Carnegie Museum of Natural History

One of the Four Carnegie Museums of Pittsburgh

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Polygyra cereolus

Image Usage Information

Family: Polygyridae

Common name: Southern Flatcoil

Discovery: Megerle von Mühlfeld, 1818

Identification

Width: 11-18 mm
Height: 3.5-4.6 mm
Whorls: 7-9

This animal’s flat shell is reminiscent of a coin (occasionally spire is slightly raised) with a very wide umbilicus that is larger than half the shell diameter. It is sculptured with delicate ribs. The aperture has a single tooth (parietal). The lip in adults is narrowly reflected (Pilsbry, 1940).

Ecology

In its native range, it can be found on low ground in sunny situations (Hubricht (1985). In northeastern North America, Polygyra cereolus can be found in disturbed areas associated with humans.

Taxonomy

Polygyra cereolus can sometimes be difficult to separate from the similar P. septemvolva. In P. septemvolva, the spire is usually a bit more elevated than in P. cereolus and the umbilicus (while variable) can sometimes be a bit smaller (although both species overlap in those characters). To be certain, check for a long internal lamella within the body whorl 0.5 to 1.0 whorl back from the aperture (requires breaking part of the shell), which is present in P. cereolus but absent in P. semptemvolva.

Synonyms for Polygyra cereolus include Helix carpenteriana, Helix cereolus, Helix febigeri, Polygyra carpenteriana, and Polygyra septemvolva var. floridana.

Distribution

Polygyra cereolus is originally from Florida and counties along the Gulf coast, and coastal areas into South Carolina. More recently, it has been introduced with tropical plants and by other means to areas as far north as Virginia.

Conservation

NatureServe Global Rank: G4, Apparently Secure

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Land Snails Ecology – Climate Change

  • Climate Change
  • Deer Brainworm
  • Deer Overbrowsing
  • Diet & Behavior
  • Forest Calcium
  • Introduced Species
  • Life History
  • Pollution Monitoring
  • Predators & Defenses

Climate change, resulting from elevated levels of greenhouse gases in the atmosphere, particularly carbon dioxide, is affecting Earth’s biota including the land snails and slugs (hereafter called snails). Two major affects of more carbon dioxide in the atmosphere are higher temperatures (including increased variability, so higher highs and lower lows) and altered precipitation patterns, both of which affect land snails. Less prominent but still important affects include more acidic water (carbon dioxide reacts with water to form carbonic acid) and altered plants that become less nutritious and more defended.

With higher temperatures, snails living near the maximum temperature they can tolerate must move to higher elevations or toward the pole, or northward in our area. For snails that are already confined to mountaintops, there is no higher elevation, so they might become extirpated from those areas (Pearce & Paustian 2013).

Water is very important to land snails, which are like leaking bags of water trying to survive on dry land. Therefore, changes in precipitation can directly affect where snails are able to survive. The first species of any organism thought to have become extinct due to climate change is a land snail, Rhachistia aldabrae, although it was decreased rainfall, not climate warming that was blamed for the extinction (Gerlach 2007). Happily, a living population of the snail was found on the other side of the island in 2014, so it is not extinct (although it loses the title of being the first climate change related extinction).

More acidic water is certainly affecting marine mollusks, which find it more difficult to grow and maintain their shells in the more acidic water, which tends to dissolve calcium carbonate shells more. In freshwater, more acidic water affects snail’s sense of smell, suggesting that they might be less able to detect predators. On land, acid rain or acid precipitation results from calcium carbonate and nitrogen oxides reacting with water vapor in the atmosphere, and the resulting acid precipitation has affected many species of terrestrial organisms. Ongoing research suggests that acid precipitation has contributed to the decline of some land snail species in the northeastern North America (T.A. Pearce unpublished).

Plants absorb carbon dioxide from the air, so it makes sense that plants should grow better in air with more carbon dioxide. In many cases that appears to be true. However, plants use carbon dioxide to make carbohydrates including sugars that contain energy. Carbohydrates are just one of the four major groups of chemicals needed by living organisms. To make proteins, another important class of chemicals, the plant requires nitrogen. So, increased carbon dioxide can lead to larger plants with more carbohydrates (energy), but less protein. Creatures that need more protein will perform more poorly if they consume many plants grown in elevated carbon dioxide (i.e., C3 plants in contrast to C4 plants, which are less susceptible to being perturbed by elevated carbon dioxide). Furthermore, many plants produce defensive chemicals. Plants whose defensive chemicals containing nitrogen (i.e., to make protein) might produce less of the chemical, while those producing defensive chemicals without nitrogen might be able to produce more of the chemical (e.g., Ng et al. 2023).

