Group G Key
Group G. Wider than tall; simple lip
This is a diverse group of snails of all sizes, 16 genera - from the smallest species to among the largest. Their uniting character is their simple unreflected lip.
G1. Heliciform, simple lip, globose to subglobose, umbilicus varies, no teeth, >5-30 mm - Anguispira, Haplotrema, and Mesomphix
G2. Heliciform, simple lip, subglobose to depressed, umbilicate to perforate, > 3-4 mm - Discus, Glyphyalinia, Oxychilus, and Zonitoides
G3. Heliciform, simple lip, subglobose to depressed, umbilicate to perforate, < 3 mm – Guppya, Hawaiia, Lucilla, Nesovitrea, Punctum, and Striatura
G4. Heliciform, simple lip, subglobose to depressed, perforate, internal teeth, 2-10 mm – Gastrodonta, Helicodiscus, and Paravitrea
G1. Heliciform, simple lip, globose to very subglobose, umbilicus varies, no teeth, >5-30 mm - Anguispira, Haplotrema, Mesomphix
Tigersnails (Anguispira) - The shell coloration is readily identifiabl, even injuvenile specimens which tend to hae a more angular body whorl. Two species in Indiana.
Go to the Anguispira Page.
Lancetooth snails (Haplotrema) - only one in the state. Very subglobose, almost depressed except for the retained curvaure of the upper shell. The umbilicus spires out widely from a pinhole start.
Go to the Haplotrema Page.
G2. Heliciform, simple lip, subglobose to depressed, umbilicate to perforate, 3-12 mm - Discus, Glyphyalinia, Oxychilus, Zonitoides
Glyph Snails (Glyphyalinia) are small to mid-sized snails with a perforate umbilicus, radial lines across the whorls, and quickly expanding whorls. The aperture opening is slightly lunate.
Go to the Glyphyalinia Page.
Gloss Snails (Zonitoides) are small snails with noticeable growth wrinkles. Their whorls grow more regularly that those of the Glyph and Glass Snails.
Go to the Zonitoides Page.
G3. Heliciform, simple lip, subglobose to depressed, umbilicate to perforate, < 5 mm – Guppya, Hawaiia, Lucilla, Nesovitrea, Punctum, Striatura
These are among the smallest of land snail species with the general shape as you hold them in your hand. Magnification is important for identification. This is an attempt to use a key to distinguish the genera:
Small Round Snail Keylet
1a. Shell 3-5 mm in diameter – go to 2
1b. Shell <3 mm in diameter – go to 3
2a. 4-5 mm in diameter; depressed shell; glossy with clear radial lines; about rapidly enlarging whorls; umbilicus wide; looks superficially like Zonitoides arboreus.- Go to Nesovitrea below
2b. about 3-4 mm in diameter, coiled shape like Helicodiscus but lacks spiral ridges; wide umbilicus, 5-5 ½ whorls, flat spire (perhaps a slight elevation) – Go to 3
3a. Shell 2-2.8 mm in diameter; without ribs or riblets - Go to 4
3b. Shell less than 2 mm in diameter; riblets low and closely spaced - Go to 5
4a. Shell less depressed, wider and shallower umbilicus – Go to Hawaiia below
4b. Shell more depressed to discoidal, umbilicus not so wide – Go to Lucilla below
5a. Shell 1.5 mm or less in diameter; initial 1 ½ whorls smooth, 3.5-4.5 whorls – Go to Punctum below
5b. Shell between 1.5-3.0 mm in diameter - Go to Striatura below
Gem Snails (Hawaiia) are tiny (~ 2.2 mm diameter), as is the rest of this group of heliciform snails. They have a wide, shallow umbilicus. The nuclear whorl is smooth but the rest of the surface is cross-hatched with fine, irregularly-spaced growth lines and minute spiral striae
Glass Snails (Nesovitrea) have radial lines much like Glyph Snails but have a small open umbilicus. The aperture opening is more round.
Go to the Nesovitrea Page.
G4. Heliciform, simple lip, subglobose to depressed, perforate, internal teeth, 2-10 mm – Gastrodonta, Helicodiscus, Paravitrea
Coil Snails (Helicodiscus) are small snails (< 4 mm) with a discoidal "cinnamon roll" shape. and distinct multiple spiral ridges.
Go to the Helicodiscus Page.
Bellytooth Snails (Gastrodonta) are heliciform snails with a simple lip, a subglobose to domelike shell, perforate, 6-8 mm diamter; over 8 whorls, 2 teeth seen in aperture and others inside that can be seen through the shell..
Go to the Gastrodonta Page.
Supercoil Snails (Paravitrea) are .heliciform snails with many very tightly coiled whorls - a key trait for comparison. They also have a shallow dome-like shell, but the whorls separate them from other species with domed shells.
Go to the Paravitrea Page.