- Helix pomatia Linnaeus 1758: 771.
Identification. Shell subglobose. Spire elevated, conical. Whorls c. 4–5, convex. Periphery rounded, medial on last whorl. Protoconch smooth. Teleoconch with irregular, low colabral ridges/riblets and spiral rows of weak granules. Aperture large, subovate-rounded, inside showing external shell colour, without teeth. Last whorl descending when shell full-grown. Lip not scarcely thickened in adults, narrowly flared outward, more expanded near columella. Umbilicus a narrow cleft. Shell opaque, pale grey-white, with lighter and darker, brownish colabral streaks and, in general, 2–5 spiral chestnut-brown bands (sometimes rather weakly marked or absent; band nearest periphery darkest and broadest); near inner edge of outer lip and columellar lip pale pinkish brown. Width to 42 mm (higher than wide).
Comparison. The large, globular shell is unlike any other species in BC. Cornu aspersum is somewhat smaller, with spiral bands having a distinctive pattern paler markings in colabral bands. Cepaea nemoralis is smaller, less globular, and with an aperture that is not so equal in height and width, and the palatal lip in that species is dark, purplish brown.
Biology. During aestivation and hibernation, this species may seal its aperture with a calcareous epiphragm.
Habitat. In BC, this species is known to inhabit gardens.
Geographic range. Helix pomatia is introduced to southern BC. It was first reported in BC by Forsyth & Kamstra (2019), who reported it from Melrose (near Trail) and Revelstoke, based on specimens collected in 2014 and 2015. Since then, more observations of this species have been made available on iNaturalist. Elsewhere in Canada, this species is known from Sarnia, Ontario (Forsyth & Kamstra 2019). In the USA, it was first reported from Michigan in 1937 (Archer 1937; Pilsbry 1939), and is now known from Wisconsin, New York, Massachusetts, Indiana, Pennsylvania, Florida, and California (GBIF 2017; NatureServe 2019).
Native to Central and Southern Europe, H. pomatia now occurs north to Scandinavia and through Western Europe to England (Neubert 2014). It also has been introduced east in Europe to at least Moscow, Russia (Sysoev & Schileyko 2009). Introduced to other continents.
Etymology. Helix (Latin), a snail. The gender is feminine. Poma (Greek), a lid (Kennard & Woodward 1926), perhaps in reference to the calcified epiphragm used to close the aperture during times of aestivation or hibernation.
References
- Archer AF (1937) Helix pomatia Linné in Jackson, Michigan. The Nautilus 51: 61–63.
- Forsyth RG, Kamstra J (2019) Roman Snail, Helix pomatia (Mollusca: Helicidae), in Canada. The Canadian Field-Naturalist 133: 156–159. https://doi.org/10.22621/v133i2.2150
- Kennard AS, Woodward BB (1926) Synonymy of the British non-marine Mollusca (Recent and post-Tertiary). British Museum (Natural History), London, United Kingdom, xxiv + 447 pp.
- Linnaeus C (1758) Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata. Laurentii Salvii, Holmiæ, [4] + 824 https://doi.org/10.5962/bhl.title.542
- Neubert E (2014) Revision of Helix Linnaeus, 1758 in its eastern Mediterranean distribution area, and reassignment of Helix godetiana Kobelt, 1878 to Maltzanella Hesse, 1917 (Gastropoda, Pulmonata, Helicidae). Contributions to Natural History 26: 1–200.
- Pilsbry HA (1939) Land Mollusca of North America (north of Mexico). Volume I, Part 1. The Academy of Natural Sciences of Philadelphia, Monographs 3: i–xvii + 1–573 + i–ix.
- Sysoev A, Schileyko A (2009) Land snails and slugs of Russia and adjacent countries. Pensoft, Sofia, Bulgaria, 212 pp. + 142 pl.