Climate change affects in northeastern North America might be slightly less than in other parts of the continent, although there will be climate warming and drying in the Mid-Atlantic and southern part of New England.

As the climate changes, snail populations will likely need to disperse to areas with more favorable habitat or perish. However, snails are the quintessential slow-moving organism, so we expect their dispersal into new areas to be slow. Furthermore, crossing inhospitable habitat, such as an agricultural field for a forest

snail, or even crossing a road (Baur & Baur 1990) can be difficult or impossible for snails. Some conservation biologists are considering the use of assisted dispersal to help land snails reach new areas of suitable habitat (Örstan 2009).

References

Baur, A. & Baur, B. 1990. Are roads barriers to dispersal in the land snail Arianta arbustorum? Canadian Journal of Zoology 68(3): 613-617.

Gerlach, J. 2007. Short-term climate change and the extinction of the snail Rhachistia aldabrae (Gastropoda: Pulmonata). Biology Letters 3(5): 581–584. doi:10.1098/rsbl.2007.0316. Ng, M., McCormick, A., Utz, R.M. & Heberling, J.M. 2023. Herbarium specimens reveal century-long trait shifts in poison ivy due to anthropogenic CO2 emissions. Applications in Plant Sciences 110(9): e16225. https://doi.org/10.1002/ajb2.16225

Örstan, A. 2009. Will assisted colonization be a viable option to save terrestrial gastropods threatened by climate change? Tentacle 17: 14-16.

Pearce, T.A. & Paustian, M.E. 2013. Are temperate land snails susceptible to climate change through reduced altitudinal ranges? A Pennsylvania example. American Malacological Bulletin 31(2): 213-224.

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Tandonia budapestensis

Image Usage Information

Family: Milacidae

Common name: Budapest Keeled Slug

Discovery: Hazay, 1880

Identification

Length: 50-70 mm

The slug Tandonia budapestensis is medium-sized, with a prominent dorsal keel from the mantle to the tail. It is yellowish gray to brown or dark gray dorsally and lighter on the sides, with a creamsole. Mantle with darker spots. The keel is usually lighter in color. Its mucus is white or colorless becoming yellowish upon irritation. Pilsbry (1948) noted that Norfolk, Virginia, specimens have a very black dorsal surface.

Ecology

Tandonia budapestensis is found in a variety of habitats in western Europe and the Mediterranean – most commonly along coasts in gardens, farms, grassy seashore, hedges, and woods in association with humans (Kerney & Cameron, 1979). It is an agricultural pest of many crops including soybeans, sunflowers, and oilseed rape (Clemente et al., 2010). In Argentina, eggs hatched at 23 days. In Canada this slug is vulnerable to frost and overwinters in the egg stage (Grimm et al., 2009).

Taxonomy

Synonyms for Tandonia budapestensis include Amalia budapestensis, Limax hewstoni, Milax budapestensis, M. gracilis, and M. hewstoni.

Distribution

This eastern European slug has been introduced to both North American coasts. In Virginia specimens have reportedly been collected from Pittsylvania and Northampton Counties, as well as Norfolk.

Conservation

NatureServe Global Rank: G5

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Monacha cartusiana

Image Usage Information

Family: Hygromiidae

Common name: Chartreuse snail

Discovery: O. F. Müller, 1774

Identification

Width: 9-18 mm
Height: 6-10 mm
Whorls: 5.5-6.5

Shell is depressed. Adults with a thickened (not reflected) lip, with an internal varix parallel to the lip edge. Periphery is well rounded. The umbilicus is very small. The shell color is cream to yellowish, and the lip is lined with reddish or brown (Kerney et al. 1979; Welter-Schultes 2012).

Ecology

In Europe, Monacha cartusiana is widespread in meadows, hedges, and on roadsides, usually not in forests. It is found in dry, sunny locations. In the USA, it is typically found in disturbed areas.

Taxonomy

A synonym is Helix olivieri.

Distribution

This European snail is considered invasive in the USA. It has recently been introduced to several places in the USA, and it appears to be spreading slowly, despite attempts to control it. It seems to have established in the Chicago and Cleveland areas. In the mid-Atlantic and northeastern states, it is known from Delaware (Port of Wilmington), and surrounding areas, Pennsylvania (Truck Stop in Bellefonte), West Virginia (Morgantown area).

Conservation

NatureServe Global Rank: G5, Secure

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Land Snails Resources – References

Terminology

References

Citing this Resource

About the Authors

Sources of Specimen Records

References

A
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Abbott, R.T. 1974. American Seashells, Second edition, Van Nostrand Rheinhold, New York, ISBN 0-442-20228-8.

