Oreohelicidae

Family Oreohelicidae Pilsbry, 1939

This distinctive family of large western North American land snails occurring from British Columbia south as far as northern Mexico. The most species-rich genus, Oreohelix, has great diversity in the western USA, including Idaho and neighbouring states. Overall, more than 80 species and subspecies are known, but they need taxonomic revision. As for most large-bodied snails, Oreohelix are not well represented in Canada, with only a few species. Called “mountainsnails”, oreohelicids predominantly occur in the Rocky Mountains and adjacent ranges. However, a few mountainsnails also occur on isolated sky islands on the Great Plains, including the Cypress Hills in Alberta and Saskatchewan, and during the Pleistocene, one species, Oreohelix cooperi, occurred east as far as Iowa and Illinois. There are at least three, possibly more, species in Canada. Oreohelix also occurs in the Okanagan, and this may possibly represent another, unrecognized, seldom-found species. In general, species of mountainsnails are allopatric, although in the Cypress Hills, two species occur together.

Oreohelix are ovoviviparous. Eggs are retained and hatch within the parent, which are later released.

Genus Oreohelix Pilsbry, 1904

  • Oreohelix Pilsbry 1904: 131; type species by original designation according to Schileyko (2006; but Pilsbry 1904 mentioned only the “Helix strigosa group” and not a species by name): Helix strigosa Gould, 1846).

Etymology. Greek: oreos, mountain + helix, a spiral. Feminine.

Oreohelix cooperi (W.G. Binney, 1858)
Oreohelix strigosa (Gould, 1846)
Oreohelix subrudis (Reeve, 1854)
Oreohelix sp. in the Okanagan (?)

Key to species of Oreohelix in Canada

  • 1a In Cypress Hills – 2
  • 1b Elsewhere: in the Rocky Mountain Foothills of Alberta; mountains and valleys of British Columbia, including the Okanagan – 3
  • 2a Shell larger (≤10 mm wide); aperture usually wider than high – O. subrudis
  • 2b Shell smaller (≥16 mm wide); aperture usually somewhat higher than wide – O. cooperi
  • 3a Okanagan, BC – O. species?
  • 3b Elsewhere (BC and Alberta) – 4
  • 4a Shell strongly bee-hived shaped or less so but with sides of spire strongly convex – O. subrudis
  • 4b Shell more lens-shaped; spire flatter so sides less strongly convex – O. strigosa