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||0||Native||Estab|
|NEP-V||Northern California to Mid Channel Islands||2005||Def||Estab|
|P090||San Francisco Bay||2005||Def||Estab|
|P093||_CDA_P093 (San Pablo Bay)||2005||Def||Estab|
|31597||Foss 2009||2005||New York Point Marina||Def||38.0400||-121.8863|
|33483||Hershler et al. 2007||2005||Contra Costa County||Def||38.0360||-122.0710|
Littoridinops monroensis is a very small estuarine snail. Its shell is conical and dextrally coiled, with a sharp, pointed apex, consisting of 5-6 whorls. The whorls are slightly convex with shallow sutures. The aperture is about 1/2 the shell height, ovate to sub-circular, and sharply angled above. The inner lip is moderately thick, while the outer lip is a 'slight glaze'. The shell has a narrow umbilicus. The periostracum is tan or brown, but with spirals in juvenile snails. Maximum size is around 5.5 mm. Female shells from the upper San Francisco Bay ranged from 3.6 to 4.3 mm. Males are smaller, reaching a maximum of 2.8 mm, and have a prominent penis which is about 0.5 mm in length (Hershler et al. 2007). The penis has 17-50 papillae along its right margin arranged in 3-5 rows (Thompson 2004). Hydrobiid snails, as a group, require identification by specialists, and are not adequately covered in general guidebooks (e.g. Abbott 1974; Morris 1975; Gosner 1978; McLean 2007).
Amnicola forsythi (Pilsbry, 1930)
Potentially Misidentified Species
Native from Florida to Maryland
Native to the Gulf Coast of Florida and Alabama
Commonly known as the New Zealand Mudsnail, widely introduced in coastal fresh-brackish waters in Western North America, and in portions of the Great Lakes.
Native to California estuaries
Native to mineralized springs of the interior West, cryptogenic in brackish marshes of the San Francisco estuary (Hershler et al. 2007)
Invasion HistoryFirst Non-native North American Tidal Record: 2005
First Non-native West Coast Tidal Record: 2005
First Non-native East/Gulf Coast Tidal Record:
General Invasion History:
Littoridinops monroensis is native to estuarine waters from Maryland to Florida, Alabama (and possibly Texas), and the Bahamas (Thompson 1999; Hershler et al. 2007; Academy of Natural Sciences of Philadelphia 2013; Rosenberg 2013). It occurs in fresh waters of the Florida peninsula (Thompson 1999) and was recently (2009) discovered in coastal lagoons of southwestern Cuba, a range extension which Vazquez et al. (2010) attributed to migratory birds.
North American Invasion History:
Invasion History on the West Coast:
Littoridinops monroensis was discovered in 2005 in tidal marshes of Suisun Bay, California in the San Francisco Delta region and in marshes of San Pablo Bay, about 30 km west (seaward), at salinities of 2-17 PSU. The snails were very abundant, over a 3-year period and appear to be well-established. This snail lacks a planktonic larval stage, but could be transported in ballast water sediments (Hershler et al. 2007). An earlier introduction in dry ballast or an introduction from freshwater populations in Florida, with ornamental aquatic plants, is also possible.
Littoridinops monroensis is a small estuarine snail, occurring in brackish tidal marshes and lagoons, and also in non-tidal fresh waters in Florida (Thompson 2004; Hershler et al. 2007). Sexes are separate and eggs are fertilized by copulation. Development is direct, without a planktonic larva (Hershler et al. 2007).
Littoridinops monroensis ranges from temperate climates (e.g. Maryland) to subtropical climates (e.g. Florida, Bahamas, Cuba) including interior freshwaters and estuaries from 1 to 31 PSU (Thompson 2004; Hershler et al. 2007; Vazquez et al. 2012). Hydrobiid snails, such as L. monroensis, feed on organic deposits, benthic diatoms, and can also scrape microbes off sand particles (Lopez and Kofoed 1980).
|General Habitat||Nontidal Freshwater|
|General Habitat||Tidal Fresh Marsh|
|General Habitat||Salt-brackish marsh|
|General Habitat||Unstructured Bottom|
|General Habitat||Fresh (nontidal) Marsh|
|General Habitat||Grass Bed|
|Salinity Range||Limnetic||0-0.5 PSU|
|Salinity Range||Oligohaline||0.5-5 PSU|
|Salinity Range||Mesohaline||5-18 PSU|
|Salinity Range||Polyhaline||18-30 PSU|
|Tidal Range||Low Intertidal|
Tolerances and Life History Parameters
|Minimum Salinity (‰)||0||This species occurs in freshwater (Thompson 1999; Hershler et al. 2007)|
|Maximum Salinity (‰)||31||Filed, Vázquez et al. 2012)|
|Maximum Length (mm)||4.3||Females. Males have a maximum size of 3.6 (Hershler et al. 2007).|
|Broad Temperature Range||Warm temperate-Subtropical|
|Broad Salinity Range||Tidal Limnetic-Polyhaline|
General ImpactsLittoridinops monroensis is abundant in some marshes in the San Francisco Bay, but no impacts are reported.
ReferencesAbbott, R. Tucker (1974) American seashells; the marine Mollusca of the Atlantic and Pacific coasts of North America, None , New York. Pp. None
2002-2016a Malacology Collection Search. http://clade.ansp.org/malacology/collections/
Foss, Stephen (2009) A survey of non-indigenous aquatic species in San Francisco Bay, None , Sacramento CA. Pp. None
Gosner, Kenneth L. (1978) A field guide to the Atlantic seashore., In: (Eds.) . , Boston. Pp.
Hershler, Robert; Davis, Cheryl L.; Kitting, Christopher L.; Liu, Hsiu-ping (2007) Discovery of introduced and cryptogenic cochliopid gastropods in the San Francisco estuary, California., Journal of Molluscan Studies 73: 323-332
Lopez, G. R.; Kofoed, L. H. (1980) Epipsammic browsing and deposit feeding in mud snails Hydrobiidae., Journal of Marine Research 38: 585-600
McLean, James A. (2007) Gastropoda, None , Berkeley CA. Pp. 713-1766
Morris, Percy A. (1975) A field guide to shells of the Atlantic, None , Boston. Pp. None
1995-2015 Malacolog. http://www.acnatsci.org
2004 An identification manual for the freshwater snails of Florida an identification manual for the freshwater snails of florida an identification manual for the freshwater snails of florida an identification guide for the freshwater sn. http://www.flmnh.ufl.edu/malacology/fl-snail/snails1.htm
2002-2021 Invertebrate zoology collections database. http://collections.nmnh.si.edu/search/iz/
Vázquez, Antonio A.; Cobian, Dorka; Sánchez, Jorge; Pointier, Jean-Pierre (2012) First record of Littoridinops monroensis (Frauenfeld, 1863) (Gastropoda: Cochliopidae) in Cuba through a likely natural dispersal event, Molluscan Research Molluscan Research 32: 50-54