This key was written in English and published in Spanish with the title “Clave de los géneros de moluscos terrestres mexicanos usando caracteres conquiológicos” in “Revista de Biología Tropical” vol 51, Supl 3, “Malacología Latinoamericana”, pages 473-482, Junio, 2003. An English version follows:
Neil E. Fahy
California Academy of Sciences, Golden Gate Park, San Francisco, CA 94118-4599 U.S.A.
Translated to Spanish by Edna Naranjo Garcia
Instituto de Biologia U.N.A.M. Apartado Postal 70-153,
Abstract: A
total of 13 shell characteristics keys are presented, allowing identification
of the 117 terrestrial mollusc genera that have been reported from
Key words:
Key, land mollusks,
----------------------
"If land snail classification were based on
the shape of the shell, there would only be
ten species."
-----------------------
The identification of land snails is a challenge. Land snail taxonomy is based on the soft anatomy, consequently the shell is only of secondary taxonomic importance. Thus, many similar appearing shells are in distant or non-related families. You soon learn that snails were never meant to be classified. Thumbing through pictures looking for your specimen can be very discouraging. But what is more important, you don't learn anything about the features which make your specimen distinct. A key is needed to highlight the specific characteristics which make this specimen different.
HOW TO USE THE KEYS
The keys are presented in the form of questions. You are to answer based on your observations of your specimen. There are usually two questions (1A and 1B). In a few cases, to reduce the number of questions, more than two questions are asked. These are recognized by the lower case letter following the question number with the last question with an upper case letter (1a, 1b, 1c, 1D). Your specimen should fit one of the choices. I have used an indented key because it has two advantages. First, it makes choice criteria more visible and secondly, it is very easy to see where you "came from".
Since the keys are based on adult characters, how can you determine if your specimen is an adult? The reflecting of the lip (when present) usually occurs when the animal approaches adulthood. If the outer edge of the mouth is soft and flexible while the rest of the shell is otherwise quite firm, the animal is probably a juvenile. Another way to determine a juvenile is by measuring the shell size and counting the number of whorls. Compare these with adult shells of related species. Is your specimen in the correct proportion to be a juvenile?
Genera with variable characters can appear more than once in the keys. These genera are indicated by “(in part)”.
If you find a specimen that does not fit any of the species, send it to an expert. You may have a new species or an extension to the range of a known species.
A note from the translator: For questions on the shell characters consult
Burch 1962 and Burch & Cruz Reyes 1987.
Slugs – Use Key L
3A-Shell width much greater than shell height.
4A-Shell spire is elevated.
Depressed - Use Key A
4B-Shell spire is not elevated. Shell is in one plane.
Discoid - Use Key B
3B-Shell width and height approximately equal.
5A-Shell spire is pointed.
Helicoid - Use Key C
5B-Shell spire is rounded.
Domed - Use Key D
6A-Shell has apex missing.
Decollated – Use Key K
6B-Shell has apex present.
7A-Aperture length more than 3/4 shell height.
Succiniform – Use Key H
7B-Aperture length less than 3/4 shell height.
8A-Shell apex rounded.
Pupilliform – Use Key E
8B-Shell apex not rounded.
9A-Shell spire tapers to a point.
Urocoptiform – Use Key F
9B-Shell spire does not taper to a point.
10A-Last whorl much wider than prior whorl.
Bulimoid – Use Key I
10B-Last whorl slightly wider than prior whorl.
11A-Aperture elongate (more than twice as long as wide).
Fusiform – Use Key G
11B-Aperture more round (less than twice as long as wide).
Conical – Use Key J
KEY A – SHELL SHAPE DEPRESSED
1A-Aperture projecting in a rounded neck.
Ceochasma
1B-Aperture not projecting in a rounded neck.
2A-Aperture with teeth or barriers.
3A-Shell with single spiral color band.
Ceres
3B-Shell without color band.
4A-Aperture lip straight.
5A-Shell without hole at bottom of columella.
6A-Lamella located on perietal wall.
Proserpinella
6B-Lamella located on middle of columella.
Linidiella
5B-Shell with hole at bottom of columella.
Helicodiscus (in part)
4B-Aperture lip reflected.
7A-Shell without hole at bottom of columella.
Lucidella (in part)
7B-Shell with a hole at bottom of columella.
