Virginia Land Snails



Key to shelled land snails of Virginia

(adult shells only)
by Ken Hotopp, with pupillids by Jeff Nekola

1a.  Shell wider than tall, or approximately as wide as tall
IDGo to 2
1b. Shell taller than wide
IDGo to 43

2a.  Shell with thickened or reflected peristome (mostly or entirely reflected, narrowly or widely)
IDGo to 3
2b. Shell with thin peristome (though may be callused or toothed within)
IDGo to 23

3a.  Shell diameter <4mm
IDGo to 4
3b. Shell diameter >4mm
IDGo to 5

4a. Shell flattened, depressed
4b. Shell taller, low conical

5a. Shell texture of radial ridges, or a fuzzy hair-like texture
IDGo to 6
5b. Shell sculpture fine radial striae; shell imperforate and dome-shaped
IDHendersonia occulta

6a. Shell umbilicate
IDGo to 7
6b. Shell imperforate or rimate
IDGo to 13

7a. Shell with teeth in aperture
IDGo to 9
7b. Shell without pronounced teeth in aperture
IDGo to 8

8a. Peristome with basal swelling; spiral stripe in fresh shells
IDAllogona profunda
8b. Peristome without basal swelling; tubular whorls
IDHaplotrema concavum

9a. Shell with a parietal tooth only
IDGo to 10
10b. Shell with two or three teeth
IDGo to 11

10a. Larger shell (>14mm), small parietal tooth
IDFumonelix wheatleyi
10b. Small shell (<8mm), sinuous peristome continuous with parietal tooth.
IDDaedalochila plicata

11a. Shell with parietal tooth and spike-like basal tooth; larger (>18 mm diameter)
IDAppalachina sayana
11b. Shell with three teeth
IDGo to 12

12a. Very small shell <6 mm wide; fresh shell with sparse “hairs”
IDLobosculum pustuloides
12b. Shell >6 mm wide; no hairs

13a. Shell flatter, depressed
IDGo to 14
13b. Shell taller, domed or rounded
IDGo to 17

14a. Shell with short parietal lamella
IDGo to 16
14b.Shell with long parietal lamella
IDGo to 15

15a. Shell with subtle basal lamella, no palatal tooth
15b. Shell with pronounced basal lamella, palatal tooth
IDXolotrema denotata

16a. Shell less than 11mm diameter
IDFumonelix christyi
16b. Shell more than 19mm diameter
IDNeohelix dentifera

17a. Shell with long parietal tooth, narrow or slit-like aperture
IDGo to 18
17b. All others, with or without teeth
IDGo to 19

18a. Sinuous and notched basal lamella, covered umbilicus
18b. No basal lamella, rimate umbilicus

19a. Peristome widely reflected, shells not banded
IDGo to 20
19b. Peristome narrowly reflected, fresh shells usually banded
IDGo to 21

20a. Shells smaller than 15mm wide
20b. Shells larger than 15mm wide
IDMesodon and Neohelix

21a. Rib-like callus just within aperture
IDCernuella virgata
21b. No rib-like callus
IDGo to 22

22a. Shell >25mm wide, light-colored with broken stripes
IDHelix aspersa
22b. Shell 25 mm wide or less, yellowish with dark continuous stripes, or no stripes

23a. Shells >4mm wide
IDGo to 24
23b. Shells <4mm wide
IDGo to 35

24a. Shell between 4-16mm diameter
IDGo to 25
24b. Shell >16mm diameter
IDGo to 32

25a. Shells with engraved radial grooves
IDGlyphyalinia and Nesovitrea
25b. Shells without radial grooves, but may have radial ridges or other sculpture
IDGo to 26

26a. Shells with very strong radial ribs, coarse texture above and below
26b. All others - shells with weak to smooth sculpture, or with spiral sculpture, or with coarse sculpture only on upper surface
IDGo to 27

27a. Shell having heavy callus or lamellae within aperture
IDGo to 28
27b. Shells without heavy callus or lamellae in aperture.
IDGo to 29

28a. Shell tightly whorled, with coarse radial sculpture on upper surfaces
28b. Shell regularly whorled, without coarser sculpture above

29a. Shell imperforate, very rapidly expanding, amber-colored and fragile
IDVitrinzonites latissimus
29b. Shells perforate or umbilicate
IDGo to 30

30a. Umbilicus < ¼ shell diameter, shell very tightly coiled, internal teeth sometimes visible through base
IDParavitrea (most)
30b. Umbilicus > ¼ shell diameter, shell regularly or rapidly expanding
IDGo to 31

31a. Shell rapidly expanding, wider umbilicus
31b. Shell regularly expanding, well-like umbilicus

32a. Smooth or finely-textured shell
IDGo to 33
32b. Shell with strong radial ribs
IDGo to 34

