Morro shoulderband snail

The Morro shoulderband snail (Helminthoglypta walkeriana), also named banded dune snail, is living in a small section of the Pacific Coast south of Cayucos in San Luis Obispo County, California [1]. It is endemic to this area and endangered due to habitat loss. Its preferred host plant is mock heather (Ericameria ericoides), found, for example, in coastal dune scrub vegetation of Montaña de Oro State Park. The park service provides the following information:

The Morro shoulderband snail, a native land mollusk, is found in the stabilized, vegetated dunes in the park. Mock heather, a preferred host plant, provides food and shelter. Loss of coastal dune habitat and competition from the introduced European brown snail have significantly reduced the population.

The Morro shoulderband species may also use areas with non-native veldt grass (Ehrharta calycina), European beach grass and ice plants. It also occurs further inland in coastal sage scrub areas, grasslands and swales with shrubs that provide canopy and leaf litter [2]. The Morro shoulderband lives together with and/or in competition with the non-endemic common garden snail or brown garden snail (Helix aspersa) and the endemic Big Sur shoulderband snail (Helminthoglypta umbillicata), which is typically found more inland in grassland and coastal sage scrub plant communities.

References
[1] California State Parks: Morro shoulderband snail (in comparison with European garden snail and Big Sur shoulderband snail).
[2] U.S. Fish and Wildlife Service: PROTOCOL SURVEY GUIDELINES for the Morro shoulderband snail (Helminthoglypta walkeriana). June 2003. PDF.
[3] Other snail species in the Family Helminthoglyptidae of the Order Stylommatophora (terrestrial snails and slugs).