Albrectson, B.R., H. Gardfjell, C.M. Orians, B. Murray, and R.S. Fritz. 2004. Slugs, willow seedlings and nutrient fertilization: intrinsic vigor inversely affects    palatability. Oikos 105:268-278.

Aloi, M.A., and N.H. Ringler. 1982. Population biology and density of Succinea chittenangoensis. Unpublished report to the New York State Dept. of    Environmental Conservation, Project E-1-7. 27pp.

Anderson, R. 2016. Aegopinella nitidula (Draparnaud 1805). In MolluscIreland. 
   http://www.habitas.org.uk/molluscireland/species.asp?ID=5. Accessed 2017-09-11.

Anderson, R. 2016. Trochulus (Trochulus) hispidus (Linnaeus 1758). In MolluscIreland. 
   http://www.habitas.org.uk/molluscireland/species.asp?ID=169 Accessed on 2017-09-11.

Anderson, R.C. and A.K. Prestwood. 1981. Parelaphostrongylosis. In Diseases and Parasites of White-tailed Deer, W.R. Davidson, Ed. Tall Timbers Research    Station, Tallahassee, FL. Pp. 274-308.

Anonymous. 2017. Snails Bred in ESF Lab Help Species Crawl Back from Brink of Extinction. College of Environmental Science & Forestry Communications.    Online resource accessed 12/11/2017. Available: http://www.esf.edu/communications/view.asp?newsID=6018.

Anonymous. 2017. U.S. Regulated Plant Pest Table. Animal and Plant Health Inspection Service, U.S. Dept. of Agriculture. Online resource accessed    1/3/2018. Available: https://www.aphis.usda.gov/aphis/ourfocus/planthealth/import-information/rppl/rppl-table.

Apley, M.L. 1970. Field studies on life history, gonadal cycle, and reproductive periodicity in Melampus bidentatus (Pulmonata: Ellobiidae). Malacologia    10(2):381-397.

Ataev, G.L., A.A. Zhukova, А.S. Tokmakova, and Е.E. Prokhorova. 2016. Multiple infection of amber Succinea putris snails with sporocysts of Leucochloridium    spp. (Trematoda). Parasitology Research.

Atkinson, J.W. 1998. Food manipulation and transport by a carnivorous land snail, Haplotrema concavum. Invertebrate Biology 117(2):109-113.

Atkinson, J.W. 2000. Behavioral responses to a change in stimulus: transport vs attack behavior in a carnivorous land snail, Haplotrema concavum.    Invertebrate Biology 119(1):38-44.

Atkinson, J.W. 2003. Foraging strategy switch in detour behavior of the land snail Anguispira alternata (Say). Invertebrate Biology 122(4):326-333.

Auffenberg, K.A., and L.A. Stange. 1993. Pleurodontid Snails of Florida, Caracolus marginella (Gmelin), Zachrysia provisoria (L. Pfeiffer), Zachrysia trinitaria
   (L. Pfeiffer), (Gastropoda: Pleurodontidae). Florida Division of Plant Industrial Entomology, Circular 356, 2pp.

B
Backeljau, T., and Van Beeck, M. 1986. Epiphallus anatomy in the Arion hortensis species aggregate (Mollusca, Pulmonata). Zoologica Scripta 15: 61–68.

Baker, F.C. 1939. Fieldbook of Illinois Land Snails. Natural History Survey Division, Urbana, IL.

Baker, G.H. 2012. The population dynamics of the Mediterranean snail Cernuella virgata (da Costa, 1778) (Hygromiidae), in continuous-cropping rotations in    South Australia. Journal of Molluscan Studies. 78(3):290-296, doi: 10.1093/mollus/eys015.

Baker, H.B. 1930. The North American Retinellae. Proceedings of the Academy of Natural Sciences, Philadelphia 82:193-219.

Balashov, I., and P. Kijashko. 2017. Relic land snails in the Caucasian glacial refugium: A first non-fossil record of Vallonia tenuilabris from western Eurasia.    Journal of Conchology 42(5):327-332.

Bank, R.A., Falkner, G., and von Proschwitz, T. 2007. A revised checklist of the non-marine Mollusca of Britain and Ireland. Heldia 5(3):41-72.

Bank, R.A. and M. Ramos. 2016. Zoogenetes harpa in Fauna Europaea. Online resource accessed 11/7/2017. Available: https://fauna-eu.org.

Barker, G.M. 2002. Gastropods as pests in New Zealand pastoral agriculture, with emphasis on Agriolimacidae, Arionidae and Milacidae. In Barker, G.M.    Molluscs as crop pests. CABI. pp. 361–423. ISBN 0-85199-320-6.

