Invasion History

First Non-native North American Tidal Record: 1843
First Non-native West Coast Tidal Record:
First Non-native East/Gulf Coast Tidal Record: 1843

General Invasion History:

Littoraria irrorata has a complex history in Northeastern North America. Its native range extends along the Gulf and East coasts from Texas northward, but it is absent from southern Florida (Abbott 1974; Rosenberg 2000). Its present northern range limit is on the Atlantic coast of New Jersey. Evidence from subfossil shells suggests that it ranged north into New England during a warm post-glacial period, but became extinct as the climate cooled (Bequaert 1943). In the late 19th century, it was re-introduced at several locations from Staten Island, New York (Smith and Prime 1870) to Vineyard Sound, Massachusetts (Verrill and Smith 1873), but apparently did not survive or reproduce (Bequaert 1943). Live specimens were found in the 1960s and 1970s in Manasquan Inlet, New Jersey and Long Island, New York (Jacobson 1965; Goldberg 1977). Climate change could result in a natural or human-assisted recolonization of southern New England.

North American Invasion History:

Invasion History on the East Coast:

Subfossil shells of Littoraria irrorata were abundant in post-glacial sediments near New Haven, Connecticut (Knight 1933). One shell was found in a Native American midden in Freetown, Massachusetts, near Fall River (Bequaert 1943). These shells date from a warm post-glacial period (3000-6000 years B.P) called the 'hypsithermal' or 'climatic optimum', when many marine and terrestrial organisms in North America extended their ranges north of their present range. Subsequent cooling led to local extinctions, or to disjunct populations in warmer coastal locations (Knight 1933; Pielou 1991). The northern limit of established living populations in the 19th century appears to have been Atlantic City, New Jersey (Say 1822).

Living specimens were found 'clinging to the stems of salt grass' in Harlem, New York by De Kay in 1843 (De Kay 1843) and 'on high sedge' at Stratford, Connecticut around 1845 (Linsley 1845, cited by Bequaert 1943), but populations apparently did not establish here. Verrill and Smith (1873) reported this snail occurring 'sparingly' in Vineyard Sound, Massachusetts, but they suggested that 'many shells of this species have undoubtedly been brought from Virginia and Maryland with the southern oysters planted in our waters’. Scattered records of live L. irrorata occurred from New York City, Long Island and Connecticut from 1933 to 1977 (Bequaert 1943; Jacobson 1965; Goldberg 1977); however, there is no evidence of prolonged survival or establishment. Transport on the hulls or decks of recreational boats, or on trailered boats is possible.


Littoraria irrorata is a mid-sized marine-estuarine snail, occurring in salt and brackish marshes. It has an ovate-conical shell, dextrally coiled, without an umbilicus. Its shell has about 5 whorls with a prominent, pointed spire. The shell is thick and robust, with numerous fine spiral grooves. The outer lip is prominent and slightly flaring, with fine grooves on the inner surface, but tapers to a thin inner edge. Adult shells commonly range from 20 to 32 mm. The color is grayish-white with fine streaks of reddish brown on the spiral ridges, and pale reddish-brown on the columella and callus of the inner lip. Description from: Bequaert 1946; Abbott 1974; Morris 1975; Kaplan 1988.


Taxonomic Tree

Kingdom:   Animalia
Phylum:   Mollusca
Class:   Gastropoda
Order:   Neotaenioglossa
Family:   Littorinidae
Genus:   Littoraria
Species:   irrorata


Litorina exarata (Philippi, 1848)
Litorina lineata (Emmons, 1858)
Littorina carolinensis (Conrad, 1863)
Littorina lindae (Petuch, 1994)
Littorina lunata (H. C. Lea, 1845)
Littorina sayi (Philippi, 1846)
Phasianella sulcata (Lamarck, 1822)
Turbo irroratus (Say, 1822)

Potentially Misidentified Species



Littoraria irrorata is a periwinkle snail associated with salt marshes. It has separate sexes. The snails copulate while out of the water on marsh grasses. Females lay eggs in single disc-shaped capsules, at or just below the water surface (Bingham 1972c). The eggs hatch into planktotrophic veligers (Bingham 1972a). Snails probably mature within 1-2 years, with females tending to be larger than males (Bingham 1972b).