33a. Shells with two brown spiral bands
IDAnguispira kochi
33b. Unbanded shells

34a. Shell with a heavy, rib-like callus within the aperture
IDCandidula intersecta
34b. Shell lacking a transverse callus within the aperture
IDAnguispira (most species)

35a. Shell with wide umbilicus, tubular whorls, low apex
IDGo to 36
35b. All others
IDGo to 39

36a. Shells with spiral lirae or fringes, which may be faint
IDGo to 37
36b. Shells lacking spiral lirae or fringes
IDGo to 38

37a. Shells with simple final whorl
37b. Shells with deflected final whorl bearing a parallel lamella
IDPolygyriscus virginianus

38a. Shell with fine radial and spiral striae, silky texture
38b. Shell glossy with rounded growth wrinkles

39a. Shell imperforate
IDGuppya sterkii
39b. Shell umbilicate
IDGo to 40

40a. Shell almost as tall as wide, beehive-shaped
40b. Shell flatter in profile
IDGo to 41

41a. Shell tightly whorled, internal teeth visible through base
IDParavitrea (in part)
41b. All others
IDGo to 42

42a. Shell regularly-coiled, whorls increasing <1.5x per revolution
42b. Shell more loosely coiled, whorls increasing >1.5x per revolution

43a.  Shell with narrow aperture parallel to column; coastal
IDMelampus bidentatus
43b. All others
IDGo to 44

44a. Relaxed spiral with no more than 3 whorls in mature shell
IDGo to 45
44b.Tighter spiral with 4+ whorls in mature shell
IDGo to 48

45a. Aperture taking up ½ of shell length
45b. Aperture more than ½ of shell length
IDGo to 46

46a. Shell and aperture narrowly ovate to elongate
46b.Shell and aperture broadly ovate
IDNovisuccinea and Succinea

47a. Shell very glossy, transparent, cylindrical, at least 4mm tall
IDGo to 48
47b. Shell silky to dull, opaque
IDGo to 49

48a. Shell yellowish or brown
48b. Shell whitish or clear
IDGo to 50

49a. Shell smooth, glossy; up to 5.5 mm tall
IDCecilioides acicula
49b. Shell textured with fine radial lines; up to 8mm tall
IDOpeas pyrgula

50a.Shell cone-shaped, with pointed apex, at least 4 mm tall
IDGo to 51
50b.Shell pupa-shaped, columnar, or spike-shaped
IDGo to 52

Shell brown with thickened, light-colored peristome
IDPupoides albilabris
51b. Shell brown with thin peristome and impressed sutures

52a. Shell very narrow, at least 2½ times taller than wide, white
52b. Shell 1½-2½ times taller than wide
IDGo to 53

53a. At least one lamella in aperture
IDGo to 54
53b. No apertural lamella
IDGo to 56

54a. Parietal lamella fused with angular forming a complex bilobed structure
54b. Parietal lamella a simple peg or plate (occasionally absent); angular lamellae (if present) not fused with the parietal
IDGo to 55

55a. Fresh shells waxy white to clear
55b. Fresh shells pale yellow to deep reddish brown

56a. Shell >3 mm tall
IDPupilla muscorum
56b. Shell <3 mm tall
IDGo to 57

57a. Shell with fewer than 4 whorls
IDimmature pupillid
57b. Shell with 4 or more whorls
IDColumella simplex

(most species: alternata, fergusoni, jessica, mordax, rugoderma, strongylodes; not including kochi)

1a. Ribs very coarse, from 0.5-1.0 mm apart; central or western
IDA. mordax
1b. Ribs moderately coarse
IDGo to 2

2a. Shell colorful - background color slightly yellowish, with reddish spots; mucus clear; eastern
IDA. fergusoni
2b. Background color pale or light brown
IDGo to 3

3a. Shell whorls rounded; narrow umbilicus
IDA. jessica
3b. Whorls angled weakly to strongly; umbilicus wider
IDGo to 4

4a. Color spots small, no radiating streaks
IDA. strongylodes
4b. Color spots larger, often radiating streaks
IDA. alternata

Carychium (clappi, exiguum, exile, nannodes)

1a. Shell surface smooth or mostly smooth
IDGo to 2
1b. Shell ribbed
IDGo to 3

2a. Shell <1.5 mm tall, thin
IDC. nannodes
2b. Shell >1.5 mm tall, robust
IDC. exiguum

3a. Aperture not thickened within; whorls more angular
IDC. clappi
3b. Aperture thickened within
IDC. exile

Catinella (avara, hubrichti, oklahomarum, vagans)

1a. Shell plain, pale
IDC. vermeta
1b. Shell yellowish, amber, or greenish
IDGo to 2

2a. Forest animal
IDC. oklahomarum
2b. Shore or marsh animal
IDGo to 3

3a. Greenish-yellow shell, James City vicinity
IDC. hubrichti
3b. Yellowish shell, Yorktown vicinity
IDC. vagans

