Overview

Overview

Cherrystone Drop (Hendersonia occulta) State Threatened, these terrestrial snails have a thick 6-8mm wide shell that is wider than it is high, usually reddish or yellowish in color, and lacks an opening in the center of the base of the shell. Inhabitants of small areas of algific habitat or the similar cool, moist, shaded sites of cliffs where algific conditions occur without substantial talus or ice. The species is most often found on wooded alluvial-soil banks and bluffs.

State status

Status and Natural Heritage Inventory documented occurrences in Wisconsin

The table below provides information about the protected status - both state and federal - and the rank (S and G Ranks) for Cherrystone Drop (Hendersonia occulta). See the Working List Key for more information about abbreviations. Counties shaded blue have documented occurrences for this species in the Wisconsin Natural Heritage Inventory database. The map is provided as a general reference of where occurrences of this species meet NHI data standards and is not meant as a comprehensive map of all observations.

Note: Species recently added to the NHI Working List may temporarily have blank occurrence maps.

Species guidance

Note: a species guidance document is not available at this time. Information below was compiled from publication PUB-ER-085-99 (now out-of-print).

Identification: The shell is thick, wider than high, reddish or yellowish in color, marked by fine spiral lines across the surface of the whorls, and about 0.25 inches (5-8 mm) in diameter. The domed shaped spire (top part of shell above the aperture) has 6½ whorls with the sutures (seams between the whorls) unimpressed. The base is rounded and without an opening, the umbilical area covered by a callous pad. In adults, the outer lip is greatly thickened forming a heavy projecting ridge.

Habitat: Inhabitants of small areas of algific habitat or the similar cool, moist, shaded sites of cliffs where algific conditions occur without substantial talus or ice. The species is most often found on wooded alluvial-soil banks and bluffs along the Lake Michigan shore. Driftless Area sites are on north-facing slopes supporting oak-maple woodland. This snail is found in the soil and leaf litter along cliffs, soil-covered ledges on cliff faces, and on talus and soil and leaf litter near the cliff base.

State Distribution: Occurs in Brown, Door, Kewaunee, Manitowoc, Sheboygan, Ozaukee, Milwaukee, Sauk, Crawford, Iron, Vernon and Grant Counties of Wisconsin.

Management Guidelines: The location of the snails in soil and leaf litter at the base of the cliffs makes them vulnerable to trampling. Preservation of habitat along the Lake Michigan shoreline will be a decisive factor in the long-term status of the snails in Wisconsin.

Other resources

Links to additional Cherrystone Drop information

• Michigan Natural Features Inventory [PDF exit DNR]

Other links related to aquatic and terrestrial snails

• NatureServe Explorer
• Animal Diversity Web - University of MI Museum of Zoology [exit DNR]
• The Field Museum [exit DNR]
• The Field Museum [exit DNR]

Photos/Video

Photos

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