Barker, G.M., Ed. 2004. Natural Enemies of Terrestrial Molluscs. CABI Publishing, Oxford, UK. 644pp.

Batie, R.E. 1987. An endemic species of special concern: the federally endangered Virginia Fringed Mountain Snail (Polygyriscus virginianus). Virginia Journal    of Science 38(4):289-291.

Bauer, B. 1993. Population structure, density, dispersal and neighbourhood size in Arianta arbustorum (Linnaeus, 1758) (Pulmonata: Helicidae). Annals of the    Natural History Museum of Wien 94/95:307-321.

Baur, B. and A. Baur.1993. Climatic warming due to thermal radiation from an urban area as a possible cause for the local extinction of a land snail. Journal of    Applied Ecology 30:333-340.

Beetle, D.E. 1973. A checklist of the land and freshwater mollusks of Virginia. Sterkiana 49:21-35.

Beier, C.M., A.M. Woods, K.P. Hotopp, J.P. Gibbs, M.J. Mitchell, M. Dovciak, D.J. Leopold, D.B. Lawrence, and B.D. Page. 2012. Changes in faunal and    vegetation communities along a soil calcium gradient in northern hardwood forests. Canadian Journal of Forest Research 42:1141-1152.

Bequaert, J.C. and W.B. Miller. 1973. The Mollusks of the Arid Southwest. University of Arizona Press, Tucson.

Berman, J. and J.T. Carlton. 1991. Marine invasion processes: interactions between native and introduced marsh snails. Journal of Experimental Marine Biology    and Ecology 150: 267-281.

Beyer, W.N. and D.M. Saari. 1978. Activity and ecological distribution of the slug, Arion subfuscus (Draparnaud) (Stylommatophora: Arionidae). American    Midland Naturalist 100(2):359-367.

Bird, J. and J.M. Garvon. 2005. Attraction of the land snail Anguispira alternata to fresh faeces of white-tailed deer: implications in the transmission of    Parelaphostrongylus tenuis. Canadian Journal of Zoology 83(2):358-362.

Blinn, W.C. 1963. Ecology of the land snails Mesodon thyroidus and Allogona profunda. Ecology 44(3):498-505.

Bobkova, M.V., O.S. Tartakovskaya, S.L. Borissenko, V.V. Zhukov, and V.B. Meyer-Rochow. 2004. Restoration of morphological and functional integrity in
   the regenerating eye of the giant African land snail Achatina fulica. Acta Zoologica 85:1-14.

Boettcher, S.E. and P.J. Kalisz. 1990. Single-tree influence on soil properties in the mountains of eastern Kentucky. Ecology 71(4):1365-1372.

Borrero, F.J., A.S.H. Breure, C.C. Christensen, M. Correoso, and V.M. Avila. 2009. Into the Andes: Three new introductions of Lissachatina fulica (Gastropoda,    Achatinidae) and its potential distribution in South America. Tentacle 17:6-8.

Branson, B.A. 1968. Two new slugs (Pulmonata: Philomycidae: Philomycus) from Kentucky and Virginia. The Nautilus 81(4): 127-132.

Branson, B.A. 1969. Genital differences in Philomycus virginicus Hubricht and P. bisdosus Branson.  Nautilus 82(2): 74.

Breisch, A.R., and R. Niver. 2006. Chittenango Ovate Ambersnail (Novisuccinea chittenangoensis) Recovery Plan, First Revision. Unpublished report to the US    Fish & Wildlife Service, Region 5, Hadley, MA. 39pp + appendices.

Brooks, S.T. 1931. A list of the land-snails of Pennsylvania with a summary of their distributions. Annals of the Carnegie Museum 22(3-4):313-331.

Burch, J.B. 1955. Some ecological factors of the soil affecting the distribution and abundance of land snails in eastern Virginia. Nautilus 69(2):26-29.

Burch, J.B. 1956. Distribution of land snails in plant associations in eastern Virginia. Nautilus 70(2):60-64.

Burch, J.B. 1962. How To Know the Eastern Land Snails. Wm. C. Brown, Dubuque. 214pp.

Burch, J.B. 1990. Thomas Say’s glossary for conchology. Walkerana 4:279-306.

Burke, T.E. 2013. Land Snails and Slugs of the Pacific Northwest. Oregon State University Press, Corvallis, OR.

C
Cameron, R.A.D. 1978. Differences in the sites of activity of coexisting species of land mollusc.  Journal of Conchology 29: 273-278.

Campbell, S.B., J.L. Frair, J.P. Gibbs, and R. Rundell. 2014. Coexistence of the endangered, endemic Chittenango ovate amber snail (Novisuccinea    chittenangoensis) and a non-native competitor. Biological Invasions 17(2):

Capinera, J. 2013. Cuban brown snail, Zachrysia provisoria (Gastropoda): Damage potential and control. Crop Protection 52:57-63.

