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Terrestrial
Gastropods of the Columbia Basin, British Columbia
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ARIONIDAE Gray in Turton, 1840
Genus Arion Férussac, 1821 There are at least six introduced European
slugs of the genus Arion in British Columbia. Arion rufus
(Linnaeus, 1758): Chocolate Arion Description: A large slug (extended length to about 180 mm); brown, reddish-brown, greenish brown or black; also yellow or orange; juveniles show a broader range of colour than adults; lateral band usually absent in adults but present in juveniles; no external shell; mantle with a granular surface; pneumostome in front of the mid-point of the mantle; tubercles on the back large, coarse and elongate; keel absent; foot fringe red, orange, yellow or black; sole of foot whitish or greyish white, all black or with broad black bands on either side of a light central area; caudal mucus pore present, located just above the tip of the tail; mucous colourless. When contracted, the animal is bell-shaped in cross-section and has a tendency to rock side to side when disturbed. Similar species: The Arion ater complex is comprised of two species, A. ater (Linnaeus, 1758) and A. rufus, which can only be distinguished by reproductive anatomy. In A. ater, the atrium is generally more slender with its proximal portion smaller and shorter than the distal part. In A. rufus, the atrium is less slender, with the proximal portion larger and much wider than the distal portion. Colour of the animal is not reliable for determination of these two species. Other species of Arion could be confused for young A. rufus. Refer to the key, or Kerney & Cameron (1979) for further figures and descriptions of other species. Habitat: Gardens, fields, other disturbed sites and wooded areas near human activity. Range: Western and central Europe (Kerney & Cameron 1979). Distribution: This slug is widespread
in southern British Columbia. Name: Genus named after a Greek poet and musician. Species name meaning "red" or "reddish". Records: Box Lake, SE of Nakusp
(50°12.4'N, 123°42.7'W) (RBCM 998-00265-008 ); Blanket
Creek Provincial Park, S of Revelstoke (50°50'N, 118°05'W)
(Staatliches Museum für Naturkunde Görlitz). View
the map. Arion species [subgenus Carinarion - Arion fasciatus group] Records: Blanket Creek Provincial Park, S of Revelstoke (50°50'N, 118°05'W) (Staatliches Museum für Naturkunde Görlitz p5961). Genus Prophysaon Bland & Binney, 1873 Prophysaon
andersoni (J.G. Cooper, 1872): Reticulate Taildropper
Prophysaon andersoni 
Description: A medium-sized slug (extended length to about 60 mm), pale brownish, reddish grey or yellowish, somewhat clouded with darker tones and with a diamond mesh pattern on the back; the mantle is often paler, usually with a pair of dark lateral bands; shell internal and oblong; head pale brown, tentacles darker; mantle with a granular surface; pneumostome close to the middle (or anterior to the middle when the animal is fully extended); keel absent; foot fringe pale; caudal mucus pore absent; body mucus lemon yellow to orangish when disturbed (Kozloff 1976). Similar Species: Prophysaon vanattae known in British Columbia from southwestern Vancouver Island (pers. observ.; Cameron 1986) has black bands on the mantle, tail and body, and has orangish pigment; it also differs significantly in its anatomy (Pilsbry 1948). There are six additional species of Prophysaon not yet reported from British Columbia. Habitat: Prophysaon andersoni occurs at all elevations, usually in woods, but sometimes in gardens and other unnatural sites, and mostly in damp conditions. In Manning Park, B.C. it is recorded from 1,829 m [6,000 ft.] (Carl et al. 1952). It lives under logs, leaf litter, rocks and plants, or may be seen crawling out in the open during wet weather. Biology: This slug is capable of self-amputation and regeneration of the tail, presumably as a defence against predators (Hand & Ingram 1950).The diagonal constriction on the tail marks the site where amputation occurs. This species was observed in Vancouver by Rollo & Wellington (1975); in the spring only juveniles were found, but by late summer and fall, all individuals were large. It may be an annual species. Range: Aleutian Islands (Hanna 1925), Alaska to California and east to Idaho (La Rocque 1953). Distribution: Probably widespread throughout B.C.; a common species. Name: Genus name meaning "forward breathing" and describing the placement of the pneumostome in front of the midline of the mantle. Species name honours Dr C.L. Anderson of Santa Cruz, California (Pilsbry 1948). Records: Creston Valley Wildlife
Management Area (49°07.34'N, 116°37.24'W) (RBCM 998-00264-003);
Glenmarry Creek Road, near Nancy Greene Provincial Park (49°15.94'N,
117°56.36'W) (RBCM 998-00280-003); W side of Slocan River,
just S of Winlaw (49°35.66'N, 117°35.47'W) (RBCM 998-00279-003);
N end of Slocan Lake, near hills (49°54.04'N, 117°23.25'W)
(RBCM 998-00266-006); S end of Trout Lake near bridge over
Lardeau, E of Upper Arrow Lake (50°30.52'N, 117°16.08'W)
(RBCM 998-00286-001); Blanket Creek Provincial Park, S of
Revelstoke (50°50'N, 118°05'W) (Staatliches Museum
für Naturkunde Görlitz); Albert Canyon Road, near
Albert Canyon Hotsprings Campground, E of Revelstoke (51°07.94'N,
117°51.61'W) (RBCM 998-00284-004); Doyle Rest Area, Hwy.
1, 20 km N of Golden (51°26.55'N, 117°05.31'W) (RBCM
998-00275-002). View the map.
Genus Hemphillia Bland & Binney, 1872 Branson
(1975) presented a key to the seven named species of Hemphillia.
A species of Hemphillia has been collected from the Columbia Basin and is currently being studied by Heike Reise (Staatliches Museum für Naturkunde Görlitz, Germany). Slug pale yellowish-grey closely speckled with darker pigment on the body, especially on the posterior half; on the mantle a pair of lateral bands are formed by coalescing of the speckles; shell partially external, platelike; mantle smoothish, without papillae; pneumostome behind the mid-point of the mantle; body not depressed to receive the dorsal visceral pouch; keel not developed; caudal "horn" absent. Hemphillia camelus
Habitat: In the Kootenays, this slug has been collected from around mossy stumps and rocks, under logs and in leaf litter in forests. Distribution: In British Columbia, this Hemphillia species is known only from the Columbia Basin region. Carl & Hardy (1945) reported H. camelus from Paradise Mine, west of Windermere; this likely is the same. Name: The genus name honours Henry Hemphill (1830-1914), early Californian malacologist (Coan & Roth 1987). Records: Creek Marsh, S end of Creston Valley Wildlife Management Area; Creek Marsh (49°05.64'N, 116°37.31'W) (RBCM 998-00281-003); Summit Creek, Blazed Creek Rest Area, Salmo-Creston Hwy.; Hwy 3 (49°08.03'N 116°47.85'W) (RBCM 998-00267-001); Kid Creek, at bridge; dirt track from Cranbrook to Creston, Moyie Creek Campsite (49°14.58'N, 116°08.92'W) (RBCM 998-00287-001); W of snow sheds, Hwy 1, Glacier National Park (circa 51°15.5'N, 117°28'W) (Staatliches Museum für Naturkunde Görlitz); Redgrave Rest Area, Hwy 1, between Roger's Pass and Golden (51°29.54'N, 117°16.18'W) (RBCM 998-00274-001). View the map. |
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