Carychium tridentatum

Carychium tridentatum (Risso, 1826)
Dentate Thorn

  • Saraphia tridentata Risso 1826: 84.
Carychium tridentatum; Queen Elizabeth Park, Vancouver, BC (RGF 11.013.3932); height 2.0 mm.

Identification. Shell minute, obese-fusiform, thin-shelled. Spire rather short in comparison with other Carychium species, sides rather convex. Apex bluntly rounded. Suture deep. Periphery rounded. Protoconch smooth. Teleoconch with weak incremental striae initially, regular, colabral striae on last two whorls. Aperture subovate; ca 2/5 of shell height, with 1 larger parietal lamella that continues internally around columella a smooth curve, 1 weakly formed lamella at base of columella that may be lacking. Lip expanded, thickened, with a strongly projecting, medial callus on inside. Peristome, viewed from side: prosocline, strongly sinuous; belly of last whorl projecting beyond the plane of peristome. Parietal callus glazed, transparent, inconspicuous. Shell colourless or translucent white; with a silken sheen. Shell height 2.0 mm (higher than wide).

Animal white with black eyespots.

Habitat. In a city park; in leaf litter of an unkempt garden of mature trees and shrubs (Forsyth & Williston 2012).

Canadian range. Introduced. British Columbia: Queen Elizabeth Park, Vancouver.

Etymology. Latin, tri + dentatus, “three-toothed”.

Remarks. The identification of BC specimens (but not that shown in the photograph) was confirmed by molecular analysis (Weigand et al. 2012).

  • Forsyth RG, Williston P (2012) Terrestrial snails from an urban park in Vancouver, British Columbia. The Festivus 44: 77–80.
  • Risso A (1826) Histoire naturelle des principales productions de l’Europe méridionale et pariculièrement de celles des environs de Nice et des Alpes Maritimes. Tome quatière. F.-G. Levrault, Paris, viii + 439 pp., 12 pls.
  • Weigand AM, Pfenninger M, Jochum A, Klussman-Kolb A (2012) Alpine crossroads or origin of genetic diversity? Comparative phylogeography of two sympatric microgastropod species. PLoS ONE 7: e37089.