Chatfield, J.E. 1976. Studies on food and feeding in some European land molluscs.  Journal of Conchology 29:5-20.

Chichester, L.F. and L.L. Getz. 1973. The terrestrial slugs of eastern North America. Sterkiana 51:11-4.2

Chichester, L.F. and Getz, L.L. 1969. The zoogeography and ecology of arionid and limacid slugs introduced into Northeastern North America. Malacologia
   7(2-3): 313-346.

Civeyrel, L., and D. Simberloff. 1996. A tale of two snails: is the cure worse than the disease? Biodiversity and Conservation 5:1231-1252.

Clemente, N.L., A.J. Faberi, C. Salvio, and A.N. López. 2010. Biology and individual growth of Milax gagates (Draparnaud, 1801) (Pulmonata:    Stylommatophora). Invertebrate reproduction and Development 54(3):163-168.

Clutts, S.A. 2008. Systematics of Anguispira (Pulmonata: Discidae) based on molecular and morphometric data. Unpublished M.S. thesis, Southern Illinois    University, Carbondale. 131pp.

Coles, B.F. and J.C. Nekola. 2007. Vertigo malleata, a new extreme calcifuge land snail from the Atlantic and Gulf coastal plains of the U.S.A. (Gastropoda,    Vertiginidae). Nautilus 121:17-28.

Coney, C.C., W.A. Tarpley, J.C. Warden, and J.W. Nagel. 1982. Ecological studies of land snails in the Hiwassee River basin of Tennessee, USA.    Malacological Review 15:69-106.

Cowie, R. H., R.T. Dillon, D.G. Robinson, J.W. Smith. 2009. Alien Non-Marine Snails and Slugs of Priority Quarantine Importance in the United States: A
   Preliminary Risk Assessment. American Malacological Bulletin 27(1-2).

Cowie, R. H., R.T. Dillon, D.G. Robinson, and J.W. Smith. 20. Alien non-marine snails and slugs of priority quarantine importance in the United States: A    preliminary risk assessment. American Malacological Bulletin 27: 113-132.

Cowie, R. H., and J. S. Jones. 1987. Ecological interactions between Cepaea nemoralis and Cepaea hortensis: competition, invasion but no niche    displacement. Functional Ecology 1:91-97.

Cowie, R. H. 2013. Biology, Systematics, Life Cycle, and Distribution of Angiostrongylus cantonensis, the Cause of Rat Lungworm Disease. Hawai‘i Journal of    Medicine & Public Health 72(6), Supplement 2: 6-9.

D
Dallinger, R. and W. Wieser. 1984. Patterns of accumulation, distribution and liberation of Zn, Cu, Cd and Pb in different organs of the land snail Helix pomatia    L. Comparative Biochemistry and Physiology – Part C: Toxicology and Pharmacology 79(1):117-124.

Ðatkauskienë. I. 2005. Characteristic of lifespan and reproduction period of Succinea putris (L.) (Gastropoda: Styllomatophora) Ekologija 3:28–33.

Davies, S.M. 1977. The Arion hortensis complex with notes on A. intermedius. Journal of Conchology 29: 173-187.

Davies, S.M. 1979. Segregates of the Arion hortensis complex (Pulmonata: Arionidae) with the description of a new species, Arion owenii. Journal of    Conchology 30:123-127.

Davison, A., C.M. Wade, M. Christopher, P.B. Mordan, and S. Chiba. 2005. Sex and darts in slugs and snails (Mollusca: Gastropoda: Stylommatophora).    Journal of Zoology, London 267:329-338.

DeCalesta, D.S. 1994. Effect of white-tailed deer on songbirds within managed forests in Pennsylvania. Journal of Wildlife Management 58(4):711-718.

Digweed, S.C. 1993. Selection of terrestrial gastropod prey by Cychrine and Pterostichine ground beetles (Coleoptera: Carabidae). The Canadian Entomologist    125:463-472.

Dillon, R.T., Jr., B.T. Watson, and T.W. Stewart. 2006. The Freshwater Gastropods of North America. Internet address: http://www.fwgna.org.

Dimitriadis, V.K. 2001. Chapter 5: Structure and function of the digestive system of Stylommatophora. Pp 237-257 in: The Biology of Terrestrial Molluscs,    G.M. Barker, Ed. CABI, New York, USA. 558pp.

Douglas, D.D., D.R. Brown, and N. Pederson. 2013. Land snail diversity can reflect degrees of anthropogenic disturbance. Ecosphere 4(2):28.

