819 Turbo neritiformis Brown, 1827 Turbo obtusatus Linnaeus, 1758 Turbo palliatus Say, 1822 Turbo retusus Lamarck, 1822

Littorina obtusata, common name the flat periwinkle, is a species of sea snail, a marine gastropod mollusk in the family Littorinidae, the winkles or periwinkles.

Description

Littorina obtusata, Flat Periwinkles, are sea snails and sea slugs. They grow to 1.5 cm in height. They can be brown, yellow, olive green, and black. They are mostly found in the colors of brown, reddish brown, or yellow, with few being red or white because of the abundance of brown seaweed. Littorina obtusata get the name, Flat Periwinkle, because they have a flattened spire and a large tear-dropped shaped aperture. The last whorl of the shell makes up 90% of their height. The maximum recorded shell length is 13.5 mm. This species is mainly littoral, but also has gill respiration. This means that they can survive both in water, and extended amounts of time on land.

L. obtusata: various shell colours

Distribution

This marine species occurs wherever brown seaweeds grow. It is widely distributed: the Baltic Sea, in European waters from Norway down to Southern Spain, in the Mediterranean Sea, in the Northeast Atlantic Ocean along the Gulf of Maine.

Scientific Background

The flat periwinkle is not highly studied, so not much is known about them. Despite this, there have been recent developments in research on them, such as the following: It has been suspected that the L. Obtusata and L. Falbalis were the same species, then diverged into two species during their evolution. Scientists were still debating when this divergence occurred. L. Obtusata tends to be bigger and live longer than L. Falbalis. Research suggests that L. Obtusata and L. Falbalis are starting to hybridize despite the strong differences in their genetics. The name of the hybridized species is L. Saxatilis, but there is little information and research on it.

Habitat

This species can be found in the littoral and sublittoral zone on rocky shores and piers, usually on brown algae of the genus Fucus. Minimum recorded depth is 0 m. Maximum recorded depth is 110 m. The habitat may define its color. On sheltered shores it has a lighter and uniform color (yellow, brown, orange or olive green). On exposed shores its color is darker and chequered. They are tolerant of low salinities and wide ranges of exposure.

Diet

Littorina obtusata are herbivores that primarily eat algae. They scrape algae from surfaces using their radula which contains thousands of tiny teeth. They are commonly associated with, and feed upon, the dominant intertidal brown algae, Ascophyllum nodosum.

Threats

Littorina obtusata are very good at adapting to new areas and predators. Their largest predator is the Carcinus maenas, the green crab. As the threat of these crabs raised, Littorina obtusata's shells have thickened to protect themselves. Wader birds also threaten Littorina obtusata's population. They forage in intertidal zones, preferring the low-water mudflats, but when they are submerged, they use the Ascophyllum/Fucus belts

Reproduction

Female Littorina obtusata deposit spawn masses on Ascophyllum nodosum, Fucus serratus, Fucus vesiculosus, and sometimes on rock surfaces. Their eggs are whitish and oval, or kidney shaped. They are encased in a mass of transparent jelly. Littorina obtusata eggs take up to four weeks to fully develop and for the snail to emerge. Sexual maturity is reached at about two years. They continue to reproduce all year round with their maximum from spring to fall

References

Notes

Bibliography

• Backeljau, T. (1986). Lijst van de recente mariene mollusken van België [List of the recent marine molluscs of Belgium]. Koninklijk Belgisch Instituut voor Natuurwetenschappen: Brussels, Belgium. 106 pp
• BODC (2009). Species list from the British Oceanographic Data Centre
• Pizzolla, P.F. 2008. The Marine Life Information Network. April 17. Accessed April 3, 2025. https://marlin.ac.uk/species/detail/1487.
• Reid, D.G. (1989a) The comparative morphology, phylogeny and evolution of the gastropod family Littorinidae. Philosophical Transactions of the Royal Society of London, Series B 324: 1–110
• Reid D.G. (1996). Systematics and evolution of Littorina. The Ray Society 463p
• Schmidt, Paul S., Megan Phifer-Rixey, Graeme M. Taylor, and John Christner. 2007. "Genetic heterogeneity among intertidal habitats in the flat periwinkle, littorina obtusata." Molecular Ecology 16 (11): 2393-2404. doi:10.1111/j.1365-294x.2007.03323.x.
• Sotelo, Graciela, Mårten Duvetorp, Diana Costa, Marina Panova, Kerstin Johannesson, and Rui Faria. 2020. "Phylogeographic history of flat periwinkles, Littorina Fabalis and L. obtusata." BMC Evolutionary Biology 20 (1). doi:10.1186/s12862-019-1561-6.
• n.d. The Wildlife Trusts. https://www.wildlifetrusts.org/wildlife-explorer/marine/sea-snails-and-sea-slugs/flat-periwinkle.
• Velasco, Schuyler. 2025. "Shells of their former selves: How sea snails have adapted to invasive predators." Northeastern University. doi:https://phys.org/news/2025-03-shells-sea-snails-invasive-predators.html.
• Wilbur, Andrew K., and Robert S. Steneck. 1999. "Polychromatic Patterns of Littorina obtusata on Ascophyllum nodosum: Are Snails." Eagle Hill Institute 189-198. https://www.jstor.org/stable/3858593.
• 2024. Flat periwinkles: Their diet and feeding behavior. January 26. Accessed April 3, 2025. https://angolatransparency.blog/en/what-do-flat-periwinkles-eat/.

External links

• "Littorina (Littorina) obtusata obtusata". Gastropods.com. Retrieved 16 May 2011.
• Photos of Littorina obtusata on Sealife Collection