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Terrestrial
Gastropods of the Columbia Basin, British Columbia
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VALLONIIDAE Pilsbry 1900
Genus Vallonia Risso, 1826 Gerber (1996)
has recently published a worldwide review of genus Vallonia.
Vallonia cyclophorella Sterki, 1892: Silky Vallonia
Description: Shell small (width, to about 2.9 mm), depressed-heliciform, thin-shelled, somewhat translucent and greyish or brownish yellow with a slight silky lustre; spire very low or a little more elevated; whorls convex and numbering about 3-3.5; periphery rounded; suture very deep; protoconch with indistinct spiral striae; teleoconch with regular and closely spaced bladelike axial ribs (approximately 40-55 on the last whorl), with finer axial striae between; aperture distinctly wider than high, ovate and without denticles; last whorl descending at the aperture; outer lip abruptly flared outward but not thickened within; umbilicus slightly elliptic and wide, about 33% or more of the width of the shell. Similar Species: Vallonia pulchella and V. excentrica lack the regular and prominent ribbing of this species, and do not have the final portion of the last whorl descending in adults. Another ribbed species, V. gracilicosta Reinhardt, 1883, is similar, but in that species, the lip is thickened within by an opaque white rib. Habitat: Living at altitudes of 1,400-3,250 m (Gerber 1996), under leaf litter and dead wood, sometimes sympatric with Vallonia perspectiva (Bequaert & Miller 1973; Roth & Reynolds 1990), and in British Columbia known from dry habitats. It was sympatric with V. gracilicosta in Kamloops, and with V. cf. perspectiva Sterki, 1893 near Lytton. Range: Pyramid Island, Alaska, to British Columbia, east to Saskatchewan (Gerber 1996), and south to Arizona, New Mexico and Texas (Pilsbry 1948; Bequaert & Miller 1973; Hubricht 1985). Distribution: British Columbia records are few and scattered: Skookumchuck (Gerber 1996); Ashnola River (Blood 1963); near Lytton; and Kamloops. Name: Genus name said to honour the goddess of the valleys (Pilsbry 1948); species name meaning "bearing small circles", likely in reference to the ringlike axial ribs. Record: Skookumchuck (Gerber 1996), likely in reference to the locality by that name on the Kootenay River (49°55'N, 115°44'W). View the map. Vallonia excentrica Sterki, 1893: Excentric Vallonia
Description: Shell small (width, 2.2 mm), depressed-heliciform, somewhat translucent and glossy white; spire moderately low; whorls convex and numbering about 3; periphery rounded; suture deep; protoconch smooth; teleoconch with very fine irregular axial striae and occasional low wrinkles; last quarter of the last whorl expands rapidly and gives the shell a distinctive elliptic outline in apical view; last whorl not descending at the aperture; aperture subcircular and without denticles; outer lip rather broad, flat and thickened within; lip flared gradually; umbilicus about 25% of the width of the shell and particularly elongatedly elliptic in outline. Similar Species: Vallonia excentrica is closely similar to V. pulchella, to which it differs by the following: generally smaller size; broadly expanded last one-quarter of last whorl (seen in apical view); gradually flared outer lip; and more elliptic shape of the entire shell and umbilicus. Habitat: Under rocks, logs, debris and in grass, leaf litter and other decaying vegetation, closely associated with human settlement. Although Vallonia excentrica is generally regarded to live in drier areas than V. pulchella (Kerney & Cameron 1979), both species often occur together. Range: Holarctic. Europe, east to the Caucasians and the west coast of the Caspian Sea; Azores, Madeira and North Africa; eastern North America from southern Ontario east to Newfoundland and south in the United States to Mississippi, northern Georgia and Wyoming and Colorado. Introduced to the western United States and Canada, and many places worldwide (Gerber 1996). Distribution: Introduced populations in populated and agricultural areas; probably synanthropic throughout the province; the most northern locality known in British Columbia is Smithers (Forsyth in press). Name: Species name likely referring to the off-centre appearance of the umbilicus. Records: McDonalds Landing, West Arm, Kootenay Lake, near Six Mile, NE of Nelson (49°34.75'N, 117°12.99'W) (Forsyth Coll. 97-094-1083; Forsyth in press); S of ferry, Kootenay Bay, E side of Kootenay Lake (49°40.4'N, 116°52.3'W) (RBCM 998-00118-001; Forsyth Coll. 97-097-1096; Forsyth in press). View the map. Vallonia pulchella (Müller, 1774): Lovely Vallonia
