Xerolenta obvia

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Xerolenta obvia
Xerolenta obvia obvia (MNHN-IM-2010-13228).jpeg
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
Order: Stylommatophora
Family: Geomitridae
Subfamily: Helicellinae
Tribe: Helicopsini
Genus: Xerolenta
Species:
X. obvia
Binomial name
Xerolenta obvia
(Menke, 1828) [1] [2]
Synonyms
  • Helicella obvia(Menke, 1828) (superseded combination)
  • Helix obviaMenke, 1828 (original name)
  • Helicella candicans(L. Pfeiffer, 1841) (junior synonym) [3] [4]
  • Helix (Eulota) interpresWesterlund, 1879 (junior synonym)
  • Helix (Xerophila) aberransMousson, 1863 [5] (junior synonym)

Xerolenta obvia is a species of air-breathing land snail, a terrestrial gastropod mollusk in the family Geomitridae.

Contents

Subspecies [2]

Distribution

Distribution Xerolenta-obvia-map-eur-nm-moll.jpg
Distribution

This land snail is believed native to the Balkans and parts of eastern Europe, but has been introduced widely so that it now occurs from Asia Minor to Spain and north to Scandinavia. [6] It has also been introduced to Canada (Bethany, Ontario detected in 1969; [7] at least 23 occurrences in southern Ontario as of 2015 [8] ) and the USA (Wayne County, Michigan since 2001; Montana since 2012 [9] [6] ).

In the USA, this species is considered to represent a potentially serious threat as a pest, an invasive species which could negatively affect agriculture, natural ecosystems, human health or commerce. Therefore, it has been suggested that this species be given top national quarantine significance in the USA. [10]

Description and identification

Shells of adult Xerolenta obvia are 7–10 mm high and 14–20 mm wide, so relatively flat. Up to 5–6 whorls are present. The umbilicus is about 1/4 the width of the shell. The shells are thick and opaque, and almost smooth (with only fine, regular striations). The shell colour is white or yellowish-white, most often decorated with quite variable, dark-brown to almost-black spiral bands. As the animals reach maturity, the body whorl scarcely descends more steeply, and no rib develops inside the aperture, but the umbilicus widens so that the centre of the spiral looks more excentricly placed. [11]

Genitalia Xerolenta obvia genitalia.png
Genitalia

In central Europe X. obvia is most likely to be confused with Cernuella neglecta and Helicella itala . The former develops a brown rip inside the aperture when it is fully grown. The latter has a somewhat wider umbilicus (about 1/3 the width of the shell) and the body whorl redirects downwards before growth ceases. The two dart sacs provide the clearest distinguishing characters. In X. obvia they are symmetrical and diverge from the vagina at their tips, which are slightly angular (cf. angels' wings). In contrast, in H. itala the sacs are longer and closely bound to the vagina; in C. neglecta the sacs lie connected over one another on one side of the vagina. [12]

Life history

Five-day-old hatchlings, with one sterile egg; photo: E. Kuznik-Kowalska Xerolenta obvia hatchlings.png
Five-day-old hatchlings, with one sterile egg; photo: E. Kuźnik-Kowalska

The ecology of this species has been studied unusually widely, including in Austria, Greece, Poland, Belarus and Montana, demonstrating considerable flexibility in life history. Whilst at some sites reproduction is restricted to autumn, at others there is evidence of it also in spring and summer. The milky-white eggs are 1.0 to 1.8 mm across; clutches are laid in the soil and their mean size varies between sites from 18 to 69 eggs. Eggs hatch within a month, sometimes within two weeks. Snails can mature within one year. At some localities snails mostly then die over winter, whereas at others they more often live for two years or even three. Snails may aestivate and/or hibernate, depending on the climate. When aestivating, they are prominent, adhering to tall shrubs. [13] [14] [15]

