Monadenia (M.) fidelis minor (Binney, 1885) Dalles sideband

Key Characteristics: Shell smaller than M. fidelis fidelis, typically 20-25 mm in diameter; adults mostly with 5 1/2 whorls. Shell colonial buff to cartridge buff; base dilute chestnut in color; supraperipheral band darker yellow-brown, with lighter oblique streaks or maculations. Upper surface typically patchily minutely lineolate. Spire low conic; whorls convex; more or less evenly rounded; very slight angulation at aperture. Suture slightly impressed. Umbilicus contained 5-7 times in diameter; apertural lip thin, very slightly reflected. Animal gray-brown with numerous bluish granules.

Illustrations: Pilsbry (1939, p. 38, fig. 16d-f [& not p. 45 fig. 18e, which is another species]).

Synonyms: (?) Helix oregonensis Lea, 1838; Arionta mormonum Binney, 1878 (pars.); Arionta dupetithouarsi (Deshayes) Binney, 1885 (pars.); Epiphragmophora (Helminthoglypta) dupetithouarsi (Deshayes) Pilsbry, 1894 (pars.); Aglaia fidelis var. minor Binney, 1885; Epiphragmophora fidelis minor (Binney) Randolph, 1896; Epiphragmophora (Monadenia) fidelis f. minor (Binney) Pilsbry, 1897; Helix (Epiphagmophora) oregonensis Lea, Edson, 1912; Epiphragmophora fidelis oregonensis (Lea) Hanna, 1922; Monadenia fidelis minor (Binney) Henderson, 1936.

Comparison of Subspecies of Monadenia (M.) fidelis in the Columbia Gorge area

Through the Columbia Gorge (along the Columbia River and as much as a fifty-mile band on either side, Portland, OR and Vancouver, WA to Biggs, OR and Goldendale, WA) Monadenia is not nearly as uniform as it is in western WA typically. Just as plant communities change drastically from mesic Douglas-fir forest to xeric sage shrub along a 90-mile east-west corridor in this region, so also do associated land snail faunas, such that less than 20% of the land snail fauna is common to both extremes. On the west end of the Columbia Gorge, typical Monadenia fidelis fidelis is prevalent, with the dark, large-umbilicus form M. fidelis columbiana added in the vicinity of Carson, WA and north of Mt. Hood, in forested areas. This subspecies is very limited in distribution, and is not found east of Hood River Co., OR. In dry and exposed basalt talus, generally in sage scrub, from about Dog Creek, WA to Rufus, OR the predominant form is M. fidelis minor, which is about 1/2-2/3 the maximum diameter of fidelis fidelis but is more depressed and has an umbilicus equal in size, i.e., proportionately almost double that of fidelis fidelis. The red granules of the typical form are generally blue in fidelis minor. Along the Deschutes River (OR), M. fidelis minor is eventually replaced to the south by a still smaller, more strongly depressed undescribed form with darker upper shell and proportionately still-wider umbilicus, also with red granules over the body.

Specimens from the Upper Klamath Lake area sometimes ascribed to this taxon and often seen in museum collections are another taxon. For description and discussion, see Frest & Johannes (1995a).

Key to Monadenia chaceana and Some Similar Species

Monadenia chaceana Berry, 1940

Key Characteristics: Diameter 18.0-26.0 mm. Shell solid, depressed, with 5.2-5.8 whorls. Spire low-domed to moderately raised, its sides weakly convex; suture moderately impressed; whorls sometimes narrowly shouldered. Periphery well rounded, occasionally weakly subangulate opposite aperture. Embryonic whorls 1.75-2.0; first whorl with fine, close, overall granulation producing a clothlike texture; second whorl with low, collabral rugae. Post-embryonic sculpture of low, irregular rugae and very fine, wavy, incised spiral striae. First neanic whorl sometimes with scattered round papillae. Last 0.1 turn of body whorl deflected downward behind aperture. Aperture ovate, at angle of about 50 to shell axis. Lip turned outward, moderately reflected, especially at base, slightly thickened by callus. Inner lip dilated, covering less than 1/4 of umbilicus. Umbilicus contained about 7-11 times in diameter. Shell straw-colored with light reddish brown band on shoulder; peripheral band strong, darker reddish brown; basal patch reddish brown. Atrium and dart sac large. Verge globose- cylindrical with subterminal meatus, abutting large pilaster on wall of penial chamber.

Synonym: M. troglodytes chaceana Berry

Key to Monadenia churchi and Some Similar Species

Monadenia churchi Hanna & Smith, 1933

Key Characteristics: Diameter 18.5-32.0 mm. Shell solid, depressed, with 5.0-6.0 whorls. Spire low-conic to moderately raised, its sides straight or weakly convex; suture moderately impressed; whorls rounded to flattened. Periphery subangulate to broadly rounded. Embryonic whorls 1.6-1.9, with fine, spirally elongated granules in diagonal series. Post-embryonic sculpture of regularly spaced papillation; papillae round or spirally elongated, at times connected by diagonally descending, thin, raised ridges of periostracum. Shoulder and body whorl with microscopic, wavy, parallel, incised striae. Aperture broadly ear-shaped, oblique. Lip turned outward, reflected, and thickened by callus. Inner lip impinging slightly on umbilicus. Umbilicus contained about 9 times in diameter. Spire and shoulder reddish brown, rarely tan with single or double narrow stripes; peripheral band strong; base reddish brown. Periostracum smooth, matte, or silky, light yellowish tan. Animal tan, or blackish with cream or salmon-colored tubercles and light mid-dorsal stripe. Mantle over lung translucent buff, with black network covering about 20% of surface. Atrium and dart sac large. Epiphallic caecum longer than penis plus epiphallus, borne in 5-6 helical coils. Verge cylindrical to ovate-conic, with slitlike lateral meatus on anterior edge; dorsal facet concavely beveled, fitting against single large pilaster on wall of penial chamber.