Description: Shell small (width, 2.5 mm); depressed-heliciform; somewhat translucent, somewhat glossy; white; spire moderately low; whorls 3.25, convex; periphery rounded; suture deep; protoconch smooth; teleoconch with very fine irregular axial striae and occasional low wrinkles; in apical view the whorls regularly spiral to the adult lip, thereby giving the shell a more or less circular outline; last whorl not descending at the aperture; aperture subcircular and without denticles; outer lip broad, flat, and heavily thickened in adults; lip flared abruptly; umbilicus medium-sized, about 25% of the width of the shell and not especially elliptic in outline. Similar Species: Vallonia excentrica. Habitat: Often abundant in damp conditions under logs, debris, rocks, decaying vegetation and in leaf litter or grass, in disturbed areas and in vacant lots of urban areas and in agricultural areas. Sometimes sympatric with Vallonia excentrica and Cionella lubrica. Range: Holarctic. Europe, North Africa, the Canaries and Cape Verde Islands, east to through Asia (Gerber 1996), to Siberia (Dall 1905); eastern North America from Manitoba to Newfoundland and south into the eastern United States (Pilsbry 1948). Introduced to many places worldwide (Gerber 1996) and to the western U.S. and Canada: California, Oregon (Hanna 1966), Colorado, Utah, Texas (Pilsbry 1948), British Columbia and Washington. Distribution: Populations of this introduced species appear limited to urban and agricultural areas, and are more common in the south. The most northern record for British Columbia is in Smithers (Forsyth in press). Like Vallonia excentrica, it is probably throughout the province in populated areas. Name: Species name meaning "lovely". Records: S of ferry, Kootenay Bay, E side of Kootenay Lake (49°40.4'N, 116°52.3'W) (RBCM 998-00118-002; Forsyth Coll. 97-097-1565; Forsyth in press); Kaslo (49°55'N, 116°55'W) (Staatliches Museum für Naturkunde Görlitz); Dogtooth Forest Service Road near Columbia River crossing, Golden (51°18.7'N, 116°59.5'W) (Forsyth Coll. 98-093-3058; Forsyth in press). View the map. Genus Zoogenetes Morse, 1864 Zoogenetes harpa (Say, 1824): Boreal Top
Description: Shell small (length 3.3 mm), ovate-conic, higher than wide; subtranslucent and poorly calcified; dark brown; spire moderately elevated; apex blunt; whorls convex and numbering about 4; periphery rounded; suture deep; protoconch with microscopic granulation; teleoconch with delicate, widely spaced, lamellar axial riblets (about 40 on the last whorl) and axial striae; axial riblets become more irregular and less defined on the last part of the last whorl; aperture ovate and without denticles; outer lip unthickened; umbilicus narrow and partially occluded by the columellar lip. The body and head is greyish with the larger, occular tentacles darker, the foot is whitish, and the mantle is darker grey. The sides of the foot are crenulated (Binney & Bland 1869; Pilsbry 1948). Similar Species: None. Habitat: In British Columbia, Zoogenetes harpa has been found living in cottonwood and trembling aspen leaf litter, and under rocks and stones, and on plants. Biology: Zoogenetes harpa is viviparous (Pilsbry 1948). Range: Holarctic. Alaska east to Newfoundland and south to southern Colorado and Massachusetts (La Rocque 1953, Karlin 1961); Siberia, Kamtschatka and the Commander Islands west to Scandinavia, Finland and Switzerland (Likharev & Rammel'meier 1952, Kerney & Cameron 1979). Distribution: Populations are sporadic in British Columbia where it is known from several locations in northern British Columbia and from the Columbia Basin. Name: Genus name meaning "animal-birth", signifying live-born young (Pilsbry 1948). Species name meaning "a harp". Records: Albert Canyon Road, near Albert Canyon Hotsprings Campground, E of Revelstoke (51°07.94'N, 117°51.61'W) (RBCM 998-00284-001). View the map. |
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