References

  1. ↑ Menke, C.T. (1828). Synopsis methodica molluscorum generum omnium et specierum earum, quae in museo Menkeano adservantur; cum synonymia critica et novarum specierum diagnosibus. Pyrmonti: Gelpke. p. 13.
  2. 1 2 MolluscaBase eds. "Xerolenta obvia (Menke, 1828)". MolluscaBase. Flanders Marine Institute. Retrieved 3 October 2025.
  3. ↑ Welter-Schultes, F. (2012). European non-marine molluscs: a guide for species identification = Bestimmungsbuch für europäische Land- und Süsswassermollusken. Göttingen: Planet Poster Ed. ISBN   3-933922-75-5.
  4. ↑ Bank, R.A. (2011). "Authorships and publication dates in malacology: some notes on the 2011 French checklist of Welter-Schultes & al". Mitteilungen der Deutschen Malakozoologischen Gesellschaft. 86: 13–24.
  5. ↑ Mousson, A. (1863). "Coquilles terrestres et fluviatiles, recueillies dans l'Orient par M. le Dr. Alex. Schläfli. Vierteljahrsschrift der Naturforschenden Gesellschaft in Zürich". Vierteljahrsschrift der Naturforschenden Gesellschaft in Zürich. 8: 275–320, 368–426.
  6. 1 2 Martínez-Ortí, A. (2023). "First location of the invasive snail Xerolenta obvia (Menke, 1828) (Stylommatophora, Geometridae) in the Iberian Peninsula" (PDF). Journal of Conchology. 43: 613–620.
  7. ↑ Grimm, W.; Wiggins, G.B. (1975). "Colonies of the European snail Helicella obvia (Hartmann) in Ontario". The Canadian Field-Naturalist. 88 (4): 421–428.
  8. ↑ Forsyth, R.G.; Oldham, M.J.; Snyder, E.; Schueler, F.W.; Layberry, R. (2015). "Forty years later: distribution of the introduced Heath Snail, Xerolenta obvia, in Ontario, Canada (Mollusca: Gastropoda: Hygromiidae)". Check List. 11 (4) 1711. doi: 10.15560/11.4.1711 .
  9. ↑ Robinson, D.G.; Slapcinsky, J. (2005). "Recent introductions of alien land snails into North America". American Malacological Bulletin. 20: 89–93.
  10. ↑ Cowie, R.H.; Dillon, R.T.; Robinson, D.G.; Smith, J.W. (2009). "Alien non-marine snails and slugs of priority quarantine importance in the United States: A preliminary risk assessment" (PDF). American Malacological Bulletin. 27: 113–132.
  11. ↑ Kerney, M.P.; Cameron, R.A.D. (1979). A field guide to the land snails of Britain and North-west Europe. London: Collins.
  12. ↑ Rosenbauer, A. (2020). "Cernuella neglecta (Draparnaud 1805) in Baden-Württemberg häufig übersehen" (PDF). Mitteilungen der Deutschen Malakozoologischen Gesellschaft. 102: 37–42.
  13. ↑ Marzec, M.; Kuźnik-Kowalska, E.; Proćków, M. (2020). "Shell morphology, growth pattern and population dynamics of the land snail Xerolenta obvia (Menke, 1828) in two areas of different climatic conditions within a temperate climate region". Acta Zoologica Academiae Scientiarum Hungaricae. 66 (1): 69–84. doi:10.17109/AZH.66.1.69.2020.
  14. ↑ Kuźnik-Kowalska, E.; Baran, M.; Proćków, M. (2020). "Reproduction and growth of Xerolenta obvia (Menke, 1828) (Gastropoda: Eupulmonata: Geomitridae) in laboratory conditions". Folia Malacologica. 28 (3): 201–209. doi:10.12657/folmal.028.015.
  15. ↑ Bittermann, W. (1990). "Populationsdynamik der xerophilen Landschnecke Helicella obvia (Menke, 1828 Mollusca, Helicidae)". Wissenschaftliche Mitteilungen Niederösterreichisches Landesmuseum. 7: 273–287.


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