Littoraria irrorata inhabits brackish salt marshes dominated by Spartina alterniflora (Smooth Cordgrass) and Juncus roemerianus (Black Needlerush) (Bingham 1972a; Vaughn and Fisher 1992). The periwinkles graze on mud substrate at low tide and tend to climb up grass stalks as the tide rises, apparently to escape predation by crabs and fishes (Bingham 1972a; Vaughn and Fisher 1992). Marshes inhabited by L. irrorata are subject to very high summer temperatures and to periods of low salinity during rainstorms (Vaughn and Fisher 1992). Littorina irrorata has been collected at salinities as low as 2 PSU (Montagna et al. 2008), but shows reduced activity below 10-15 PSU (Bingham 1972a). This snail grazes on marsh plants, particularly Spartina alterniflora, inflicting wounds, but not actually consuming much plant tissue. Instead, they primarily graze on ascomycete fungi growing in the wounded areas (Silliman and Newell 2003). Marsh periwinkles prefer S. alterniflora to an invasive marsh grass, Phragmites australis (Common Reed), apparently because of deterrent chemicals in Phragmites (Hendricks et al. 2011). They are preyed on by Blue Crabs (Callinectes sapidus), mud crabs (Panopeidae), Diamondback Terrapins (Malaclemmys terrapin), and other predators (Silliman and Bertness 2002).


algae, fungi

Trophic Status:




General HabitatCoarse Woody DebrisNone
General HabitatUnstructured BottomNone
General HabitatOyster ReefNone
General HabitatMarinas & DocksNone
General HabitatRockyNone
General HabitatSalt-brackish marshNone
Tidal RangeLow IntertidalNone
Tidal RangeMid IntertidalNone
Tidal RangeHigh IntertidalNone

Tolerances and Life History Parameters

Minimum Temperature (ºC)0Based on geographical range
Maximum Temperature (ºC)36Field, Galveston Bay TX (Bingham 1972)
Minimum Salinity (‰)2Field, southwest Florida rivers (Monatagna et al. 2008). Adults tolerated salinities down to 0 PSU for at least 2 weeks, but showed reduced activity below 15 PSU (Bingham 1972a). The Marsh Periwinkle inhabits meso-polyhaline marshes, but tolerates short-term reductions in salinity during rainstorms (Bingham 1972a; Lippson and Lippson 1997).
Maximum Salinity (‰)37Typical Gulf of Mexico salinity
Minimum Reproductive Salinity20Experimental, successful larval development (Bingham 1972)
Maximum Length (mm)32Kaplan 1988
Broad Temperature RangeNoneWarm temperate
Broad Salinity RangeNoneMesohaline-Euhaline

General Impacts

Littoraria irrorata are important grazers, affecting the biomass and structure of salt marshes along the coast of the Southeast US (Silliman and Bertness 2002; Silliman and Newell 2003). However, the sporadic introductions of these snails in coastal New York State and New England has not resulted in established populations or had significant impacts. However, climate change could extend the range and impacts of L irrorata northward.

Regional Distribution Map

Bioregion Region Name Year Invasion Status Population Status
CAR-I Northern Yucatan, Gulf of Mexico, Florida Straits, to Middle Eastern Florida 0 Native Estab
CAR-VII Cape Hatteras to Mid-East Florida 0 Native Estab
NA-ET3 Cape Cod to Cape Hatteras 1869 Native Estab
M040 Long Island Sound 1843 Def Extinct
M128 _CDA_M128 (Eastern Lower Delmarva) 0 Native Estab
M130 Chesapeake Bay 0 Native Estab
M120 Chincoteague Bay 0 Native Estab
M110 Maryland Inland Bays 0 Native Estab
M100 Delaware Inland Bays 0 Native Estab
M090 Delaware Bay 0 Native Estab
M080 New Jersey Inland Bays 0 Native Estab
N195 _CDA_N195 (Cape Cod) 1872 Def Extinct
M060 Hudson River/Raritan Bay 1886 Def Failed
M070 Barnegat Bay 1964 Native Unk
M050 Great South Bay 1972 Def Unk

Occurrence Map

OCC_ID Author Year Date Locality Status Latitude Longitude


Abbott, R. Tucker (1974) American Seashells, Van Nostrand Reinhold, New York. Pp. <missing location>

Allen, J. Frances (1954) Notes on the molluscan fauna of Galesville, Md., The Nautilus 67(4): 108-112