8A-Aperture relatively small in relation to overall size of shell.
Polygyra
8B-Aperture usually relatively large in relation to size of shell.
Ashmunella (in part)
2B-Aperture without teeth or barriers.
9A-Shell surface with ridges.
10A-Ridges are spiral
11A-Shell size less than 3 mm.
Lucidella (in part)
11B-Shell size 3 to 10 mm.
Schasicheila (in part)
10B-Ridges are radial.
12A-Shell with true ribs or rib-like structures.
13A-Aperture lip straight.
14A-Shell without hole at bottom of columella.
Schasicheila (in part)
14B-Shell with width of hole at bottom of columella greater than
1/4 shell diameter.
15A-Shell aperture shape circular.
Amphicyclotus (in part)
15B-Aperture shape not circular.
16A-Shell size less than 3 mm.
17A-Shell size 2 mm or less.
18A-Aperture outline elongated horizontally.
Striatura
18B-Aperture outline not elongated horizontally.
19A-Aperture height less than 1/2 shell
height.
Punctum (in part)
19B-Aperture height greater than 1/2 shell
height.
Chanomphalus
17B-Shell size 2 mm or more.
Radiodiscus
16B-Shell size 3 to 10 mm.
Pycnogyra
13B-Aperture lip reflected.
20A-Shell without hole at bottom of columella or hole to 1/10
shell diameter; shell size 3 to 10 mm.
Glyphalinia
20B-Shell with width of hole at bottom of columella to 1/4 shell
diameter; shell size less than 3 mm.
Vallonia (in part)
12B-Shell with strong growth lines.
21a-Shell with width of hole at bottom of columella to 1/10 shell
diameter.
22A-Shell tightly coiled.
Zonites (in part)
22B-Shell loosely coiled.
Omphalina (in part)
21b-Shell with width of hole at bottom of columella 1/10 to 1/4
shell diameter.
23a-Shell size less than 3 mm.
Miradiscops (in part)
23b-Shell size 3 to 10 mm.
Zonitoides (in part)
23C-Shell size greater than 10 to 30 mm.
Gonyodiscus
21C-Shell with width of hole at bottom of columella greater than 1/4
shell diameter.
24A-Shell size 3 to 10 mm.
25A-Shell loosely coiled; size greater than 6 mm.
Haplotrema
25B-Shell tightly coiled; size less than 6 mm.
Thysanophora
(in part)
24B-Shell size greater than 10 to 30 mm.
Dicrista (in part)
9B-Shell surface without ridges.
26A-Shell surface with color pattern.
27A-Shell with radial color pattern.
Xenocyclus
27B-Shell with spiral color pattern.
28A-Shell with a single spiral color band.
29A-Aperture lip straight.
30A-Shell without hole at bottom of columella.
Schasicheila (in part)
30B-Shell with hole at bottom of columella.
Sonorella (in part)
29B-Aperture lip reflected.
31a-Shell without hole at bottom of columella.
[Author Note: There are no Mexican genera in this
category]
31b-Shell with width of hole at bottom of columella to 1/10
shell diameter.
32A-Aperture greater than 1/2 shell height.
Leptarionta (in part)
32B-Aperture less than 1/2 shell height.
Sonorella (in part)
31c-Shell inner edge of aperture lip covering all or most of
hole at bottom of columella.
Omphalina (in part)
31d-Shell with width of hole at bottom of columella to 1/4
shell diameter.
33A-Spiral band on periphery of shell.
Tryonigens
33B-Spiral band above periphery of shell.
The following genera are only distinguished by
internal anatomy.
Eremarionta
Sonorella (in part)
31E-Shell with width of hole at bottom of columella greater
than 1/4 shell diameter.
Trichodiscina (in part)
28B-Shell with more than one spiral band.
34A-Aperture lip straight.
35a-Shell without hole at bottom of columella.
Schasicheila (in part)
35b-Shell with width of hole at bottom of columella to 1/10
shell diameter.
Mesomphix (in part)
35c-Shell with width of hole at bottom of columella to 1/4
shell diameter.
36A-Shell size greater than 10 to 30 mm.
Neocyclotus (in part)
36B-Shell size greater than 30 mm.
Megacyclotus
35D-Shell with width of hole at bottom of columella greater
than 1/4 shell diameter.
