Ventura County Wildlife - Terrestrial Snails and Slugs
Below are selected maps and photographs of native terrestrial (land) snails found the mainland portion of Ventura County, California. While not often seen, there are only thirteen native species (taxa) of native terrestrial snails, and slugs, in various natural habitats of Ventura County, and another nine nonnative species. Some of these snails are rare, including taxa endemic to Ventura County, such as Helminthoglypta venturensis (Ventura Shoulderband Snail).
All maps and photos copyrighted by David L. Magney 2004-2011, unless otherwise indicated.
This page created 26 January 2008, and updated 17 November 2011.
Below are bits of information for thirteen (13) species of native terrestrial snails found in Ventura County. The 28 taxa known to occur in Ventura County, including those only found on the islands, are listed below:
Ariolimax columbianus stramineus
Binneya notabilis - (San Nicolas Island only)
Catinella rehderi - (San Nicolas Island only)
Catinella vermeta
Cochlicopa lubrica
Haplotrema caelatum
Haplotrema duranti duranti - (San Nicolas Island only)
Helminthoglypta ayresiana - (Middle Anacapa Island only)
Xerarionta tyroni hemphilli - (San Nicolas Island only)
Xerarionta tyroni tyroni - (San Nicolas Island only)
Zonitoides arboreus
An atlas of the native snails can be seen/downloaded here - Ventura County Snail Atlas (5.5 MB PDF), showing the counties in California in which they has been found. Single maps for each species can be viewed separately below. Rarity ranking has been established for each taxon based on its global and national distribution, population size, and sensitivity by NatureServe, a nonprofit organization with a network of Natural Heritage Programs throughout the nation and internationally. The Global and National ranking is provided for each taxon, and a State ranking if the California Natural Diversity Database has assigned a State rank.
Ariolimax columbianus stramineus, Pacific Banana Slug - Arionidae Family
This snail, or slug, a snail without a hard shell, is infrequent in Ventura County, preferring mesic (moist - not dry) forest habitats, ranging from British Columbia to California. It is fairly large, reaching 25 cm long, and can be bright yellow, hence its name. NatureServe has assigned this taxon a G5N5 rank (Secure). I have found it under California Bay (Umbellularia californica) at Wheeler Gorge, just up the road and slope from the cliff-side spring/seep as seen in the photos below.
Catinella vermeta, Suboval Ambersnail - Succineidae Family
This small snail is common in North America, given a G5N5 rank (Secure) by NatureServe. It has a fairly short shell with a relatively large conical spire and a rounded-ovate aperture (opening). I have not yet found this snail in the wilds of Ventura County.
Cochlicopa lubrica Muller, Glossy Pillar - Cionellidae Family
This small snail is common in North America, given a G5N5 rank (Secure) by NatureServe. It has a tall conical shell which is steeply spiraled. I have not yet found this snail in the wilds of Ventura County.
Haplotrema caelatum, Slotted Lancetooth - Haplotrematidae Family
This snail is a southern California endemic, known from Santa Barbara, Ventura, Los Angeles, and San Diego Counties, and rare in Ventura County. NatureServe has givin this species a G1N1 rank (Critically Imperiled globally and nationally). Ventura County Planning Division has placed this snail on its list of locally sensitive species. Its shell is quite narrow and flat. I have not yet found it in Ventura County.
Helminthoglypta phlyctaena, Zaca Shoulderband - Helminthoglytidae Family
This snail is a Santa Barbara/Ventura County California endemic, known only from Santa Barbara and Ventura Counties. NatureServe has givin this species a G1G2N1N2 rank (Critically Imperiled globally and nationally). Ventura County Planning Division has placed this snail on its list of locally sensitive species. Its shell has a distinct band or strip to one side of the shell. The type locality is likely near or at Zaca Lake, hence its common name. I have not yet found it in Ventura County.
Helminthoglypta salviae salviae, Sage Shoulderband - Helminthoglytidae Family
This snail is a Ventura County endemic, known from the northwestern portion of the county in the Cuyama Badlands. It has been collected from Apache and Quatal Canyons. NatureServe has givin this species a G2N2 rank (Imperiled globally and nationally). Ventura County Planning Division has placed this snail on its list of locally sensitive species. I have not yet found it in Ventura County.