Allen, J. Frances (1954) Notes on the gastropods collected in the vicinity of Crisfield, Maryland, The Nautilus 67(3): 92-94

Bequaert, Joseph C. (1943) The genus Littorina in the Western Atlantic, Johnsonia 1(7): 1-27

Bingham, Frasier O. (1972a) The influence of environmental stimuli on the direction of movement of the supralittoral gastropod Littorina irrorata, Bulletin of Marine Science 22(3): 309-335

Bingham, Frasier O. (1972b) Shell growth in the gastropod Littorina irrorata, The Nautilus 85: 136-141

Bingham, Frasier O. (1972c) Some aspects of the reproductive biology of Littorina irrorata, Nautilus 86(1): 8-10

Crist, R. Wyle, Banta, William C. (1983) Distribution of the marsh periwinkle Littorina irrorata (Say) in a Virginia salt marsh, Gulf Research Reports 7(3): 225-235

De Kay, James E. (1843) Mollusca, Vol. 5, Zoology of New-York., In: (Eds.) Zoology of New-York. , Albany. Pp. <missing location>

Goldberg, Richard (1977) New and unusual species of shells on Long Island., Of Sea and Shore 8(3): 148, 150

Gould, Augustus A. (1870) <missing title>, Wright and Potter, State Printers, Boston. Pp. <missing location>

Henderson, John B.; Bartsch, Paul (1914) Littoral marine mollusks of Chincoteague Island, Virginia, Proceedings of the United States National Museum 47(2055): 411-421

Hendricks, Lindsey G.; Mossop, Hannah E.; Kicklighter, Cynthia E. (2011) Palatability and chemical defense of Phragmites australis to the Marsh Periwinkle snail Littoraria irrorata, Journal of Chemical Ecology 37: 838-845

Jacobson, Morris K. (1965) New records for New York and New Jersey., Nautilus 78(3): 83-86

Kaplan, Eugene H. (1988) A Field Gude to Southeastern and Caribbean Seashores, In: (Eds.) . , Boston. Pp. <missing location>

Knight, J. Brookes (1933) Littorina irrorata, a post-Pleistocene fossil in Connecticut, American Journal of Science Ser. 5, Vol. 26: 130-133

Lippson, Alice Jane; Lippson, Robert L. (1997) <missing title>, Johns Hopkins University Press, Baltimore. Pp. <missing location>

Montagna, Paul A.; Estevez, Ernest D.; Palmer, Terry A.; Flannery, Michael S. (2008) Meta-analysis of the relationship between salinity and molluscs in tidal river estuaries of southwest Florida, U.S.A, American Malacological Bulletin 24(1): 101-115

Morris, Percy A. (1975) A field guide to shells of the Atlantic, Houghton-Mifflin, Boston. Pp. <missing location>

Perkins, George H. (1869) Molluscan fauna of New Haven. A critical review of all the marine, fresh water and land Mollusca of the region, with descriptions of many of the living animals and of two new species. Part I. Cephalopoda and Gasteropda, Proceedings of the Boston Society of Natural History 13: 109-136

Pielou, E. C. (1991) <missing title>, University of Chicago Press, Chicago IL. Pp. 366

Rosenberg, Gary 1995-2023 Malacolog 4.1.

Say, Thomas (1822) An account of some of the marine shells of the United States, Journal of the Academy of Natural Sciences of Philadelphia 2: 221-248, 258-276,

Silliman, Brian R.; Newell, Steven Y. (2003) Fungal farming in a snail, Proceedings of the National Academy of Sciences 100(26): 15643-15648

Silliman, Brian Reed; Bertness, Mark D. (2002) A trophic cascade regulates salt marsh primary production, Proceedings of the National Academy of Sciences 99(16): 10500-10505

Smith, Sanderson; Prime, Temple (1870) Report on the Mollusca of Long Island, N. Y., and of its dependencies, Annals of the Lyceum of Natural History 9: 377-407

U.S. National Museum of Natural History 2002-2021 Invertebrate Zoology Collections Database.

Vaughn, Caryn C.; Fisher, Frank M. (1992) Dispersion of the salt-marsh periwinkle Littoraria irrorata: effects of water level, size, and season, Estuaries 15(2): 246-250

Verrill, A.E.; Smith, S.I. (1873) <missing title>, 1 Report of the United States Commission of Fish and Fisheries, <missing place>. Pp. 1-757