37A-Aperture shape circular.
Amphicyclotus (in part)
37B-Aperture shape not circular.
38A-Shell size less than 12 mm.
Averellia (in part)
38B-Shell size greater than 12 mm.
Trichodiscina (in part)
34B-Aperture lip reflected.
39A-Whorl periphery outline angular.
Oligyra (in part)
39B-Whorl periphery outline round.
40A-Shell size less than 15 mm.
Practicolella
40B-Shell size greater than 15 mm.
Leptarionta (in part)
26B-Shell surface without color pattern.
41A-Aperture lip straight.
42a-Shell without hole at bottom of columella.
43A-Shell size 12-15 mm.
Xanthony
43B-Shell size 18 mm or greater.
Bunnya
42b-Shell with width of hole at bottom of columella to 1/10 shell
diameter.
44a-Shell size less than 3 mm.
Guppya (in part)
44b-Shell size 3 to 10 mm.
Zonitoides (in part)
44C-Shell size greater than 10 to 30 mm.
Mesomphix (in part)
42c-Shell with width of hole at bottom of columella to 1/4 shell
diameter.
45A-Shell size less than 3 mm.
46A-Shell surface shinny.
Miradiscops (in part)
46B-Shell surface dull.
Hawaiia
45B-Shell size greater than 10 to 30 mm.
47A-Shell size less than 15 mm.
Aperostoma (in part)
47B-Shell size greater than 15 mm.
Neocyclotus (in part)
42D-Shell with width of hole at bottom of columella greater than 1/4
shell diameter.
48A-Shell size less than 3 mm.
49A-Aperture outline vertically elongated.
Retinella
49B-Aperture outline not vertically elongated.
Helicodiscus (in part)
48B-Shell size greater than 3 mm.
50A-Aperture with a groove or notch.
Aperstoma (in part)
50B-Aperture without a groove or notch.
Amphicyclotus (in part)
41B-Aperture lip reflected.
51a-Shell without hole at bottom of columella.
Schascheila (in part)
51b-Shell with width of hole at bottom of columella to 1/10 shell
diameter.
52A-Shell size less than 3 mm.
Punctum (in part)
52B-Shell size greater than 10 to 30 mm.
Ashmunella (in part)
51c-Shell with width of hole at bottom of columella to 1/4 shell
diameter.
Vallonia (in part)
51D-Shell with width of hole at bottom of columella greater than 1/4
shell diameter.
Averellia (in part)
1A-Shell with radial ribs.
Rotadiscus
1B-Shell without radial ribs.
2A-Shell with spiral color pattern.
Trichodiscina (in part)
2B-Shell without a color pattern.
Hendersoniella
KEY C – SHELL SHAPE HELICOID
1A-Shell surface with ribs or strong growth lines.
2A-Shell with spiral ridges.
3A-Shell without hole at bottom of columella.
4A-Shell surface with spiral and radial ribs; shell size 3 to 10 mm.
Oligyra (in part)
4B-Shell surface with only spiral ribs; shell size greater than 10 to 30 mm.
Helicina (in part)
3B-Shell with width of hole at bottom of columella to 1/4 shell diameter.
Annularia (in part)
2B-Shell with radial ribs or strong growth lines.
5A-Shell with radial ribs.
6A-Shell with width of hole at base of columella to 1/10 shell diameter;
shell size 3 to 10 mm; aperture shape not circular.
Thysanophora (in part)
6B-Shell with width of hole at bottom of columella to 1/4 shell diameter;
shell size greater than 10 to 30 mm; aperture shape circular.
Annularia (in part)
5B-Shell with strong growth lines or corrugated surface.
7A-Shell with strong growth lines.
8A-Aperture lip straight.
9A-Shell without hole at bottom of columella.
Simpulopsis (in part)
9B-Shell with width of hole at bottom of columella to 1/10 shell
diameter.
10A-Shell with single spiral band; shell size greater than 10 to
30 mm.
Zonites (in part)
10B-Shell without spiral band; shell size 3 to 10 mm.
Guppya (in part)
8B-Aperture lip reflected or thickened.
Pyrgodomus (in part)
7B-Shell with corrugated surface.
Simpulopsis (in part)
1B-Shell surface without ribs or strong growth lines.
