Tag: Helicidae

• Helix aspersa O.F. Müller 1774 in 1773–1774: 59.

Identification. Shell subglobose. Spire elevated, conical. Whorlsc. 4½, convex. Periphery rounded. Protoconch smooth. Teleoconch with weak, raised colabral threads, fine spiral striae, and weak malleations. Aperture nearly rounded, without teeth. Last whorl descending when shell full grown. Lip in adults not much thickened but strongly expanded. Umbilicus closed by the broadly expanded lip, or rarely a narrow cleft. Shell opaque, straw-yellow or pale brown with darker brown spiral bands interrupted with irregular pale streaks; lip white. Width to 32 mm (higher than wide).

Comparison. Helix pomatia is larger and banded but without the distinctive pale markings.

Habitat. In BC, in warm places in gardens, along roads, and on vacant, disturbed ground.

Geographic range. This species is introduced to southern BC. It is known to occur on Vancouver Island in Greater Victoria, several mid-island cities, such as Nanaimo, Parksville, and Port Alberni (unpublished), and north to Campbell River (iNaturalist), as well as Salt Spring Island and Metro Vancouver (Forsyth 2004b). This species was first reported from BC by Forsyth (1999). In the USA,

Cornu aspersum is native to the Mediterranean region. Seven clades and origins of c. a. aspersum in North Africa (Sherpa et al. 2018). This differs from the earlier conclusion of Guiller & Madec (2010) who hypothesized a European origin (Tyrrhenian) and spread north in Europe over millennia.

Etymology. Cornu (Latin), a horn. The gender is neuter.Aspersum (Latin), speckled.

Remarks. Although in the past placed in the genus Helix, morphological characters and molecular data show that C. aspersum is not that closely related to the genus Helix, but rather to other genera outside of the tribe Helicini (Nieber et al. 2022; Razkin et al. 2015).

As a large, common European species, with a complex biographical history, and importance as a food item in some countries, the genetics of C. aspersum has received much attention. The complete mitochondrial genome ofc. aspersum was published by Gaitán et al. (2013), and the genetic structure of populations of this species in Europe was studied by Guiller & Madec (2010). Genetic data points to distinct subspecies. Presumably, BC snails belong to the nominotypical subspecies, C. a. aspersum, which is the common, widespread subspecies over most of Western Europe (Sherpa et al. 2018) and the one known to be introduced to North America and other continents (Kougiagka et al. 2022).

References

• Forsyth RG (1999) Distributions of nine new or little-known exotic land snails in British Columbia. The Canadian Field-Naturalist 113: 559–568. https://doi.org/10.5962/p.358656
• Forsyth RG (2004) Land Snails of British Columbia. Royal BC Museum, Victoria, BC, Canada, iv, 188 pp.
• Gaitán-Espitia JD, Nespolo RF, Opazo JC (2013) The complete mitochondrial genome of the land snail Cornu aspersum (Helicidae: Mollusca): intraspecific divergence of protein-coding genes and phylogenetic considerations within Euthyneura. PLoS ONE 8(6): e67299. https://doi.org/10.1371/journal.pone.0067
• Guiller A, Madec L (2010) Historical biogeography of the land snail Cornu aspersum: a new scenario inferred from haplotype distribution in the Western Mediterranean basin. BMC Evolutionary Biology 10: 18. https://doi.org/10.1186/1471-2148-10-18
• Razkin O, Gómez-Moliner BJ, Prieto CE, Martínez-Ortí A, Arrébola JR, Muñoz B, Chueca LJ, Madeira MJ (2015) Molecular phylogeny of the Western Palaearctic Helicoidea (Gastropoda, Stylommatophora). Molecular Phylogenetics and Evolution 83: 99–117. https://doi.org/10.1016/j.ympev.2014.11.014
• Sherpa S, Ansart A, Madec L, Martin M-C, Dréano S, Guiller A (2018) Refining the biogeographical scenario of the land snail Cornu aspersum aspersum: natural spatial expansion and human-mediated dispersal in the Mediterranean basin. Molecular Phylogenetics and Evolution 120: 218-232. https://doi.org/10.1016/j.ympev.2017.12.018
• Kougiagka E, Gkafas GA, Exadactylos A, Hatziioannou M (2022) Morphology and genetic structure profile of farmed snails Cornu aspersum aspersum and Cornu aspersum maximum in Greece. Sustainability 14: 15965. https://doi.org/10.3390/su142315965
• Müller OF (1774) Vermium terrestrivm et fluviatilium, seu animalium infusorium, helminthicorum, et testaceorum, non marinorum, succincta historia. Volumen alterum: testacea. Heineck & Faber, Havniæ & Lipsiæ, xxxvi + 214 + [x] pp. https://doi.org/10.5962/bhl.title.46299
• Neiber MT, Korábek O, Glaubrecht M, Hausdorf B (2022) A misinterpreted disjunction: the phylogenetic relationships of the North African land snail Gyrostomella (Gastropoda: Stylommatophora: Helicidae). Zoological Journal of the Linnean Society 194: 1236–1251. https://doi.org/10.1093/zoolinnean/zlab059
• Razkin O, Gómez-Moliner BJ, Prieto CE, Martínez-Ortí A, Arrébola JR, Muñoz B, Chueca LJ, Madeira MJ (2015) Molecular phylogeny of the western Palaearctic Helicoidea (Gastropoda, Stylommatophora). Molecular Phylogenetics and Evolution 83: 99–117. https://doi.org/10.1016/j.ympev.2014.11.014

• 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.