Cepaea (hortensis, nemoralis)

1a. Shell <22 mm, with light-colored peristome
IDC. hortensis
1b. Shell >22 mm, usually with brown peristome
IDC. nemoralis

Cochlicopa (lubrica, lubricella, morseana)

1a. Cylindrical, width/height ratio <0.35
IDC. morseana
1b. Bulging, width/height ratio >0.35
IDGo to 2

2a. Wider, usually smaller, often with rosy peristome
IDC. lubrica
2b. A bit narrower, often larger, plain peristome
IDC. lubricella

Discus (bryanti, catskillensis, nigrimontanus, patulus, whitneyi)

1a. Shell >7 mm wide
IDGo to 2
1b. Shell <7 mm wide
IDGo to 3

2a. Periphery weakly angled, small basal lamella
IDD. patulus
2b. Periphery strongly angled, no lamellae
IDD. nigrimontanus

3a. Taller, with rounded whorls
IDD. whitneyi
3b. Lower, with angled whorls
IDGo to 4

4a. Carinate (angled) body whorl
IDD. catskillensis
4b. Bicarinate (two-angled) body whorl
IDD. bryanti

Euchemotrema (fraternum, leai)

1a. 5+ whorls, densely hirsute
IDE. fraternum
1b. 6+ whorls, sparsely hairy
IDE. leai

Euconulus (chersinus, dentatus, fulvus, trochulus)

1a. Final whorl containing 1-3 radial lamellae
IDE. dentatus
1b. Without lamellae
IDGo to 2

2a. Shell angular, with pointed apex
IDE. trochulus
2b. Shells more blunt, beehive-shaped
IDGo to 3

3a. Final whorl more than half the shell’s height
IDE. fulvus
3b. Final whorl half or less than shell height, relatively tall, matte finish
IDE. chersinus

Gastrocopta (armifera, clappi, contracta, corticaria, cristata, holzingeri, pellucida, pentodon, procera, riparia, tappaniana)

1a. Shell >3¼mm tall, cylindrical or barrel-shaped; translucent white when fresh  (subgenus Albinula)
IDGo to 2
1b. Shell <3¼mm tall; ovoid-conical; color white to brown
IDGo to 3

2a. Columellar lamella with distinct forward and basally pointing lobes, appearing more or less pyramidal in apertural view; shell usually >4 mm tall           
IDG. armifera
2b. Columellar lamella a simple plate, with lower end slightly more deeply inserted into aperture than upper; shell usually <4 mm tall 
IDG. clappi

3a. Angulo-parietal lamella a simple peg-like tooth
IDGo to 4
3b. Angulo-parietal lamellae not peg-shaped
IDGo to 6

4a. Fresh shells brown-red
IDG. cristata
4b. Fresh shells white-transparent
IDGo to 5

5a. Shell narrowly conical, with height more than 1½ times width; lower palatal lamella deeply entering aperture 
IDG. pentodon
5b. Shell broadly conical, with height less than 1½ times width; lower palatal lamella not deeply entering aperture
IDG. tappaniana

6a. Angulo-parietal lamella a single large, folded sheet 
IDG. contracta
6b. Angular and parietal lobes of angulo-parietal lamellae distinct
IDGo to 7

7a. Fresh shells whitish
IDGo to 8
7b. Fresh shells yellow-brown to brown-red
IDGo to 9

8a. Basal and palatal lamellae absent; shell >2.4 mm tall
IDG. corticaria
8b. Basal and palatal lamellae present; shell <2 mm tall
IDG. holzingeri

9a. Shell tan-yellow; height <2¼ mm tall; apertural margin unthickened 
IDG. pellucida
9b. Shell red-brown; height >2¼ mm tall; apertural margin with thickened callus
IDGo to 10

10a. Angular lobe of angulo-parietal lamella reduced to a small protuberance 
IDG. cristata
10b. Angulo-parietal lamella distinctly bi-lobed
IDGo to 11

11a. Lower palatal lamella inserted at roughly the same depth as the upper palatal, positioned approximately at a right angle to the lower aperture margin
IDG. riparia*
11b. Lower palatal lamella inserted more deeply into aperture than upper palatal, positioned approximately parallel to the lower apertural margin
IDG. procera

Gastrodonta (fonticula, interna)

1a. Open, well-like umbilicus, height 4 mm or less
IDG. fonticula
1b. Umbilicus small or closed, height 4 mm or more
IDG. interna

Glyphyalinia and Nesovitrea (G. carolinensis, cryptomphala, cumberlandiana, indentata, lewisiana, luticola, picea, praecox, raderi, rhoadsi, sculptilis, solida, specus, virginica, wheatleyi; N. electrina)