11A-Shell surface with spiral color pattern.
12A-Aperture lip straight.
13a-Shell without hole at bottom of columella.
Schasicheila (in part)
13b-Shell with width of hole at bottom of columella to 1/10 shell
diameter.
Humboldtiana
13D-Shell with width of hole at bottom of columella to 1/4 shell diameter.
Dicrista (in part)
12B-Aperture lip reflected.
14A-Shell tightly coiled.
Helicina (in part)
14B-Shell loosely coiled.
15A-Shell aperture greater than 1/2 shell height; shell size greater
than 30 mm.
Lysinoe
15B-Shell aperture less than 1/2 shell height; shell size greater than
10 to 30 mm.
Leptarionta (in part)
11B-Shell surface without color pattern.
16A-Aperture lip straight.
17A-Shell size less than 3 mm; shell coiling loose.
Pupisoma (in part)
17B-Shell size 3 to 10 mm; shell coiling tight.
18A-Shell size less than 4 mm.
Guppya (in part)
18B-Shell size greater than 4 mm.
Habroconus
16B-Aperture lip reflected.
Helicina (in part)
KEY D – SHELL SHAPE DOMED
1A-Aperture lip straight.
Euconulus
1B-Aperture lip reflected.
Strobilops
KEY E – SHELL SHAPE PUPILLIFORM
1A-Shell coiling sinistral.
Gastrocopta (in part)
1B-Shell coiling is dextral.
2A-Aperture projecting in a rounded neck.
3A-Aperture with teeth or barriers; shell size less than 3 mm.
Gastrocopta (in part)
3B-Aperture without teeth or barriers; shell size greater than 10 to 30 mm.
4A-Shell apex domed.
Coelostemma (in part)
4B-Shell apex pointed.
Holospira (in part)
2B-Aperture attached to body wall or columella.
5A-Aperture with teeth or barriers.
6A-Shell surface with radial ridges.
7A-Shell size less than 3 mm.
Vertigo (in part)
7B-Shell size 3 to 10 mm.
Pupilla (in part)
6B-Shell surface without radial ridges.
8A-Aperture lip straight
Pupilla (in part)
8B-Aperture lip reflected.
9A-Aperture outline circular.
Chaenaxis
9B-Aperture outline not circular.
10A-Shell without hole at bottom of columella.
Sterkia
10B-Shell with width of hole at bottom of columella to 1/10 shell
diameter.
Bothriopupa
5B-Aperture without teeth or barriers.
Pupilla (in part)
KEY F – SHELL SHAPE UROCOPTITIFORM; (Aperture projecting in a
rounded neck)
1A-Last whorl distorted, appearing sinistral.
Metastoma
1B-Last whorl not distorted.
2A-Shell surface with radial ribs.
3A-Aperture lip straight.
Coelostemma (in part)
3B-Aperture lip reflected.
4A-Shell shape is skinny (shell height greater than 3 times shell diameter).
Propilsbrya (in part)
4B-Shell shape is not skinny (shell height less than 3 times shell diameter.
Holospira (in part)
2B-Shell surface without radial ribs.
Coelostemma (in part)
KEY G – SHELL SHAPE FUSIFORM
1A-Columella truncated.
2A-Shell surface with ribs.
3A-Shell shape is skinny (shell height greater than 3 times shell diameter).
Mayaxis
3B-Shell shape is not skinny (shell height less than 3 times shell diameter).
4A-Shell aperture greater than 1/2 shell height.
Euglandina (in part)
4B-Shell aperture less than 1/2 shell height.
Ochrodermella
2B-Shell surface without ribs.
5A-Whorl periphery outline flat.
Karolus
5B-Whorl periphery outline round.
6A-Shell size 3 to 30 mm.
Salasiella (in part)
6B-Shell size greater than 30 mm.
Euglandina (in part)
1B-Columella straight.
7A-Aperture with a fold on the columella.
Streptostyla
7B-Aperture without a fold on the columella.
8A-Aperture outline elongated vertically.
9A-Shell shape is skinny (shell height greater than 3 times shell diameter).
Cecilioides
9B-Shell shape is not skinny (shell height less than 3 times shell
diameter); shell dull.
Rabdotus (in part)
8B-Aperture outline not elongated vertically.
10A-Shell size less than 6 mm.