Helminthoglypta traskii traskii, Trask or Peninsular Range Shoulderband - Helminthoglytidae Family
This snail is a southern California endemic, known from Ventura, Los Angeles, Orange, and San Diego Counties, and rare in Ventura County. It also extends into northern Baja California. NatureServe has givin this species a G1G2T1 rank (Critically Imperiled globally and nationally), and the California Natural Diversity Database has assigned it an S1 rank (Critically imperiled statewide). Ventura County Planning Division has placed this snail on its list of locally sensitive species. This snail has been found in the Conejo Valley south of Newbury Park (Thousand Oaks), Ventura County, and has also been observed at Malibu Lagoon State Park. Its preferred habitat is Coastal Sage Scrub and chaparral.
Helminthoglypta tudiculata convicta, Southern Shoulderband - Helminthoglytidae Family
This snail is a southern California endemic, known from the Transverse Ranges of Ventura, Los Angeles, and San Bernardino Counties, possibly to Riverside County, in the Los Angeles Basin, and in the Peninsular Ranges to northwestern Baja California. The shell is helicoid; the spire is broadly conic; the inner lip covers half or more of the umbilicus; the lower chamber of penis flars at insertion on the atrium. The shell is large, reaching 30-40 mm in diameter. NatureServe has given this species a G2G3N2N3 rank (Imperiled globally and nationally). Ventura County Planning Division has placed this snail on its list of locally sensitive species. I have not yet found it in Ventura County.
Helminthoglypta venturensis, Ventura Shoulderband - Helminthoglytidae Family
This snail is a Ventura County endemic, known only from the type locality (which is too general to map) and the western end of Simi Valley, in Ventura County. NatureServe has givin this species a G1QN1 rank (Critically Imperiled globally and nationally). Ventura County Planning Division has placed this snail on its list of locally sensitive species. I have not yet found it in Ventura County, but it has recently been collected by another in western Simi Valley.
Helminthoglypta willetti, Matilija Shoulderband - Helminthoglytidae Family
This snail is a Ventura County endemic, known from mountainous areas in the county, including upper Sisar Canyon below Topatopa Bluffs. NatureServe has givin this species a G1N1 rank (Critically Imperiled globally and nationally). Ventura County Planning Division has placed this snail on its list of locally sensitive species. It occurs in chaparral, Coast Live Oak, and riparian woodland habitats. I have collected it from Ojai and upper Sisar Canyon.
Punctum californicum, California Ribbed Spot - Punctidae Family
This snail is a wide-ranging western U.S. species, known from most of the coast, Transverse and Peninsular Ranges, and Sierra Nevada, to British Columbia and northern Montana and South Dakota, Colorado, and Arizona. NatureServe has givin this species a G5N5 rank (Secure globally and nationally). Its shell is very small, to about 1.8 mm, light chestnut brouw and with a shining lustre; spire moderately elevated; whorls convex and about 3.75 in number; periphery rounded; suture deep; protoconch smooth; teleconch with fine, closely sparce axial riblets (bearing very narrow lamellar edges) and with finer axial and spiral striae between; aperture rounded and without denticles; outer lip thin and unexpanded; umbilicus about 20% of the width of the shell I occurs under sticks, bark, small logs, and loose rocks between 1,113 and ,.768 m elevation. I have not yet found it in Ventura County.
Striatura pugetensis, Northwest Striate - Zonitidae Family
This snail is a wide-ranging Pacific species, known from most of the coast and Sierra Nevada. NatureServe has givin this species a G5N5 rank (Secure globally and nationally). Its shell is quite narrow and flat, which is translucent. I have not yet found it in Ventura County.
Zonitoides arboreus, Arboreal Glass Snail or Quick Gloss - Zonitidae Family
This snail is a wide-ranging North American species, known from much of the coast and Sierra Nevada. NatureServe has givin this species a G5N5 rank (Secure globally and nationally). Its shell is quite narrow and flat, which is translucent. I have not yet found it in Ventura County.
Besides the native snails descussed above, there are ten (10) nonnative terrestrial snails and slugs known to occur in Ventura County: Discus rotundatus, Helix aspersa, Otala lactea, Arion intermedius, Milax gagates, Lehmannia valentiana, Limax flavus, Deroceras reticulatum, Vallonia pulchella, and Rumina decollata, none of which are mapped or described here.
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