Minnesota Snails and Slugs

 

Class Gastropoda

Gastropoda (gastropods) is the class of invertebrates that includes sea, freshwater, and land snails, and sea and land slugs. It is a very large class, second only to insects in the number of known species, and the largest class in the phylum Molluska (Mollusks).

There are about 13,000 genera in 721 families of gastropods. This includes both still living (extant) gastropods and those known only from the fossil record. About 85,000 extant species have been described, but estimates put the total number at about 240,000. Snails are those species that have a shell large enough that the body can completely withdraw into it. Slugs are those species without a shell. Semi-slugs are those species with a shell too small to completely contain the body.

Gastropods are characterized by the following:

  • during development, the visceral mass rotates 180 degrees to one side (undergoes torsion), placing the anus more or less above but to one side of the head;
  • a muscular foot;
  • two or four sensory tentacles with eyes at the end or near the outer bases of the tentacles; and
  • a long, file-like tongue that can be extended greatly.

  Orange-banded arion  
  Photo by Alfredo Colon  

 

Recent Additions

Dusky slug

Dusky slug (Arion subfuscus/fuscus) is common, exotic, terrestrial slug. It is native to northern Europe and was introduced into North America in the vicinity of Boston in 1842. By 1940 it was widespread across North America. It is found in moist or wet areas in deciduous and coniferous woodlands, in meadows on rocks, and in old fields and waste places. It is often encountered in areas of human activity, including in roadsides, gardens, campgrounds, wood piles, and window wells. In natural areas it is sometimes more abundant than native snail and slug species. It can a pest of agricultural crops, forest replantings, and gardens.

  dusky slug

Photo by Greg Watson

Two species of dusky slug are often treated as a single species complex, a group of species so similar that the boundaries are unclear. Aside from their geographic distribution, the two species can only be distinguished by the size and color of the genitalia of dissected individuals, or by analysis of their alloenzymes. Both species have been introduced into North America.

Adults are long and slender when extended, short and bell-shaped when contracted. The body is covered with rows of pale bumps, giving it a finely granular appearance. It is variable in color, but populations generally fit into one of four color groups: blackish-brown, yellowish-brown, orange, and reddish-brown. The orange or yellowish-orange color is mostly – or completely – due to a covering of mucus. When handled, the mucus will stain the handler’s fingers. There is usually a brown stripe on each side.

Great pond snail

Great pond snail (Lymnaea stagnalis) is a very large, air-breathing, freshwater snail. It is commonly sold as an aquarium pet. The body contains both male and female reproductive organs (hermaphroditic). During copulation either the male role or the female role can be performed, though not both. This makes it the ideal subject for recent scientific research into handedness (chirality).

Great pond snail occurs in Europe, Asia, North America, and southern Australia. It occurs throughout the United States and Canada, but it is uncommon south of the 40th parallel. It is common in Minnesota. It is found in permanent, slow or still waters, usually with dense vegetation, including creeks, streams, rivers, marshes, swamps, and reservoirs, and at the edges of lakes and large ponds.

  great pond snail

Photo by Luciearl

The shell is thin and has 4½ to 6 whorls. The last whorl is the body whorl and is greatly inflated. The remaining whorls are elevated forming a sharply pointed spire. When seen with the tip at the top and the opening facing up, the opening is on the right side. There is no door-like structure covering the opening of the shell. The shell is variable in color, tan to dark brown, and it has no obvious markings. A cavity within the shell has an air bubble that is refreshed every time the snail rises to the water surface to breathe.

Gray field slug

Gray field slug (Deroceras reticulatum), also known as milky slug, is a common, exotic, terrestrial, smooth land slug. It is native to northern Europe, North Africa, and the Atlantic islands. It was introduced into North America and now occurs across the continent. It is most common in southern Canada and northern United States. It can be a serious crop pest, but is not listed as invasive nationally or in Minnesota. It is usually found above ground but under stones or leaf litter in open areas, especially cultivated areas.

Gray field slug is stout, 1 to 2 long and white, cream, gray, or tan. When at rest, the body is contracted and the tentacles are retracted. When traveling, the body is stretched out, the tentacles are extended, and it exudes a clear mucus. When disturbed, it exudes white mucus over its entire body, leading to one of its common names, milky slug.

  gray field slug

Photo by Alfredo Colon

Orange-banded arion

Orange-banded arion (Arion fasciatus) is a common, exotic, land slug. It is native to northern Europe and was introduced into North America during the colonial era. It has slowly spread from New England north to Quebec, south to North Carolina, and west to Minnesota. It is listed as invasive in Wisconsin, but not in Minnesota and not nationally. It is found in ground litter and on herbaceous plants in forests, wet meadows adjacent to streams, and open and cultivated areas, including old fields and gardens.

Orange-banded arion is 1¼ to 2 long and slender when extended, short and bell-shaped when contracted. It is grayish to yellowish-brown and is covered with rows of pale bumps, giving it a granular appearance. There are two lateral, dark, blurry, longitudinal stripes. The area just below each stripe is yellowish, and the area below that is whitish. The head and tentacles are black.

  orange-banded arion

Photo by Alfredo Colon

Other Recent Additions

 

 

 

 

 

 

 

 

 

 

This list includes only gastropods that have been recorded in Minnesota, but not all of the gastropods found in Minnesota.

