Plants and Animals

Helicodiscus singleyanus Smooth coil

Key Characteristics

The smooth coil is a small (diameter to about 1/16th inch), yellowish, somewhat flattened and smooth-shelled land snail, with 3-4 whorls and a rounded aperature lacking teeth. The body appears large when compared with the shell, with long slender eye peduncles and small slim tentacles.

Status and Rank

US Status:
State Status: SC - Special Concern (rare or uncertain; not legally protected)
Global Rank: G5 - Secure
State Rank: SNR - Not ranked

Occurrences

CountyNumber of OccurrencesYear Last Observed

Information is summarized from MNFI's database of rare species and community occurrences. Data may not reflect true distribution since much of the state has not been thoroughly surveyed.

Habitat

This species prefers open and grassy habitats such as dry prairies, meadows, rock outcrops, urban yards, roadsides and railroads rights-of-way (Hubricht 1985, Nekola 2009).

Natural Community Types

For each species, lists of natural communities were derived from review of the nearly 6,500 element occurrences in the MNFI database, in addition to herbarium label data for some taxa. In most cases, at least one specimen record exists for each listed natural community. For certain taxa, especially poorly collected or extirpated species of prairie and savanna habitats, natural community lists were derived from inferences from collection sites and habitat preferences in immediately adjacent states (particularly Indiana and Illinois). Natural communities are not listed for those species documented only from altered or ruderal habitats in Michigan, especially for taxa that occur in a variety of habitats outside of the state.

Natural communities are not listed in order of frequency of occurrence, but are rather derived from the full set of natural communities, organized by Ecological Group. In many cases, the general habitat descriptions should provide greater clarity and direction to the surveyor. In future versions of the Rare Species Explorer, we hope to incorporate natural community fidelity ranks for each taxon.

Management Recommendations

The smooth coil seems to be well-adapted to anthropogenically disturbed sites. Occuring often in roadside habitats, it may be negatively affected by the use of road salt in winter (Nekola 2009). As snails have been found to bioaccumulate heavy metals and chemicals (Berger and Dallinger 1993, Hall et al. 2009), other concerns for this species may include roadside vehicular pollution (Regoli et al. 2006), and pesticide treatment of residential yards.

Active Period

Breeding from first week of May to fourth week of June

Survey Methods

As visual detection of this species is difficult, specimens are collected by litter sampling in suitable habitat. Samples are thoroughly heat-dried, soaked in water for a number of hours to separate the various components, and finally passed through a series of sieves. The shells are then able to be hand-picked from the remaining sample material (Nekola 2003).

Litter sampling

Survey Period: From first week of April to first week of October

Time of Day: Daytime

References

Survey References

  • Nekola, J.C. 2003. Large-scale terrestrial gastropod community composition patterns in the Great Lakes region of North America. Diversity and Distributions 9:55-71.

Technical References

  • Berger, B. and R. Dallinger. 1993. Terrestrial snails as quantitative indicators of environmental metal pollution. Environmental Monitoring and Assessment 25(1):65-84.
  • Hall, C.M., S.M. Rhind, and M.J. Wilson. 2009. The potential for use of gastropod molluscs as bioindicators of endocrine disrupting compounds in the terrestrial environment. Journal of Environmental Monitoring 11(3):491-497.
  • Hubricht, L. 1985. The Distributions of Native Land Mollusks of the Eastern US. Field Museum of Natural History. Fieldiana: Zoology, No. 24.
  • Nekola, J.C. 2009. Conservation Prioritization of the Ontario and Quebec Land Snail Faunas. Final Report Submitted to: Committee on the Status of Endangered Wildlife in Canada (COSEWIC). 120 pp.
  • Regoli, F., S. Gorbi, D. Fattorini, S. Tedesco, A. Notti, N. Machella, R. Bocchetti, M. Benedetti, and F. Piva. 2006. Use of the Land Snail Helix aspersa as Sentinel Organism for Monitoring Ecotoxicologic Effects of Urban Pollution: An Integrated Approach. Environmental Health Perspectives 114(1):63-69.