- Punctum clappi Pilsbry 1898: 133.
Identification. Shell subdiscoidal. Spire nearly flat. Whorls few, c. 3½. Suture deep. Periphery rounded. Aperture almost round. Lip thin, simple. Last whorl with scarcely a downwards deflection. Umbilicus broad, c. ¼ of shell width. Protoconch indistinctly, microscopically granular. Teleoconch sculpture prominent, erect, fragile, colabral periostracal ribs (but sometimes eroded off), c. 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.
Comparison. Shells of ribbed Vallonia spp. are superficially similar, but they are whitish and with a flared, usually thickened peristome in adults. Paralaoma borealis has a slightly larger shell, with a higher spire and narrower umbilicus, and colabral ribs which are numerous.
Habitat. This species lives in leaf litter in rich, moist areas in forests.
Geographic range. In BC, this species occurs from Haida Gwaii to Vancouver Island and the southern coastal mainland. It is expected from along the mainland North Coast, although there are no records from this area. It occurs in the wet southern interior mountains but is possibly rare there (Forsyth 2004b; Ovaska et al. 2010, 2020).
Alexander Archipelago, Alaska (unpublished data) and south to Trinity County (Klamath Mountains) and Mendocino County, California (Roth 1985; Roth & Sadeghian 2003); northern Idaho (Frest and Johannes 2001; Burke 2013).
Etymology. Planogyra: Planus (Latin), flat + gyros (Greek), whorl. The gender is masculine. Clappi: named after Dr George Hubbard Clapp (1858–1949), an American conchologist, numismatist, and early 20th century industrialist (Wikipedia).
References
- Burke TE (2013) Land snails and slugs of the Pacific Northwest. Oregon State University Press, Corvallis, Oregon, USA, 344 pp.
- Forsyth RG (2004b) Land Snails of British Columbia. Royal BC Museum, Victoria, BC, Canada, iv, 188 pp.
- Frest TJ, Johannes EJ (2001) An annotated checklist of Idaho land and freshwater mollusks. Journal of the Idaho Academy of Sciences 36: 1–51.
- 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 (“2019” 2020) Surveys for terrestrial gastropods in the Kootenay region of British Columbia, with new records and range extensions. The Canadian Field-Naturalist 133: 221–234. https://doi.org/10.22621/cfn.v133i3.2287
- 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.