Montana Field Guide

A moderately large slug of about 55 mm extended, but may reach 80 mm. As with all species of Hemphillia, the shell is partly exposed through a slit on the mantle about one-third its length, the mantle elevated into a visceral hump and sometimes covered with small bumps. Dorsal base color is pale cream-colored to golden-brownish or pale gray; head coloration is pale brown or cream centrally, sometimes with an irregular single grayish lateral stripe on each side; small irregular markings on the mantle form lateral stripes. Pneumostome is posterior to the midline of the mantle on the right side. The foot is somewhat narrow, with a median groove and tail pore near the posterior end, sometimes a low keel. The sides of the foot with a uniform series of indistinct oblique grooves covered with brownish or grayish patches that highlight a cream-colored or pale brown mid-dorsal stripe. The sole is undivided (not tripartite) and mucous can be milky in disturbed individuals. Sometimes responds to disturbance by thrashing the foot side to side and flipping themselves, hence the name jumping-slug (Hendricks 2012, Burke 2013). Internal anatomy is described in Pilsbry (1948). Originally described from animals taken at Old Mission, Kootenai County, Idaho.

A mantle elevated into a hump distinguishes this slug from all others in Montana except the Marbled Jumping-slug. The two species are similar, but the Pale Jumping-slug is generally pale to tan and has a pale mid-dorsal stripe on slightly broader tail that is lacking or indistinct in the darker brown to blackish Marbled Jumping-slug. The mantle may appear granular, but it lacks the small papillae found on the Marbled Jumping-slug.

No information; relatively sedentary.

Mostly in mesic mixed conifer forest, typically near water such as stream-side riparian areas and seeps. Canopy species include Western Redcedar, Western Hemlock, Engelmann Spruce, Subalpine fir, Grand Fir, Douglas-fir, alder, birch, and Black Cottonwood. Usually found under woody debris and leaf litter or in downed rotten logs, sometimes under rocks (Hendricks 2012).

Hermaphroditic, based on internal anatomy (Pilsbry 1948). Copulation and egg-laying in the wild have been observed in late September, the eggs in clusters of 10-25 and opaque white. A captive individual laid eggs in mid-December (Hendricks 2012).

Habitat occupied by Hemphillia camelus (low to moderate elevation mixed conifer forest, often in valley bottoms near water) is threatened by logging, grazing, fire, and possibly weed control and rural home development. The impact of fire retardant on this and other terrestrial mollusks is not known. Little is known about this species, including its sensitivity to disturbance.