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Home/Species/ Blue-gray Taildropper Slug

Prophysaon coeruleum

Cockerell, 1890

Blue-gray Taildropper Slug

G3Vulnerable (G3G4) Found in 7 roadless areas NatureServe Explorer →
G3VulnerableGlobal Rank
HighThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.117511
Element CodeIMGAS62030
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryInvertebrate Animal
Endemicoccurs (regularly, as a native taxon) in multiple nations
KingdomAnimalia
PhylumMollusca
ClassGastropoda
OrderStylommatophora
FamilyArionidae
GenusProphysaon
Other Common Names
Blue-gray Taildropper (EN) Blue-grey Taildropper Slug (EN) Limace-prophyse bleu-gris (FR)
Concept Reference
Turgeon, D. D., J. F. Quinn, Jr., A. E. Bogan, E. V. Coan, F. G. Hochberg, W. G. Lyons, P. M. Mikkelsen, R. J. Neves, C. F. E. Roper, G. Rosenberg, B. Roth, A. Scheltema, F. G. Thompson, M. Vecchione, and J. D. Williams. 1998. Common and scientific names of aquatic invertebrates from the United States and Canada: Mollusks. 2nd Edition. American Fisheries Society Special Publication 26, Bethesda, Maryland. 526 pp.
Taxonomic Comments
This is the broad concept of Prophysaon coeruleum that includes Prophysaon sp. 1 (Klamath Taildropper). A molecular study by Wilke and Duncan (2004) reported three major clades among specimens collected from throughout the range of this species complex. One clade (Prophysaon sp. 1 in this database) has been confirmed as being genetically distinct (Roth and Sadegdian 2006; Smith et al. 2018)
Conservation Status
Review Date2010-04-21
Change Date2006-05-11
Edition Date2010-04-21
Edition AuthorsCordeiro, J. (2010); Steiner, M. (1996)
Threat ImpactHigh
Range Extent1000-5000 square km (about 400-2000 square miles)
Number of Occurrences21 - 300
Rank Reasons
It occurs in the Coast Range, Oregon and Washington Cascades, Puget Trough, Klamath Mountains of southwestern Oregon and northern California, western Idaho and southern Vancouver Island, British Columbia. Although somewhat widespread and abundant in southwestern Oregon, it is rare and perhaps declining elsewhere in its range (including the rest of Oregon, and in California, Washington, Idaho, and British Columbia) with populations scattered and somewhat disjunct.
Range Extent Comments
It ranges from southern British Columbia south to Puget Lowlands in Washington and through the Cascade Range into Oregon and northern California (COSEWIC, 2006). This includes the Coast Range, Oregon and Washington Cascades, Puget Trough, Klamath Mountains of southwestern Oregon and northern California, western Idaho and southern Vancouver Island, British Columbia (Wilke and Duncan, 2004).
Occurrences Comments
In British Columbia (the only known Canadian subnation of occurrence), this species has a very small extent of occurrence (~ 150 km2) and area of occupancy (< 5 km2), and a continuing decline is projected in quality of habitat. It is currently known from only 5 locations on southern Vancouver Island. Ovaska et al. (2004) report on new populations in southwestern British Columbia on Vancouver Island (2 sites on Rocky Point Peninsula, about 500 m apart in Metchosin); at 2 sites 30 km apart in the Couer d'Alene Lake watershed in Idaho (a disjunct population); and at 2 sites in the Cispus River watershed and 1 at Pine Creek, Washington.
Threat Impact Comments
In British Columbia (Vancouver Island), threats at the four known locations include habitat loss, fragmentation, and degradation through human activities and land conversions including heavy recreational use and the impacts of introduced plants and animals, including introduced invasive slugs and snails (COSEWIC, 2006)..
Ecology & Habitat

Habitat

It inhabits moist, coniferous or mixed-wood forests of varying age classes (Wilke and Duncan, 2004; Kelley et al., 2009). All records from British Columbia are from within the Coastal Douglas fir biogeoclimatic zone while in Washington, it is often associated with older forests and required microhabitat features include abundant coarse woody debris or other cover, a deep forest litter layer, and shaded, moist forest floor conditions (COSEWIC, 2006).
Terrestrial Habitats
Forest - ConiferForest - Mixed
Other Nations (2)
CanadaN2
ProvinceRankNative
British ColumbiaS2Yes
United StatesN3
ProvinceRankNative
IdahoS1Yes
CaliforniaSNRYes
OregonS3Yes
WashingtonS1Yes
Roadless Areas (7)
Oregon (7)
AreaForestAcres
Brown Mt.Winema National Forest3,117
Calf - Copeland CreekUmpqua National Forest15,696
Limpy RockUmpqua National Forest6,782
MarshWinema National Forest1,226
Middle SantiamWillamette National Forest7,316
Sky Lakes AWinema National Forest3,940
Sky Lakes BWinema National Forest9,615
References (11)
  1. Burke, T.E. 2013. Land snails and slugs of the Pacific Northwest. Oregon State University Press, Corvallis. 352 pp
  2. COSEWIC. 2006. COSEWIC assessment and update status report on the blue-grey taildropper slug <i>Prophysaon coeruleum</i> in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa, Canada. 27 pp.
  3. Frest, Terry. Deixis Consultants. Seattle, Washington
  4. Gaines, E. Zoology Data Manager, Oregon Natural Heritage Program, Oregon Field Office, Portland, Oregon. Pers. comm.
  5. Kelley, R., S. Dowlan, N. Duncan, and T. Burke. 1999. Field guide to survey and manage terrestrial mollusk species from the northwest forest plan. Unpublished report of the Bureau of Land Management, Oregon State Office. 114 pp.
  6. McGraw, R., N. Duncan, and E. Cazares. 2002. Fungi and other items consumed by the blue-gray taildropper slug (<i>Prophysaon coeruleum</i>) and the papillose taildropper slug (<i>Prophysaon dubium</i>). The Veliger, 45(3): 261-264.
  7. Ovaska, K., W.P. Leonard, L. Chichester, T.E. Burke, L. Sopuck, and J. Baugh. 2004. <i>Prophysaon coeruleum</i> Cockerell, 1890, blue-gray taildropper (Gastropoda: Arionidae): new distributional records and reproductive anatomy. Western North American Naturalist 64(4): 538-543.
  8. Roth, B. and P.S. Sadeghian. 2006. Checklist of the land snails and slugs of California. 2nd ed. Santa Barbara Museum of Natural History Contributions in Science 3. 82 pp.
  9. Smith, M.L., M. Ruffley, A.M. Rankin, A. Espíndola, D.C. Tank, J. Sullivan, and B.C. Carstens. 2018. Testing for the presence of cryptic diversity in tail-dropper slugs (Prophysaon) using molecular data. Biological Journal of the Linnean Society 124(3): 518-532.
  10. Turgeon, D. D., J. F. Quinn, Jr., A. E. Bogan, E. V. Coan, F. G. Hochberg, W. G. Lyons, P. M. Mikkelsen, R. J. Neves, C. F. E. Roper, G. Rosenberg, B. Roth, A. Scheltema, F. G. Thompson, M. Vecchione, and J. D. Williams. 1998. Common and scientific names of aquatic invertebrates from the United States and Canada: Mollusks. 2nd Edition. American Fisheries Society Special Publication 26, Bethesda, Maryland. 526 pp.
  11. Wilke, T. and N. Duncan. 2004. Phylogeographical patterns in the American Pacific Northwest: lessons from the arionid slug <i>Prophysaon coeruleum</i>. Molecular Ecology 13: 2303-2315.