1a. Shell very small - with 4 whorls, but 4 mm or smaller diameter
IDGo to 2
1b. Shell medium or large diameter; more than 4 mm diameter
IDGo to 4

2a. Umbilicus width nearly 1/3 shell diameter
IDG. raderi
2b. Umbilicus smaller
IDGo to 3

3a. Umbilicus approximately 1/4 shell diameter
IDG. cumberlandiana
3b. Umbilicus approximately 1/5 shell diameter
IDG. lewisiana

4a. Shell large, >6 mm diameter
IDGo to 5
4b. Shell < 6mm diameter
IDGo to 9

5a. Shell very large, >10 mm
IDGo to 6
5b. Shell <10 mm
IDGo to 7

6a. Widely spaced indented lines, 5.5 whorls maximum
IDG. carolinensis
6b. Closely-spaced and regular indented lines, up to 7 whorls
IDG. sculptilis

7a. Umbilicus imperforate
IDG. solida
7b. Umbilicus perforate, with tiny opening
IDGo to 8

8a. Shell up to 7.1 mm wide
IDG. picea
8b. Shell up to 6.3 mm wide
IDG. praecox

9a. Umbilicus covered, imperforate
IDG. cryptomphala
9b. Shell perforate or umbilicate
IDGo to 10

10a. Shell umbilicate
IDGo to 11
10b. Shell perforate
IDGo to 14

11a. Umbilicus approximately 1/5-1/6 of shell width
IDG. rhoadsi
11b. Umbilicus more than 1/5 shell diameter
IDGo to 12

12a. Shell deep, 2.5-2.8 mm tall
IDNesovitrea electrina
12b. Shells < 2.5 mm tall
IDGo to 13

13a. Slightly larger (5 mm+ diameter)
IDG. wheatleyi
13b. Slightly smaller (usually <4.5 mm diameter)
IDG. virginica

14a. Shell slightly deeper (up to 3 mm tall) and with slightly more whorls (4.5-5)
IDG. indentata
15b. Shell subtly flatter (up to 2.6 mm tall), with fewer whorls (4-4.5)
IDG. luticola

Hawaiia (alachuana, minuscula)

1a. Cross-hatched microsculpture, lip of aperture meets penultimate whorl close to umbilicus; diameter approximately 3.5x the umbilical width
IDH. minuscula
1b. Primarily radial microsculpture, lip of aperture meets penultimate whorl away from midline; diameter approximately 2.5x the umbilical width
IDH. alachuana

Helicodiscus (diadema, fimbriatus, hadenoecus, lirellus, multidens, notius, parallelus, shimeki, triodus)

1a. Shell with palatal, basal, and parietal lamellae in final whorl
IDGo to 2
1b. Shell with palatal and basal lamellae only (no parietal lamellae), or with no lamellae
IDGo to 5

2a. Shell with one or more sets of basal and palatal teeth joined into a single notched lamella, radially flattened; flange-like parietal tooth
IDH. multidens
2b. Shell with one or more sets of distinct basal and palatal teeth, flange-like parietal tooth
IDGo to 3

3a. Basal and palatal teeth distinct, but flattened radially – flange-like
IDH. lirellus
3b. Basal and palatal teeth distinct, rounded or cone-shaped
IDGo to 4

4a. Shell with “hairs” adorning the lirae, though they may be sparse or mostly worn off
IDH. diadema
4b. Shell without hairs
IDH. triodus

5a. Shell with distinctly fringed lirae, which may be worn off, flat apex and shallow umbilicus, no teeth visible in aperture
IDH. fimbriatus
5b. Shell with lirae but no distinct fringes, teeth may or may not be visible in aperture
IDGo to 6

6a. Shell small (<3 mm), with spiral lirae and radial ridges, interrupted at intervals by growth ridges; may be nearly smooth except on base; without teeth in final whorl
IDH. hadenoecus
6b. Shell larger, with distinct spiral lirae
IDGo to 7

7a. Shell with flat apex, shallow umbilicus
IDH. shimeki
7b. Shell with slightly raised apex, deeper umbilicus
IDGo to 8

8a. Spiral striae on embryonic whorl distinct
IDH. notius (of questionable validity)
8b. Spiral striae on embryonic whorl weak
IDH. parallelus

Inflectarius (inflectus, kalmianus, rugeli)

1a. Shell globe-shaped, lacking teeth in aperture
IDI. kalmianus
1b. Shell somewhat depressed, with three teeth in aperture
IDGo to 2

2a. Shell smaller (9.5-12 mm wide), basal tooth visible in side view
IDI. inflectus
2b. Shell larger (11-15 mm wide), basal tooth not visible in side view, though seen from below
IDI. rugeli

Lucilla (scintilla, singleyana)