 

Profile Photo Video      
       

acute bladder snail (Physa acuta)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

dusky slug

 

 

 

 

 

 

 

gray field slug

great pond snail

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

red raspberry slime mold

       

amber glass (Nesovitrea electrina)

       

angular disc (Discus catskillensis)

       

banded mysterysnail (Viviparus georgianus)

       

bellmouth rams-horn (Planorbella campanulata)

       

black striate (Striatura ferrea)

       

blade vertigo (Vertigo milium)

       

blue glass (Nesovitrea binneyana)

       

bluff vertigo (Vertigo meramecensis)

       

blunt ambersnail (Oxyloma retusum)

       

bottleneck snaggletooth (Gastrocopta contracta)

       

Briarton pleistocene vertigo (Vertigo briarensis)

       

broad-banded forestsnail (Allogona profunda)

       

brown-banded arion (Arion circumscriptus)

       

callused vertigo (Vertigo arthuri)

       

cherrystone drop (Hendersonia occulta)

       

Chinese mystery snail (Cipangopaludina chinensis)

       

chrysalis snail (Pupilla hudsoniana)

       

comb snaggletooth (Gastrocopta pentodon)

       

common whorl snail (Vertigo pygmaea)

       

compound coil (Helicodiscus parallelus)

       

corpulent rams-horn (Planorbella corpulenta)

       

crested vertigo (Vertigo cristata)

       

deep-throat vertigo (Vertigo nylanderi)

       

delicate vertigo (Vertigo bollesiana)

       

disc gyro (Gyraulus circumstriatus)

       

dull gloss (Zonitoides limatulus)

Profile Photo Video  

dusky slug (Arion subfuscus/fuscus)

       

eastern flat-whorl (Planogyra asteriscus)

       

eastern glass snail (Vitrina angelicae)

       

eightfold pinecone (Strobilops affinis)

       

fine-ribbed striate (Striatura milium)

       

flamed disc (Anguispira alternata)

       

forest disc (Discus whitneyi)

       

glass spot (Punctum vitreum)

       

grassland whorl snail (Vertigo ovata)

Profile Photo Video  

gray field slug (Deroceras reticulatum)

       

Great Lakes snaggletooth (Gastrocopta similis)

Profile Photo Video  

great pond snail (Lymnaea stagnalis)

       

greenhouse slug (Milax gagates)

       

high-spire column (Columella simplex)

       

ice thorn (Carychium exile)

       

Iowa pleistocene ambersnail (Novasuccinea n. Sp. minnesota b)

       

lambda snaggletooth (Gastrocopta holzingeri)

       

lance aplexa (Aplexa elongata)

       

mammoth lymnaea (Bulimnaea megasoma)

       

marsh pondsnail (Stagnicola elodes)

       

marsh rams-horn (Planorbella trivolvis)

       

marsh slug (Deroceras laeve)

       

maze pinecone (Strobilops labyrinthicus)

       

midwest pleistocene vertigo (Vertigo hubrichti hubrichti)

       

Minnesota pleistocene ambersnail (Novasuccinea n. sp. minnesota a)

       

minute gem (Hawaiia minuscula)

       

moss chrysalis snail (Pupilla muscorum)

       

multirib vallonia (Vallonia gracilicosta)

       

mystery vertigo (Vertigo paradoxa)

       

obese thorn (Carychium exiguum)

       

occult vertigo (Vertigo occulta)

Profile Photo Video  

orange-banded arion (Arion fasciatus)

       

oval ambersnail (Novisuccinea ovalis)

       

plains snaggletooth (Gastrocopta abbreviata)

       

pleistocene catinella (Catinella exile)

       

pondsnail (Stagnicola reflexa)

       

quick gloss snail (Zonitoides arboreus)

       

ribbed grass snail (Vallonia costata)

       

ribbed striate (Striatura exigua)

       

Rogers’ snaggletooth snail (Gastrocopta rogersensis)

       

sharp hornsnail (Pleurocera acuta)

       

sharp sprite (Promenetus exacuous)

       

shiny glass snail (Zonitoides nitidus)

       

shiny hive (Euconulus alderi)

       

six-whorl vertigo (Vertigo morsei)

       

slippery moss snail (Cochlicopa lubrica)

       

small spot (Punctum minutissimum)

       

smooth grass snail (Vallonia pulchella)

       

southern flatcoil (Polygyra cereolus)

       

spindle lymnaea (Acella haldemani)

       

striped whitelip (Webbhelix multilineata)

       

suboval ambersnail (Catinella avara)

       

tapered vertigo (Vertigo elatior)

       

tawny glass snail (Euconulus fulvus)

       

thicklip rams-horn (Planorbula armigera)

       

thin pillar snail (Cochlicopu lubricella)

       

thin-lip vallonia (Vallonia perspectiva)

       

trumpet vallonia (Vallonia parvula)

       

two-ridged rams-horn (Helisoma anceps)

       

umbilicate sprite (Promenetus umbilicatellus)

       

variable pleistocene vertigo (Vertigo hubrichti variabilis n. subsp.)

