Planogyra clappi

Planogyra clappi (Pilsbry, 1898)
Western Flat-coil

  • Punctum clappi Pilsbry 1898: 133.
Planogyra clappi; Moresby Island, Haida Gwaii, BC; width 1.85 mm (RGF 04.018.5406).

Identification. Shell subdiscoidal. Spire nearly flat. Whorls few, ca 3½. Suture deep. Periphery rounded. Aperture almost round. Lip thin, simple. Umbilicus ca ¼ of shell width. Protoconch indistinctly, microscopically granular. Teleoconch sculpture prominent, erect, fragile, colabral periostracal ribs (but sometimes eroded off), ca 35 on last whorl; microscopic spiral striae, especially on base; microscopic incremental striae. Shell with a silky sheen, brown. Width to 2.2 mm (wider than high).

Animal translucent white; head and ocular tentacles grey.

Planogyra asteriscus from Eastern and Atlantic Canada and the Maritimes has a slightly broader umbilicus (ca ⅓ of shell width) and somewhat fewer, more strongly erect colabral riblets (ca 18–30 on last whorl). Shells of ribbed Vallonia spp. are superficially similar, but whitish and with a flared, usually thickened, apertural lip in adults.

Habitat. Rich, moist forests, especially in cedar woods. In leaf litter.

Global range. Alexander Archipelago, Alaska (unpubl. data) and south to Trinity County (Klamath Mountains) and Mendocino County, California (Roth 1985, Roth & Sadeghian 2003); northern Idaho (Burke 2013) and south-eastern BC.

Canadian range. British Columbia: along coast, Haida Gwaii to Vancouver Island and mainland, and also in the wet southern interior mountains (Forsyth 2004, Ovaska et al. 2020).

Etymology. Named for Dr George Hubbard Clapp (1858–1949), an American conchologist.


References

  • Burke TE (2013) Land snails and slugs of the Pacific Northwest. Oregon State University Press, Corvallis, 344 pp.
  • Ovaska K, Chichester L, Sopuck L (2010) Terrestrial gastropods from Haida Gwaii (Queen Charlotte Islands), British Columbia, Canada, including description of a new northern endemic slug (Gastropoda: Stylommatophora: Arionidae). The Nautilus 124: 25–33.
  • Ovaska K, Sopuck L, Heron J (2020 “2019”) Surveys for terrestrial gastropods in the Kootenay region of British Columbia, with new records and range extensions. The Canadian Field-Naturalist 133: 221–234.
  • Pilsbry HA (1898) Descriptions of new American land shells. The Nautilus 11: 133–134.
  • Roth B (1985) A new species of Punctum (Gastropoda: Pulmonata: Punctidae) from the Klamath Mountains, California, and first Californian records of Planogyra clappi (Valloniidae). Malacological Review 18: 51–56.
  • Roth B, Sadeghian PS (2003) Checklist of the land snails and slugs of California. Santa Barbara Museum of Natural History Contributions in Science 3: 1–81.