1a. Shell clear or whitish, up to 3 mm wide, flat spire
IDL. singleyana
1b. Shell yellowish, <2.5 mm wide, slightly raised spire
IDL. scintilla

Mesodon and Neohelix (M. andrewsae, clausus, elevatus, mitchellianus, normalis, thyroidus, zaletus; N. albolabris, major, solemi, dentifera)

1a. Shell bearing a parietal tooth
IDGo to 2
1b. Shell without a parietal tooth
IDGo to 5

2a. Umbilicus narrowly open, slit-like
IDM. thyroidus
2b. Umbilicus closed
IDGo to 3

3a. Aperture with low, ridge-like basal lamella
IDM. elevatus
3b. Aperture without basal lamella
IDGo to 4

4a. Shell very depressed, low spire
IDN. dentifera
4b. Shell slightly depressed
IDM. zaletus

5a. Umbilicus narrowly open
IDM. clausus (probably M. thyroidus)
5b. Umbilicus closed
IDGo to 6

6a. Shell <20 mm wide
IDM. mitchellianus
6b. Shell >20 mm wide
IDGo to 7

7a. Shell with a wide, low basal lamella, close to the columella; western
IDM. normalis
7b. Shell without a low basal lamella
IDGo to 8

8a. Shell very thin, found above 2,000’ elevation
IDM. andrewsae
8b. Shell robust
IDGo to 9

9a. Shell >28 mm (some overlap with below); only found central-to-west
IDN. major
9b. Shell <32 mm (some overlap); found statewide
IDGo to 10

10a. Relatively narrow lip (basal lip average width <0.65 mm); found on the Coastal Plain
IDN. solemi
10b. Average lip (basal lip width average >0.65 mm); widespread
IDN. albolabris

Mesomphix (capnodes, cupreus, inornatus, perlaevis, rugeli, subplanus)

1a. Microsculpture of body whorl has spiral and radial striae that create a pattern of tiny papillae
IDGo to 2
1b. No pattern of papillae                    
IDGo to 4

2a. Shell diameter 28 mm or more
IDM. capnodes
2b. Shell diameter <28 mm
IDGo to 3

3a. Papillae in dense, neat, rows and columns; shell lower
IDM. inornatus
3b. Papillae weak in most places; shell taller
IDM. perlaevis

4a. Umbilicus small, but obvious; shell often with dark brown peristome
IDM. cupreus
4b. Umbilicus tiny, perforate; shell lip plain
IDGo to 5

5a. Shell quite flattened
IDM. subplanus
5b. Shell moderately or strongly domed
IDGo to 6

6a. Shell moderately domed; spiral striae across the top of growth ridges
IDM. perlaevis
6b. Shell very domed; lacking spiral striae
IDM. rugeli

Novisuccinea and Succinea (N. ovalis; S. campestris, wilsonii)

1a. Found in woods, especially in stream valleys
IDN. ovalis
1b. Found on coastal dunes, marshes, tidewater
IDGo to 2

2a. Shell quite rounded, light-colored; dunes and shoreline
IDS. campestris
2b. Apex variable in height, shell usually yellow; brackish water, marshes
IDS. wilsonii

Oxychilus (cellarius, draparnaudi)

1a. Shell smaller, <4 mm tall
IDO. cellarius
1b. Shell larger, >4 mm tall
IDO. draparnaudi

Oxyloma (effusum, retusum, subeffusum)

1a. Shell aperture approximately 2/3 the total shell length
IDO. retusum
1b. Shell aperture larger than 2/3 total shell length
IDGo to 2

2a. Shell aperture approximately 3/4 total shell length
IDO. subeffusum
2b. Shell aperture 4/5 total shell length
IDO. effusum

Paravitrea (blarina, capsella, dentilla, hera, mira, lamellidens, multidentata, placentula, pontis, reesei, septadens, seradens, subtilis, tridens)

1a. Shell width 5 mm or less
IDGo to 2
1b. Shell width >5 mm
IDGo to 7

2a. Teeth or lamellae absent
IDP. blarina
2b. Teeth present (though may be deeply recessed)
IDGo to 3

3a. Shell 3.5 mm wide or more
IDGo to 4
3b. Shell <3.5 mm wide
IDGo to 5

Shell with lunate aperture; 1-3 curved radial lamellae
IDP. lamellidens
4b. Shell with deeply-recessed basal teeth in final whorl; aperture somewhat triangular, widest at base
IDP. reesei

5a. Shell with 1-2 simple radial lamellae in final whorl
IDP. septadens
5b. Shell with rows of teeth in final whorl
IDGo to 6

6a. Shell with radial but curved rows of several small teeth in final whorl
IDP. multidentata
6b. Final whorl with Radial rows of teeth, but not angled or curved
IDP. subtilis