Dourson, D.C. 2010. Kentucky’s Land Snails and their Ecological Communities. Goatslug Publications, Bakersville, NC. 298pp.

Dourson, D.C. 2011. Descriptions of three new land snails from Kentucky. Journal of the Kentucky Academy of Sciences 72(1):31-45.

Dourson, D.C. and J. Beverly. 2008. Diversity, substrata divisions and biogeographical affinities of land snails at Bad Branch Nature Preserve, Letcher County,    Kentucky. Journal of the Kentucky Academy of Sciences 69(2):101-116.

Dourson, D.C. and J. Dourson. 2006. Land Snails of the Great Smoky Mountains (Eastern Region). Digital field guide. 55pp.

Dourson, D.C. 2008. The feeding behavior and diet of an endemic West Virginia land snail, Triodopsis platysayoides. American Malacological Bulletin 26:
    153-159.

Dundee, D.S. 1957. Aspects of the biology of Pomatiopsis lapidaria (Say) (Mollusca: Gastropoda: Prosobranchia). Miscellaneous Publications of the Museum    of Zoology, University of Michigan 100:1-37.

E
Eisner, T. and E.O. Wilson. 1970. Defensive liquid discharge in Florida tree snails (Liguus fasciatus). Nautilus 84(1):14-15.

Elwell, A.S. and M.J. Ulmer. 1971. Notes on the biology of Anguispira alternata (Stylommatophora: Endodontidae). Malacologia 11(1):199-215.

Emberton, K.C. 1980. Ecological notes on two sympatric, conchologically convergent polygyrid land snails in Ohio. Bulletin of the American Malacological    Union, Inc. 1980:27-30.

Emberton, K.C. 1988. The genitalic, allozymic and conchological evolution of the eastern North American Triodopsinae (Gastropoda: Pulmonata: Polygyridae).    Malacologia 28(1-2):159-273.

Emberton, K.C. 1991. The genitalic, allozymic and conchological evolution of the tribe Mesodontini (Pulmonata: Stylommatophora: Polygyridae). Malacologia    33(1-2):71-178.

Emberton, K.C. 1995. When shells do not tell: 145 million years of evolution in North America’s polygyrid land snails, with a revision and conservation    priorities. Malacologia 37(1):69-110.

F
Fairbanks, H.L. 1986. The taxonomic status of Philomycus togatus (Pulmonata: Philomycidae): a morphological and electrophoretic comparison with    Philomycus carolinianus. Malacologia 27(2):271-280.

Fairbanks, H.L. 1989. The reproductive anatomy and taxonomic status of Philomycus venustus Hubricht, 1953 and Philomycus bisdosus Branson, 1968    (Pulmonata: Philomycidae). The Nautilus 103(1): 20-23.

Fofonoff, P.W., Ruiz, G. M., Steves, B., Hines, A.H.; Carlton, J. T. 2003. National Exotic Marine and Estuarine Species Information System: Chesapeake Bay    Introduced Species Database: http://invasions.si.edu/nemesis/chesapeake.html Accessed 10/25/2017.

Forsyth, Robert G. 2014. First record of Deroceras invadens Reise, Hutchinson, Schunack & Schlitt, 2011 (Gastropoda: Pulmonata: Agriolimacidae) from the    island of Newfoundland, Canada. Check List 10(1): 149–150.

Forsyth, R.G. 2004. Land snails of British Columbia. Royal BC Museum, Victoria, Canada.

R.G. Forsyth, J.M.C. Hutchinson, and H. Reise. 2001. Aegopinella nitidula (Draparnaud, 1805) (Gastropoda: Zonitidae) in British Columbia—first confirmed    North American record. American Malacological Bulletin 16: 65–69.

Foster, B.A. and A.E. Stiven. 1994. Effects of age, body size, and site on reproduction in the southern Appalachian land snail Mesodon normalis (Pilsbry,    1900). American Midland Naturalist 132:294-301.

Franzen, D.S. 1981. Catinella vagans (Pilsbry) and a new species of Catinella (Succineidae Pulmonata) from the shore of Lake Waccamaw, North Carolina.    Nautilus 95(3):116-124.

Frest, T. J. 1991. Summary Status Reports on Eight Species of Candidate Land Snails from the Driftless Area (Paleozoic Plateau), Upper Midwest. Final    Report, Contract #301-01366, USFWS Region 3, Ft. Snelling, Minnesota.

Frest, T.J. 1990. Field survey of Iowa spring fens. Final report (contract number 65-2454) to Iowa Department of Natural Resources, Des Moines, Iowa.