Cochlicopa
10B-Shell size greater than 6 mm.
Orizosoma
KEY H – SHELL SHAPE SUCCINIFORM
1A-Shell surface with strong growth lines.
Succinea
1B-Shell surface without strong growth lines.
2A-Aperture outline vertically elongated; shell size greater than 10 to 30 mm.
Strebelia
2B-Aperture outline not vertically elongated; shell size 3 to 10 mm.
Simpulopsis (in part)
KEY I – SHELL SHAPE
BULIMOID
1A-Shell surface with ribs or strong growth lines.
2A-Shell with spiral ribs.
Licina (in part)
2B-Shell with strong growth lines.
3A-Columella truncated.
Leptinaria (in part)
3B-Columella not truncated.
Catinella
1B-Shell surface without ribs or strong growth lines.
4A-Shell surface with a color pattern.
5A-Color pattern is spiral.
Drymaeus (in part)
5B-Color pattern is radial.
6A-Aperture lip reflected.
Drymaeus (in part)
6B-Aperture lip straight.
7A-Shell without hole at bottom of columella; shell size greater than
30mm.
Orthalicus
7B-Shell with width of hole at bottom of columella; shell size less than
30 mm.
Rabdotus (in part)
4B-Shell surface without a color pattern.
8a-Shell without hole at bottom of columella.
Rabdotus (in part)
8b-Shell with width of hole at bottom of columella to 1/10 shell diameter.
9a-Shell size less than 3 mm.
Pupisoma (in part)
9b-Shell size 3 to 10 mm.
Lamellaxis (in part)
9C-Shell size greater than 10 to 30 mm.
Bulimulus
8C-Shell inner edge of aperture lip covering all or most of hole at bottom of
columella.
Allopeas (in part)
KEY J – SHELL SHAPE CONICAL
1A-Shell coiling sinistral.
Adelopoma
1B-Shell coiling dextral.
2A-Aperture is projecting in a rounded neck.
3A-Shell shape is skinny (shell height greater than 3 times shell diameter).
4A-Aperture shape circular.
5A-Whorl periphery outline flat.
Propilsbrya (in part)
5B-Whorl periphery outline round.
Brachypodella
4B-Aperture shape square.
Epirobia (in part)
3B-Shell shape is not skinny (shell height less than 3 times shell diameter).
6A-Shell surface with ribs.
Tomocyclus (in part)
6B-Shell surface without ribs.
Epirobia (in part)
2B-Aperture is not projecting in a rounded neck.
7A-Aperture with teeth or barriers.
8A-Aperture outline circular; shell size greater than 30 mm.
Oligostylus (in part)
8B-Aperture outline not circular; shell size not greater than 30 mm.
9A-Shell size less than 3 mm.
Carychium
9B-Shell size 3 to 10 mm.
10A-Aperture lip straight.
Tornatellides
10B-Aperture lip reflected.
Pupoides
7B-Aperture without teeth or barriers.
11A-Columella truncated.
12A-Shell surface with ribs.
13A-Shell size 3 to 10 mm.
14A-Shell size 6 to 7 mm.
Leptinaria (in part)
14B-Shell size 7 to 9 mm.
Lamellaxis (in part)
13B-Shell size greater than 10 to 30 mm.
Pseudosubulina
12B-Shell surface without ribs.
Subulina
11B-Columella not truncated.
15A-Shell surface with ribs or strong growth lines.
16A-Shell with true ribs.
17A-Shell surface with a color pattern.
17B-Shell surface without a color pattern.
18A-Shell shape is skinny (shell height greater than 3 times
shell diameter).
19A-Shell aperture outline circular; lip reflected.
Propilsbrya (in part)
19B-Shell aperture outline not circular;
lip not reflected.
20A-Aperture lip straight.
21A-Shell without hole at bottom of columella.
Opeas (in part)
21B-Shell with hole at bottom of columella.
Allopeas (in part)
20B-Aperture lip thickened.
Coelostele
18B-Shell shape is not skinny (shell height less than 3
times shell diameter).
22A-Aperture lip straight; aperture outline not
circular.
23a-Shell size less than 3 mm.
Spiraxis (in part)
23b-Shell size 3 to 10 mm.
24A-Shell size less than 6 mm.