7a. Shell diameter 5-6.5 mm
IDGo to 8
7b. Diameter >6.5 mm
IDGo to 12

8a. No teeth in adult shells
IDGo to 9
8b. Teeth or lamellae in adult shells
IDGo to 11

9a. Shell a depressed dome with umbilicus showing preceding 1.5+ whorls. Umbilicus approximately 20% of shell width
IDP. pontis
9b. Shell a taller dome with a well-like umbilicus approximately 15% of shell diameter
IDGo to 10

10a. Shell widespread. Immatures with radial pairs of teeth
IDP. capsella
10b. Shell not reported in Virginia, but may occur in the far west. Immatures with radial sets of three teeth
IDP. tridens

11a. Shell 5.5 mm; low dome 2.8 mm
IDP. seradens
11b. Shell 6.3 mm; taller dome 3.9 mm
IDP. mira

12a. Umbilicus approximately 1 mm wide
IDP. hera
12b. Umbilicus >1 mm wide
IDGo to 13

13a. Juveniles with sets of paired teeth; shell up to 7.5 mm wide
IDP. placentula
13b. Juveniles with sets of 5-6 teeth; shell up to 7 mm wide
IDP. dentilla

Patera (appressa, laevior, panselenus)

1a. Shell bears scattered sparse, tiny papillae in spiral pattern
IDP. appressa
1b. No papillae
IDGo to 2

2a. Shell sculpture includes deeply incised spiral lines; usually >18 mm diameter
IDP. panselenus
2b. Weak spiral striae; usually <18 mm diameter
IDP. laevior

Pomatiopsis (cincinnatiensis, lapidaria)

1a. Shell usually <5 mm long; narrower
IDP. cincinnatiensis
1b. Shell usually >5 mm long; stouter
IDP. lapidaria

Punctum (blandianum, minutissimum, smithi, vitreum)

1a. Aperture with small basal tooth
IDP. smithi
1b. No teeth
IDGo to 2

2a. Umbilicus wider, shell width <3x umbilicus width
IDP. blandianum
2b. Umbilicus narrower, shell width >3x umbilicus width
IDGo to 3

3a. Larger ribs widely spaced with cross-hatch pattern between
IDP. vitreum
3b. No cross-hatch pattern; ribs all of similar size
IDP. minutissimum

Stenotrema (altispira, barbatum, burringtoni, edvardsi, hirsutum, macgregori, pilula, spinosum, stenotrema)

1a. Shell angular or lens-like
IDGo to 2
1b. Shell rounded, depressed globe shape
IDGo to 3

2a. Edge of final whorl very angular or carinate; no “hairs”; shell >10 mm diameter
IDS. spinosum
2b. Edge of final whorl angular; “hairy” above; shell <10 mm diameter
IDS. edvardsi

3a. Shell very small, <6.5 mm diameter; southern edge of Virginia, if at all
IDS. pilula
3b. Shell >6.5 mm diameter
IDGo to 4

4a. Interdenticular sinus indistinct
IDGo to 5
4b. Interdenticular sinus pronounced
IDGo to 6

5a. Apex low, shell deep
IDS. barbatum
5b. Apex domed
IDS. macgregori

6a. Shell smaller, up to 9.5 mm diameter; widest part of body whorl above equator
IDGo to 7
6b. Shell larger, up to 11 mm diameter; widest part of body whorl at or below the equator
IDGo to 8

7a. Shell with sinuous parietal lamella, deeply inserted in interdenticular sinus; deeply notched basal lip with a small tooth on the right side
IDS. burringtoni
7b. Shell with nearly horizontal parietal lamella, shallow interdenticular sinus; shallow notch in basal lip, no tooth to the right side
IDS. hirsutum

8a. Parietal lamella large, in side view extends to edge of shell, obscuring aperture
IDS. stenotrema
8b. Parietal lamella smaller, does not obscure entire aperture
IDS. altispira

Striatura (exigua, ferrea, meridionalis, milium)

1a. Shell diameter >2 mm
IDGo to 2
1b. Shell diameter <2 mm
IDGo to 3

2a. Shell covered with fine spiral and radial lines, silky texture
IDS. ferrea
2b. Shell with transverse ridges, between the ridges are wavy spiral lines crossed by radial lirae
IDS exigua

3a. Embryonic whorls smooth
IDS. milium
3b. Embryonic whorls sculptured with spiral lirae
IDS. meridionalis

Strobilops (aeneus, labyrinthicus, texasianus)

1a. Angular periphery of the body whorl
IDS. aeneus
1b. Rounded periphery
IDGo to 2

2a. Ribs extending strongly onto the underside
IDS. texasianus
2b. Ribs above become faint below the periphery
IDS. labyrinthicus

Triodopsis (alabamensis, anteridon, burchi, fallax, fraudulenta, hopetonensis, juxtidens, messana, obsoleta, pendula, picea, tennesseensis, tridentata, vulgata)