Frest, T.J. & L.P. Fay. 1981. Vertigo meramecensis (Pulmonata: Pupillidae) from the Niagaran Escarpment, Iowa. The Nautilus. 95:33-37.

Frest, T.J. and R. Sanders Rhodes. 1982. Oxychilus draparnaldi in Iowa. Nautilus 96(2):36-39.

G
Getz, L.L. 1959. Notes on the ecology of slugs: Arion circumscriptus, Deroceras reticulatum, and D. laeve. The American Midland Naturalist 61: 485-498.

Gleich, J.G., F.F. Gilbert, and N.P. Kutscha. 1977. Nematodes in terrestrial gastropods from central Maine. Journal of Wildlife Diseases 13:43-46.

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Land Snails Resources – Terminology

Terminology

References

Citing this Resource

About the Authors

Sources of Specimen Records

Terminology

Below are some words used frequently in the study of land snails. For more terms, see Burch, 1990. Primary reference: Burch (1962).

acute—pointed or sharp.

anal pore—opening in the mantle to allow waste elimination.

angular—a lamella at the top right of the aperture in pupillid or vertiginid snails.

angulo-parietal—the denticle on the body whorl in pupae-shaped shells, the result of the convergence of two denticles (the angular and the parietal) through evolution.

antennae—the long projections from a snail’s head, for detecting scents and orientation, and sometimes having eyespots. Also known as tentacles.

anterior—the front or head.

apertural—within the shell opening for the snail’s body.

aperture—the opening of a snail shell from which the snail’s soft body emerges, sometimes called the “mouth.”

apex—the top end of a shell’s columella, opposite the umbilicus and furthest from the aperture.

apical/apically—toward the apex or top of a shell.

axial—a direction parallel to a shell’s columella.

basal—the bottom or floor of a shell’s aperture or shell when viewed apex up, umbilicus down.

basal notch—a central gap in the lower peristome, often in slitmouth snails.

base—the bottom of a land snail shell, when viewed with the aperture to the right.

body whorl—the final, most exterior whorl of an adult shell.

breathing pore—an opening in the mantle to allow air passage. Also called the pneumostome.

buttress—a ridge or support beneath a denticle, or “tooth.”

calcified—a shell feature that is hardened or covered by layers of calcium carbonate.

callus—a thickening in the shell wall.

carina—a spiral shell ridge at the outside edge of a whorl.

caudal—a direction referring to the tail.

chevron—an angular marking, often in a series upon a slug’s mantle.

columella—the central, structural axis of a snail shell. At the top of the columella is the shell’s apex and at the bottom, the shell’s umbilicus (though it may be covered).

columellar—toward or referring to the central axis of a shell.

columnar—tubular with parallel sides.

concave—a dished or hollowed surface.

concentric—a nested series of curves or rings.

congener—a relative in the same genus.

convex—a rounded or bulging surface.

cylindrical—a tube-shaped object such as a snail’s antenna.

dart—a tiny calcareous spear injected into a potential mate’s flesh prior to copulation. Transmits reproductive hormones that increase fertility.

deflected—turned downward or away, relative to the body whorl.

denticle—a solid calcium carbonate deposit integral to a land snail shell, usually at the aperture or within the shell. Denticles are often referred to as “teeth,” and are supposed to aid in shell positioning, predator deterrence, or calcium provisioning.

depressed—lowered or flattened.

dextral—a direction meaning whorled to the right. A dextral shell’s aperture appears on the right to an observer when the shell is positioned with apex up and umbilicus down and aperture toward the observer.

dorsal—upper or top surface.

elongate—lengthened or thin.

embryonic whorl—the initial part of snail’s shell, formed within the egg. Also called the nuclear whorl.

epiphragm—a membrane of dried mucus formed across the aperture of a snail shell, it helps to prevent dessication when the snails is inactive for long periods.

foot—the muscular organ whose contractions propel a land snail, the foot is located on the ventral surface of the animal’s soft body.

gastropod—Latin for the class of “belly-foot” mollusks, so called because they crawl upon a muscular foot beneath their body.

genital pore—the opening to a land snail’s reproductive organs, usually located on the right side of the head behind the right eye tentacle. Most of Pennsylvania’s land snails are hermaphroditic, so the genital pore provides access to both a vagina and extendible penis.

granulose—a shell texture that appears as many small raised bumps.

growth lines—a series of radial ridges and grooves developed as a shell grows.

growth wrinkles—see growth lines.

gutter—a groove or depression, often behind the peristome of a shell.

heliciform—in the shape of a helix, a spiral around a central column, in snail shells referring to the more rounded shapes.

imperforate—not having an opening, often referring to a shell umbilicus that is closed.

impressed—a shell groove or indentation.

incised—indented or excavated, in snail shells often referring to grooves in the surface.

