Oreohelix subrudis

Oreohelix subrudis (Reeve, 1854)
Subalpine Mountainsnail

  • Helix subrudis “L. Pfeiffer” Reeve 1854 (1851–1854): pl. 198, fig. 1390a, b.
  • Helix limitaris Dawson 1875: 347.
  • Oreohelix subrudis apiarium Berry 1919a: 198, pl. 10.
  • Other possible synonyms.
Oreohelix subrudis.
Oreohelix subrudis
Oreohelix subrudis, Flathead valley, BC.

Identification. Shell subglobose to distinctly bee-hive-shaped (adults). Spire moderately to well elevated, with sides convex. Whorls ca 6, convex (in adults). Last whorl descending in adults. Suture moderately indented. Periphery in adults usually convex, medial. Teleoconch with irregular wrinkle-like incremental striae; some faint spiral striae evident. Aperture subrotund-subovate, edentulous. Lip simple, thin, or slightly thickened. Umbilicus rather small, ca 1/7 of shell width. Shell opaque, greyish pale brown, usually with two main spiral brown band (above and below periphery) and often with additional weaker bands. Shell to 16–23 mm wide (wider than high or height and width about equal).

Animal buff to brown.

In places where both tall and flatter shell forms occur together, young snails were present inside deceased the parent snails (unpubl. data), which indicates that these flatter-shelled snails were sexually mature and do not represent immature specimens having not yet developed a tall spire.

In Cypress Hills, where this species is sympatric with O. cooperi, it is recognized by its larger size, and different general proportions of the shell (width > height) and aperture (width > height). Oreohelix subrudis has a generally taller shell than the flatter (more lentil-shaped) O. strigosa.

Habitat. In forests, and wooded scree slopes. In leaf litter and under dead wood, vegetation, and rocks.

Global range. South-eastern BC, south in Washington, Idaho, and Montana, to Arizona and New Mexico (Pilsbry 1939); disjunct population in Cypress Hills, Alberta/Saskatchewan (unpubl. data, Dempsey et al. 2019, 2020).

Canadian range. South-eastern British Columbia, Rocky Mountain Foothills of Alberta from north of the Crowsnest Pass and Lundbreck to the border at Waterton Lakes National Park; in the Cypress Hills of Alberta and Saskatchewan (unpubl. data; Dempsey et al. 2019, 2020).

Oreohelix subrudis seems not to co-occur with O. strigosa in BC (unpubl. data), but in the Cypress Hills, O. subrudis is sympatric in some places with O. cooperi (unpubl. data; Dempsey et al. 2019).

Etymology. Latin: subrudis, somewhat rough.

Remarks. Several putative subspecies have been described, including O. subrudis limitaris and O. subrudis apiarium, which were treated as subspecies by Pilsbry (1939). Helix limitaris was described from Waterton Lake, Alberta by Dawson (1875), and Oreohelix subrudis apiarium was described from Glacier National Park, Montana, by Berry (1919) for what appears to be similar, or more likely, the same form. As these forms are similar and the type localities of both taxa are close, there it is likely that they are the same. Shells figured by Pilsbry (1939) seem to show that limitaris has a somewhat flatter spire than apiarium, but shells with higher and lower spires occur together in some places in south-eastern BC and from the Alberta side of the Rockies which suggest that all belong to a single species. It is also uncertain that limitaris/apiarium can be separated from normal O. subrudis.