1a. Pointed or small palatal tooth
IDGo to 2
1b. Wide or blunt palatal tooth
IDGo to 7

2a. Palatal tooth very small, weak
IDGo to 3
2b. Palatal tooth pronounced
IDGo to 5

3a. Shell diameter >18 mm
IDT. tennesseensis
3b. Shell diameter <18 mm
IDGo to 4

4a. Parietal tooth pointing at or below the palatal tooth; basal tooth nearly obsolete, upon a wide buttress
IDT. burchi
4b. Parietal tooth pointing above the palatal tooth; basal tooth small and pointed
IDT. obsoleta

5a. Palatal tooth a small point upon the dorsal end of a broader buttress
IDT. pendula
5b. Parietal tooth not upon a buttress
IDGo to 6

6a. Parietal tooth points below the palatal tooth
IDT. tridentata
6b. Parietal tooth points at or above the palatal tooth
IDT. juxtidens

7a. Palatal tooth not bent inward        
IDGo to 8
7b. Palatal tooth bent strongly inward, or recessed, or upon a dished peristome
IDGo to 10

8a. Basal tooth small, upon a wide peristome
IDT. picea
8b. Basal tooth upon the distal end of a buttress
IDGo to 9

9a. Aperture crowded, narrow space between large parietal and basal teeth
IDT. fallax
9b. Aperture more open, teeth smaller
IDT. pendula

10a. Shell large, >14 mm diameter
IDT. fraudulenta
10b. Shell <14 mm diameter
IDGo to 11

11a. Lower margin of peristome rounded
IDGo to 12
11b. Lower margin of peristome flat
IDGo to 13

12a. Parietal tooth continuous with peristome; shell smaller, up to 14 mm diameter
IDT. messana
12b. Parietal tooth not connected by a callus to the peristome; shell larger, up to 15 mm diameter
IDT. vulgata

13a. Parietal tooth larger, connected to peristome by a callus
IDT. alabamensis
13b. Parietal tooth small and straight, not continuous with peristome
IDT. hopetonensis

Vallonia (costata, excentrica, parvula, perspectiva, pulchella)

1a. Shell with growth ridges but not prominent ribs
IDGo to 2
1b. Prominent, widely-spaced ribs
IDGo to 3

2a. Umbilicus round; lip expanded at exterior margin
IDV. pulchella
2b. Umbilicus more oval-shaped; lip widens but not rapidly expanded to exterior (is reflected within the aperture)
IDV. excentrica

3a. Peristome narrowly reflected, continuous upon body whorl of shell
IDV. perspectiva
3b. Peristome widely reflected, not continuous upon body whorl
IDGo to 4

4a. Shell diameter 2 mm or less
IDV. costata
4b. Shell diameter >2 mm
IDV. parvula

Ventridens (acerra, arcellus, cerinoideus, coelaxis, collisella, decussatus, demissus, gularis, intertextus, lasmodon, lawae, ligera, pilsbryi, suppressus, theloides, virginicus)

1a. No lamellae within aperture (though there may be a callus)
IDGo to 2
1b. One or more lamellae within aperture
IDGo to 8

2a. Shell >10 mm diameter
IDGo to 3
2b. Shell <10 mm diameter
IDGo to 6

3a. Shell texture fine, but not glossy; often with subtle spiral line on the outside of the final whorl
IDV. intertextus
3b. Shell smooth, glossy
IDGo to 4

4a. Umbilicus narrow but well-like
IDV. arcellus
4b. Umbilicus very narrow, perforate
IDGo to 5

5a. Base of shell rounded, not as glossy
IDV. ligera
5b. Base flattened, shell very glossy
IDV. acerra

6a. Umbilicus perforate
IDV. demissus
6b. Umbilicus nearly covered by the expanded edge of the lip
IDGo to 7

7a. Basal edge of lip not deflected; Coastal Plain animal; live animal dark-colored
IDV. cerinoideus
7b. Basal edge of lip deflected; inland forest dweller; live animal pale
IDV. theloides

8a. Shell small, <7 mm diameter
IDGo to 9
8b. Shell >7 mm diameter
IDGo to 11

9a. Umbilicus >0.4 mm
IDV. coelaxis
9b. Umbilicus <0.4 mm
IDGo to 10

10a. Columellar lamella bilobed
IDV. virginicus
10b. Columellar lamella singular
IDV. suppressus

11a. Usually with two lamellae
IDGo to 12
11b. Often with a single lamella and a columellar callus
IDGo to 15

12a. Very wide umbilicus, approximately 1/3 of shell diameter
IDV. lasmodon
12b. Umbilicus smaller
IDGo to 13

13a. Small but open umbilicus; spiral lines crossing radial striae on outer half of base
IDV. decussatus
13b. Perforate or rimate umbilicus
IDGo to 14