Spiraxis (in part)
24B-Shell size 6 to 9 mm.
25A-Shell diameter less than 3 mm; length
6 to 9 mm.
Allopeas (in part)
25B-Shell diameter greater than 3 mm; length
6 to 9 mm.
Synopeas (in part)
23C-Shell size greater than 10 to 30 mm.
Microceramus (in part)
22B-Aperture lip reflected; aperture outline circular.
26A-Shell size greater than 10 mm; aperture outline
extending well beyond periphery of prior whorl.
Chondropoma (in part)
26B-Shell size 10 mm or less; aperture outline
extending slightly beyond periphery of prior
whorl.
Microceramus (in part)
16B-Shell with strong growth lines.
Spiraxis (in part)
15B-Shell surface without ribs.
27A-Shell surface with a radial color pattern.
Drymaeus (in part)
27B-Shell surface without a color pattern.
28A-Shell shape is skinny (shell height greater than 3 times
shell diameter); shell size greater than 10 to 30 mm.
29A-Shell without hole at bottom of columella.
30A-Shell size less than 3 mm.
Opeas (in part)
30B-Shell size greater than 3 mm.
Rabdotus (in part)
29B-Shell with a hole at bottom of columella.
Allopeas (in part)
28B-Shell shape is not skinny (shell height less than 3 times
shell diameter).
31A-Shell size 3 to 10 mm.
32A-Aperture outline circular.
Pupoides (in part)
32B-Aperture outline not circular.
Allopeas (in part)
31B-Shell size greater than 10 mm.
Drymaeus (in part)
KEY K – SHELL SHAPE DECOLLATE
1A-Shell aperture projecting in a rounded neck.
2A-Shell surface with radial ribs.
3A-Whorl outline flat.
Eucalodium (in part)
3B-Whorl outline round.
Tomocyclus (in part)
2B-Shell surface without radial ribs.
4A-Aperture lip straight.
Oligostylus
4B-Aperture lip reflected.
5A-Aperture outline circular.
6A-Shell without hole at bottom of columella.
Eucalodium (in part)
6B-Shell with width of hole at bottom of columella to 1/10 shell
diameter.
Coelocentrum
5B-Aperture outline not circular.
7A-Shell size less than 30 mm.
Liocentrum
7B-Shell size greater than 30 mm.
Anisospira (in part)
1B-Shell aperture not projecting in a rounded neck.
8A-Shell surface with radial ribs.
9A-Aperture outline circular; lip reflected; shell size greater than 10
to 30 mm.
10A-Shell aperture height greater than 1/2 shell height.
Tomocyclus (in part)
10B-Shell aperture height less than 1/2 shell height.
Choanopoma (in part)
9B-Aperture outline not circular; lip thickened; shell size 3 to 10 mm.
Truncatella
8B-Shell surface without radial ribs.
11A-Shell size greater than 10 to 30 mm.
Anisospira (in part)
11B-Shell size greater than 30 mm.
Dissotropis
KEY L – SLUGS
1A-Mantle covers the entire animal.
2A-Sole of foot divided into three longitudinal sections; Ridge on edge of mantle;
elongated length greater than 30 mm. [Genera can be distinguished by internal
anatomy]
Leidyula
Phyllocaulis
Sarasinula
2B-Sole of foot not divided into three longitudinal sections; No ridge on edge of
mantle; elongated length less than 30 mm. [Genera can be distinguished by
internal anatomy]
Pallifera
Philomycus
1B-Mantle does not cover the entire animal.
3A-Mantle located in middle third of the foot.
4A-Breathing pore located in posterior half of mantle; foot length greater
than 30 mm.
Metostracon
4B-Breathing pore located in anterior half of the mantle; foot length less
than 30 mm.
Semiconchola
3B-Mantle located in the anterior third of the foot.
5A-Sole of foot divided into three longitudinal sections.
Deroceras
5B-Sole of foot not divided into three longitudinal sections.