       

variable vertigo (Vertigo gouldii)

       

white snaggletooth (Gastrocopta tappaniana)

       

whitelip (Neohelix albolabris)

Acella haldemani (spindle lymnaea)

Allogona profunda (broad-banded forestsnail)

Anguispira alternata (flamed disc)

Aplexa elongata (lance aplexa)

Arion circumscriptus (brown-banded arion)

Arion fasciatus (orange-banded arion)

Arion subfuscus/fuscus (dusky slug)

Bulimnaea megasoma (mammoth lymnaea)

Carychium exiguum (obese thorn)

Carychium exile (ice thorn)

Catinella avara (suboval ambersnail)

Catinella exile (pleistocene catinella)

Cipangopaludina chinensis (Chinese mystery snail)

Cochlicopa lubrica (slippery moss snail)

Cochlicopu lubricella (thin pillar snail)

Columella simplex (high-spire column)

Deroceras laeve (marsh slug)

Deroceras reticulatum (gray field slug)

Discus catskillensis (angular disc)

Discus whitneyi (forest disc)

Euconulus alderi (shiny hive)

Euconulus fulvus (tawny glass snail)

Gastrocopta abbreviata (plains snaggletooth)

Gastrocopta contracta (bottleneck snaggletooth)

Gastrocopta holzingeri (lambda snaggletooth)

Gastrocopta pentodon (comb snaggletooth)

Gastrocopta rogersensis (Rogers’ snaggletooth snail)

Gastrocopta similis (Great Lakes snaggletooth)

Gastrocopta tappaniana (white snaggletooth)

Gyraulus circumstriatus (disc gyro)

Hawaiia minuscula (minute gem)

Helicodiscus parallelus (compound coil)

Helisoma anceps (two-ridged rams-horn)

Hendersonia occulta (cherrystone drop)

Lymnaea stagnalis (great pond snail)

Milax gagates (greenhouse slug)

Neohelix albolabris (whitelip)

Nesovitrea binneyana (blue glass)

Nesovitrea electrina (amber glass)

Novasuccinea n. sp. minnesota a (Minnesota pleistocene ambersnail)

Novasuccinea n. Sp. minnesota b (Iowa pleistocene ambersnail)

Novisuccinea ovalis (oval ambersnail)

Oxyloma retusum (blunt ambersnail)

Physa acuta (acute bladder snail)

Planogyra asteriscus (eastern flat-whorl)

Planorbella campanulata (bellmouth rams-horn)

Planorbella corpulenta (corpulent rams-horn)

Planorbella trivolvis (marsh rams-horn)

Planorbula armigera (thicklip rams-horn)

Pleurocera acuta (sharp hornsnail)

Polygyra cereolus (southern flatcoil)

Promenetus exacuous (sharp sprite)

Promenetus umbilicatellus (umbilicate sprite)

Punctum minutissimum (small spot)

Punctum vitreum (glass spot)

Pupilla hudsoniana (chrysalis snail)

Pupilla muscorum (moss chrysalis snail)

Stagnicola elodes (marsh pondsnail)

Stagnicola reflexa (pondsnail)

Striatura exigua (ribbed striate)

Striatura ferrea (black striate)

Striatura milium (fine-ribbed striate)

Strobilops affinis (eightfold pinecone)

Strobilops labyrinthicus (maze pinecone)

Vallonia costata (ribbed grass snail)

Vallonia gracilicosta (multirib vallonia)

Vallonia parvula (trumpet vallonia)

Vallonia perspectiva (thin-lip vallonia)

Vallonia pulchella (smooth grass snail)

Vertigo arthuri (callused vertigo)

Vertigo bollesiana (delicate vertigo)

Vertigo briarensis (Briarton pleistocene vertigo)

Vertigo cristata (crested vertigo)

Vertigo elatior (tapered vertigo)

Vertigo gouldii (variable vertigo)

Vertigo hubrichti hubrichti (midwest pleistocene vertigo)

Vertigo hubrichti variabilis n. subsp. (variable pleistocene vertigo)

Vertigo meramecensis (bluff vertigo)

Vertigo milium (blade vertigo)

Vertigo morsei (six-whorl vertigo)

Vertigo nylanderi (deep-throat vertigo)

Vertigo occulta (occult vertigo)

Vertigo ovata (grassland whorl snail)

Vertigo paradoxa (mystery vertigo)

Vertigo pygmaea (common whorl snail)

Vitrina angelicae (eastern glass snail)

Viviparus georgianus (banded mysterysnail)

Webbhelix multilineata (striped whitelip)

Zonitoides arboreus (quick gloss snail)

Zonitoides limatulus (dull gloss)

Zonitoides nitidus (shiny glass snail)

 

No Species Page Yet?

If you do not see a linked page for an amphibian in the list at left you can still upload a photo or video or report a sighting for that amphibian. Click on one of the buttons below and type in the common name and/or scientific name of the amphibian in your photo, video, or sighting. A new page will be created for that amphibian featuring your contribution.

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