14a. Weak, rounded striae on upper shell surface
IDV. pilsbryi
14b. Distinct striae on upper shell
IDV. gularis

15a. Deep, well-like umbilicus
IDV. lawae
15b. Umbilicus tiny, perforate
IDV. collisella

Vertigo (alabamensis*, bollesiana*, clappi, cristata*, elatior*, gouldii, malleata*, milium, oralis, oscariana, ovata, parvula, pygmaea, teskeyae, tridentata, ventricosa)

*not yet reported for Virginia

1a. Body whorl strongly pustulose
IDV. malleata*
1b. Body whorl lacking strong pustulose bumps 
IDGo to 2

2a. Upper palatal lamella long, tall and longitudinally curved, allowing long axis to be visible in apertural view
IDGo to 3
2b. Upper palatal lamella short, low and straight, with long axis barely visible in apertural view
IDGo to 4

3a. Aperture margin thickened; shell color deep yellow; imperforate
IDV. alabamensis*
3b. Aperture margin not thickened; shell color light yellow to horn; narrowly umbilicate 
IDV. clappi

4a. Shell surface smooth or weakly striate
IDGo to 5
4b. Shell surface strongly striate
IDGo to 19

5a. Five or fewer apertural lamellae 
IDGo to 6
5b. Six or more apertural lamellae 
IDGo to 7

6a. Four or fewer apertural lamellae  
IDGo to 11
6b. Five apertural lamellae  
IDGo to 15

7a. Shell surface dull
IDGo to 8
7b. Shell surface shiny
IDGo to 9

8a. Angular lamella absent; weak or absent sinulus; callus on palatal wall light-colored; shell surface with satin luster 
IDV. pygmaea
8b. Angular lamella present; strong sinulus; callus on palatal same color as rest of shell; shell surface striate and with faint spiral lines
IDV. oralis

9a. Shell <1.9 mm tall; ovate; lower palatal lamella long, curved and deeply entering shell 
IDV. milium
9b. Shell >2.0 mm tall; basally obese; lower palatal lamella short and not deeply entering shell  
IDGo to 10

10a. Aperture wider than tall; columellar lip of aperture broad, more or less straight and angled away from palatal wall; shallow suture 
IDV. teskeyae
10b. Aperture as tall as wide; columellar lip of aperture rounded, and curved towards palatal wall; deeper suture 
IDV. ovata

11a. Body whorl narrower than penultimate whorl, making shell bluntly conical at both top and bottom; columellar lamella elongate and vertical
IDV. oscariana
11b. Body whorl at least as wide as the penultimate whorl; columellar lamella peg-shaped 
IDGo to 12

12a. Body whorl inflated, making shell height less than twice the width 
IDGo to 13
12b. Body whorl not greatly inflated, making shell height approximately twice the width  
IDGo to 14

13a. Shell height >2 mm; strong apertural lamellae and sinulus
IDV. ovata
13b. Shell height < 2 mm; moderate apertural lamellae and sinulus 
IDV. ventricosa*

14a. Shell height >1¾ mm; a weak upper palatal lamella often present 
IDV. tridentata
14b. Shell height <1¾ mm; upper palatal lamella always absent 
IDV. parvula

15a. Shell height less than twice the width, with marked basal inflation 
IDGo to 16
15b. Shell height twice the width or more, ovoid 
IDGo to 17

16a. Shell height >2 mm; strong apertural lamellae and sinulus
IDV. ovata
16b. Shell height < 2 mm; moderate apertural lamellae and sinulus 
IDV. ventricosa*

17a. Shell weakly striate; single deep depression behind aperture over palatal lamellae 
IDV. bollesiana*
17b.Shell smooth; separate slight depressions under each palatal lamellae, or none 
IDGo to 18

18a. Shell surface dull; strong crest; light-colored callus on palatal wall
IDV. pygmaea
18b. Shell surface shiny; crest less prominent; callus of same color as shell 
IDV. elatior*

19a. Four apertural lamellae
IDV. cristata*
19b. More than four apertural lamellae 
IDGo to 20

20a. Six apertural lamellae 
IDV. oralis
20b. Five apertural lamellae 
IDGo to 21

21a. Striae indistinct, with shell often appearing smooth under low (x10) magnification; single deep depression over both palatal lamellae; ~1¾ mm tall  
IDV. bollesiana*
21b. Striae distinct, with shell not appearing smooth under low (x10) magnification; palatal depression weak or absent; most forms >1¾ mm tall, with small southern Appalachian forms being ~1¾ mm 
IDV. gouldii

Zonitoides (arboreus, elliotti)

1a. Shell >7 mm diameter; basal lip slightly reflected
IDZ. elliottii
1b. Shell <7 mm diameter; lip simple
IDZ. arboreus