inflated—rounded or bulging.

infraparietal—a tooth position in pupillid snails at the top of the aperture and left of center.

insertion/inserted—in snail shells the convergence of a part with the main body of the shell, often where the peristome meets the body whorl.

interdenticular sinus—a concavity at the right side of the peristome of slitmouth snail shells.

iteroparous—life history in which adult snails have more than one reproductive cycle.

keel—a longitudinal ridge on the top of a snail or slug’s tail.

lamella—an elongated denticle or “tooth” located at the aperture or within a snail’s shell.

lamellae—plural of lamella.

laminae—plural of lamina, in snail shells referring to a callus or denticle.

lateral—a position to the side, not forward or back.

lip—an informal name for the edge of the aperture, also called the peristome. The shape and features of the lip can be important in species identification.

longitudinal—a feature parallel or following the direction of the shell or body.

lirae—raised spinal ridges.

malacologist—a scientist who studies mollusks (the Phylum of animals that includes land snails).

mantle—the membrane–like organ that builds the shell in shelled snails, found around the aperture. The mantle is also present in slugs, where it serves as a dorsal covering.

margin—edge.

matte—a non-reflective shell finish. Dull, not shiny.

microsculpture—shell surface shapes and textures often requiring magnification.

nuclear whorl—the part of a land snail’s shell formed in the egg prior to hatching, sometimes with a unique microsculpture pattern.

obtuse—a wide angle, between 90º and 180º.

odontophore—cartilage structure in the mouth over which the radula is drawn to rasp food.

opaque—a membrane or shell through which light cannot pass.

operculum—a hardened cover that closes the aperture of a shell, present only in one Pennsylvania terrestrial species, Hendersonia occulta, and the amphibious species Pomatiopsis lapidaria.

ovate—an oval shape wider at one end; egg-shaped.

ovate-conical—generally egg-shaped but relatively longer.

oviposition—egg laying.

palatal—a direction referring to the part of a shell aperture away from the columella when viewed apex up, umbilicus down.

papillae—numerous small bumps upon a shell’s microsculpture.

parietal—a direction referring to the part of a shell aperture closest to the columella when viewed apex up, umbilicus down.

pentagon—a five-sided shape.

perforate—having a tiny hole, often referring to the umbilicus of a shell.

periphery—the outside or edge of an object, often the peristome, or lip, of a shell.

peristome—the edge of the aperture, also called the “lip.”

pneumostome—an opening in the mantle to allow air passage. Also called the breathing pore.

radial— shell sculpture perpendicular to a shell’s coils, running around the whorls.

radula—a chitinous organ in the mouth of a snail, covered with series of tiny teeth that function to rasp food.

reflected—a feature that appears to be turned back, often referring to the shape of the peristome. A reflected peristome appears much wider than the relatively thin shell.

reticulation—a complex pattern of color without a clear edge, upon a snail’s skin.

revolution—one complete (360°) whorl of a shell.

riblets—small radial ridges.

rimate—having a narrowly reflected edge.

rupicolous—dwelling among rocks.

semelparous—life history in which adult snails mate once and then die.

sinistral—a direction meaning whorled to the left. A sinistral shell’s aperture appears on the left to the observer when the shell is positioned with apex up and umbilicus down. None of Pennsylvania’s land snails, excepting anomalies, exhibit this character.

sole—the underside or contact surface of a snail’s foot.

spermatophore—a sperm packet exchanged during mating.

spermoviduct—a canal in the reproductive system through which sperm move and in which fertilized snail eggs are developed.

spiral—a direction parallel to a shell’s direction of whorl growth.

spire—the part of a snail shell above the final full whorl.

striae—tiny shallow grooves in the surface of a shell.

striate—having grooves or scratches.

subglobose—a somewhat flattened sphere shape.

suture—the seam at which sequential whorls of a shell meet.

tentacle—one of two to four elongate, retractable sensory appendages at the snail’s head; they are devoted to chemoreception and most have eyespots as well.

tooth—often the informal name for a denticle or lamella upon a shell, usually in the aperture or body whorl. Not to be confused with the tiny teeth upon a snail’s radula.

translucent—a membrane or shell through which light can pass.

transparent—a shell through which the internal organs can be seen.

tubercles/tubercular—on a snail’s body, a surface pattern of repeating raised sections, separated by indentations or furrows.  On a shell, a small denticle, or “tooth.”

umbilicus—the depression at the base of a snail shell, leading into the interior space of the columella. The spire may be open; perforate, very tiny; or closed, covered by shell material.

ventral—direction meaning lower or underside.

whorl—each 360 revolution of a snail’s shell, measured from the apex.