Mesodon mitchellianus
Sealed globelet

Key Characteristics

The polished, thin and yellowish shell of the sealed globelet (Mesodon mitchellianus, also Polygyra mitchellianus and Helix mitchellianus) is up to .6 inches in diameter with 5 finely striated whorls and a globose-cone shape. The aperature is smooth and round. The body of this species is large in comparison to its shell and coarsely granulated, with the short tentacles and long tapering eye peduncles being slightly darker in color than the rest of the body.

Status and Rank

  • State Status: SC
  • State Rank: SNR
  • Global Rank: G4

Occurrences

County NameNumber of OccurrencesYear Last Observed
Macomb1
Distribution map for Mesodon mitchellianus

Updated 1/31/2017. 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 most commonly occurs in meadows, roadsides and floodplains, emerging from beneath organic litter when the ground is wet (Hubricht 1985).

Natural Community Types

Methodology

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

The first step in managing for this species is to gain a better understanding of its current population, distribution, and habitat requirements. Being small and primarily sessile creatures, land snails depend on suitable microhabitat conditions, which in turn depend on large-scale landscape factors. Moist and sheltered areas suitable for many species of land snail may be preserved by maintaining forest canopy and vegetative ground cover, reducing heavy recreational traffic and grazing, and preventing an increase in edge area (Applegarth 1999, Gotmark et al. 2008, Suominen 1999, Walden 1995). High intensity fire can harm land snails through direct mortality and reduction of ground vegetation, woody debris and leaf litter. Retention of snags may provide important shelter during times of extreme heat and drought (Applegarth 1999). Herbicide and insecticide spraying pose a threat to gastropods, as they rapidly bioaccumulate chemicals and heavy metals (Berger and Dallinger 1993) Species that make use of roadside habitats, such as the sealed gobelet, may be impacted by road salt (Nekola 2009) and pollution from vehicular traffic (Regoli et al. 2006).

Active Period

Breeding from first week of May to fourth week of June

Survey Methods

In wet conditions, this species can be found visually. As it often hides among organic litter layers, specimens can also be 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).

Page Citation

Michigan Natural Features Inventory. 2007. Rare Species Explorer (Web Application). Available online at http://mnfi.anr.msu.edu/explorer [Accessed May 28, 2017]

References

Survey References

Technical References

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