Monadenia churchi differs from M. troglodytes by the strong papillation over the entire shell, even in adults, generally duller shell surface, and darker color. The spire is usually higher and the last whorl more tightly coiled.

Synonyms: None

Monadenia fidelis klamathica Berry, 1937

Monadenia fidelis ochromphalus Berry, 1937

Key Characteristics (Monadenia fidelis): Diameter 24-37+ mm. Shell solid, broadly conic to depressed, with 5.5-6.8 whorls. Spire conic to low-domed, its sides straight to convex; suture impressed; whorls flattened, sometimes narrowly shouldered. Periphery angulate in juvenile shells but usually rounded at maturity. Embryonic whorls about 1.75, with fine, confluent diagonal granulation producing a clothlike texture. Post-embryonic shell smooth or with indistinct collabral rugae; fine, incised spiral striae often present, particularly on shoulder and base. Periostracum with glossy, matte, or silky luster, sometimes dull on spire and glossy on base. Aperture broadly ovate, oblique. Lip turned outward, reflected, and thickened by callus. Inner lip more or less dilated, covering one-fourth to two-thirds of umbilicus. Umbilicus contained about 10-12 times in diameter. Spire variously yellow, orange, or reddish brown, with one or more darker brown bands on shoulder (sometimes almost or totally covering ground color); traces of radial striping sometimes present; peripheral band and basal patch strong, blackish brown; subperipheral band of ground color, yellowish, orange, or reddish brown. Animal ranging from pink through purplish to reddish black, with tips of dermal tubercles usually lighter. Atrium large; dart sac medium-sized to large. Verge broadly cylindrical or club-shaped (widest slightly above free end), with terminal meatus. Duct of mucus gland not markedly thick-walled.

Comparison of Subspecies of M. fidelis in Klamath Mountains

In the southern part of its range, Monadenia fidelis, which elsewhere is relatively uniform in morphology, tends to form distinctive local geographic races, many of which have been given subspecific names. Most Californian occurrences are referable to the subspecies Monadenia fidelis callidina Berry, 1940, characterized by rather large size, low-conic spire, dull to silky periostracal surface on the upper side of the shell, and the frequent presence of multiple color banding. Monadenia fidelis klamathica Berry, 1937, is dark with a glossy surface. Monadenia fidelis leonina Berry, 1937, from Beaver Creek, Siskiyou County, tends to be small-shelled and rugose; many specimens are pale yellowish, even on the base. In Monadenia fidelis ochromphalus Berry, 1937, the umbilical region is yellow. Monadenia fidelis salmonensis Talmadge, 1954, from streams tributary to the Salmon River, is similar but has a dull periostracum.

Synonyms: None.

Monadenia troglodytes Hanna & Smith, 1933

Monadenia troglodytes wintu Roth, 1981

Key Characteristics (Monadenia troglodytes, sensu lato): Diameter 20.6-29.3 mm. Shell solid, depressed, with 5.0-6.1 whorls. Spire low, its sides weakly convex; suture weakly impressed; whorls flattened. Periphery broadly rounded. Embryonic whorls 1.5-1.9, nuclear tip smooth, followed by fine granulation tending to form wavy radial riblets below suture; granules elsewhere spirally elongated, in diagonal series or irregularly scattered. Post-embryonic sculpture of increasingly sparse papillation, disappearing by third or fourth whorl. Body whorl with fine growth rugae and microscopic, wavy, parallel, incised striae, most evident behind lip. Aperture broadly ear-shaped, oblique. Lip turned outward, reflected, and thickened by callus. Inner lip impinging slightly on umbilicus. Umbilicus contained 5-11 times in diameter. Ground color white or light tan; spire and shoulder reddish brown, usually with darker radial steaks, sometimes tan with single or double narrow brown stripes. Peripheral band strong. Base whitish to reddish brown. Periostracum smooth, colorless or light yellowish tan. Animal gray to sooty black with reddish or purplish cast, darker on the dorsum, with a light mid-dorsal stripe. Mantle over lung translucent buff, with gray penciling covering less than 10% of surface. Atrium and dart sac large. Epiphallic caecum longer than penis plus epiphallus, borne in 4-7 helical coils. Verge cylindrical to ovate-conic, with slitlike lateral meatus on anterior edge; dorsal facet concavely beveled, fitting against single large pilaster on wall of penial chamber. See Roth (1981, Distribution, reproductive anatomy, and variation of Monadenia troglodytes Hanna and Smith (Gastropoda: Pulmonata) with the proposal of a new subgenus. Proceedings of the California Academy of Sciences 42(15): 379-407) for figures and description of the reproductive system.

Two subspecies are recognized. Monadenia troglodytes troglodytes occurs around limestone outcrops along McCloud River arm of Shasta Lake. It tends to be low-spired, with relatively broad umbilicus and light, translucent shell. Monadenia troglodytes wintu Roth, 1981, from between Pit River and Squaw Creek arms of Shasta Lake and near Mountain Gate, is larger and higher spired on the average, and the shell is more highly colored on an opaque white ground. The epiphallus tends to have more coils than that of M. t. troglodytes.

Synonyms: None.