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Terrestrial Snails

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People and Biological Diversity

Terrestrial snails are an interesting group. I have to admit that I had a certain ignorance about them. In fact, I did not realize there were significant numbers of terrestrial snails in Iowa until I was an adult. Of course, there is a lack of good guide books that deal with land snails--I am not aware of any that are currently in publication right now.

I have photographed a number of Iowa's terrestrial snails and have located a few sources of information about them. I understand a lot more about them than I used to. However, it still seems that the more I find out about them the more I understand that I don't know.

A great number of Iowa's snails are very small--in the range of one to three millimeters in shell length. The differences between some of them are very subtle.

We have a small pad of cement in our yard. I have found several species of snail in that area, sometimes in the open after a rain, and sometimes under pieces of wet wood. It seems that some days there are fairly high numbers and other days there are none. Sometimes the days with many snails seem identical to the days with none. I don't know what causes the difference, and I have searched long and hard to find snails on the days when they don't seem to be present. They must be somewhere but I can't find them.

I have put together a list of Iowa's terrestrial snails, based on searchable museum database records, NatureServe Explorer records, and range maps from Hubricht (1985). By my tentative list, Iowa has about 130 species of terrestrial snails.

One thing that might be worth noting is the position of the eyes on these two terrestrial snail species shown. They have two pairs of tentacles, and the eyes are on the very tip of the uppermost pair. Almost all terrestrial species have this arrangement, and none of the aquatic snails do. Most terrestrial snails belong to the order Stylommatophora, which is a group of lung (Pulmonata) snails. Pomatiopsis lapidaria, which is shown on the aquatic snail page is usually considered a terrestrial snail by terrestrial snail experts. It is a gilled snail. One species, Hendersonia occulta is a "Prosobranchia" or gilled snail and is undisputedly a terrestrial snail.

I plan to add pages for a few snails to give a little more in-depth information and possibly some photographs. I do this with the caveat that I am not an expert--I key these things out to the best of my ability. I appreciate feedback from anyone who can point out my errors.

Here is my list of Iowa's terrestrial snails. There is still quality control work to be done on it, so there will likely be some changes.