Binneya
Index to genera in Mexican land snail keys
(117 Genera)
Genus
Key
|
Adelopoma |
J |
|
Allopeas |
I, J |
|
Amphicyclotus |
A |
|
Anisospira |
K |
|
Annularia |
C |
|
Aperostoma |
A |
|
Ashmunella |
A |
|
Averillia |
A |
|
Binneya |
L |
|
Bothriopupa |
E |
|
Brachypodella |
J |
|
Bulimulus |
I |
|
Bunnya |
A |
|
Carychium |
J |
|
Catinella |
I |
|
Cecilioides |
G |
|
Ceochasma |
A |
|
Ceres |
A |
|
Chaenaxis |
E |
|
Chanomphalus |
A |
|
Choanopoma |
K |
|
Chondropoma |
J |
|
Cochlicopa |
G |
|
Coelocentrum |
K |
|
Coelostele |
J |
|
Coelostemma |
E, F |
|
Deroceras |
L |
|
Discrita |
A, C |
|
Dissotropis |
K |
|
Drymaeus |
I, J |
|
Epirobia |
J |
|
Eremarionta |
A |
|
Eucalodium |
K |
|
Euconulus |
D |
|
Euglandina |
G |
|
Gastrocopta |
E |
|
Glyphyalinia |
A |
|
Gonyodiscus |
A |
|
Guppya |
A, C |
|
Habroconus |
C |
|
Haplotrema |
A |
|
Hawaiia |
A |
|
Helicina |
C |
|
Helicodiscus |
A |
|
Hendersoniella |
B |
|
Holospira |
E, F |
|
Humboldtiana |
C |
|
Karolus |
G |
|
Lamellaxis |
I, J |
|
Leidyula |
L |
|
Leptarionta |
A, C |
|
Leptinaria |
I, J |
|
Licina |
I |
|
Linidiella |
A |
|
Liocentrum |
K |
|
Lucidella |
A |
|
Lysinoe |
C |
|
Mayaxis |
G |
|
Megacyclotus |
A |
|
Mesomphix |
A |
|
Metastoma |
F |
|
Metostracon |
L |
|
Microceramus |
J |
|
Miradiscops |
A |
|
Neocyclotus |
A |
|
Ochrodermella |
G |
|
Oligostylus |
J, K |
|
Oligyra |
A, C |
|
Omphalina |
A |
|
Opeas |
J |
|
Orizosoma |
G |
|
Orthalicus |
I |
|
Pallifera |
L |
|
Philomycus |
L |
|
Phyllocaulis |
L |
|
Polygyra |
A |
|
Praticolella |
A |
|
Propilsbrya |
F, J |
|
Proserpinella |
A |
|
Pseudosubulina |
J |
|
Punctum |
A |
|
Pupilla |
E |
|
Pupisoma |
C, I |
|
Pupoides |
J |
|
Pycnogyra |
A |
|
Pyrgodomus |
C |
|
Rabdotus |
G,I,J |
|
Radiodiscus |
A |
|
Retinella |
A |
|
Rotadiscus |
B |
|
Salasiella |
G |
|
Sarasinula |
L |
|
Schasicheila |
A, C |
|
Semiconchola |
L |
|
Simpulopsis |
C, H |
|
Sonorella |
A |
|
Spiraxis |
J |
|
Sterkia |
E |
|
Strebelia |
H |
|
Streptostyla |
G |
|
Striatura |
A |
|
Strobilops |
D |
|
Subulina |
J |
|
Succinea |
H |
|
Synopeas |
J |
|
Thysanophora |
A, C |
|
Tomocyclus |
J, K |
|
Tornatellides |
J |
|
Trichodiscina |
A, B |
|
Truncatella |
K |
|
Tryonigens |
A |
|
Vallonia |
A |
|
Vertigo |
E |
|
Xanthony |
A |
|
Xenocyclus |
A |
|
Zonites |
A, C |
|
Zonitoides |
A |
REFERENCES
Burch, J. B. 1962 “How to know; The Eastern Land Snails”. Wm. C. Brown Company
Publishers,
Burch, J. B. & A. Cruz Reyes 1987 “Clave gerérica para la identifición de gastrópodos
de agua dulce en México”. Instituto de Biologia, UNAM, 46 p.
Burch, J.B. & T.A. Pearce. 1990. Terrestrial Gastropoda, p.201-309. In D.L. Dindal
(ed),
Soil Biology. John Wiley & Sons,
Richardson, L.C. 1991. Urocoptidae: catalog of species. Tryonia, 22:1-245.
Vaught, K.C. 1989. A classification of the living Mollusca. American Malacologists.