order family genus species
Neritopsina Helicinidae Hendersonia occulta (Say, 1831)
Neotaenioglossa Pomatiopsidae Pomatiopsis cincinnatiensis
Pomatiopsis lapidaria (Say, 1817)
Basommatophora Carychiidae Carychium exiguum
Carychium exile exile I. Lea, 1842
Lymnaeidae Fossaria parva Note: aquatic snail found in terrestrial habitats  
Stylommatophora Arionidae Arion fasciutus  
Limacidae Deroceras reticulatum
Deroceras laeve (O.F. Müller, 1774)
Philomycidae Megapallifera mutabilis (Hubricht, 1951)
Pallifera ohioensis (Sterki, 1908)
Pallifera dorsalis (A. Binney, 1842)
Philomycus carolinianus (Bosc, 1802)
Cionellidae Cochlicopa lubrica (O.F. Müller, 1774)
Cochlicopa lubricella (Rossmässler, 1834)
Cochlicopa morseana Doherty, 1878
Discidae Anguispira alternata (Say, 1816)
Angiospira cochi (Pfeiffer)
Discus catskillensis
Discus macclintocki (Baker, 1928)
Discus marmorenosis
Discus patulus (Deshayes, 1830)
Discus shimekii (Pilsbry, 1890)
Discus whitneyi (Newcomb, 1864)
Haplotrematidae Haplotrema concavum (Say, 1821)
Helicarionidae Euconulus fulvus (O.F. Müller, 1774)
Euconulus chersinus
Guppya sterkii (Dall)
Helicodiscidae Helicodiscus natins natins
Helicodiscus parallelus (Say, 1817)
Helicodiscus shimeki Hubricht, 1962
Helicodiscus singleymns
Oreohelicidae Oreohelix strigosa (Gould, 1846)
Oreohelix strigosa cooperi (W.G. Binney, 1858)
Polygyridae Allogona profunda (Say, 1821)
Mesodon clausus clausus (Say, 1821)
Mesodon elevatus
Mesodon thyroidus (Say, 1816)
Mesodon zaletus  
Neohelix alleni (Sampson, 1883)
Patera appressa  
Patera laevior (Pilsbry, 1940)
Patera pennsylvanica (Green, 1827)
Stenotrema barbatum (Clapp, 1904)
Stenotrema hirsutum (Say, 1817)
Stenotrema labrosum
Webbhelix multilineata (Say, 1821)
Xolotrema fosteri (Baker, 1921)
Euchemotrema fraternum fraternum (Say, 1824)
Euchemotrema leai aliciae (Pilsbry, 1893)
Euchemotrema leai leai (A. Binney, 1841)
Punctidae Punctum minutissimum (I. Lea, 1841)
Punctum vitreum (Baker, 1930)
Pupillidae Gastrocopta abbreviata (Sterki, 1909)
Gastrocopta armifera (Say, 1821)
Gastrocopta contracta (Say, 1822)
Gastrocopta corticaria (Say, 1816)
Gastrocopta crestata {cristata?}
Gastrocopta holzingeri (Sterki, 1889)
Gastrocopta pentodon (Say, 1822)
Gastrocopta procera - (Gould, 1840)
Gastrocopta riograndensis
Gastrocopta rogersensis - Nekola and Coles, 2001
Gastrocopta similis - (Sterki, 1909)
Gastrocopta tappaniana (Adams, 1842)
Pupilla blandi  
Pupilla muscorum muscorum (Linnaeus, 1758)
Pupoides albilabris (Adams, 1841)
Vertigo binneyana - Sterki, 1890
Vertigo bollesiana - (E.S. Morse, 1865)
Vertigo brierensis - (Leonard, 1972)
Vertigo elatior - Sterki, 1894
Vertigo gouldi  
Vertigo hubrichti
Vertigo meramecensis Van Devender, 1979
Vertigo milium (Gould, 1840)
Vertigo modesta - (Say, 1824)
Vertigo occulta  
Vertigo ovata Say, 1822
Vertigo pygmaea - (Draparnaud, 1801)
Vertigo tridentata Wolf, 1870
Vertigo ventricosa - (E.S. Morse, 1865)
Columella columella aticola (Ingersoll, 1875)
Columella edentula (Draparnaud, 1805)
Columella simplex
Strobilopsidae Strobilops aeneus Pilsbry, 1926
Strobilops affinis  
Strobilops labyrinthicus (Say, 1817)
Succineidae Novisuccinea chittenangoensis - (Pilsbry, 1908)
Novisuccinea ovalis (Say, 1817)
Novisuccinea sp. 3
Novisuccinea sp. 4
Oxyloma haydeni (W.G. Binney, 1858)
Oxyloma retusum (I. Lea, 1834)
Oxyloma sillimani (Bland, 1865)
Succinea chittenangoensis {found only as a fossil}
Succinea concordialis Gould, 1848
Succinea forsheyi - I.Lea, 1864
Succinea grosvenori I. Lea, 1864
Succinea higginsi Bland
Succinea indiana  
Succinea ovalis (Say, 1817)
Catinella gelida (Baker, 1927)
Catinella vermeta (Say, 1829)
Catinella wandae - (Webb, 1953)
Valloniidae Vallonia costata (O.F. Müller, 1774)
Vallonia cyclophorella - Sterki, 1892
Vallonia exocentricia
Vallonia gracilicosta Reinhardt, 1883
Vallonia parvula Sterki, 1893
Vallonia perspectiva
Vallonia pulchella (O.F. Müller, 1774)
Zonitidae Glyphyalinia electrina
Glyphyalinia indentata (Say, 1823)
Hawaiia minuscula (A. Binney, 1841)
Mesomphix friabilis (W.G. Binney, 1857)
Nesovitrea binneyana - (E.S. Morse, 1864)
Nesovitrea electrina (Gould, 1841)
Striatura exigua - (Stimpson, 1850)
Striatura milium (Morse, 1859)
Zonitoides arboreus (Say, 1816)
Zonitoides limatulus (A. Binney, 1840)
Zonitoides nitidus (O.F. Müller, 1774)
Mesomphix inornatus (Say)